First Linotype Melt Lots of Dross

[rhouser]

I melted down about 35 lbs of Linotype this afternoon and cast it into ingots. I am new to all of this so I have to ask about my melt.

I seem to have ended up with about 5 lbs of dross. Some was spacers that wouldn't melt, but, most was a foamy (?) layer that my skimming ladle picked up easily. When I dropped the on my "trash" board it had alot of structure(kept its height) The dross is Very Hard and the tails are Very Sharp (needle like). I had to use gloves to handle it.

Is this normal? Was I melting at the wrong temprature. I fluxed the melt 3 times trying to get this layer of dross to remix. I finally skimmed it off and cast the shiney metal without incident.

Is a large amount of lumpy or foamy dross normal for a melt of Linotype? From the hardness scratch test I did on an ingot, it might have been monotype. Is there a way to tell linotype from monotype? It took a 3H pencil to "cut a curl" in the ingot.

Thanks in advance for any help
rc

[white eagle]

I have had the same
did it also smell musty,moldy
I am not sure what that would be but I have had the same issues
with lino
after yo use it from ingot form you won't get it
and if you do it will be minor

[midnight]

I smelted a 125 lb batch today in a 12 in cast iron dutch oven and had about a one inch thick layer floating on top just as you describe. I sprinkled a very liberal amount of sawdust on it and kept stirring it in. After about 4 or 5 minutes all that was left floating on top was about a 1/2 in thick layer of fine black dust which was skimmed off. After ladeling half the batch into muffin tins I fluxed it again. Sawdust seems to do a fine job of fluxing, especially when melting large batches.

Bob

[onondaga]

That is not normal for Linotype, your heat may have been much too low for fluxing .
If you saved what you skimmed off, it will likely go back in at a higher temperature mix and fluxing. Dross is a fine powdery lightweight substance with oxides of lead, tin. What you skimmed off was heavy good metal that wasn't hot enough to be fluid or hot enough to be fluxed.

A simple temperature test is dip a paint stir stick in your melt for 10 seconds, pull it out and it should be blackened, smoking and visibly smoldering.

Gary

[rhouser]

onodaga, I saved the Dross in two zip lock bags. How hot do you think the melt needs to be?
I used gulf wax for my flux. Maybe I needed something with more carbon potential. Might try sawdust like midnight. I hate to go too high on the heat cause I end up with the "Rainbow Dross" from overheating my lead. When/If that happens, I shut down my heat, let the pot go solid than start again to a lower temp.
Learning where the temp is right is part of the curve I guess. Hot enough for the tin and antimony, but, not so hot the lead breaks into the rainbow colors.

thanks to all rc

[lwknight]

What is floating is not really dross. Its partly dross with a lot of goody stuff wrapped around it.
The easies temperature test is when a bit of wax auto ignites you are just as hot as you ever want it to be and plenty hot for whatever.

The linotype has a LOT of oxidation because of the great amount of surface area.
It will all go back into sweet beautiful shiny alloy if you will drop in a pecan sized chunk of wax/tallow or whatever waxy hydrocarbon compound and stir the living heck out of it while it smokes and auto ignites and scares the wits out of you.

You have to smash and dunk it and eventually only a little carbon dust will be left.

[Lee W]

I melted some very old linotype still in letter form. The melt looked like a 100 pound bowl of shiny oatmeal. A couple of tablespoons of plumbers flux and a lot of smoke left me with nice looking metal and a few spoons of dirt.

[Armorer]

+1 on stirring with a wooden stick. That seems to me to be the simplest way to actually get my fluxing agent under the surface of the melt. Any kind of wood works in my estimation. Right now I have been using a length of ¼" dowel and it works great.

My ¢2
Armorer

[onondaga]

The answer from lwknight is good. The melt has to be hot enough to burst a wax flux into flames. . Stirring during the flame-up and using a big spoon to rub the clumpy stuff against the side of your pot and push it down will usually get it back into alloy.

The rainbow oxides left after getting the lumpy stuff back into alloy is a GOOD sign that your pot was hot enough. Then turn it down , flux again and pour ingots. The rainbows usually form about 800 degrees. You only need about 750 to flux real well and 600-650 for casting.

Gary

[rhouser]

My melt flamed the wax within two turns with my spoon. I used pieces about 1/2 x 1/2. I am new to this whole game, so maybe I didn't stir enough, maybe I didn't add enough wax. The last wood stir stick I tried was a paint stir stick from home depot. It carboned but held it's own till the wax flamed then the entire length of the stick was on fire up to my glove and broke into burning char fragments into the pot.

I think I have may have enough heat according to the above, so maybe I just need more wax and much harder stiring.

Thanks and I am going back to the casting pot now. Great afternoon to all.

rc (new guy, Bad Fluxer, AND Bad Caster, but, learning)

[madsenshooter]

Tossing in a little citric acid helps to get the oxides back into the pot too. Smokes, will burn if you put a flame too it, but sorta smells like a bakery. I imagine there's a considerable amount of antimony in your dross, good thing you saved it. The oxide portion of a metal oxide wants one of two things, carbon, or hydrogen. Citric acid has 3 hydrogen protons it can donate to those oxides. I get the pure stuff from a farm supply, not the stuff used for canning as it contains silicon dioxide that can make occlusions in your bullets. The stuff is used on the farm to alter the pH of water and increase the bioavailability of antibiotics therein. More info than you wanted? I get the citric acid from here: http://www.qcsupply.com/540923-citric-acid-410-gm.html

[454PB]

If the metal is relatively clean to start with, you don't even have to flux it.

The trick is getting it hot enough, and stirring.

I made up several hundred pounds of ingots from letter monotype, and didn't flux it at all.

If it is lumpy or has that "oatmeal" appearance, it's simply not hot enough, and no amount of fluxing will fix it.

[9.3X62AL]

Heat is your friend and ally when blending type metals. I do a lot of this, mixing foundry type, monotype, and linotype with unalloyed lead to form my favorite alloy--92/6/2. The sawdust I get from Pat Marlin is another fine co-combatant in this contest, and does fine work as a flux.

Ken--this thread and its content needs consideration as a sticky in this sub-section. I stumbled over this same issue as a newer caster, and the info herein would greatly benefit many folks new to the hobby.