Sand used as a flux?

[kogatana]

Have you ever tried a forge welding using sand as a flux? I'm just reading in the book "forging" from J. Jernberg that this is possible, and that borax is a substitute for flux.

Interesting anyway. What act as a flux in the sand, is it silica?

Ludo

PS: I read further, and you might be interested to know that borax can be heated red hot (I believe you put it in a pan on a stove) and left to cool. It become vitrous and have almost all of its water gone. In the form of powder, that "dry" borax won't boil when heated in the forge and will remain more easily on the pieces to weld.

[Woody]

Lodo sand can be used as a flux, as can many things, Boric Acid for instance. In Richardson's Practical Blacksmithing the list several recipes for flux that contain sand.

As for dehydrating borax, heat it in the oven at 200 degrees F. the only drawback is that once it is dehydrated if you don't store it in an air tight container, it immediately starts absorbing moisture out of the air again.

Woody

[Ian]

Kogotana,
In England, and several other countries in Europe, silica sand was THE primary flux used for forge welding. In fact a lot of the old Smiths in England didn't actually use a flux at all, and if you can get the right kind of non oxidising fire you can do it without, but flux does make the task easier Old casting sand is quite good and you can usually get it free from the Foundry (they just chuck it away most times) The main difference between sand and borax is the temperatures at which they melt and become liquid and the temperatures that they help you forge weld at. Sand works at a higher temperature than borax.

[easilyconfused]

So does sand work with modern mild steels then or only at the higher temps for welding wrought iron?

[bruce wilcock]

providing the sand melts at a lower temp than the steel ,sand is the stone its made from ,so soap stone sand wont work , as to welding without flux in the uk i dont use flux at all and i do a good bit of welding ,i think the coal and coke we use has a lot to do with the welding fire ,if the coal has a clay mesure along with it the clinkers will have a glassy look and the clinker is a flux ,constant fire cleaning is not a help towards welding with this type of coal providing the air can get through ,the chain makers worked all morning and the fires were cleared at midday ,if using sand crush some scale up in your hand then take some sand along with it and throw it on the fire as you come towards a heat ,for the next weld push the job into the clinker and it will coat it with melted sand and of again,thats the way the chain makers worked

[primtechsmith]

Saw someone try it once...didn't work at all.

Peyton

[ThomasPowers]

What are you trying to accomplish? For someone starting out borax will work a whole lot better than sand and a box of it will be one of the cheapest items in the forge.

For someone doing very traditional work clean quartz sand and real wrought iron might be just the ticket.

If you are trying to go neo-tribal, charcoal ash will work as a flux; shoot one of the FoxFire books mentioned using dirt dauber nests as a flux! (Rice straw ash is used as a flux in japanese swordmaking)

Thomas

[kogatana]

Thank you all.

Thomas,

I'm just trying to first understand what's flux and how to use it. That's the textbook and IForgeIron part. Next is to put into practice the information gathered which will be another story.
I plan to forge weld to make a small knife or woodworking tool.

Ludo

[ThomasPowers]

Flux works to liquify the scale coating on the piece to prevent access by oxygen to the piece and to lower the melting point of the surface of the piece a tiny bit.

High alloy scale is harder to liquify/dissolve and so more aggressive fluxes are suggested.

Old WI with it's high silica content was almost self fluxing and with it's much higher temperature tolerance the liquify the scale can be done mostly by heat.

May I suggest you start with the *easiest* methods and go to the more esoteric ones once you find welding easy.

[blkbear]

What about mixing metal filings with Borax. Would it make a "better" flux? Or just make more work by gathering metal filings for no real appreciable gain?

Brian

[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?

[a fellow blacksmith]

i use borax and never had aplroblen with it

[Dan W]

I just joined and noticed this thread. The 'sand' if used should be mud daubers nest, taken whole, crushed and sprinkled onto the pieces to be forged. When the mud or dirt dauber builds its nest, it uses only the purest silica it can find. I have seen this used by a smith in Alabama about two years ago and the weld is still holding.

[Conan_568]

I bought 5 lbs. of anhydras borax on ebay for $10.
It's way better then that 20 mule team stuff.
I keep it in a sealed jar until I'm ready to use it.
Add nothing to it, just use straight borax.
Borax is all I ever use and I never make a bad weld.

[Pault17]

reading through all this is both thought provoking and amazing. REgarding the use of mud-dauber nests, when I was working in the smithy at the state fair, I noticed a coffee can full of the things. when I asked what they were for, they said welding but that nobody had ever tried.

[Mr Smith]

I've seen sand used. It works.

The idea being that small amounts are used as and where needed to stop the sparking.

As for cost - it's lying around all over.