Harold,
In your 'bio' you list a 50Kw induction furnace - tell me all about it & do you have your own hydro-electric dam to power it [img]/ubb/images/graemlins/smile.gif"%20alt="[/img]
Calling Harold V - 50Kw induction furnace
Moderator: Harold_V
-
AndrewMawson
- Posts: 286
- Joined: Sat Jan 04, 2003 5:46 pm
- Location: Battle, East Sussex
Calling Harold V - 50Kw induction furnace
Andrew Mawson
Battle, East Sussex, UK
Battle, East Sussex, UK
Re: Calling Harold V - 50Kw induction furnace
Hi Andrew,
I'm not sure the story about how the furnace came to me would make great reading, but I can describe in some detail the furnace and power supply. Fortunately, while we don't own our own hydro-electric dam, we do live near them! [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]
The unit, built by Ajax Magnethermic, is a 2nd generation device, meaning it is a motor generator type, not solid state. The modern solid state devices (third generation) are, of course, most desirable, but are beyond reach of my retirement income. In order to operate the power supply, 3 phase power is required, and to that end I have a 240 volt 400 amp three phase delta service. The output of the power supply is 400 V, 3,000 Hz. single phase.
The power supply weighs 6,000 pounds and consists of the motor generator, sophisticated controls, meters, a bank of capacitors and a large switch for cutting them in or out, in steps, for balancing power factor, which is constantly changing as the charge melts. The entire unit is water cooled. The melting furnace that came with the power supply is a 100 pound box, but is fitted with a 50 pound coil, so the capacity at this point is 50 pounds. The furnace is in need of relining and I'm considering building the 100 pound coil. That would provide a decent amount of metal so a few items could be cast at one time. I've built the shop around that idea and have provided for a small crane to carry the molten metal safely. My plan is to cast primarily ductile iron, but you probably know that melting most anything is possible because induction furnaces are not limited in producing heat.
The furnace was owned by a branch of the government (Bureau of Mines) and was sold as surplus, but only after having been stored outside in brutal Utah winters. As a result, the capacitors (which were PCB filled) and meters were destroyed. That part is a near tragedy, considering the machine was virtually new, had only 1,259 hours of operation when removed from service.
The story is long, but the government paid for proper disposal of the caps (US$1,000 ), and I was provided rebuildable meters by Ajax Magnethermic at no charge. The meters have since been rebuilt by the original meter source. The power supply is ready to be cleaned up and assembled, but I am building our new home at the moment and working on the unit is not timely. I am a good distance away from getting it operational, but I have all the new components.
If you care to see a pic, I could post one. It won't be pretty, for all I have is the one I took when I found the power supply, which came to me about a year after I acquired the furnace proper. They got separated in the surplus yard and how they came together again is quite strange.
I'm willing to talk on, but only if you care to hear more. I imagine I've already bored you to tears. Should you have any specific questions, feel free.
Harold
I'm not sure the story about how the furnace came to me would make great reading, but I can describe in some detail the furnace and power supply. Fortunately, while we don't own our own hydro-electric dam, we do live near them! [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]
The unit, built by Ajax Magnethermic, is a 2nd generation device, meaning it is a motor generator type, not solid state. The modern solid state devices (third generation) are, of course, most desirable, but are beyond reach of my retirement income. In order to operate the power supply, 3 phase power is required, and to that end I have a 240 volt 400 amp three phase delta service. The output of the power supply is 400 V, 3,000 Hz. single phase.
The power supply weighs 6,000 pounds and consists of the motor generator, sophisticated controls, meters, a bank of capacitors and a large switch for cutting them in or out, in steps, for balancing power factor, which is constantly changing as the charge melts. The entire unit is water cooled. The melting furnace that came with the power supply is a 100 pound box, but is fitted with a 50 pound coil, so the capacity at this point is 50 pounds. The furnace is in need of relining and I'm considering building the 100 pound coil. That would provide a decent amount of metal so a few items could be cast at one time. I've built the shop around that idea and have provided for a small crane to carry the molten metal safely. My plan is to cast primarily ductile iron, but you probably know that melting most anything is possible because induction furnaces are not limited in producing heat.
The furnace was owned by a branch of the government (Bureau of Mines) and was sold as surplus, but only after having been stored outside in brutal Utah winters. As a result, the capacitors (which were PCB filled) and meters were destroyed. That part is a near tragedy, considering the machine was virtually new, had only 1,259 hours of operation when removed from service.
