Seeding the forum with casting Do's and Don't's

Home enthusiasts discuss their Foundry & Casting work.

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Orrin
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Seeding the forum with casting Do's and Don't's

Post by Orrin » Sat Jan 04, 2003 12:39 pm

I can think of no better way to start out with a forum than to list some Do's and don't's. Here's my 2¢
(First, don't try to use the Tab key when insetting.)

1) Do use protective apparel: Full face shield, boots, apron, long sleeves, leather gloves and respirators, when appropriate.

2) Don't use iron crucibles or allow iron to contact molten aluminum.

3) Don't conduct your foundry operations in a damp area.

4) Do dry all tools and equipment before using them for foundry work.

You are welcome to add your do/don't. This is a familiarization run. Hmmm. I wonder if line wrap will show up on the finished product. So far, it's my biggest complaint in trying to type something.
So many projects, so little time.

e2cub
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Re: Seeding the forum with casting Do's and Don't's

Post by e2cub » Sat Jan 04, 2003 12:49 pm

Why not use an iron crucible for alum? Does that apply to a welded steel crucible also? Thanks, Larry

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Roy
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Re: Seeding the forum with casting Do's and Don't's

Post by Roy » Sat Jan 04, 2003 1:12 pm

I don't think there is anything wrong in using iron or steel for a crucible. I would not be afraid to wager that the majority of home foundry folks all started off using and most continue to use a steel pipe crucible. While the use of iron in an aluminum foundry is not the best approach, it certainly is in fact a reasonable approach for a hobbyist. The biggest potential is to contaminate a casting with iron, which in the commercial field is a no no, but as a home user, usually does not present any problems. There are ways to help reducing any inclusion of iron into the alum, and that is by coating your steel pipe crucible with a wash of refractory coating. This coating will also help preserve and make your steel pipe last a lot longer and less prone to flaking.

A steel pipe crucible is as safe as any other if it is treated right, and its made of a sufficiently thick enough pipe or material, and properly constructed. I don't particularly like hearing of folks using a tin can to do their melts in, thats just looking for trouble, but its done daily in the hobby foundry world.

I do however agree with all the other statements regarding casting / foundry.

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Orrin
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Re: Seeding the forum with casting Do's and Don't's

Post by Orrin » Sat Jan 04, 2003 1:15 pm

Iron contamination of aluminum is bad. The cast aluminum will have very poor physical
properties. It other words, it will lack strength. Iron is very easily dissolved by molten
aluminum. It only takes a tiny fraction of a percent of iron content to do its damage.

If someone goes to all the trouble of making a melting furnace, getting the sand,
building flasks, making the patterns, etc., one would think that they'd like to have
a good end-product. Yet, a surprising number of aluminum casters will take the one
shortcut that they shouldn't. They will use iron crucibles and their end-product will
have half-assed strength.

This information comes from knowledgeable (not me) foundrymen, one of whom
has been in the business for over 40 years.

If you wish, I can dig up their posts and e-mail them to you. I'd post them to the
forum, but I'm having trouble navigating through these long lines.
So many projects, so little time.

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Roy
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Re: Steel Pipe Crucibles

Post by Roy » Sat Jan 04, 2003 1:26 pm

Orin, I am not dissagreeing with your statement at all. I am merely saying that the majority of home casters use steel pipe crucibles. I have to dissagree with half assed stregths etc and porosity, as I will put any of my castings up against castings done in a clay or silicon carbide crucible, and short of doing an x-ray or some other hi-tech proceedure to examine them, there is nothing weak or porus or deficieint about them.
Coating a crucible inside and out before use with refractory or "mold kote" eliminates most any chance for contamination as well. Most hobby casters have other problems getting decent castings than the use of a steel pipe crucible.

Of course a commercial foundry business is not going to take a chance, but for the majority of hobbyists out there, to tell them they should not use one is absurd. Even the NAVY Foundry manual references using a cast iron pot for melting aluminum in.

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Re: Steel Pipe Crucibles

Post by Harold_V » Sat Jan 04, 2003 3:25 pm

I'm afraid I have to side with Orrin. I have several books, one of which is published by the American Foundry Society, and in no case is an iron or steel crucible recommended, especially without a wash. No one denies that you get a casting, but the qualities of the aluminum are seriously compromised by iron contamination.

I am constantly at odds with readers because I support good and proper procedures. Lots of guys don't seem to care much about the little things that make a difference, but if you aspire to doing good work, all of the issues should be dealt with. Even melting oily material presents problems, but to some they are not even recognized. I guess it's all a matter of what's important to the individual. For me, I like to do it right. Other's mileage may vary! [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.

