Zink Wheel Weights Do Float - Finally Took a Picture

[mfraser264]

Been refining wheel weights into ingots for better storage this past weekend. After hand sorting, some Zinc weights still made it through. Decided to take a picture to show they float. Checking metal temp a few times the temp of the pot never went above 650. If you are having suspected Zinc issues, I would suspect the pot temp is way too high. Zinc melt point is 787.2°F.

The high surface tension if molten lead will even keep the steel weights a float. The Zinc weight in this picture sat for more than 10 minutes and was still floating. Hope this helps.


147944

[Beagle333]

Cool pic. I don't have my smelter set up for controlled temp, so I use the ol' sidecutter pliers test on mine. It's slow, but fortunately I don't smelt a lot of my own WW.

[Chris24]

I had this happen to me recently. I usually get all the zinc out, but I was tired and let a few zinc weights slip through. When I smelted the batch, five or six zinc weights sat on top with the clips. I pulled them off with no problems. I don't use a thermometer, I just keep the lead barely above melting point.

[NavyVet1959]

Since zinc is less dense that lead, of course it is going to float. I doubt that surface tension has anything to do with it.

I usually don't bother sorting my wheelweights -- I just toss everything in the smelting pot and settle for whatever alloy I get. The zinc, steel, and clips all float and get skimmed off.

[Ola]

I usually don't bother sorting my wheelweights -- I just toss everything in the smelting pot.. The zinc, steel, and clips all float and get skimmed off.
Also the ball bearings, nuts, bolts, monkey wrenches and other tools they use at the tire shop float..

[Retumbo]

Even melted zinc will float as pictures in the zinc contamination thread shows.

[bangerjim]

Not surface tension......density. Zn and CI and steel and dirt and rocks are lighter than Pb so they float. Until you reach the liquid point of Zn and then Zn magically disappear!

I keep my temps around 700-730 (guestimate from past years of experience and depending on alloy) and never had any zinkers melt in. But I quit messing with COWW's almost 2 years ago when Pb turned out to be only ~50% of the buckets. Not worth MY time. I can buy good clean alloys at local yards that need no fluxing and messing with.

Do not rely on that old "oatmeal" indicator! If you have Pb alloy at just under it's liquid temp, it can & will appear like that. 5 more degrees and it all goes away. No Zn at all......just under temp lead alloy melt. Too many new melters get paranoid with the oatmeal thing.

Sort B4 re-melting always. Eliminates those "did I miss one....do I have Zn in my pot" questions.

[williamwaco]

Zinc weights will float but if you walk away and let them cook, they will also melt. Remove them quickly.

[NavyVet1959]

Zinc weights will float but if you walk away and let them cook, they will also melt. Remove them quickly.

Technically, if they are melting, you are running your pot at too high of a temperature. :)

[toallmy]

My first casting I thought I had got zink in the mix ,but it counot have Ben it was pure soft lead with tin.it cast fine when I made my ingits.after several attempts to cast I got the temp right and figured out what I was doing wrong. It did stop me from using coww to the for several months , since I figured out melt temp I am sitting up ww rout . Going to have themonter in the pot.

[toallmy]

My first casting I thought I had got zink in the mix ,but it counot have Ben it was pure soft lead with tin.it cast fine when I made my ingits.after several attempts to cast I got the temp right and figured out what I was doing wrong. It did stop me from using coww to the for several months , since I figured out melt temp I am sitting up ww rought . Going to have themonter in the pot.

[toallmy]

Still working on the computer .but gettin better at casting.

[bangerjim]

You guys in VA sure do talk funny!

HA.......ha!

[Seeker]

Was gonna tell a joke about the guy with a hair lip but didn't want to get "off topic"

Anyhow.. it still amazes me how all the dirt and sand just comes floating to the top.

[toallmy]

Tipe and spell weard to .I'm all most 50 and just started casting and computers same time.not gitting any better at computer.

[NavyVet1959]

Anyhow.. it still amazes me how all the dirt and sand just comes floating to the top.

That which does not somehow seem to be able to avoid laws on buoyancy and get attracted to the pour nozzle on the Lee bottom pour pots. :)

[bangerjim]

That has always amazed me too! dirt and garbage and Zn float. But that black stuff that you can scrape off the bottoms and sides almost seems to be in infinite supply. And can get down in the spigot!

