Lead allowed?

[mrbob1000]

Is lead considered a hazardous substance if it is fully contained within aluminum tubing?

[lbarger]

Lead is hazardous to handle without proper safety equipment. While it may be 'safe' when fully contained, the process containing it will pose a hazard to you and your team mates. While you may sneak it past an inspector at competition, I would recommend against it.

If this is for ballast or mass, there are other dense metals that will be nearly as effective without the safety concerns of lead such as stainless and standard steels and some copper alloys such as brass and bronze.

A free online resource for searching materials based on specific properties is www.matls.com.

[Dave Flowerday]

Al (a lead inspector) posted this last year: "Lead in any form must be sealed (painted, coated or dipped) and may not be machined in the pit."

Thread here: http://www.chiefdelphi.com/forums/sh...ad.php?t=76636

If it's fully contained it should be OK. You need to be careful when handling it at home, especially if you're doing any drilling or machining on it.

Keep in mind, though, that the only authoritative source of answers is the official Q&A at forums.usfirst.org. Nothing posted on CD, no matter who wrote it, will work as a defense if you get questioned by an inspector.

[imp]

You can use Bismuth instead of lead. It is almost exactly the same just less hazardous.

[mrbob1000]

Thank you for the information, i now feel much more confident in my teams usage of lead.

[travis]

Pb? HAH! Only the bumpkinest of rubes go to Plumbum (specific gravity=11) for density -- it's just half that of the high end stuff and has dismal physical properties.

It is some kind of cruel joke that Earth didn't get more Pt. Even with the high density (SG=21), if it were more abundant they would probably make turbine compressor vanes out of it. You can boil Pt under pure oxygen and it will never react, all with better strength than Ti (pffft SG=5). Best of all, your friendly inspector could file it into powder and make a healthful beverage from it. Several rappers and I even have teeth made from the stuff. You can have about 2.5 Oz and still be under the cost limit.

Someone out there sells depleted U (SG=19) counterweights for the aircraft industry and unitednuclear.com gets a hunk now and then. Non radioactive U is still chemically poisonous though. The IAEC will send inspectors to your school should you amass more than 15 lbs of it.

I spent months tracking down a guy in Sweden to sell me a used Ta (SG=17) sputtering target to make my wedding ring from. Polished Ta is like looking into the cosmos; there is nothing like it. A W/Re (SG~=20) alloy ended up on my finger for various reasons, but I will trade a size 9 Ta ring for a Haas tool room milling machine with full software upgrades and will throw in the Ta remnants for a 6" Kurt vise.

As so often is the case, none of the really cool stuff is a viable option, but you are in luck. Your local expensive outdoor store should have W (SG=19), both in the form of fishing weights and bird shot, for about 10X what they charge for Pb. Forget about the inspectors, call a tooling manufacturer if you figure out how to machine W in the pits. There have been more studies linking Al (SG=a paltry 3) to heath problems than W, so you could leave it uncoated and in the open.

[the man]

If lead must be coverd, contained, or painted what happens when you soder ends together?

[EricH]

Originally Posted by the man

If lead must be coverd, contained, or painted what happens when you soder ends together?

Ends of what? Wire? If you choose to use leaded solder for some reason, then you break out the electrical tape afterwards and wrap that connection solidly.

[Dick Linn]

Tungsten is pretty dense stuff. Even Tungsten Carbide isn't bad. If you can find scrap electrodes from TIG welders or get scrap carbide mills and inserts from a machine shop they would work OK if you can pack them closely. Most recent price I saw for Tungsten shot was $24./lb. Scrap carbide tooling is maybe $8./lb.

Tantalum inlay rings: http://www.ringworksstudio.com/Pages...ack-Rings.html

[eugenebrooks]

If you are going to use tungsten electrodes,
make sure that you don't use the thoriated
ones. They are radioactive.

We like to use gold paint on lead to make it safe.

Eugene