Marvelux?

[Martin Luber]

Anyone use is as flux for casting? I had, years ago, but it was hydroscopic which lead to spattering when my tools were immersed. It didn't seem to dissolve well, from memory.

I hadn't used it since, finding parrafin and sawdust work well. However someone gave me more...

Thoughts? Thanks

[fatelk]

I know some people like it, but my experience was the same as yours. I bought a can back in the '90s, hated it, and ended up throwing it away.

I remember it seemed to attract moisture, and anything it touched spattered and rusted. My first lead pot back then eventually rusted out because of it. There must be a certain way to use it that works, because they still make the stuff and some people like it, but I wouldn't touch it if you gave it to me.

[Gtek]

Hard ring around pot and spoon handles, had to chip it off almost like brazing flux. Non for me, thank you.

[jdfoxinc]

It is made from borax which is used as you guessed it brazing flux. Instead of causing a reduction reaction returning lead oxide to lead it sequesters the lead oxide in a borax glass.

[44Blam]

I like sawdust...

[Winger Ed.]

I got a jar of it years ago when I didn't know any better.

I still use it because I can't bring myself to throw it away.
Its messy, probably doesn't work any better than other things, and won't buy any more.

[Murphy]

RUN!

Long story. I was already aware of the crud build up and having to pre-heat my ladle and stirring spoon before sticking it into molten lead. I'll just say it was the 2nd worse visit from the Tinsel Fairy I've ever dealt with, but I got in a hurry. None the less, it didn't work anywhere near as well as many touted it to. Needless to say, I tossed over half a jar of it out following the Tinsel Fairy incident.

Murphy

[44Blam]

I used it a little long ago and I remember getting crud on the walls of my pot. But I didn't use it for long. I am 99% sure that I stopped using before my current pot. I generally use wood shavings / saw dust because it is really easy to get. You can make it from pine off cuts from 2x4s and a grater planer in a hurry.
In my current pot, I have NO crud - it all goes into the melt with the flux.

[abunaitoo]

I have a can someplace.
Tried it once, and never used it again.
Sawdust is all I use.

[Martin Luber]

That's what I thought...thanks

[Dusty Bannister]

Bill Ferguson, the Antimony man always suggested that those types of flux be kept dry and applied with a salt shaker to avoid over application which would result in those puddles of glass like material. While I have some, I seldom use it because I use the 20 Mule Team borax instead. But some will recommend that it be used when blending antimony into lead, if used sparingly. Probably as sparingly as the application of synthetic two stroke oil to molds for a mold lube. One of these days, I will give it a try and see for myself how well it works for that application.

[Three44s]

I do not favor the stuff one bit.

There is another use that some like though. In high temp casting there are folks that create a layer of the Boron (Marvelux) after the melt is clean and do not add anymore lead alloy until the pot runs dry. You would have to do this with a bottom pour because ladling through the liquid Boron layer would defeat the purpose (that of keeping air away from the top of the molten lead pool) and thus allow oxides to form anyway.

The trouble is a bottom pour lead furnace is the most difficult to clean and that is where one would be using the Boron with.

Three44s

[mdi]

I too tried it years ago with similar results, tossed it. I am beginning to learn to throw some things away. For most of my life I subscribed to the "I might need that or find a use for that one day" type thinking. My shop looks like that now but I am learning to think "I've had this laying around and haven't used it for a very long time, don't know it I will ever use it, so adios"...

[Shuz]

I have been using Marvelux for many years. I find it does an excellent job. To minimize the hydroscopic nature, I completely wipe down my thermometer with an old leather glove and often leave my stirring spoon in the pot as it solidifies.

I remain an approved recipient for all the unwanted and unloved Marvelux out there. Contact me for shipping instructions.

[KCSO]

Plain old sawdust works just as good and costs less.

[45-70 Chevroner]

I have been using Marvelux for many years. I find it does an excellent job. To minimize the hydroscopic nature, I completely wipe down my thermometer with an old leather glove and often leave my stirring spoon in the pot as it solidifies.

I remain an approved recipient for all the unwanted and unloved Marvelux out there. Contact me for shipping instructions.

Ditto! I have a container that I've been using for a very many years. It only takes a pinch with three fingers and it has worked very well. That crud on your stirring spoon tells you that it is working like it should. As for rusting out a pot I can guarantee it's not the Marvelux. All of you that don't like it as Shuz said just send it to me.

[Maven]

"I have been using Marvelux for many years. I find it does an excellent job. To minimize the hydroscopic nature, I completely wipe down my thermometer with an old leather glove and often leave my stirring spoon in the pot as it solidifies. I remain an approved recipient for all the unwanted and unloved Marvelux out there. Contact me for shipping instructions." ...Shuz

What Ray said! Btw, I prefer sawdust for smelting, but for indoor casting it's Marvelux.

[mdi]

I guess I used too much. But now I just use free stuff...

[georgerkahn]

My very first "flux", in the early 1970s, was in fact Marvelux. I knew no better, and it seemed to work -- my then casting only alloy for .38 S&W Special mid-range wadcutters. Through the years -- THANKS MAINLY to smarter than me persons on this site and similar -- I now use a combination of soft-wood sawdust and the red wax which coats Gouda and similar cheeses as my fluxing agents in my Mould-Master and Pro-Melt bullet casting pots. HOWEVER, when I fill my (thank you Davy Crockett!) Freon tank with coww's, mystery lead, some RotoMetal Superhard, scrap plumber's lead, lead pipe, solder, and God-knows-what alloy -- I almost ALWAYS flux with Marvelux. Glenn Fryxall wrote (if I remember correctly) that one of the "baddies" re Marvelux is it eats tin; so, it is when I melt the ingots in my casting pots that I add pure tin (from Roto Metals) to my mix. 99% (give or take a few ) of the time, my casting pot looks like a mirror, with maybe just a few black specks atop. I've tried/using the "trick" of a layer of sawdust atop, but truly see no difference with or without it. When casting drops level about 1/3rd, in addition to more ingots and sprues, I add about a tablespoon of sawdust and a marble-sized piece of the red cheese coating.
Just me -- what I do. I find no negative effects from using the Marvelus in my outdoor, propane fired, "first melt".
geo

[Elkins45]

I still have a jar I bought 30 years ago. I might use it again if I decide I absolutely must cast some bullets on an extremely cold day where I can’t open the door. To me its only good quality is that it doesn’t smoke. Normally I run a fan behind the bench and just blow the fumes out the open garage door. I vastly prefer rosin as a flux. Or shortening. Or even the remnants of old bullet lube experiments.