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