Another dumb fluxing question plus a few

[AggiePharmD]

So I processed my first pots of lead this past weekend. First I did the plumbing lead that I accumulated from a plumber buddy. This came out well with little to no trash upon fluxing.

Next I did a goodly amount of SOWW which turned into a nasty mess. First it took a good while to melt as my thermometer read I was getting about 600 degrees which might just be the melting point of SOWW or the upper limit of my setup. Anyhow I used a heaping handful of pine shavings like you put in a hamster cage, lite those on fire, stirred like crazy with a broken wood broom handle and then looked in the pot after the smoking stopped. Blackened shavings along with other stuff floating.

Now the question: I kept dipping the **** out and before it was over I had a hill of shiny silver mixed with **** about 12" high. Is this normal when fluxing WW or did I screw something up? I put all that ****, to include the trash (bolts, other metals, etc) back in my pot to remedy next time. Also, I had some weights that sunk to the bottom and assumed those weren't Pb since they hadn't melted by then?

Question 2: I have a large, heavy guage aluminum pot for the melt down process. Is the aluminum an issue?

Question 3: When using the shavings for fluxing, those are scooped off and not left in the pot correct? That way you don't get shavings in you lead bars or whatever shape you form them into

Some dumb questions I know.

TIA.

[Tonto]

Hopefully by now some additional research by you has provided some answers....anything on the bottom is heavier than your melt, and the fluxing mess sounds like possible zinc contamination. Wheel weights are either pure lead, lead/tin/antimony ( both of these will melt nicely), zinc ( will melt with more difficulty and screw things up) and steel which will not melt/change at all. A search of this site may give some ideas but your better option might be to try with what you have one more time, don't add more anything and see if a hotter melt works, if not, chalk it up to experience and keep that silver sculpture handy as a reminder. Learn how to distinguish the different kinds of wheel weights from each other, more info on that buried in this site. Good luck too, everybody on here has had a smelting mystery at one time, if they say they have not, they are being less than honest. Second read, those stick on Ww's might be pure lead and require a little hotter temp to liquidize, turn up the heat...

[AggiePharmD]

First please pardon the stars that look like four letter words. I'm using my phone on a break and it seems to translate the word "stuff" to a four letter word.

Secondly, I appreciate your reply. It is hard to describe the particulate matter that was floating on top of the SOWWs. I would like to think that it was the sticky sludge from the back of the weights. Once I got past that and removed it (there was alot of it.) I had a liquid that looked and poured like the plumbers lead. Unless my thermometer is just way out of calibration (brand new) it read at its highest of 600 degrees, which is WAY under the melting point of zinc which looks to be 750 plus.

I've been lurking here reading for around 6 months now and while I don't know it all I've paid attention.

I hate to throw away the silver sculpture and wanted to try to remelt it to see what I could get out. Otherwise I'll keep it as a reminder to watch better what I'm doing.

Again thanks for the reply.

[MrWolf]

My guess is you did not get the lead hot enough. I would remelt your sculpture and see what happens. I avoid the problem of the adhesives on the back of the SOWW by soaking them in my used mixture or mineral spirits, xylene, etc. let it sit for a few days and they come out clean. Good luck.

[RickinTN]

I'm surprised no-one has mentioned.....Don't use the aluminum pot. It's not a matter of "if' it will fail, it is a matter of "when" it will fail. 20 to 40 or more pounds of molten lead running down your leg would certainly be no fun.
Good Luck to you,
Rick

[AggiePharmD]

My guess is you did not get the lead hot enough. I would remelt your sculpture and see what happens. I avoid the problem of the adhesives on the back of the SOWW by soaking them in my used mixture or mineral spirits, xylene, etc. let it sit for a few days and they come out clean. Good luck.

Great tip. Learn something new daily round here. Thanks.

[AggiePharmD]

I'm surprised no-one has mentioned.....Don't use the aluminum pot. It's not a matter of "if' it will fail, it is a matter of "when" it will fail. 20 to 40 or more pounds of molten lead running down your leg would certainly be no fun.
Good Luck to you,
Rick

Super tip. Appreciate it. Off to find another vessel.

[nagantguy]

First listen to them do not use the aluminum pot danger danger danger.

[RickinTN]

A stainless pot of whatever size you prefer from the thrift store should work well. Some folks prefer cast iron but I've always used stainless.
Rick

[jsizemore]

Melting temp of lead is 629F. Raise your temp to about 700F. Keeping it less then 750F will keep the zinc bogey man at bay. SOWW leave a nasty mess from the stick on part. Multiple fluxing with sawdust and STIRRING and SCRAPING is necessary. I know your temp wasn't very high cuz you didn't comment on the blue, and purple and black colors on the surface. Pure Pb will do that. Your hill of silver shiny mess is lead mixed in with the dross cuz your temp was too low. Cast iron dutch oven will hold heat better then the stainless steel cookware pans but they are better then aluminum.

[RogerDat]

I followed a suggestion from another member to grind a flat end on a slotted spoon from the thrift store to use for scraping, stirring the flux in and cleaning the dross off. It works well that flat tip allows getting the bottom of the pot and into the edge around the bottom. I'm surprised your wood chips did not burn into a grey ash. I use sawdust but after that is done burning off there is nothing but grey ash, none is only partly burned.

Maybe someone that uses wood chips will offer their experience as a guide.

