SteveC Posted July 18, 2010 Share Posted July 18, 2010 I'm just getting started in Blacksmithing, new to NEB, ABANA and this forum. When buying metal at a scrap yard, flea market etc.. how can I be certain that the metal is safe to forge? Galvanized metal is easy to spot, at least it has been so far. Thanks in advance, any advice you can offer is much appreciated. Quote Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted July 18, 2010 Share Posted July 18, 2010 Mainly watch for platings; zinc (galvanized), cadmium (gold,grey), and chrome. If it is bar stock , plating can be turned off with a lathe, if you have one. Would only say to do that for something like a hydraulic shaft that you know is decent material to start with. ALL metals pose some hazards. Some from what is in the alloy, others from how it may be processsed;sanding,polishing,heating,etc. which could lead it to being ingested by breating it in. Lead can be a hazardous metal, but it can also be safely used, and is used by many people. It is also used for alloying a lot of different metals from steel to copper. I have breathed in my share of zinc fumes , never got the chills, but enough that I knew it. It happens from time to time, just don't make a habit of it. A lot of the hazards from metals are accumulative, so it will take some long term exposure to affect you. I would be more concerned with what the metal had been used for rather that what it was made from. Was it used in chemical processing? What is that funky goo on it? Most scrap yards are very careful about what they let into the yard nowadays to protect their workers, as well as keeping the EPA happy, but some stuff still gets through. The yard I took my scrap to in Richmond CA had Geiger counters on the inbound scale to detect any radioactive items. Radioactive materials are that prevelent?!? Most of us have a radioactive device in our homes, and are glad to have it. It is called a smoke detector. It can be dangerous if used incorrectly,as can any number of items. I would say that you are more prone to injury while scrounging around the yard than from the materials that you are collecting. Be safe, and happy scrounging. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 19, 2010 Share Posted July 19, 2010 If it is rusting it's generally safe to use. Note that old paint on steel can be quite high in lead so I try to stick to old rusty metal. The Geiger counters are from an "Oops" back a couple of decades now. In Mexico a stolen piece of medical equipment was sold to a scrap yard where it was melted down and the metal incorporated in a bunch of things including re-bar and seats for a fast food restaurant chain. Turns out the original equipment contained Cobalt-60 and the resultant steel was quite radioactive! It was finally found out when a truck carrying rebar went in the exit gate of a nuclear facility that had Geiger counters mounted to make sure no radioactive stuff got out accidentally and they went off big time. Hmm seems to be a lot more prevalent than I had realized: http://www.recyclingtoday.com/Article.aspx?article_id=17361 Quote Link to comment Share on other sites More sharing options...
ofafeather Posted July 19, 2010 Share Posted July 19, 2010 Are car/truck parts like leaf/coils springs & axles generally safe? Quote Link to comment Share on other sites More sharing options...
pkrankow Posted July 19, 2010 Share Posted July 19, 2010 Are car/truck parts like leaf/coils springs & axles generally safe? That is the best. Axles are medium carbon and springs high carbon. The coatings are often only paint or oil. Body sheet metal is often good, newer can be galvanized though. Bolts and nuts can be piled and faggot welded into thick stock, or used for small stock as is. If the part looks forged, then you are in great shape. If it looks cast you may have something not as useful. Small cast iron pieces can be used to hard face mild parts by crayoning the iron on at welding heat. Phil Quote Link to comment Share on other sites More sharing options...
Rob Browne Posted July 19, 2010 Share Posted July 19, 2010 If you are in a rural area then the tynes off a scarifier are really good steel. Plow disks are good but tend to be difficult to use because you have to rough cut the object out of them. Quote Link to comment Share on other sites More sharing options...
John McPherson Posted July 20, 2010 Share Posted July 20, 2010 Rare, but some high performance engine valves were sodium filled, cutting one open or chucking one in the fire might be too exciting. There are forgeable copper alloys, but dust/fumes from arsenic or beryllium bronze are highly toxic. I personally would not forge or cast unknown brassy scrap without a quality respirator. Torch and cutoff wheel work: many people have been hurt cutting apart springs under tension or compression, or shocks and hydraulic cylinders for the shafts. Any enclosed cylinder or tank, whether or not it once held chemicals, poses an explosion hazard under the right conditions. Brake cleaner and other off the shelf products can produce military grade toxic gases when heated. One whiff can do permanent damage, a lung full can kill. Read the fine print on the labels, or find a safer alternative. Beware of greasy parts scrounged from garages. Leaded or sulfured free-machining steels are not dangerous, just disappointing to weld or forge, as they crumble and crack. Quote Link to comment Share on other sites More sharing options...
pkrankow Posted July 20, 2010 Share Posted July 20, 2010 Rare, but some high performance engine valves were sodium filled, cutting one open or chucking one in the fire might be too exciting. That could be exciting. Apparently sodium filled valves are only partially filled and the hollow stems are sealed. They sometimes rattle but otherwise you need to weigh them or otherwise measure them and know what they came out of to tell. Could be very exciting. There is no common way to extinguish a sodium fire. Phil Quote Link to comment Share on other sites More sharing options...
SteveC Posted July 20, 2010 Author Share Posted July 20, 2010 Thanks everyone, that's a lot of great, useful information Be safe and be well, Steve Connor Quote Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted July 20, 2010 Share Posted July 20, 2010 The exhaust valves on the not even near high performance GMC 305/351/etc V-6 series from the 60's are sodium filled. Dad told me that it was common practice to bury the old sodium filled valves out of the radial aircraft engines out back of the Air Force maintenance shops. Look for a spot in a field, dig hole, toss valves in, and bury. Quote Link to comment Share on other sites More sharing options...
Rob Browne Posted July 20, 2010 Share Posted July 20, 2010 What is the idea of the sodium fill in these valves? Quote Link to comment Share on other sites More sharing options...
pkrankow Posted July 20, 2010 Share Posted July 20, 2010 What is the idea of the sodium fill in these valves? Sodium metal melts at about 200F. This liquid then circulates helping remove heat, transporting it up the valve stem and helping improve the function of the valve, reducing the likelihood of heat damage to what is a rather delicate part in the combustion chamber. Google is wonderful, there is a wealth of discussion on sodium filled valves: patents, maintenance bulletins, performance forums, etc. Phil Quote Link to comment Share on other sites More sharing options...
Rob Browne Posted July 20, 2010 Share Posted July 20, 2010 Thanks Phil :) Quote Link to comment Share on other sites More sharing options...
pkrankow Posted July 20, 2010 Share Posted July 20, 2010 Thanks Phil You are welcome. Phil Quote Link to comment Share on other sites More sharing options...
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