The story is long, but the government paid for proper disposal of the caps (US$1,000 ), and I was provided rebuildable meters by Ajax Magnethermic at no charge. The meters have since been rebuilt by the original meter source. The power supply is ready to be cleaned up and assembled, but I am building our new home at the moment and working on the unit is not timely. I am a good distance away from getting it operational, but I have all the new components.
If you care to see a pic, I could post one. It won't be pretty, for all I have is the one I took when I found the power supply, which came to me about a year after I acquired the furnace proper. They got separated in the surplus yard and how they came together again is quite strange.
I'm willing to talk on, but only if you care to hear more. I imagine I've already bored you to tears. Should you have any specific questions, feel free.
Harold
Wise people talk because they have something to say. Fools talk because they have to say something.
-
AndrewMawson
- Posts: 286
- Joined: Sat Jan 04, 2003 5:46 pm
- Location: Battle, East Sussex
Re: Calling Harold V - 50Kw induction furnace
Harold,
You LUCKY fellow - I really hanker after an induction furnace. The whole concept seems so much more efficient with the heat being developed in the charge itself, and not having to be conducted through a nice insulating crucible.
If you have them to hand I would love to see pictures and am happy to hear the FULL story.
Alternatively put it in a few shipping containers and send it over here [img]/ubb/images/graemlins/smile.gif"%20alt="[/img]
You LUCKY fellow - I really hanker after an induction furnace. The whole concept seems so much more efficient with the heat being developed in the charge itself, and not having to be conducted through a nice insulating crucible.
If you have them to hand I would love to see pictures and am happy to hear the FULL story.
Alternatively put it in a few shipping containers and send it over here [img]/ubb/images/graemlins/smile.gif"%20alt="[/img]
Andrew Mawson
Battle, East Sussex, UK
Battle, East Sussex, UK
Re: Calling Harold V - 50Kw induction furnace
Andrew,
You're a real sucker for punishment. [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]
OK, the story begins with my visit to a government surplus yard some time ago, when I resided in Utah. Interestingly, had I been aware, I attended the auction in which the induction furnace was sold, but my attention on that day was on some Sunnen hones. [img]/ubb/images/graemlins/frown.gif"%20alt="[/img] On that fateful day, the power supply, already separated from the furnace, was sold to the highest bidder, a fellow in the city that dealt with surplus electrical devices. I did not bid on it, for I had no idea it was in the auction. As stated, my interest was in the hones, which I did not get. I learned all of this at a later date. Jump forward to another point in time. I returned to the surplus yard and found, on a pallet, the furnace portion of the induction furnace. It had written on it some numbers, and the fact that it was item 2 of 2. I wondered where item 1 was, which would have been the power supply.
The furnace sat for the longest time, and was finally included in a batch of items for auction. I was totally dumbfounded to attend the auction and see the lot of items sold before I could raise my hand to bid. Not being very pleased, I approached the successful bidder and inquired of his purpose. He was interested in a man lift that was in the lot, which he got for only US $125, so I offered him $75 for the furnace. He was so concerned he might be giving away something of extreme value that he wouldn't commit, but eventually agreed to accept my offer, though it was quite some time later, when he discovered that it was of no value without the power supply.
In the mean time, I had found and purchased an old Sunnen hone, which was in bad need of a full restoration, having been stored outside. It had on it a ½ horse 480 volt 3 phase motor, but I was not interested in using 3 phase for such a small demand. After rebuilding it completely, I was looking for a used single phase motor and dropped by the store of the fellow that had acquired the power supply, quite unbeknownst to me, about two years previously.
We talked about a motor, which he did not have, and in passing I asked if he ever dealt with induction furnaces. He replied that he indeed had done so in the past, and just happened to have one on hand at the moment. I could scarcely believe my eyes when we walked out in the yard and there sat item 1 of 2, covered in snow. I negotiated a low price because of the damage and we finally came to terms. Norm, the seller, had found a source for capacitor replacement, and in the mean time I had contacted Ajax to find out more about the furnace. It was Ajax that told me who had originally purchased the furnace. Interestingly, a fellow with whom I had worked previously was now employed by the Bureau of Mines, so I went there and talked to him. At this point I already knew that the caps would need to be disposed of, so I suggested that since they are the ones that destroyed the caps, they might be willing to dispose of them. It took a month to get the reply, which had to go to Washington DC for a disposition, but the Bureau concluded that it was their responsibility for the caps getting on the market, so they paid for disposal. I removed and packaged them to proper requirements and it was done.
