Match Plate and Core Sand Pattern

[Harold_V]

There's a question in my mind on the addition of antimony. It may not be a good idea. Anyone know?

I've followed this entire thread with considerable interest, as foundry work has always been of keen interest to me. I've learned a great deal, thanks to the guidance provided by Rod. It is very much appreciated.

Harold

[RCW]

Antimony is a major component of the new solders that are supposed to save us all from the dangers of lead poisoning. [I don't advise exposure to lead, but I have never imbibed much lead from electrical solder.]

And I echo Harold's appreciation for the posts above.

[steamin10]

Lead added to brasses, that are zinc alloy, tends to make them much more machinable, and less prone to cracking, as they add a small amount of ductility. But they dull fairly quickly.

Antimony will add hardness, and tendancies towards cracking for stressed areas. Bronze being a tin/copper base, will also respond to leading, with greater machinability, and the same tendancy to dull. Old formula solder [50-50, 60-40-etc] can be added to bronzes, as can stripped copper electrical wire. It is added by first melting the copper, the highest temperature metal, and then adding the other components. Tin, lead, and Mercury will boil off as vapors, at high temperatures, so ventilation is a concern, and I must mention it for safty sake. Mercury can appear from unknown sources as a contaminant, and its presence should never be ignored or taken for granted, as the health effects are long term, crippling, and even lethal. Heavy metals poisoning is no joke, as all of the lead, tin, and so forth are heavy metals that can work into and be held in the body, most effect the nervous system, in some order and cause palsy, and tremor like conditions.

pg 2234, 21st edition, Machinery's handbook: Bronze bearing castings. SAE 66o, Cu, 81-85%, tin 6.5-7.5, lead 7-8, zinc 2-4, iron [max] 0.20, Animony [max] 0.20.-- I use this hard strong brass compound as an example, as it is 30,000 psi and 14,000 yield, and contains Antimony. It is used for piston bearings and bushings, being quite hard and durable. Other 60 series compounds have varied ratios, and lesser psi ratings by adjusting the alloy components. Most of these materials from the ' leaded gunmetal' to forgable bronze is listed and can be compared here. 70 series brass is called cartridge brass, [rolled brass sheet] and can be impact formed cold. This is notable in that brasses are hot short, and crack rather than bend at any high temperature, yet the 6o series can hold up to high heat situations. What is important here is to understand that it is small changes in percentages of alloys can make wide swings in performance. So critical parts should be of known stock alloys, and junk cast in a home foundry must be husbanded closely, to mimic the desired materials needed.

The machinists handbook has a section on brass and bronze alloys and common compounds as comercially sold, for their working qualities. An understanding of those qualities will allow you to guess the workings of a created compound from scraps, if their commercial numbers can be guessed or discerned by the obvious traits. So a non-standard mimic that falls between commercial compounds will have qualities in the ranges in between those of the certified formulas, and be close enough for most work in model and hobby settings.

Most lino-type I have run into were tin-lead, for the self casting machines. The older letter sets were 60-30-10 or there abouts, lead, tin, antimony/bismuth. Most of this material has disappered into toy soldiers, fish sinkers, home cast bullets, and the like, as those printing machines died off. My Aunt ran a lino-type for years until she retired in the late 60's. She died childless, and it was thought the leading is what made her barren. When she died in the late 70's, she was 'goofy as a pet coon' some said, and probably affected by the years of working the old gas fired linotypes, that no doubt cast a fume into her workspace and giving her heavy metal poisoning.

I am not a chemist, nor am I an expert at metal /art casting. Just parrot what I have learned and had to unlearn about working molten metals. It is fascinating to me, yet a lifetime of experience I dont have, only where I dabbled hard, and learned from those that were happy to talk to me. I am half deaf, but not dumb, I listen well to experieince.

I hope I sharpened your curiosity, and answered your question.

[Harold_V]

Antimony is a major component of the new solders that are supposed to save us all from the dangers of lead poisoning.

Indications are that antimony (Sb) isn't a major component, although it is present in three of nine solders offered by J.W. Harris.

Their Bridgit ® solder has a range of 4.5%/ 5.5% Sb. content.

Their StaySafe 50® shows a 3% Sb content

Their 95/5 solder shows a 5% Sb content.

The major constituent in all cases is Sn (Tin), with a content of 91% or greater in all cases.