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Roy
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Re: Steel Pipe Crucibles

Post by Roy » Sat Jan 04, 2003 4:00 pm

I DO NOT dissagree, however the statement not to use one because it casues poor catings etc etc, is just not sufficient as compared to other problems a hobby caster can have to warrant not using a steel pipe. How many have the proper temp reading equipment? Not to darn many, but out of a lot of those a good portion probably has a sc or clay crucible, and theiy are just as prone to having probelsm. The statement DON'T is too broard. You youraself stated UNLESS the crucible is coated with a refractory, yes, thats what I stated as well. If you use a steel pipe its best to coat it.

Face it, everyone can't afford all the necessary items a commercial foundry has or even the luxuary of buying ready made refractory, hence these folks use what is at hand......and to just arbitrarily say that they can't produce a quality product is just not true. While it may not meet a standard spec, it more than satisfies their requirment. If the price of having to buy a sc crucibile holds someone out of getting involved in a hobby foundry, thats a shame, as much can be produced and quality work can be attained with a steel pipe for a crucible and getting ones feet wet. Everyones standards and pocket book ($$$$) is different, and to fault or discourage someone in doing what they can is not just. I use a sc but certainly would not discourge some one from using a steel pipe if their funds could not support it. Just becasue someone uses a sc crucible, is still no guarantee their product is going to be abny better. I know folks with a shop full of tools of name brand type, and the work they perform is deplorable, but they are satisfied, and it meets their requirements, however having a name brand tool does not make the finished product any better. When I see somneone that has a casting made out of scrap window screens, that was melted in a tuna fish can, in a hole in the ground with a weed burner and finished with sandpaper, its a good feeling. These people don't set back and sull becasue they don't have the proper equipment, but they improvised and did it safe and got their feet wet in the process. Everything does not have to have a spec on it either. Makes you wonder what some of the major companies use as a spec for their products they produce...... Lets not scare folks away from getting started that don't have the $$ to buy all the so called required spec'd equipment, just inform them of ramifications of using such items, but not a blanket statement of DON'T USE.....it makes it sound like its liable to blow up or something.
My 2 cents on it!

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Re: Steel Pipe Crucibles

Post by Harold_V » Sat Jan 04, 2003 4:59 pm

Hi Roy,
Yeah, your point is well taken. I can see that the newbie may get discouraged by the "don'ts", but there's no better time to learn the pitfalls than from the very beginning. I think that good solid advice is just that.

I've seen so much of this in the machining field that it drives me crazy. As a result, poor procedures are learned and then never abandoned. Someone comes along and tries to improve the poor system and is met with incredible resistance. "We always do it like this" seems to be the standard answer, or "yeah, in the commercial shops, but this is home machining". As if that's a reason to do stupid things, or to use poor procedures.

Whether a person has a state-of-the-art CNC or a flat belt Southbend lathe, there are certain things that dictate good procedure and should be adhered to. The potential for better results are part of the benefits, but safety is generally a good reason as well.

It is my opinion that the newbie should be introduced to proper procedures from the beginning so bad habits are not formed. On the other hand, as I've stated, I'm constantly at odds with readers because I beat to death the idea of good procedures. Some clearly don't give a damn and don't want to be bothered with learning things properly. We have to provide for all of them somehow.

Maybe it would be a little better if when the caution sign went up that the pitfalls be mentioned but allowances made for the guy starting out to explore the lesser accepted methods. I don't have a solution for the problem, but I sure as hell can't support poor procedures in the name of economy. How economical is it to produce junk at any price?

While my refining of precious metals may not be significant in this instance, one thing I learned early on as a result is the negative results of contamination in metals. The slightest amount of lead in a gold alloy totally destroys its qualities. To the uneducated person it may make no difference, but to the guy on the bench trying to set a diamond, it makes all the difference in the world.

I'm going to go out on a limb and suggest the same thing applies to the home foundry. Poor castings that are the result of poor procedures may totally escape the novice because he may have no clue what he are is seeing, or what to do to correct problems when they are recognized. In my opinion, it's always a good idea to be armed with the proper information. I think that if a guy reads the pitfalls from the beginning and then goes in with his eyes open, he'll quickly understand the reasons certain things should not be done.

How do you suggest we address this such that the lessons that need to be learned are learned, yet the home shop guy can still be in business? It costs something to set up poorly, and that money is lost when good and proper equipment is then purchased. My feeling is that if a guy cares enough to build a furnace, he'd be far better served to start out with the right tools. That way nothing is lost in converting down the road. Tough call, isn't it?

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.