Ajax cooperated with me totally. They shipped countless prints and even provided the meters of which I spoke earlier, and would accept nothing in the way of compensation. After considerable research I finally found the branch of Hickok Electric that builds and rebuilds meters, so after arranging to have mine rebuilt, I shipped everything I had to them. They managed to rebuild three of the four needed meters from the eight that I had shipped to them, but I had to purchase one new one, luckily the least expensive of all. My cost in meters alone was right at $600. Had I purchased them all new, my cost would have been around $2,000.
Capacitors were ordered and received, only to be shipped back to the manufacturer because of leaking seals. They were returned after the leaks were repaired and they now sit waiting to be installed. I intend to clean up the unit such that it will be presentable, but that must wait until we have finished the house and are no longer living in the shop. Because of exposure to the elements, the switching devices must be dismantled and cleaned and freed up so they perform as originally intended. I expect the restoration to be quite time consuming.
I've attached a photo of the power supply in all its glory. The photo was taken shortly after I found the unit. It was about 5 months later that I loaded it and took it to my home. I'll post a second pic of the furnace, and will apologize now for the poor quality. I can't take another photo because the furnace is buried in storage. Some fool opened the camera before rewinding the film on the one posted, so it is rather poor in quality. It's the only photo available, however, so it will have to do.
You are probably already aware of the great qualities of induction melting. For the most part, metals come out as they went in, they are not changed by the products of combustion like in a cupola. There is considerable stirring action in induction melting, so one has a yield of a very homogeneous metal. Metals are melted and held at pouring temps with no effort by reducing power. Gray or ductile iron is easily produced from scrap steel, simply by inoculating the heat in the ladle before pouring.
Something interesting, should you not be aware. The first generation of induction melters, spark gap units, were not very efficient. They ran at only about 25%. The second generation, motor generator devices, were superior in efficiency, approaching 50%, but the third generation devices, solid state ones, run at almost 100%. What that tells you is that a 100 KW spark gap unit has the same capacity to melt as a 25KW solid state unit.
Frequency and melting volume are related. Larger furnaces run at lower frequencies, and can be run at line frequency when large enough. The smaller units have difficulty in starting to melt, so large items must be introduced to initiate melting. By raising the frequency, that problem is eliminated. With that in mind, I might have preferred that my furnace was a 10,000 Hz model, which was also produced. I'll know if my hunch is correct when I start using it.
If I've left out anything you may be interested in knowing, feel free to ask.
Harold
You're a real sucker for punishment. [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]
OK, the story begins with my visit to a government surplus yard some time ago, when I resided in Utah. Interestingly, had I been aware, I attended the auction in which the induction furnace was sold, but my attention on that day was on some Sunnen hones. [img]/ubb/images/graemlins/frown.gif"%20alt="[/img] On that fateful day, the power supply, already separated from the furnace, was sold to the highest bidder, a fellow in the city that dealt with surplus electrical devices. I did not bid on it, for I had no idea it was in the auction. As stated, my interest was in the hones, which I did not get. I learned all of this at a later date. Jump forward to another point in time. I returned to the surplus yard and found, on a pallet, the furnace portion of the induction furnace. It had written on it some numbers, and the fact that it was item 2 of 2. I wondered where item 1 was, which would have been the power supply.
The furnace sat for the longest time, and was finally included in a batch of items for auction. I was totally dumbfounded to attend the auction and see the lot of items sold before I could raise my hand to bid. Not being very pleased, I approached the successful bidder and inquired of his purpose. He was interested in a man lift that was in the lot, which he got for only US $125, so I offered him $75 for the furnace. He was so concerned he might be giving away something of extreme value that he wouldn't commit, but eventually agreed to accept my offer, though it was quite some time later, when he discovered that it was of no value without the power supply.
In the mean time, I had found and purchased an old Sunnen hone, which was in bad need of a full restoration, having been stored outside. It had on it a ½ horse 480 volt 3 phase motor, but I was not interested in using 3 phase for such a small demand. After rebuilding it completely, I was looking for a used single phase motor and dropped by the store of the fellow that had acquired the power supply, quite unbeknownst to me, about two years previously.
We talked about a motor, which he did not have, and in passing I asked if he ever dealt with induction furnaces. He replied that he indeed had done so in the past, and just happened to have one on hand at the moment. I could scarcely believe my eyes when we walked out in the yard and there sat item 1 of 2, covered in snow. I negotiated a low price because of the damage and we finally came to terms. Norm, the seller, had found a source for capacitor replacement, and in the mean time I had contacted Ajax to find out more about the furnace. It was Ajax that told me who had originally purchased the furnace. Interestingly, a fellow with whom I had worked previously was now employed by the Bureau of Mines, so I went there and talked to him. At this point I already knew that the caps would need to be disposed of, so I suggested that since they are the ones that destroyed the caps, they might be willing to dispose of them. It took a month to get the reply, which had to go to Washington DC for a disposition, but the Bureau concluded that it was their responsibility for the caps getting on the market, so they paid for disposal. I removed and packaged them to proper requirements and it was done.
