Loss of tin during the melt & cleaning of WW's

[rcsch]

I'm new to the cast bullet world. I have been reading a LOT here and have learned a lot.
After my first couple of 50 lb, WW melting/cleaning into ingot, sessions, I began scratching my head wondering if I did it wrong. While skimming out the clips & crud from my sorted & trash cleaned lead WW, I still managed to find a few steel, zinc, and plastic weights floating in the melt - got rid of them. I skimmed off the film on the top, while scrapping sides and bottom of my cast iron pot, fluxed several times using candle wax. Most of the film I skimmed off seemed to be powdery/ash like. I did stick a thermometer in a couple times and temp read about 700-750. After the WWs were liquid, clips removed, skimmed off, and ingots poured, about an hour or a bit less had passed.
My worries began then, after remembering about the loss of Tin and antimony,etc.

My question is - did I loose the tin & antimony from the WWs by scraping off all that scum?
any and all comments will be appreciated.
thanks
Roy

[Outpost75]

If you flux well and melt temperature is kept below 750 degs. F you are OK.

[bhn22]

The powdery stuff is ash from the paraffin in the candle wax. It should have been light and fluffy. Wheelweights don't generally have much more that 1/2% of tin to begin with. You'll probably want that number to match the antimony percentage (around 3%) if you're having issues with bullet fillout.

[rcsch]

Gentlemen, Thanks for the help.
so if I understand correctly - I should give the melt a try by casting some bullets and go from there if problems arise??

[jsizemore]

Since COWW alloy is low in tin, your antimony will look a bit frothy on top if too hot. I turn the heat down a little just after I remove clips and commence the flux and stir and scrape ritual. You can check your ingots in a day or 2 by squeezing a 1/2" steel ball between a known pure lead ingot and one of the suspect ingots. Don't go crazy with the squeeze. Of course the pure Pb ingot will have a larger diameter indent. Simple. No vice, hit it with a hammer, or step on it.

[LAGS]

Sort your WW's first before trying to smelt them.
IE : pick out all the Zinc ones for sure, and as much of the steel as you can.
This is done for two reasons.
One , if the steel is still in there, you will have a tendancy to turn the heat up to see if they melt.
And if you get just a little too hot or wait just a little too long, any of the Zinc ones will start to melt.
I check EVERY Weight with a pair of wire cutters before putting it in my Lead Pot.
Zinc and Steel ones wont even dent with wire cutters.
Then out of those, the Zinc ones wont stick to a magnet on the ends, but the clips still will.
Same goes for the process when I do SOWW's

[BNE]

I think you are FINE. 750 is not too hot. I have done a lot of testing on how quickly Tin will oxidize and then get scraped away. It does not happen as quick as some people think. I ran my pot over 800F for a few hours. I took scrapings from the top of the melt every 15 minutes. I was not able to measure a difference in the composition after the testing. Also the "scrapings" were also VERY similar. (I have access to an XrF at work.)

That being said, you may need to add tin to your mix if you are not getting good fill out. A lot of guys say to add 1 to 1.5%. (COWWs typically only have 0.5 to 0.75%) If you get good fill out, then don't worry about it.

I posted this data in the past, but I am not sure I can find it. I will post some tests I ran on COWWs and Stick On WWs.

http://castboolits.gunloads.com/showthread.php?229666-Stick-On-WW-XrF-Data

This one has the test. It is a LONG post:
http://castboolits.gunloads.com/archive/index.php/t-213625.html

[rcsch]

Again gentlemen - thanks for the info. I appreciate the other links for even more info on the SO & CO WWs.
Just by dumb luck I had read the link about how to ID WWs so I did know about the steel, zinc, and other bad weights. my first melt I didn't think to segregate SO from COs but I did the second batch. I'll continue to seperate them from here on out. I'll have to try the sawdust flux - sounds much better than the candle wax I used.
thanks again.