What did I do wrong adding Tin and Super Hard?

[GSSP]

In a 4-1/2 qt Dutch Oven over a propane single burner I brought a 15.3 lb piece of pure lead to 625 F. I fluxed with Marvelux and skimmed off the dross. I made sure it was 625 F and added my .2 lb of Tin, stirring for several minutes. Didn't seem to mix too well. I then brought it up to 725 F for the Super Hard and again, added Marvelux. With a thin layer of flux on the surface, I gently settled in the numerous pieces of Super Hard (1.5 lbs) so they would get coated with the flux. For several minutes I kept stirring, getting the temp up to about 750 F. Seemed to be a huge mess with irregular chunks on top. I'd been smelting CWW much of the day and was tired so I turned off the heat and walked away for the day.

What did I do wrong? How can I fix the current mess and what do I do differently next time? My goal, using the Lead Alloy Calc is a 11.4 BHN mix. I used a Lyman lead thermostat.

Alan

[ShooterAZ]

My recommendation would be to remelt the mix, and flux it with some clean dry sawdust. I will also add a little beeswax when doing this. My experience with Marvelux hasn't been all that great.

[lightman]

When I'm blending different alloys I put them all in the pot at the beginning and let them melt together. I never cared for Marvelux. If the lead is dirty I flux with pine sawdust followed by wax. If the lead is clean I just flux with wax. Beeswax, old candles, ect doesn't seem to make much difference. There have been some threads about Lyman thermometers being off a good bit. The one that I had disagreed with my PID by 40º so you may want to check it. Its nor perfect but you can start with some salted down ice for the low point of 32 and boiling water for the high point of 212.

I think your lead will be fine. When you get back to it just melt it all and flux it.

It seems like I'm beating up on your equipment and I apologize. I've just had bad results with Marvelux and my experience with Lyman thermometers mirrors some of the internet bashing that they have received.

[Toymaker]

When I make Lyman #2 (BHN 15) I work at 750°F and melt the Super Hard first. I stir well, use candle wax to flux but I don't skim any dross. Then I add my pure lead. When it is melted I stir well and add another dose of candle wax. Now I'll stir well and carefully skim the dross. Last I add my tin and stir until it is melted. Then I start making ingots FAST. Stir, stir, pour ingots. Stir, stir, pour more ingots. At a point I'll turn off the heat and finish making the last of my ingots.
Once I start I work fast. Once something melts I'm stirring madly and adding the next ingredient. I use a turkey fryer burner, 5 quart cast iron pot and a multi-meter with a temperature probe.
Since it seems you started running into an issue when you added your tin are you sure it was pure? No zinc?

[Grmps]

+1 on the pine sawdust AND wax of some kind

either one alone just isn't as efficient!

[243winxb]

More heat.

[shell70634]

My Lyman thermometer was off by 50. In the trash it went

[GSSP]

\
Since it seems you started running into an issue when you added your tin are you sure it was pure? No zinc?

$500 worth of pure Tin from Rotometals; 30 lbs.

[Walks]

I've learned the hard way (No pun intended) to melt the tin & hardener(antimony mix) first, then add the lead in prepared 1lb ingots. 10lbs at a time, stirring & fluxing until I reach the pots 60lb limit. The melt comes out smooth and extra clean, ready to be poured into ingot molds according to alloy.

Works for me.

[HangFireW8]

Heap on the sawdust, put the lid in, leave it at 700 for an hour, check, redo with fresh sawdust if necessary. The super hard will dissolve slowly in the oxygen free environment, not so much melt but dissolve. As one poster here put it, like a lozenge in your mouth, its not at the melting point of sugar.

I use Marvelux once during scrap lead "smelting" to help remove contaminates before making ingots, then never again. For clean alloying metal I do not bother with it.

[Mike W1]

According to what another fellow told me and it's worked for me. After getting the lead up to temperature you should have added the Superhard next and got that up before adding the tin. Otherwise you end up with what happened to you. I suspect heating things up and adding a reductant may straighten things out. If you want I can post a copy of what the gentleman told me.

[dragon813gt]

Why were you using Marvelux in a lead alloy? It will remove the tin that you were trying to alloy w/ the lead. Do yourself a favor and throw it away. It does nothing but leave a residue in the pot, suck up moisture and remove elements that you want in the alloy.