Ajax cooperated with me totally. They shipped countless prints and even provided the meters of which I spoke earlier, and would accept nothing in the way of compensation. After considerable research I finally found the branch of Hickok Electric that builds and rebuilds meters, so after arranging to have mine rebuilt, I shipped everything I had to them. They managed to rebuild three of the four needed meters from the eight that I had shipped to them, but I had to purchase one new one, luckily the least expensive of all. My cost in meters alone was right at $600. Had I purchased them all new, my cost would have been around $2,000.
Capacitors were ordered and received, only to be shipped back to the manufacturer because of leaking seals. They were returned after the leaks were repaired and they now sit waiting to be installed. I intend to clean up the unit such that it will be presentable, but that must wait until we have finished the house and are no longer living in the shop. Because of exposure to the elements, the switching devices must be dismantled and cleaned and freed up so they perform as originally intended. I expect the restoration to be quite time consuming.
I've attached a photo of the power supply in all its glory. The photo was taken shortly after I found the unit. It was about 5 months later that I loaded it and took it to my home. I'll post a second pic of the furnace, and will apologize now for the poor quality. I can't take another photo because the furnace is buried in storage. Some fool opened the camera before rewinding the film on the one posted, so it is rather poor in quality. It's the only photo available, however, so it will have to do.
You are probably already aware of the great qualities of induction melting. For the most part, metals come out as they went in, they are not changed by the products of combustion like in a cupola. There is considerable stirring action in induction melting, so one has a yield of a very homogeneous metal. Metals are melted and held at pouring temps with no effort by reducing power. Gray or ductile iron is easily produced from scrap steel, simply by inoculating the heat in the ladle before pouring.
Something interesting, should you not be aware. The first generation of induction melters, spark gap units, were not very efficient. They ran at only about 25%. The second generation, motor generator devices, were superior in efficiency, approaching 50%, but the third generation devices, solid state ones, run at almost 100%. What that tells you is that a 100 KW spark gap unit has the same capacity to melt as a 25KW solid state unit.
Frequency and melting volume are related. Larger furnaces run at lower frequencies, and can be run at line frequency when large enough. The smaller units have difficulty in starting to melt, so large items must be introduced to initiate melting. By raising the frequency, that problem is eliminated. With that in mind, I might have preferred that my furnace was a 10,000 Hz model, which was also produced. I'll know if my hunch is correct when I start using it.
If I've left out anything you may be interested in knowing, feel free to ask.
Harold
Wise people talk because they have something to say. Fools talk because they have to say something.
Re: Calling Harold V - 50Kw induction furnace
Andrew,
The second photo is attached, the very poor quality one of the furnace.
The second photo is attached, the very poor quality one of the furnace.
Wise people talk because they have something to say. Fools talk because they have to say something.
-
AndrewMawson
- Posts: 286
- Joined: Sat Jan 04, 2003 5:46 pm
- Location: Battle, East Sussex
Re: Calling Harold V - 50Kw induction furnace
Wow Harold, as I said before you LUCKY fellow. With that history the unit was obviously destined for you a long time ago.
The actual induction coil I assume is embedded in the tilting furnace - is it tubing with water passing through? If so it must pose a few insulation problems as I think that you said it was at 400 volts
I always thought that the frequency had to be tuned to the load in the furnace, but with yours being a motor / generator it must be fixed at the 3Khz that you mentioned earlier.
Have you any indication of its performance in terms of melting rate - 50 lb coils you say and 50 Kw - I would expect it to be pretty quick!
My first furnace was diesel powered - burnt 5 gallons an hour - I seem to remember working out that was something like 33 Kw but at a very low conversion efficiency.
The actual induction coil I assume is embedded in the tilting furnace - is it tubing with water passing through? If so it must pose a few insulation problems as I think that you said it was at 400 volts
I always thought that the frequency had to be tuned to the load in the furnace, but with yours being a motor / generator it must be fixed at the 3Khz that you mentioned earlier.
Have you any indication of its performance in terms of melting rate - 50 lb coils you say and 50 Kw - I would expect it to be pretty quick!
My first furnace was diesel powered - burnt 5 gallons an hour - I seem to remember working out that was something like 33 Kw but at a very low conversion efficiency.