I had reservations on the addition of antimony as I know, from casting lead bullets for hand loading, that it is recognized as making metals brittle. To that end, I did a search, as I was not satisfied that it is a good idea to add to copper alloys. It appears that may be correct. You may wish to follow this link for more information.

http://www.jstor.org/discover/10.2307/2 ... 2107270573

Harold

[steamin10]

Ya. The reason antimony is added to tin solder is to stop the tendancy for the tin to 'crystal creep' when exposed to water, and electrolytes. It will grow microscopic hair of tin crystals. Oddly enough it was discovered this action to be very excited in vacuum settings, and was responsible for shorting out closely manufactured circuit boards, used in outer space. The additions of lead, and silver stopped this. It is the instability of tin over time that has caused the failures of cell phones and radios in the field for years, aggrevated by moisture from the body and the salt present. These are known engineering facts, and the reason boards are sprayed with paintlike compounds to deter water and contamination that cause the breakdowns in a physical sense. It is not noticed so much in cell phones anymore, because the replacement rate in the field is so high, social obsolesence takes the old phones out of service way before the acknowledged failures occur.

[RCW]

My apologies to Steamin10 and Harold. I did not intend to imply that lead was safe. Since I have a field in architectural restoration, I am very aware of the historic and tragic consequences of lead paint chips on small children. Lead fumes in a factory that is soldering circuit boards could well have horrible consequences. That is less probable at home. When I solder electrical components, I try to always have an exhaust fan near by. The fumes from overheated plastic are really nasty and cause headaches almost immediately. I'd bet they have horrible potential long-term consequences, as well. Parrot owners (a category to which I do not belong, alas!) are told never to allow non-stick cookware in the house. Vapors from teflon and other plastics can kill birds quickly. Many such compounds are thought to be carcinogenic to humans, too, but since the results are not so quick they may be less noticeable.

I hope this post isn't a hijack. To get closer back to topic, perhaps it would be a good idea to mention two materials that we should NOT consider for match-plates or pattern material. Ohio, California and the EPA all consider Western Red Cedar a really serious carcinogen (tiny PPM). I know a woodworker who never smoked a single cigarette, but who nearly died of lung cancer from sawdust, even though most wood is benign. I do not allow MDF in my shop--period. I cut one sheet and wound up really sick. A quick Google search revealed that I was fortunate. The nastiest consequences are for long-term exposure. If even half of the stuff about MDF is true, then a wise person will ban it from the premises.

Sorry about this long post. Harold and Steamin10 are absolutely correct about the dangers of heavy metal vapor (by the way, including welding galvanized stuff--don't ask how I know). But there are also many nasty chemical in our shops that we should handle with cautioun. And even "natural stuff" like Western Red Cedar can ambush us.

Forgive me if I seem overly sensitive about this topic. I hope to have my grandkids in the shop a lot during the next few years. I hope they will develop some good skills and build some wonderful memories as a result. But I pray that they will not have cancer or emphysema 40 years from now.

[steamin10]

No need to apologize, I did not have taht take on things. ?Further astray here, I have been blindsided by Isocyanate paints overwhelming a chemical mask, (Cyanide cure vapors) Welding on old leaded iron, and of course burning some zinc sheet and angle and tacking the same back on farm equipment. ( The zinc caused founders Ague, in the old bell and brass foundries. It was thought drinking milk warded off the effects.)

Wood dust in its finest is most dangerous, my suction equipment vents outdoors both on sandblaster cabinet, and wood working separator. Even when vacuuming the house I insist on venting the shop vac through a cheep black sump pump hose outside, for the extra fine dust that the filter just misses. So it is gone outside to be consumed by nature, and not me. (I have animal dander.) Most people dont understand that common house dust is by a majority human skin cells, and ground up fiber materials from walking on the floor, that settles in that fine moondust all over everything.

Redwood, Red Cedar, Black Walnut, and Hemlock, are poisonous in their own right, and breathing protection and vacuuming should be paramount when processing those woods, along with gloves for handling any treated outdoor woods. I use red cedar and Walnut alot for various small projects, but knowing is the key to protection.

Ok, now back to the program...

[Harold_V]

My apologies to Steamin10 and Harold. I did not intend to imply that lead was safe.

One of the features of this forum is the ability to discuss issues without fear of offending. I'd like to think that we are adults here, and have the ability to behave accordingly. Each of us stands to learn a great deal if we keep our minds open and not focus on things we *think* we know and take them as gospel. In no way have I interpreted your comments as being in favor of lead, nor do I feel you should not air your views. That's how we learn.

Without making this a political discussion, I'm of the opinion that we have been lead far astray by fear mongers, who are using legislation to advantage. That's not to suggest that lead and other heavy metals are not poisonous---they are---just as copper is poisonous---- in excess. Some of them we can't live without, albeit in just trace quantities. The bottom line is we are now being railroaded by legislation that prohibits many of these things, but exceptions are at one's disposal, so long as a penalty (read that a *tax*) is paid (does a carbon foot print ring a bell?). I'll leave this alone from this point forward, as we should not discuss politics.

