Using “Magic Flame” to prevent firescale

by shelbyvision on March 10, 2009

This subject was brought up last week, and since I have nothing else to report, I decided to do a little pictorial about it. “Magic Flame Soldering Compound”, available from Rio Grande, is one of those products that appears to be too good to be true. It does claim be be a soldering flux, and I had no luck using it for that, but it is fabulous for preventing firescale when annealing or soldering. Over a long period of use, I have fine-tuned the procedure. The stuff is very expensive when using it for large scale pieces as I do, so I dilute it to the max, mixing it 50/50 with “Cabosil”, which is fumed silica, an inert filler/thickener used commercially in everything from varnish to makeup. It’s the thickener in Navel Jelly. I pre-mix it with water to a pudding-like consistency so it’s ready to mix with the Magic Flame. I mix these two ingredients with rubbing alcohol, which is less dangerous than denatured alcohol. I’ve tried using water instead, but it won’t coat the metal very well; the metal tends to resist it, leaving spots unprotected. This process works extremely well on brass, which is mostly what I work with, but I have also used it successfully on sterling silver, nickel silver, and copper. If I ever have enough money for gold, I’ll give it a try. 😉

The first pictures show the Magic Flame compound as it comes from the jar, the Cabosil, and the two mixed with alcohol, ready to use.
Magic FlameCabosilMixed
The next pictures show the mixture getting brushed on; it’s such a thin coating it doesn’t look like it would do anything. Then annealing. Then what it looks like after annealing.
Brushing it onAnnealingAnnealed
The next pictures show the piece being pickled to remove the coating, which takes about 10-15 minutes if the pickle is hot, much longer if cold. Then it’s ready for some more hammering.
PicklingDoneDone

{ 6 comments… read them below or add one }

shelbyvision August 1, 2009 at 9:24 pm

Hi Rikki,
You need to read more carefully. 😉 It says “I’ve tried using water instead, but it won’t coat the metal very well; the metal tends to resist it, leaving spots unprotected.” I’ve never measured the amount; I just put enough in to give it the right consistency for brushing it on and getting a thin coating. It will take a little experience to learn how much is just right, but the proportions are not critical.

Rikki Mitman August 1, 2009 at 8:16 pm

‘scuse me, still kind of new to metal — what’s the purpose of adding alcohol to the mix? And how much alcohol in proportion to the 50/50 mix of the first two ingredients?

Thanks very much!

shelbyvision March 12, 2009 at 11:39 am

It works great, for preventing firescale while soldering. I coat the piece with the same dilute solution, dry it out with the torch, and then apply liquid soldering flux to the joint to be soldered. I use the “self pickling” type flux that’s a bright yellow-green liquid, dispensed from a needle type dispenser bottle.

jason March 12, 2009 at 10:03 am

Just yanking your chain.

I assume you use Magic Flame for soldering too, does it work well? Do you use the same diluted formula?

shelbyvision March 11, 2009 at 8:01 am

Thanks Jason. I always misspell that word; it should be “naval”.

jason March 10, 2009 at 10:58 pm

I don’t know about you, but the thickener in my navel jelly is lint from the inside of my t-shirt.

That’s brilliant work by the way. I’ll definitely have to try it next time I do anything with brass. It doesn’t cost much more than Handy Flux, and is a downright bargain since Handy Flux sucks as a firecoat for brass in my hands.

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