Andrew Mawson
Battle, East Sussex, UK
Battle, East Sussex, UK
Re: Calling Harold V - 50Kw induction furnace
Andrew,
The coil is copper tubing, wound in a helix, with the refractory acting as the insulator for the 400 V we have discussed, and, of course, is water cooled. The water consumption of the entire unit is about 9 gallons/minute, and is recommended to not be cold, which causes considerable condensation to accumulate inside the power supply. That would be a major concern here in Western Washington. There is a pressure switch that shuts down the generator if there is a water pressure failure. I recall that it must have at least 35 pounds pressure to function.
Properly built, there is a reasonable distance between the coil and the bore of the furnace. This particular construction actually uses a crucible inside, with refractory rammed up around the crucible. There should be no reason that one couldn't use a form and eliminate the crucible, selecting only the proper refractory.
One of the meters is a KVAR meter, which I understand to be a meter that measures power factor. One of the controls is a large switch that selects the proper wiring arrangement of the capacitors, and cuts out the field on the generator to unload it while capacitors are either added our subtracted from the operation to control power factor. That allows for switching without doing any harm. When the handle of the switch is pushed back in, the field is again energized. As you stated, frequency is fixed, a function of the construction of the generator and speed of the motor.
I've given some thought to the melting speed of the unit as well and concluded that it might be lightning fast, too. If my calculations are correct, the unit could actually melt 200 pounds, albeit slowly. In my opinion, 200 pounds would be a bit over kill for a home foundry, but then who knows? I'm hoping that my choice of 100 pounds is a good one because at that level the furnace should perform reasonably well.
The next problem will be to see if Ajax is willing to part with a blueprint for the 100 pound coil. They gladly provided me with the 50 pound drawings.
I'm afraid it's now time for you to tell me about you! [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]
What is this talk of the diesel generator? In one breath you speak of yearning for an induction furnace, then you make overtures about perhaps running one? Did I get the wrong impression? Please fill me in. [img]/ubb/images/graemlins/smile.gif"%20alt="[/img]
I'd be interested in hearing of what you make and how you do it. Do you melt any of the high temperature metals? (Anything above copper and its alloys). I'd also enjoy hearing how you prepare your sand and anything else you'd like to share.
I have a motorized centrifuge and adequate equipment to go with it to do investment casting. That, too, is an area that interests me. I may even try some shell molding. Do you have any experience in that arena?
I took note of your bio and am pleased to read that you own grinding equipment. I spent considerable time as a precision grinder early in my years and found that work to be the most satisfying of all. Do you use your grinders much? Does your cylindrical grinder have an internal attachment?
I'm sure I will find more to ask, but for now perhaps this is enough.
Best regards,
Harold
The coil is copper tubing, wound in a helix, with the refractory acting as the insulator for the 400 V we have discussed, and, of course, is water cooled. The water consumption of the entire unit is about 9 gallons/minute, and is recommended to not be cold, which causes considerable condensation to accumulate inside the power supply. That would be a major concern here in Western Washington. There is a pressure switch that shuts down the generator if there is a water pressure failure. I recall that it must have at least 35 pounds pressure to function.
Properly built, there is a reasonable distance between the coil and the bore of the furnace. This particular construction actually uses a crucible inside, with refractory rammed up around the crucible. There should be no reason that one couldn't use a form and eliminate the crucible, selecting only the proper refractory.
One of the meters is a KVAR meter, which I understand to be a meter that measures power factor. One of the controls is a large switch that selects the proper wiring arrangement of the capacitors, and cuts out the field on the generator to unload it while capacitors are either added our subtracted from the operation to control power factor. That allows for switching without doing any harm. When the handle of the switch is pushed back in, the field is again energized. As you stated, frequency is fixed, a function of the construction of the generator and speed of the motor.
I've given some thought to the melting speed of the unit as well and concluded that it might be lightning fast, too. If my calculations are correct, the unit could actually melt 200 pounds, albeit slowly. In my opinion, 200 pounds would be a bit over kill for a home foundry, but then who knows? I'm hoping that my choice of 100 pounds is a good one because at that level the furnace should perform reasonably well.
The next problem will be to see if Ajax is willing to part with a blueprint for the 100 pound coil. They gladly provided me with the 50 pound drawings.
I'm afraid it's now time for you to tell me about you! [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]
What is this talk of the diesel generator? In one breath you speak of yearning for an induction furnace, then you make overtures about perhaps running one? Did I get the wrong impression? Please fill me in. [img]/ubb/images/graemlins/smile.gif"%20alt="[/img]
I'd be interested in hearing of what you make and how you do it. Do you melt any of the high temperature metals? (Anything above copper and its alloys). I'd also enjoy hearing how you prepare your sand and anything else you'd like to share.
