Marvelux flux: Mea Culpa!

[Maven]

When I first began casting [indoors], I used candle stubs for flux and was very happy with how clean it left my alloy, but needless to say, neither I nor my wife was pleased with residual smoke. After reading about Marvelux, I bought some and faithfully used it (for more than 20 years!)...until the other day. As I had a candle on my work bench and had my Lee 10 lb. pot ready to go, I figured I'd try it again, but with a floor fan aimed so that whatever smoke remained after igniting the wax would be blown out the open window and door. It worked perfectly and my 100% Pb was clean, with no black, soupy residue (was casting RB's for my BP revolver).

Btw, I have always saved the skimmed Marvelux residue and smelted it outdoors a few weeks ago using candle wax as a flux. Suffice it to say, I reclaimed 1 lb. of alloy and only had dust, not black soup to dispose of. Candle wax, and better, saw dust (when I can get it) are going to be the fluxes of choice from now on.

 

[fiver]

it has the habit of sucking moisture out of the air.
so if you have any residual borax on anything metal or anything going under the surface of the alloy you will have moisture present.

it has it's uses though.
I have used it as a flux to alloy antimony in, and to pull gunk like nickel out of an alloy.

 

[Winelover]

I too used it for years, works, but leaves a build up on the sides and metering rod of bottom pour pots that is hard to remove.

 

[Brad]

I too used it long ago. I don't miss the goo and the trapped moisture. Learned to set the stir spoon on the melt to fully dry before stirring. It worked to get rid of dirt but seemed to cause almost as much trouble itself.
I now use shaved wood pet bedding and am very pleased with it.

 

[Rick]

I used Marvacrap long ago also, will now not allow it in my shop much less in my lead pots. Somewhat better using it with pure Pb but with an alloy it will remove all the stuff you don't want removed such as your expensive tin. Then there is the hydroscopic issue and even worse is how gunked up it leaves your pot and tools. Never again for me.

 

[KHornet]

Still have a can of the stuff, from probably 35-40 years ago.
Tried it ONCE!

Paul

 

[Ian]

On a happier note, Marvacrap makes EXCELLENT brazing flux......so not all is lost if you are unfortunate enough to be stuck with a container of the stuff.

 

[300BLK]

I started using it in the early '80s, but didn't appreciate how rusty my 10# lee would get. I found part of a tub of the stuff in my garage some time ago and tossed it in the trash.

 

[RicinYakima]

It liberates HCl the gas that mixed with water makes hydrochoric acid. Here in the desert it mixes with whatever moisture is in the air and rusts everything it touches. Great flux, used conservatively