Has anyone made their own flux?

A friend of mine who is a Blacksmith in England (Darenth Valley Forge) never buys commercial flux, he makes his own.

For basic welds he uses 45% Anhydrous borax, 45% pure silica sand and 10% iron filings. Works like a charm.

Anyone else use their own "brand" instead of someone else's?

There have already been plenty of posts about it, Mainly in the knife sections for pattern welding. What to use is partly dependent on what you are welding. For pattern welded blades I dont want the iron filings as they will spoil the looks at the weld lines, Silica sand hand been used with good results for centuries.

I use 90% borax and 10% boric acid. But for higher alloys I would add other things, like Florine compounds that I wont list here. Not for privacy or secrecy, but they are very aggressive and toxic, and I don't want beginners to poison themselves playing with it.

I use a 4:1 ratio of borax and boric acid.

Frosty

I use 100% Anhydrous borax
Buy it by the 50# bag but sell most of it
It is not the 20 mule team from the store stuff

I do pretty "ordinary" welds, no pattern stuff for blades, and find that borax, sand and iron filings work really well. Borax by itself actually does for most of my jobs.

Plain old 20 mule borax and boric acid about ten to one.
Finnr

Where exactly does one get Boric acid?

Where exactly does one get Boric acid?

try "Roach Proof" from the harware store... comes in a quart can that looks like and old oil can ...its yellow with black writing

have to be carefull some od the roach bate has sugar in it. I use 20 team borax. Have used boric acid with iron powder it works well.

Roach Proof is 98% boric acid, the remaining 2% is inert and as yet I fail to see any problems using it. Just that it makes visitors wonder seeing such a large supply of roach powder in my shop :D

You can also get boric acid in the pharmacy. RoachPruf is cheaper but the pharmacy product is purer.

Either way the stuff isn't expensive, especially compared to buying flux.

Frosty

Edited January 28, 200917 yr by Frosty

you could always put duck tape around the container

The differences between 20 mule team and anhyrous is when you put 20 mule team on it boils up and if you turn the piece over to put borax on the other side it falls off. The reason is even though the 20 mule team is powder dry it had chemical water in it that doesnt like the heat. When put on the hot stel it boils off the water.

The bad thing about borax is in humid weather a few days to months later there will be a white stain on the iron unless you soak in acid or something as when etching damascus.

Tal Harris recently told me to soak the piece in the slack tub overnight and it will wash off and not be a problem. Havent tried it yet as I am a watcher not a doer.

The easiest way to dehydrate Borax is to find an old casserole dish (I got one from a Yard sale for a buck) and put it in the oven at 250 for about an hour.
After that it won't "dance" on the metal anymore.

I'm going to have to take the other side of the coin in this discussion and say that the commercial fluxes work perfectly well for me - so to jeopardize a forge weld on a $3000 gate or $1500 knife with homemade concoctions seems like poor economics unless you are absolutely sure it will work 100% of the time. That doesn't mean you can't make your own flux and it will be fine (it can be as simple as straight borax, which I have in the shop) but spending time and resources on reinventing a relatively inexpensive part of the equation is not something I relish.

It's similar to making your own rivets - you should practice the process until fully competent to do it on demand, then immediately go out and buy a large variety of commercial rivets; life is too short to worry about making them for a project. I carry about 25 sizes of rivets in stock and find I only use about 5 or 6 of those very consistently, but I don't have to think about it when the need arises because I know that 99% of the jobs that come through the shop will be able to use one of them.

You can get boric acid, technical grade or heat treating prodcucts from Rose Mill Co.

Nice bunch of guys there.

I use Anti Borax EZ weld and 20 Mule team. And fine sand. ( If you bake 20 mule team for a while it'll become anhydrous borax)

I'm willing to try anything, that's why I catch my steel filings and drilling, just to add to my flux if I think I need it.

I have never used anything other than 20 Mule Team Borax. However, pure Boric Acid can be acquired from pharmacies that sell the Boric Acid powder for women to put into capsules that they then use to treat vaginal infections. These pharmacies tend to cater to people, and not be part of discount pharmacy chains.

Mixing in some Boric Acid seems like something worth trying, but be careful and use lots of ventilation, after all, they use it to kill cockroaches.

You get Boric Acid in the drug store just ask for it. I use plain old 20 mule team boarax. It does everything I need and it becomes "anyhdrous" pretty fast when it hits red hot metal. You can bake 20 mule team into anhydrous borax in the over but the problem is it starts absorbing moisture out of the air as soon as it comes out of the oven.

Oh and by the way boric acid powder in the drug store is much less expensive than Roach Powder.