I have a motorized centrifuge and adequate equipment to go with it to do investment casting. That, too, is an area that interests me. I may even try some shell molding. Do you have any experience in that arena?
I took note of your bio and am pleased to read that you own grinding equipment. I spent considerable time as a precision grinder early in my years and found that work to be the most satisfying of all. Do you use your grinders much? Does your cylindrical grinder have an internal attachment?
I'm sure I will find more to ask, but for now perhaps this is enough.
Best regards,
Harold
Wise people talk because they have something to say. Fools talk because they have to say something.
-
AndrewMawson
- Posts: 286
- Joined: Sat Jan 04, 2003 5:46 pm
- Location: Battle, East Sussex
Re: Calling Harold V - 50Kw induction furnace
Harold,
If they gave you the 50 lb blueprint, a bit of wangling should do the trick for the 100 lb job !
Unlike you, my background isn't in mechanical engineering - I've spent my career in computer support - initally as an engineer but mainly in management. The mechanical engineering has always been a relaxation - hide in the workshop and the 'phone never gets to me! I retired a couple of years ago but do still do a bit of consultancy when my arm is twisted.
Years ago I was rebuilding a hovercraft (as one does!) and needed to get some aluminium 'pudding basins' cast as adaptors between the engine flywheels and the propellers. Got them done commercially, but this set me thinking, and I went searching for a furnace. Only really wanted something small and capable of aluminium - the sort that school workshops used to have 'when I was a lad'. Never found one, but tripped over a Morgan Crucible No 5. This was a fairly large oil burner - 5 gallons an hour as previous posting taking crucibles up to maybe 12" diameter. Ran this for several years, but it had a bit of a problem - until it was hot it was impossible to avoid creating a cloud of fog while lighting. No real problem as it was at the bottom of my garden, until my neighbour sold half his land for another house to be built and I had someones kitchen 10 foot from my foundry ! Decided to replace the oil burner with a propane one, and this is what I now use. It will melt cast iron but only just - takes a while to get there. I also have a small radiant electric furnace (Ramsell Nabier) that is rated up to 1300 deg C but I only run it up to 1000 as the elements are a fortune. Use it for aluminium when I need to be concerned about metal quality and hydrogen inclusion.
Now you see why a small induction furnace holds my attention - no problems reaching a high temperature, and it all happens relatively silently.
The cylindrical grinder is a bit of a sore point today ! Yes it is fully equipped with internal spindle and the works - absolutely excellent bit of kit. Why the sore point - yesterday, the wall cupboard that houses all its bits and bobs including face plate, three jaw, four jaw, and a couple of spare internal spindles, decided to give way, and lowered itself gracefully down the wall a few inches coming to rest on an electric wall socket and my linisher. No damage done other than to the cr***y chipboard cupboard, but it was jammed so I couldn't get into it to empty it - spent this morning breaking in through a door to recue the tooling. Must run a batten under it's replacement
If they gave you the 50 lb blueprint, a bit of wangling should do the trick for the 100 lb job !
Unlike you, my background isn't in mechanical engineering - I've spent my career in computer support - initally as an engineer but mainly in management. The mechanical engineering has always been a relaxation - hide in the workshop and the 'phone never gets to me! I retired a couple of years ago but do still do a bit of consultancy when my arm is twisted.
Years ago I was rebuilding a hovercraft (as one does!) and needed to get some aluminium 'pudding basins' cast as adaptors between the engine flywheels and the propellers. Got them done commercially, but this set me thinking, and I went searching for a furnace. Only really wanted something small and capable of aluminium - the sort that school workshops used to have 'when I was a lad'. Never found one, but tripped over a Morgan Crucible No 5. This was a fairly large oil burner - 5 gallons an hour as previous posting taking crucibles up to maybe 12" diameter. Ran this for several years, but it had a bit of a problem - until it was hot it was impossible to avoid creating a cloud of fog while lighting. No real problem as it was at the bottom of my garden, until my neighbour sold half his land for another house to be built and I had someones kitchen 10 foot from my foundry ! Decided to replace the oil burner with a propane one, and this is what I now use. It will melt cast iron but only just - takes a while to get there. I also have a small radiant electric furnace (Ramsell Nabier) that is rated up to 1300 deg C but I only run it up to 1000 as the elements are a fortune. Use it for aluminium when I need to be concerned about metal quality and hydrogen inclusion.
Now you see why a small induction furnace holds my attention - no problems reaching a high temperature, and it all happens relatively silently.