[RogerDat]

Considering one can spoil a pot of WW's by getting it hot enough to melt zinc AND repeating a successful bullet cast in part depends on having lead at same and correct temperature that worked last time a thermometer is most useful. Nothing fancy but certainly functional at $22 http://www.amazon.com/Tel-Tru-LT225R-Replacement-Thermometer-degrees/dp/B0055777EU one has to ask how much is a pot of spoiled lead worth?

Also very useful when posting a question of "why do my bullets look like...." because melt temp is one more data point you can specify. You can say casting with such and such an alloy at this temperature. To which people will respond "too cold" or "too hot" or "lead is hot enough so...." Or all three ;-)

[PbHurler]

Do zinc weights usually have the Zn identifier marked on them somewhere? (see OP's photo), I haven't done a batch melt in a long while but I always hand sort by type(s) and use a thermometer to be on the safe side.

[Retumbo]

95% will be marked

[BK7saum]

There are some that have a rounded profile similar to lead wheelweights and are marked with 10, 15, 20, etc that are zinc. I have had one or two slip through that were caught at smelting. Other than that, I don't have a problem identifying the zn and fe weights.

[NavyVet1959]

The steel wheelweights are pretty much a non-issue. Other than wasting energy heating them up to lead smelting temperatures, there is no real downside to having them in the pot. If you get them up to a temperature that can melt, your pot is probably going to also be melting. :)

The zinc ones on the other hand have a melting point close enough to the melting point of lead that we need to be concerned with it. With the natural gas burner that I use and the cast iron dutch oven that I use for smelting, I have been able to take the leftover wheelweights after skimming and recover molten zinc out of the scrap, but it too noticeably longer to heat them up to that temperature than heating up lead. There also was not much zinc recovered. Probably so little that it might have just given me a slightly harder lead allow instead of being a detrimental contaminant. I probably only ended up with a 1/8" sheet of zinc at the bottom of the pot out of a couple of 5g buckets of wheelweights.

[mfraser264]

Some of the stick on Zinc weights are not identified with Zn - most of the time what stick on weights I see are either Iron (Fe) or Zinc. Nice bonus for me if they are few of the lead stick on weights in a bucket. Always have a chunk of a magnet from a flywheel when melting.

[bangerjim]

Fast easy & cheap way find FeWW's:

http://t.harborfreight.com/30-lb-capacity-powerful-handle-magnets-67156.html

[NavyVet1959]

Fast easy & cheap way find FeWW's:

http://t.harborfreight.com/30-lb-capacity-powerful-handle-magnets-67156.html

Except for the fact that the lead and zinc clip-on wheelweights have steel clips which will also get picked up by that magnet.

[P Flados]

The unpainted lead is easy to pick out.

Most zinc is obvious (see the ones on the left in the first photo below).

Most all zinc is painted. Some lead is painted.

Batch before last, I used a bolt cutter and chopped any that looked like lead, but were painted

A few of the painted ones that looked like lead were actually zinc, for example the two on the right below.

148076

Last week I was at my mechanic's shop to pick up a car. Got a little over a half a 5 gallon bucket for $20.

I did a quick sort this time without the bolt cutter routine.

I had been thinking about my previous crude smelting routine and had worked out a plan for something better. A combined function "lead smelting / pine cone disposal" furnace.

Sunday I picked up some free paving stone block stuff from a scrap pile I had spotted.

Assembled a first attempt improved furnace and went at it.

148077

After it looked 90% melted, I threw in enough fuel to last for a while so I could scoop out clips.

Next thing I know I spotted some not melted and /or half melted weights with nothing un-melted in the corners.

I quickly scooped out everything on top without adding any more fuel.

All of the 44 lb batch looked clean, poured good and cooled off without any appearance of contamination.

Later I confirmed removal of some zinc that was starting to melt.

148078

[leebuilder]

No matter how diligent i sort i still find steel and zinc in my smelt. There is a point were they float i wait for it and skim, it is around the point were the lead wont stick to the steel clips, realy glad the zinc comes to the top.
Be well

[P Flados]

Next time, I am going to make sure and have enough "sure fire" lead to get at least a 1/2" covering the bottom.

This will be pretty easy, I will just keep the painted stuff or iffy ones separate from the obvious bare lead when I sort.

If I feel like it, I can chop the painted one with my bolt cutters, but the real protection will come when I melt.

After I get a good layer of clean molten lead, I will then then add a scoop at a time. The zinc ones float pretty good.

Last time, I had so many clips on top I could not really see the zinc floaters.