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DICKEYBIRD
11-11-2007, 08:52 AM
I made a hammer mold yesterday and tryed my hand at metal casting. It came out OK but the tire weights I melted down are very soft. Is there something I can add to the mix that will harden it a little? Hopefully something I'd have lying around?

I copied John's (bogstandard over on the Home Model Engine Machining forum) method of making the mold, using a piece of electrical conduit for a handle and it worked well. There's a piece of aluminum driven into the end to keep the lead from running into the handle.

The little hobbyist style propane torch was too slow so I picked up a "Weed Burner" at Harbor Freight to get some serious heat. I was going to make one of the many Reil-style burners found all over the web but the fittings and hoses needed to hook it up to a BBQ propane jug were too expensive. I just bought one of these puppies on sale for $18.99. It works great! It roars like a jet engine on afterburner when you squeeze the "Turbo" handle. No need to waste gas using that feature just to melt lead though!
http://i57.photobucket.com/albums/g227/DBAviation/WeedBurner.jpg
I made the hammer head 1 1/4" x 2 1/8" which came out to about a pound which is what I wanted to whack the drawbar on my mill and tap parts down in the vise.
http://i57.photobucket.com/albums/g227/DBAviation/HammerMold-2.jpg
http://i57.photobucket.com/albums/g227/DBAviation/Hammer.jpg

ps: D'ja ever notice how Murphy's law applies itself to machining so well? The hammer head mold was only the 2nd or 3rd time I've used a boring head in the mill so I used this project as practice for when I really need to bore a precisely sized hole. As I got closer to the non-critical 1.250" dimension, I carefully measured the I.D., made the calculation and adjusted the cutter. I made the cut, backed out the cutter and it was as perfect as I can measure with my inside mike! Beaming with pride I reset everything and bored the hole for the handle which actually NEEDED to be pretty close....you guessed it, .006" oversize!:(

Evan
11-11-2007, 09:01 AM
Looks good and is very handy for beating on machine tool parts. A sack of charcoal works just fine for melting lead. I cast the counterweight for my milling machine head using just that on a warm summer day. No forced air required, just a grill with a cast iron pot on it. I used less than 1/2 bag of briquettes to melt about 80 lbs of lead.

http://vts.bc.ca/pics/lead2.jpg

John Stevenson
11-11-2007, 09:09 AM
Good article here.

http://www.key-to-metals.com/Article88.htm

Seems like Antimony is one of the better ones.

.

Lew Hartswick
11-11-2007, 09:11 AM
Tire weights already have some Antimony in the lead to harden it .
If you need it harder Sn (tin) is the easiest to get into solution.
Antimony would be better BUT it is very hard to get into solution
unless it is cut up very fine, it has to disolve since it has a much higher
melting point.
...lew...

tony ennis
11-11-2007, 09:24 AM
I saw the following in a book called "Shop Savvy" by Moungovan.

Moungovan looooves lead. He had a hammer comprised of a 2-part clamshell head and a handle. The striking faces were lead 'biscuits' which were captured in the clamshell head. Replacement is quick and easy. The guy made about a dozen faces at a time using a plywood form.

JerryL
11-11-2007, 01:29 PM
Hi You can use a bar of tin 50/50 and it also comes in other mixes . when you are trying to mix tin /wheel weights etc. get a few bars of canning wax etc and as you stir the molten mixture add ( very carefully some wax and stir. This will flux and make the mixture mix . you have to skim off the top and pour fairly quickly . ( Not quickly into the mold .) The mold might work a tad better if it is preheated before poring )
Hope this helped a bit .

As in any shop procedures wear eye protection for blow outs and splatters ---of course gloves etc are a bad idea either .

JerryL

jdunmyer
11-11-2007, 01:34 PM
Cast lead will be much harder if you quench it after pouring. Many bullet casters drop the bullets from the mold, directly into a can of water.

Also, the lead tends to get harder after it ages for a while.

thistle
11-11-2007, 01:47 PM
I should imagine that if you get spent rounds from a shooting range the the lead from the bullets should have a fair amount of antimony in it .

I dont know about the health side of melting high antimony lead is though.

DICKEYBIRD
11-11-2007, 02:03 PM
Great...thanks for the info guys! I think I'll try the quenching trick on the next one and see how that works.

jdunmyer
11-11-2007, 02:21 PM
Thistle,
"Range Lead" is actually not all that desirable for bullet casting, as it's not as hard as you might think:

A high percentage is often .22 bullets, which are pretty pure lead (IE: soft)
Another high percentage is jacketed bullets, where the core is usually pure lead.
Only a small percentage is hard-cast bullets.

One of the best all-around bullet materials, in my experience, is wheel weights. If you really want to get into it, get a copy of Lyman's Cast Bullet Manual.

Yankee1
11-11-2007, 02:44 PM
Try antimony to make it harder and stronger. Use tin to make the mold fill out nicer. Flux with beeswax to remove dross. Be careful not to skim off that grey looking powder on top {its tin} If there is tin on top it needs to have beeswax stirred in. I have casted thousands of bullets. If a bullet mold is supposed to cast a 240 gr. bullet and it comes out of the mold heavy then it has too much lead and will be soft. If it comes out lighter then it will be harder. We can tell what to add to make what we wish.
Chuck

sconisbee
11-11-2007, 03:47 PM
Bees wax works as a casting flux? damn never knew that and i got tons of the stuff from our hives.

Yankee1
11-11-2007, 04:07 PM
Hi,
It works very well and is quite expensive in the states.
Chuck

Evan
11-11-2007, 04:41 PM
Beeswax is also a preferred lubricant for drilling aluminum in the aircraft business. Comes in sticks and you run the drill bit into the cake to load the flutes. Then you are good for the next 50 holes or so as it melts off a bit each time you drill.

sconisbee
11-11-2007, 06:17 PM
yeah I was told about the beeswax as a aluminum drilling lube by an old boat building friend of mine a couple of years back, didn't really think of it as a flux ill have to try it next time i cast some hammer heads. Anyone wanna buy some beeswax? :D lol just kidding most of its already been earmarked for other things.

speaking of casting lead (and hopefully not stealing the topic too much) is lead any good as soft jaws for bench vises and the like for when your dealing with the easier to mark metals like som softer bronzes/brasses and aluminium?

lazlo
11-11-2007, 06:32 PM
Tire weights already have some Antimony in the lead to harden it.

Babbit is 80.25% lead, 14.75% antimony, and 5% tin.