Harold

[steamin10]

Heh! A freind was subject to an old loggers trick. Copper is of course poisonous, but more so to certain things than others.

Ol Buck, that built a 3/4 Tich and a Raritain, got an offer to remove some unsightly trees from a farm property. Down the lane on this property were no less than 6 grand old Black Walnut trees. These trees are indiginous to our region, but the orignal settlers would plant all sorts of nut and fruit trees within an easy walk of the farmhouse, (1840's+) to be looked upon for key ripeness and to protect them from roving deer, (which were often shot in the early morning when drawn by downed and rotting apples and pears).

At any rate, the offer , that was quite substantial, was refused. Several months latter, two of the trees began to loose leaves, and for all looks were dying. A quick inspection revealed the telltale green oxide streaks on the bark, leading to some copper roofing nails, about a dozen in each tree. A hammer, crowbar, and some looking with a borrowed metal detector, removed about a hundred nails from the six trees. The smallest on the end of the lane, about 30 inches in diameter, died some two years later. but the others recovered and set even more nuts after the stress. The tree was sold to a company that came in, and harvested white oak, on a five acre cowpasture, grown over with huge trees, and provided much needed income. It seems that copper nails especially are a killer for some tree species, including Black Walnut reputed to be more sensative than others. It should be noted that farmers are aware of the black Walnuts hulls for the nuts being poinsonous, which is a reason they were planted along lanes and drives. No other trees, and few brushy bushes will grow around the leaves, and especially the hulls of black walnut, So they are a natural deterant to other species to invade that space. A natural tree-wacker. This of course meant less time spent on property maintenance, which makes sense for someone that has to follow the whims and swings of nature, to survive growing crops.

Alas, modern people in their wisdom do not like the mess of hulls and leaves, and generally remove the Walnut trees at greedy oportunities, because the lore and benefit is not understood. The pungent nut is hard to recover, and the English walnut is thought to be suprerior in taste, and ability to recover the nut, and has supplanted the Black varieties in any way notable.

Now this is way off topic, except to say that traditional wood founding flasks wer made of dense cherry, and walnut, until those woods became scarce and pricey, and other metal flasks were developed, as founding developed into higher production, and greater weights of product. Hand process founding today is often done with the much lighter traditional wooden flasks to not wear out the human robots that operate them.

In the late 1800s many pieces of brass and cast iron of rather small weights were made in foundries, to provide the suitable shapes that the market demanded. This weakened and fell prey to stamping and forging technologies, makeing better (cheaper, faster) parts then the older castings. Casting has held out in the complex contoured parts market, making cavities and shapes where forging cannot. Fabrications have taken a bite too, but sometimes the sheer weight of product, like gearcases, dictate a strong cast box, where a weldment of equal weight may move or spring, proving to be inferior in use.

[Pipescs]

Boy have we pirated this thread or what.

But what the heck it is all about communication and education.

Grantham we can't thank you enough or the initial show and tell you gave us and all the neat information on the filters . looking forward to testing them when you can send a few. I need to go ahead and order a thousand so that I can also pass them out to the next generation.

Especially enjoyed the discussion on the blending of metals. I really think Steamin10 should start a stand alone thread on this side of the hobby as I will admit I am a total guesser on this aspect.

Your mention of the Walnuts brought back good memories of my childhood so last but not least I will end my input on this thread with my other passion.

When I built this house to retire in I put out 200 Black Walnuts across the back of the property, 13 Pecans along the drive and recently 12 English Walnuts. They are slow growing and needless to say kill all plants round them.

Don't ask me why. Just that my Grandfathers yard in Texas had them and I enjoy the memory of the whippings we got for getting all stained up having Walnut fights as kids. Seems the stuff will not wash out of your Sunday best.

I look forward to my grand kids shooting at all my fat squirrels with the old 410 in the closet. Who knows, maybe there will be a track wondering thru them some day.

[Grantham]

Charlie, just tell me where to send the mica strainers. Send me your address to rod@granthams.com . I tried to send you a private e-mail a few days ago, and it's still sitting in my outbox. Google Chrome seems to have abducted it. Rod

[Harold_V]

Boy have we pirated this thread or what.

Chuckle! Yep, we sure have, but look at the good that has come from veering somewhat from the topic.

I've never been too concerned with drifting, so long as conversation remains polite and readers exchange useful information. When it's important enough, we always manage to get back on topic.

I've found this (wandering) thread to be of particular interest. Wish more of them provided so much useful information.

Harold