What is This?

[leadman]

I picked these stick-on weights out of a bucket of rusty clip-ons and other stick-ons. All the other weights were very dull in color, while these 2 look almost as shiny as chrome.
The metal is as soft as pure lead per the side cutter test.

Any idea what metal this could be? Tin?

[lurch]

Doubt it's tin. Try bending it. Tin is a lot harder to bend than lead and it makes a distinct crackling sound when you do. Even some bar solder will sometime crackle a bit when bent. One way to get a pretty good idea is to weigh it. Then measure its volume (think how much water does it displace?) Get enough lead together to displace the same amount of water and then weigh that. I'll bet they are pretty close to the same weight. If so, it's probably just lead.

[leadman]

This bends harder then the other stick on lead weights. It isn't plated either, as when I tried the side cutters on it it is the same bright color all the way thru.
I just bent the big on and it crackled, then cracked on the mark.
The color reminds me of the plumbers lead free solder. I can't imagine wheel weights being made out of tin and antimony. Plumbers lead free solder is running $30 to $45 at Grainger.
I may melt it tomorrow and see what the melt temp is. I could cast it in a mold and then cast a pure lead slug in the same mold.

[357maximum]

.......................drifts off into a dream sequence where all "environMENTAL" wheelweights are made of pure tin and/or sb/sn...............awake now sorry I drifted off for a minute.:veryconfu

[Linstrum]

Oh, fudge! Back to reality.

You've got pure zinc. The reason why it looks so fresh and bright is because it could be quick dip-plated or flash electro-plated with tin a few millionths of an inch thick to keep it looking good, although most stick-on weights are applied where you can't see them and how they look is not important. When fresh, zinc is very bright and shiny and only turns the characteristic gray color of a concrete sidewalk after exposure to moist air for a few weeks. Think of the rolls of roof flashing sheet metal down at the hardware store, they are zinc plated and stay nice and pretty on the shelf.

Tin can be plated on other metals simply by dipping in a tin solution as long as the metal being tinned is more chemically reactive than tin, which is a good many metals. Until about 100 years ago, iron stick pins used for sewing used to be tin-plated using a quaint old-fashioned method by dipping them in a tinning solution made by boiling tin metal filings in beer!

When you bend zinc metal it also makes a pronounced cracking, snapping noise that you can also feel in your fingers. When tin metal bends it makes a strong groaning squeaking noise, but more of a high-pitched squeak than zinc, which is low pitched and more like breaking a bunch of little glass rods.

I'd mark the weights as zinc to keep them out of your lead stash, and save them since some day not too long from now we will all be casting boolets out of zinc die-cast. During World War 2, Zamak #2 zinc die-casting alloy was used for casting bullets with excellent results, it melts at about the same temperature as the lead alloys we use and produces castings with extremely fine and sharp details. We'll have to call those "boolitz" with the Z for zinc.

Have fun!


rl580

[leadman]

I meltd down some of the is in my Lyman ladle with a propane torch today. Poured it into a Lee 44-310 mould. Then poured another boolit from pure lead. The stick-on boolit weighed 307grs. the pure weighed 306grs. The wrinkles could make a difference in the weight.
Stick-on boolit is 6BHN (Saeco 2), the pure lead is less than 0 on my Saeco tester, about -3 Saeco.
There is a plating on the lead so I measured it at .007" with a mic. I tried to melt this in my ladle, but it would not melt even though the ladle was red hot. Feels like chrome plate.

Shouldn't have to worry about another contaminate to our lead supply.

[rhead]

They are for the high reflectance chrome wheels. I am not sure how they get such a thick plating on the lead but they are nearly pure lead with a heavy plating. The ones around here are about the size and shape of the little squares a Hershey bar breaks into. A little thicker. I use them as pure lead.

[leadman]

The plating reminds me of what used to peel off the car bumpers from the 50s. The lead is thicker than the normal stick-on, but about the same hardness as the stick-ons.

[S.R.Custom]

They are for the high reflectance chrome wheels. I am not sure how they get such a thick plating on the lead but they are nearly pure lead with a heavy plating...

It's chrome plating. They're used on bikes, too. Link:

http://tinyurl.com/lbxtgo

[Linstrum]

The respective weights of your Lee 44310 castings being 306 grains and 307 grains changes everything, what you have is exactly what rhead says.

Lead.

The crackling noise when you bent the weights was the chrome metal of the plating breaking since it does not bend. Both tin metal and zinc metal form long crystals internally that also resist bending, hence the squeaking and cracking noises they produce when those metals are bent and their internal crystal arrangements fracture. Chrome is one of the hardest, unbendable, non-malleable, and high melting point of all the metals, that is why it is used for both industrial and decorative plating. Hydraulic cylinder piston rods are hard chrome plated to resist abrasion from sand in the work environment and corrosion from being left outdoors in wet weather for decades. It doesn't surprise me that you couldn't melt the plating since chromium melts at 3465°F - that's pretty hot!


To find the specific gravity of small objects is pretty easy with your powder scale if it is a beam-type. A digital platform scale is not directly suitable, though. The specific gravity of pure lead is 11.34 and most commonly used alloying agents, such as antimony, tin, arsenic, copper, etc, are substantially less, around 6 to about 8 with copper a bit more at 8.94.

Next, take a short length, say under 12" (30 cm), of fine flexible sewing thread that is easy to tie a knot in. Either tie the thread onto the object or use the tiniest drop of Super Glue that will do the job and fasten the thread onto the object. Place your powder scale at the edge of a table and hang the object from the weighing pan so it is hanging in mid-air and then cut off all excess thread. Weigh the object in question as accurately as you can and write it down. Then take a clear glass of ordinary water that is deep enough to totally submerge the object. Take a pencil or something similar and tease off all the air bubbles hanging onto the object and thread, and then with the glass of water holding still, weigh the object again while under water and record the new weight. Subtract the weight in air from the value obtained under water. Divide the in-air weight of the object by the difference that was found by subtraction. This number is the specific gravity, which is the weight of an object in relation to an equal VOLUME of water. The specific gravity of pure water is exactly 1 at 39.2°F or 4°Celsius, the specific gravity of water is a universal constant. At room temperature the change in specific gravity is so slight that it can be ignored for our purpose of finding the specific gravity of a piece of metal. Specific gravities are extremely useful in identifying what things are.

If the specific gravity of the stick-on wheel weight metal is close to 11.34 that would indicate that it is close to pure lead. The lower its specific gravity is, the less lead it has in it. If you know what the alloying metal is you can easily and fairly accurately calculate its composition. Look in stickies for my post and other posts on calculating alloy composition, the math formula needed is over there.


rl581