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Re: Steel Pipe Crucibles

Post by driggars » Sun Jan 05, 2003 12:12 am

I have been casting for a few years and I definatly do not see any thing wrong wrong with using pipe crucibles, I get very good castings. Now if I were casting a product for someone else and the very best quality was a concern, then I would use the appropriate crucibles, but for backyard casting, my opinion they are just fine
Clint

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Re: Steel Pipe Crucibles

Post by Harold_V » Sun Jan 05, 2003 12:53 am

Hi Clint,
The truth concerning this subject is that no one has said you won't get results. You would get results of sorts melting in a cup hollowed out in the ground, the question then becomes one of what is important to the success of your particular application.

There is no doubt that your aluminum is not of good quality if you melt in a pipe crucible that is unprotected by a wash, but are the inherent problems significant for your application? If a guy is making ornamental things and isn't concerned about tensile strength, that may be no big deal. You might liken it to building a steam boiler from pipe, using 6013 filler rod. No one said you can't do it, and no one said it won't work, but should you do it? Considering there are no approved methods for welding on common pipe with 6013 filler for use as a boiler, a prudent individual would likely decide against doing it, but there are boilers out there made exactly that way. I would question the motive of the builder, especially when it can be done properly almost as easily as it can be done improperly.

Problems associated with metallurgy tend to be beyond notice of the casual observer. Your castings, should they be subjected to proper analysis, would in all likelihood have many defects that go unnoticed to most of us, one of which could be reduced tensile strength. Considering the weakness of cast aluminum to begin with, my feeling is there's not much room for loss. I'll equate that to my history of refining precious metals. You can go through all the motions of refining and improve gold, yet leave it of questionable quality in spite of the fact that it has been "refined", simply by not doing a thorough job of removing certain contaminants. And so it is with aluminum melting with ferrous containers. You introduce to the aluminum certain elements that mess with the strength and general quality of the aluminum. How it effects you is what matters. If you have had acceptable results using your methods, great, but if you were to attempt work that must be certified, you'd have to start over. Again, there is no right or wrong in this issue, it's a matter of how much you are willing to accept in a negative vain. Melting in an iron container is a negative, of that there is no doubt, not according to books written for the foundry industry by foundry authorities, anyway.

My position on this issue? I wouldn't do it, but if you or anyone else out there isn't concerned about the metallurgy of their heats, go for it. [img]/ubb/images/graemlins/smile.gif"%20alt="[/img]

The home shop guy is generally never subjected to the reality of an inspection routine, the one thing that immediately disqualifies poor workmanship and poor procedures. He, above all others, can proudly say he has never made any scrap, for what ever turns out can and will be used, regardless of its general high or low quality. [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]

I guess it can all be summed up this way. If melting in iron containers was so good, wouldn't industry be doing it? The scaling of iron, the trouble with applying the wash, the lost motion and time is more expensive than doing it with non-metallic crucibles, so they win out. [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]

How all that strikes the hobbyist is very personal, so each one will do it their own way. Just don't bid on any government contracts while using the unrecommended procedures!

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.

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Roy
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Re: Steel Pipe Crucibles

Post by Roy » Sun Jan 05, 2003 9:47 am

What this whole thing actually sums up to is we are talking the common, home shop backyard foundryman, who is not subjected to a stringent inspection of his work, and by and large for the most part his castings will be sufficient for anything he is capable or confident in making. Everyone does not have a need to meet a given standard, and most home shop items fall in this catagory. There is really no point in splitting hairs and getting the tolerance on something into the 5th decimal place if +- 1/4" will do, its more a personal thing if you want to take it to extremes and have that hole to attach the clothes line too drilled to within.0001" Self satisfaction. Or by polishing up the rebars before you place them in your shops slab. It really means very little. Perhaps a polished up and nick free rebar may mean a whole lot in a place like 3 mile Island, but ina shop floor.NOPE! My whole entire point on my posts is once again. Yes a steel pipe can be used.......and if we are going to make statements about something the reasons also needs to be to stated. By and large a steel pipe is suitable for most back yarders. I assume there are not to many professinals hanging out in this group looking for info on running their foundry, but there are probably more hobbyists looking for advice. I am for giving correct info, but also in the interests of all that info may also be counter to what industry standards are as a whole. I for one certainly would not tell someone Don't do this.without laying out all the pros and cons. So my stand is steel pipes are very acceptable for most hobby casters use, "as is", a steel pipe coated with a refactory wash is better than an uncoated pipe crucible, and if you can afford a silicone or clay crucible they are the best way to go, but if all you have is a soup can to use, use it, just be carefull. Were not talking precious metals reclaim here, were talking John Doe the back yard foundryman casting odds and ends for the love of it and making what is on hand work, but doing it safely.

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Re: Steel Pipe Crucibles

Post by timekiller » Sun Jan 05, 2003 4:51 pm

Have to agree with you Roy. There is a place for exact specification and practice. I can recall some where the specifications grossly overpriced items (claw hammers & toilet seats come to mind). [img]/ubb/images/graemlins/wink.gif"%20alt="[/img]

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