Sand used as a flux?

[ThomasPowers]

A better flux for WHAT? It makes a worse flux for doing pattern welded billets; but some people find it's easier to weld with for general drop the tongs welding.

It can leave pimples as well requiring cleanup afterwards.

[julian]

I use 20 mule team borax with a coke forge, it works just fine. Sand seems kinda dodgy to me, considering the dirt that might be in it, and how you would fine sand pure enough to weld with. Anyhydrous ( I think it's called) borax that is cooked to get the water out of it just makes it melt on contact with hot steel; usually it jumps around a bit.

[Dan P.]

There is a very eminent smith here in the UK who only uses silver (quartz? silica?) sand as flux. He takes the merest pinch and casts it atop his fire while heating the work to be welded. Watching him do this led me to the conclusion that, while he referred to this action as fluxing his work, he was in fact either fluxing his fire, or, more likely, simply performing a confidence enhancing ritual with no real effect.
As noted before, for the majority of welding flux is not really necessary, and in some cases can even be a hindrance. With correct fire management, even high carbon steel can be welded without flux.

[mark stephen]

Sand as flux works if the material your working with has a very high working temps. like the old bloomery and puddled irons.For todays mild and tool steels it will just cause more problems.Use borax.

[gerald]

Bob Patrick told me that Flint Silica made a passable flux and was a little easier to clean up behind than borax. I bought a sack at a pottery supply place (@ $9 (US) for 50 #). The idea (I think) is to pitch it in the fire since it won't melt and run into the weld like borax does. I haven't been able to make it work, though, admittedly, I only tried it a few times. As Thomas Powers said earlier, borax is the thing unless you just want to try some of the other stuff.

BTW, if you decide to try some, get the coarsest grind you can find as large amounts of it floating around the shop can be unsafe to brethe.

[kbaknife]

Considering what Silica is, you can pulverize clear glass and use it for a flux. That way you don't need to be concerned about dirt and impurities.
Don't add metal filings??!!
That would just burn up, oxidize, and add to the problem you're trying to avoid - scale!

[ThomasPowers]

Some people add filing *to* consume excess O2 so what scales up is the goop that gets splashed out during a weld instead of the surface of the metal.

I once lined my gas forge with chunks of industrial coke I found along the RR, it worked great as an O2 consumer and I was able to heat treat a blade with almost no surface change.

Ground Glass is mentioned as a flux in the old smithing books.

[Phil Patrick]

This thread kinda got me thinking. At what point in the history of blacksmithing, that some clever smith in some time in some country got the notion to use something to protect the materials he was trying to weld. That is a pretty HUGE advance of technology if you think about it!!! Even if it was sand or rice straw ash like Thomas said, or whatever,, that is an amazing piece of advancement.

Think for a moment, making implement for farming got easier, or tools, or hinges for doors for houses. Or weapons. Or,, the ability to make even larger items of iron might have become easier, or more important, more consistant and predictable. Anvils, even!! Then all these factors gave us as a race that little more of an edge to push forward. All over something as simple as flux.

See,, proof again that blacksmiths are the coolest people.

[Dodge]

Like most advances in technology, it may have happened by accident. Perhaps some substance spilled on the iron as the smith removed it from the fire. It welded better so he started to experiment with different substances till he found a flux that got good results on a predictable basis. I don't believe, before that, he had any idea that oxygen was preventing him from a successful weld. Probably was cussing evil spirits before the "accident"

[ThomasPowers]

I would *guess* it came in with the use of coal in the high middle ages. The cruder the wrought iron the more "natural flux" it contains and charcoal ash is a flux for wrought iron as well; so as your iron gets better and you switch to a "non-fluxing" fuel a bit more flux might help.

As for accidental; how about dropping the piece on a sandy smithy floor and finding out after reheating that it worked better?