The cylindrical grinder is a bit of a sore point today ! Yes it is fully equipped with internal spindle and the works - absolutely excellent bit of kit. Why the sore point - yesterday, the wall cupboard that houses all its bits and bobs including face plate, three jaw, four jaw, and a couple of spare internal spindles, decided to give way, and lowered itself gracefully down the wall a few inches coming to rest on an electric wall socket and my linisher. No damage done other than to the cr***y chipboard cupboard, but it was jammed so I couldn't get into it to empty it - spent this morning breaking in through a door to recue the tooling. Must run a batten under it's replacement
Andrew Mawson
Battle, East Sussex, UK
Battle, East Sussex, UK
-
GeorgeGaskill
I would hardly qualify as a professional shell ...
moulder (I also am a computer professional, although not yet well healed enough to retire) but I have done a fair amount of shell moulding in a junior college art class I have attended for a number of years. Mostly what I cast is sub-scale muzzleloading artillery pieces; my most recent thrust has been 1/2 scale 1841 mountain howitzers. Anyway, I am familiar with the process and materials; feel free to ask questions. A good reference for the "backyard" foundryman is "Metal Casting: Appropriate Technology in the Small Foundry" by Steve Hurst available from amazom.com for $27.50. It covers investment casting using several primitive technologies as well as the modern fused silica/colloidal silica system. A full scale system carries some significant expense as the materials come in 100 pound bags and 40 gallon drums, etc., and some kind of mixing system is needed for the colloidal silica dipping liquid to keep it from solidifying. A fluidized bed sander also makes things a lot easier although hand sanding works OK. See the following for further details: http://www.chaski.com/cgi-bin/machine_a ... read=45749
Re: I would hardly qualify as a professional shell ...
George,
Don't let money stop you from retiring! [img]/ubb/images/graemlins/smile.gif"%20alt="[/img] Think of all the great stuff you can do without a job to take up your time. [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]
You may not be a professional, but you've certainly had more experience than I have where it comes to shell molding. I've seen it done and am aware of the slurry that must be agitated constantly. That's about the extent of my knowledge. On a hobby basis, using the slurry would be a hit and miss proposition, and will likely be the reason I should abandon any thoughts of using the system. However, I would hope that there's some way for the guy that does it intermittently to use the process. If not, I'd like to attack sand casting from a precision perspective. I've seen some items so cast that rivaled investment work. I'm of the opinion that if one approaches the work from the perspective of accuracy and throws speed to the wind, sand can do a great job. I guess trying will tell the tale.
Thanks for the link on the shell process.The information provided was interesting, makes it sound as if one can get involved without mortgaging the house. I'll explore the information and see what I can learn.
Investment casting is no stranger to me, so I have few questions in that regard, but size limits me. The largest flask I can throw is only 4" diameter and about 7" long. If I intend to do any large quality of casting, it will have to be by the shell method unless fine sand casting works.
I appreciate your offer to answer questions, and as I get closer to realizing my plan, I'm sure I'll have many of them for you. I'm not actively pursuing any of the work at the moment, but enjoy talking about it and laying plans for the future. Considering I am still building our house, I have ample time to explore many options, so I'm not closing any doors yet. At the rate I'm going, who knows what new technology will be available when I'm finished. [img]/ubb/images/graemlins/smile.gif"%20alt="[/img]
One of my interests is in muzzle loading cannon. I didn't realize you were involved in that activity. Would it be possible for you to share some pics of your work? My primary interest is in the smooth bore weapons, especially the very ornate barrels produced in the 1700's by the Spaniards. I'd enjoy seeing anything you'd like to offer, so please feel free to post anything you're inclined to share, or feel free to send them to me privately.
Thanks for the book information, "Metal Casting: Appropriate Technology in the Small Foundry" by Steve Hurst. While I have several books pertaining to foundry, that is not one of them. I'll add it to the collection on your recommendation.
Harold
Don't let money stop you from retiring! [img]/ubb/images/graemlins/smile.gif"%20alt="[/img] Think of all the great stuff you can do without a job to take up your time. [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]
You may not be a professional, but you've certainly had more experience than I have where it comes to shell molding. I've seen it done and am aware of the slurry that must be agitated constantly. That's about the extent of my knowledge. On a hobby basis, using the slurry would be a hit and miss proposition, and will likely be the reason I should abandon any thoughts of using the system. However, I would hope that there's some way for the guy that does it intermittently to use the process. If not, I'd like to attack sand casting from a precision perspective. I've seen some items so cast that rivaled investment work. I'm of the opinion that if one approaches the work from the perspective of accuracy and throws speed to the wind, sand can do a great job. I guess trying will tell the tale.