You don't say what your heat source is but when I used an electric hot plate it struggled to melt plain lead which is what SOWW's that are lead would be. Your plumbers lead if scrap pipe with joints or joint fills might have a little tin in it which would lower the melt temp. and produce a nicer melt. At 10% tin the melt temp drops by about 100 degrees. Seems to me even a couple of percent tin makes a difference. As in my hot plate can melt it without help from a propane torch. Reason I bought a propane fish fryer.

[MrWolf]

I also use a cut off propane tank for my smelting. Pretty easy to do and handles 150lbs easy.

[AggiePharmD]

Melting temp of lead is 629F. Raise your temp to about 700F. Keeping it less then 750F will keep the zinc bogey man at bay. SOWW leave a nasty mess from the stick on part. Multiple fluxing with sawdust and STIRRING and SCRAPING is necessary. I know your temp wasn't very high cuz you didn't comment on the blue, and purple and black colors on the surface. Pure Pb will do that. Your hill of silver shiny mess is lead mixed in with the dross cuz your temp was too low. Cast iron dutch oven will hold heat better then the stainless steel cookware pans but they are better then aluminum.

That all makes sense for sure. I'd say you nailed it. Thanks

[AggiePharmD]

I followed a suggestion from another member to grind a flat end on a slotted spoon from the thrift store to use for scraping, stirring the flux in and cleaning the dross off. It works well that flat tip allows getting the bottom of the pot and into the edge around the bottom. I'm surprised your wood chips did not burn into a grey ash. I use sawdust but after that is done burning off there is nothing but grey ash, none is only partly burned.

Maybe someone that uses wood chips will offer their experience as a guide.

You don't say what your heat source is but when I used an electric hot plate it struggled to melt plain lead which is what SOWW's that are lead would be. Your plumbers lead if scrap pipe with joints or joint fills might have a little tin in it which would lower the melt temp. and produce a nicer melt. At 10% tin the melt temp drops by about 100 degrees. Seems to me even a couple of percent tin makes a difference. As in my hot plate can melt it without help from a propane torch. Reason I bought a propane fish fryer.

I'll work on the spoon idea for sure. I suspect my chips would have burnt better had my temp been higher. I'm using a homemade setup for fish frying my dad had no use for with LPG. My flame isn't as blue as I'd like though so I need to get my temp up.

[Forgetful]

Large chips like that don't easily reduce to a powder, and with the powder comes the surface area that you want for fluxing. Sawdust is much better. People go to Home Depot with an empty bag and fill it for free, but I'd be cautious or avoid that because it is often contaminated with particle board glue, MDF, plywood.. Keep the glue out if you can. I just use crushed walnut shell from a giant bag I bought for my tumbler, from a pet store. I wait until the melt is quite hot before fluxing, you can tell it's hot enough because it'll start smoldering immediately after sprinkling it in. Then light it.

You'll have a layer of carbon, the more the merrier. Scoop the surface flotsam together, then pour ladles through this floating pile from a couple of inches above the melt. This is the fluxing action. Stirring doesn't do very much compared to pouring through.

Remelt your "dross". You should be able to get that pile down to almost nothing, unless you really do have zinc contamination. For $10, get a bottle of root kill from a plumbing department. Use a tablespoon of that blue powder as flux before fluxing. It turns white, then pour your melt through that. After a while of that, if you still have white chunks in your flotsam you won't need to use more blue powder. This stuff is copper sulfate, cupric sulphate pentahydrate, it has a bunch of names. IMO this stuff should be a required buy for casting! I will always extol it's use.. especially because you can intentionally contaminate lead with zinc and use this stuff to replace the zinc with COPPER, providing corrosion resistance and hardening your lead.

[RogerDat]

However I think copper sulfate will also remove Sn and/or Sb which you don't want to remove. Hear copper sulfate mentioned mostly for recovery of zinc contaminated lead rather than as normal part of fluxing. But do seem to recall some discussion of using it to feed in copper with the understanding that the removed alloys would have to be replaced. Now if one contaminated plain lead with zinc one might make lead & copper alloy for use in casting sith copper sulfate, if one had an alloy such as COWW's to start with I think the loss of good alloy to the copper sulfate would outweigh the gain from copper enough that it might not be worth doing on purpose.

There are also some threads regarding getting copper from melting tin and chopped fine strand copper wire together and adding to the lead. Would have to search the site on the specifics of that approach.

[Forgetful]

Sb is not depleted from CuSO4. The Sn reaction is much slower than with Zn, you won't be losing very much tin, 1% to 5% of available tin. I know the Zn reaction has ended because the oatmeal stops, and the extra CuSO4 floating stay white-blue.

[canyon-ghost]

The sticky stuff on the back of the weights turns into a messy syrup. I use parafin and light it to burn it down, sometimes it takes a lot. The stick-on weights are pretty messy. They are almost pure lead and soft. Spend a few bucks and get away from the aluminum pot.

Good Luck,
Ron

[D Crockett]

a trick a I learned is I take some gas and soak the soww in and the backing comes off then I melt them I used to have a guy that would complain to the cops when I melted soww because of the smoke so I started the gas trick end of problem D Crockett

[RogerDat]

So it is the tin that gets pulled out. Knew it was one of the desirable alloys, figured someone that had experimented with it would chime in if I brought it up.

[Forgetful]

So it is the tin that gets pulled out. Knew it was one of the desirable alloys, figured someone that had experimented with it would chime in if I brought it up.

not exactly. It would take a lot of effort to take 2% tin content down to 1.5%. You lose more tin by scooping dross. The reactivity is so low you can ignore it for all intents and purposes. Zinc has a relatively high reactivity, in comparison.