[ABJ]

Late to the party, but first thing is increase the heat. #2 buy a Lyman digital thermometer not the dial type. #3 flux with beeswax/oil mix and stir well, I use rendered animal fat and beeswax at 50/50 and it doesn't take much. Also use sawdust or pine bedding and stir well. As others have said old candles or a little dab of boolit lube also works. #4 Superhard being 30% Antimony requires higher than normal heat to mix well, but once it is mixed you can go back to your normal casting temps.
One more thing on fluxing, KEEP doing it until you get a dry blackish powder on top. Do not remove the oatmeal looking stuff with a silver coloring to it because that is your tin and antimony not yet mixed. It may take 3 or 4 fluxing's to clean up and don't be afraid to take to 800 degrees give or take. My experience is add a little flux and stir, stir, stir, add a little more and repeat. Adding a lot of flux at one time does not work as well for me.
Some soft/sheet lead will dross very heavy with chunky black dross, it is okay to remove that as long as no silver metals are mixed in. If so just keep stirring till it's gone.
Good luck,
Tony

[HangFireW8]

Forget oil, it only adds stink.

Fluxing helps alloy the metals and separate dross. That's something you do at the end of the run.

But you need something to prevent oxidation during the long and hot run while the Superhard dissolves. That's where sawdust comes in, pile it on top at the beginning and don't mix it in, put a lid on top to create an oxygen depleted environment on top of the melt. If the sawdust turns to charcoal leave it, if it turns to ash remove the ash and put more sawdust on and continue.

Once everything is dissolved you can remove the charcoal and ash and get on with the fluxing. Fluxing in the middle of the run might be fun but (as long as you keep sawdust on top) is a waste of time.

[garandsrus]

People seem to be making this harder than it is.

I have never used super hard but have used foundry type, which should be even harder. It doesn’t take long to melt/mix. 1.5 pounds of anything should melt pretty quickly when added to 15+ pounds of molten metal.

I have never heard of letting an alloy “cook” for an hour in an oxygen free environment. Melted is melted! The order of adding the material shouldn’t matter either. I think you just didn’t have the metal hot enough based on your faulty thermometer.

I have gotten an oatmeal like consistency on top of the melt with type metal. The consistency goes back to normal as it is fluxed and heated more.

Re-melt your pot, add sawdust and wax to flux after it is liquid and you should be all set. You are using known materials so there shouldn’t be any surprises.

Tin in a hot melt will literally disappear as you add it. When using a plumbing roll of tin solder, just putting the strand into the melt will make it disappear as fast as I plunge it in.

[HangFireW8]

I have never heard of letting an alloy “cook” for an hour in an oxygen free environment. Melted is melted!

Unless it doesn't melt. Which was the OP's problem. Then you have to wait for it to dissolve. Which is why I said dissolve and not melt.

[GSSP]

It's been a couple of weeks. New RCBS thermometer. The Lyman reads 108 deg less than the RCBS. Wow! I verified them both with the PID on the RCBS Pro-Melt 2.

Didn't have any sawdust; future purchase. I did have some wax. Cranked up the propane burner under the cast iron Dutch oven (same one I simply turned the heat off on) and got the melt really hot; like 800 F, dropped a hunk of wax in and dropped the lid on. Something was happening 'cause lot of flames and smoke "tried" to get out..without success. Just little bits here and there. After a few minutes, popped the lid, stired like a mad man for 5 minutes; still something on top. Figured, "oh well', time to buy the sawdust. Pushed the floaty stuff to the side and poured in several mold fulls of boolits to test on my LBT Harndness tester. Got the "junk" off the top and into another pan. Poured off the lead into pie shaped pan (Lodge corn bread muffin pan). Once the bullets cooled, I tested them and got 11.25 to 12 BHN; pretty much what I planned for. Took a look at the "junk" I skimmed off the top of the smelt. Seemed lighter than expected. Maybe it's not Antimony? I'll gladly test the bullets I cast each day to verify their BHN.

Alan

[garandsrus]

The wax Was burning, which is normal. You can also stir the mix with a stick which is similar to fluxing with sawdust. Sawdust is better though.

[GSSP]

Where does one get a cheap source of sawdust?

[dragon813gt]

Where does one get a cheap source of sawdust?

Make it yourself. Or go into Home Depot w/ a bag and sweep up around their cutting saws. They won’t care since you’re cleaning up for them.