Thanks for the link on the shell process.The information provided was interesting, makes it sound as if one can get involved without mortgaging the house. I'll explore the information and see what I can learn.
Investment casting is no stranger to me, so I have few questions in that regard, but size limits me. The largest flask I can throw is only 4" diameter and about 7" long. If I intend to do any large quality of casting, it will have to be by the shell method unless fine sand casting works.
I appreciate your offer to answer questions, and as I get closer to realizing my plan, I'm sure I'll have many of them for you. I'm not actively pursuing any of the work at the moment, but enjoy talking about it and laying plans for the future. Considering I am still building our house, I have ample time to explore many options, so I'm not closing any doors yet. At the rate I'm going, who knows what new technology will be available when I'm finished. [img]/ubb/images/graemlins/smile.gif"%20alt="[/img]
One of my interests is in muzzle loading cannon. I didn't realize you were involved in that activity. Would it be possible for you to share some pics of your work? My primary interest is in the smooth bore weapons, especially the very ornate barrels produced in the 1700's by the Spaniards. I'd enjoy seeing anything you'd like to offer, so please feel free to post anything you're inclined to share, or feel free to send them to me privately.
Thanks for the book information, "Metal Casting: Appropriate Technology in the Small Foundry" by Steve Hurst. While I have several books pertaining to foundry, that is not one of them. I'll add it to the collection on your recommendation.
Harold
Wise people talk because they have something to say. Fools talk because they have to say something.
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GeorgeGaskill
I have approached the artillery issue from the ...
perspective of a machinist rather than artist so my creations have been of the most modern muzzleloaders which had little or no decoration so they could be machine finished. I did see on a PBS show a while back a very pretty old bronze cannon that was raised from a Carribean wreck. Supposedly the gun is at "The Pirate Museum" somewhere in Florida (maybe elsewhere on the Gulf coast) but I have been unable to locate the place via the Internet (although I haven't looked recently.) That kind of barrel would be a prime candidate for production via shell molding since the underlying barrel wax could be created from a fiberglass mould made from a manufactured pattern and the decoration applied separately before the wax was invested (also it would impress the arteeests in the art class more than the plain ones do.) 
I think I will do another search for the place now.
Also I have taught a cannon making class during the summer at the Lassen College NRA Gunsmithing program (www.lassengunsmithing.com/html/specprj1.htm, click through to the next page also) but these are also the most modern barrels.
I think I will do another search for the place now.
Also I have taught a cannon making class during the summer at the Lassen College NRA Gunsmithing program (www.lassengunsmithing.com/html/specprj1.htm, click through to the next page also) but these are also the most modern barrels.
Re: I have approached the artillery issue from the ...
George,
I have some pics of a beautiful barrel, one of two, that sit in front of one of the buildings at Fort Lewis. They are like the ones I mentioned, brass cannon from Spain, dated in the late 1700's. The workmanship in the barrels is hard to believe. They are truly a work of art. In the future I'd like to build a model similar to them. Sadly, in most cases, the barrels remain, but carriages are gone. That's the case with these.
I'd like to discover a source for prints or photos, even if they have no dimensions. I'm a bit taken with the "pirate" era and would love to build a few complete models that would be in keeping with shipboard guns of that period.
One of the first projects I undertook as a boy when I bought my first lathe was to build a simple muzzle loading cannon from a piece of automobile axle. I've always loved them. I was further inspired by an article in Popular Mechanics when they ran a feature article about a gentleman named Harold Hurd, who had built a number of very nice models and was shown firing them. That was in the early to mid 50's. I may have the article in my files.
Harold
I have some pics of a beautiful barrel, one of two, that sit in front of one of the buildings at Fort Lewis. They are like the ones I mentioned, brass cannon from Spain, dated in the late 1700's. The workmanship in the barrels is hard to believe. They are truly a work of art. In the future I'd like to build a model similar to them. Sadly, in most cases, the barrels remain, but carriages are gone. That's the case with these.
I'd like to discover a source for prints or photos, even if they have no dimensions. I'm a bit taken with the "pirate" era and would love to build a few complete models that would be in keeping with shipboard guns of that period.
One of the first projects I undertook as a boy when I bought my first lathe was to build a simple muzzle loading cannon from a piece of automobile axle. I've always loved them. I was further inspired by an article in Popular Mechanics when they ran a feature article about a gentleman named Harold Hurd, who had built a number of very nice models and was shown firing them. That was in the early to mid 50's. I may have the article in my files.
Harold
Wise people talk because they have something to say. Fools talk because they have to say something.