borax

[Luke]

ive read i can use borax and a little water,make a paste to use for soldering,will this work or did i read wrong. thanks

[mark esterly]

i doubt it will work with low temp solder.  silver solder and brazing is another story.  borax melting point is around 1700 degrees

[docone]

For high temp soldering/brazing, mix it with Boric Acid, and wet it to a paste. I also like to mix it with Denatured Alcohol.
The main advantage to this, is, it acts as firescale preventer beyond the solder joint. Another trick I use, mix it with powdered charcoal. I pulverize a briquette and mix the powder with the Borax, and Boric Acid. Makes for simple pickling and clean up.
When I use Denatured Alcohol in the mix, I light it, then begin soldering.

[SROG]

So, you are telling me that this is used as a heat shield (when mixed wet ).  Heat stop paste ?

Thanks

[heinz]

Luke, if you are0looking for an old time tinning flux use ammonium chloride, also called Sal ammoniac.  It is corrosive

[docone]

Not an heat shield, an anti firescale agent.
It keeps the O2 from entering the joint and surrounding areas. At least as much as possible.
The Borax then can be removed with Pickle.

[David R. Pennington]

Borax makes an excellent flux for forge welding and I suppose it would work as well for brazing and silver soldering where the temperature is higher but I havn't tried it. I agree it probably wouldn't work for low temp solder. The most important thing to remember is that the metal needs to be shiny bright clean BEFORE applying the flux. The flux does not clean the metal, only provides a layer of protection to prevent oxidation of the metal while it is being heated.

[davec2]

Borax, mixed with potash and table salt (2 parts to 2 parts to 1/2 part) makes an excellent silver solder / brazing flux.  Can be used wet or dry.  Borax fluxes are too high a melting temp for any soft solder application.  Boric acid in either denatured ethanol or even rubbing alcohol is used to prevent or reduce fire scale in high temp soldering.  The boric acid does not dissolve in the alcohol.  Just shake it up to get the boric acid powder suspended in the alcohol and paint it on the surface to be heated with a small brush.  Fire the alcohol and when it burns off it will leave a film of boric acid powder on the work piece.  The actual solder flux can be applied before or after the boric acid.  heat the part and run the solder in the joint.  Pickle in diluted hydrochloric acid to remove the flux, boric acid, and any residual fire scale.

Borax, potash, and salt are used for smelting operations when refining gold, silver, etc.  They help float all the impurities of the melt to the top of the crucible and allow all the metal to congeal into a "button" at the bottom.

[kutter]

I use the powdered Boric Acid to keep fire scale from forming on small tools when I harden them.
I use it mostly making small engraving background texture punches & stamps, but also handy when making small parts.

Mix enough alcohol (I use cheap rubbing alcohol) with the boric acid to form a thick paste.

Coat the tool with the paste. The alcohol will start to quickly evaporate and leave a hard coating or shell around the part. Recoat to build it up to make sure it's completely sealed up.

Light the coating to burn off the remainder of the alcohol in the coating and you'll be left with a hard but brittle shell of boric acid. That will protect the tool (punch, blade, graver, ect) from heat scale when hardening.

Handle carefully so as not to break it off while heating (brittle),,it will heat up as the same color as the steel inside of it.

When you quench (oil or water) the boric acid shell will shatter and completely break free of the part leaving it clean and bright,,ready for annealing.
Easy to see the heat annealing colors on the clean steel.

Wear eye protection of course.

You can get boric acid cheap at home improvement stores in the garden section. Sold as insect killer for roaches. Small and large containers,usually plastic with a nozzle top.
Also sold as rug treatment for fleas.
Check the lables,,they are usually 98% boric acid.

[smylee grouch]

Is this boric acid past safe to handle barehanded or should we be using rubber or vinal gloves?    Smylee

[kutter]

Is this boric acid past safe to handle barehanded or should we be using rubber or vinal gloves?    Smylee

It can be handled safely with out gloves. It won't burn your skin. I wouldn't get it into a cut or open wound though.  Don't ingest it. It can be poisonous in heavy doses.

It's used as an medical antiseptic in mild solutions, even an eye wash.,,among a hundred other uses.

[wilkie]

I believe you are talking 20 mule team borax, the laundry additive and household cleaner.  I have used this as a brazing flux for years.  It also is great for getting rid of ants and roaches.  You can find it at walmart and other stores. 

[anvil]

Willie, I too have used borax for years, but just recently started adding boric acid to the borax, and it takes it to a whole nother. Level. Give it a try. Its cheap and found it our local pharmacy. It seems to lower the forge welding temp, keeps the iron cleaner and gets rid of those pesky cold shuts that seem to plague one side or the other of the weld. I started with 1/3 boric acid to 2/3 borax by volume, and have worked it down to around 10% boric acid.

[docone]

Boric acid is the Roach Killer.
Mix it 25% to 75%.
Works real well.
I mix that with alcohol to make fire scale preventer.

[wilkie]

Thanks guys for the info about adding boric acid to borax, I'll try that soon. My Grandfather was a blacksmith in the 1920's and I believe he used borax when forge welding.

[der mike]

and to think I have been paying big bucks all these years for silver solder flux.........you guys are great

[Dphariss]

Borax works perfect for brazing flux right from the box, brazing steel, in a forge or whatever. Never used anything else. Weld flaws in brass castings with this, some brass and a acetylene torch, if careful enough.

Dan

[Bible Totin Gun Slinger]

I believe you are talking 20 mule team borax, the laundry additive and household cleaner.  I have used this as a brazing flux for years.  It also is great for getting rid of ants and roaches.  You can find it at walmart and other stores. 

Wilkie, can you elaborate on the ant/roach thing?   I got ants, the Grand kids bring em.
I'm good on flux.

[JBlk]

When I was a child mom always used water and boric acid as an eye wash.

[AZshooter]

I believe you are talking 20 mule team borax, the laundry additive and household cleaner.  I have used this as a brazing flux for years.  It also is great for getting rid of ants and roaches.  You can find it at walmart and other stores. 

Wilkie, can you elaborate on the ant/roach thing?   I got ants, the Grand kids bring em.
I'm good on flux.

Just sprinkle the borax into the cuffs of their britches to deter the ants - put some in their shoes, too to prevent adolescent stinky-foot.  If they bring ants in jars, don't worry, since once away from the nest, they will die off in a few days and can't reproduce on their own.

[FL-Flintlock]

I believe you are talking 20 mule team borax, the laundry additive and household cleaner.  I have used this as a brazing flux for years.  It also is great for getting rid of ants and roaches.  You can find it at walmart and other stores. 

Wilkie, can you elaborate on the ant/roach thing?   I got ants, the Grand kids bring em.
I'm good on flux.

Email sent RE: bugs

[red owl]

For all you experts....Is borax (the laundry soap) the same borax you would use as a flux?  Is Boric Acid (Roach Killer) have borax in it or is it a different chemical? I read Wayne Goddard's $50 Knife Shop and he spoke of using Borax as a flux in forge welding cable into knife material.  You use straight as a powder? I thought the purpose of flux was to prevent oxidation of the metal surface that would then hinder welding. The powder alone would seem to let air though but then I know nothing. I'm probably not alone. I'm sure others want to learn what's what.
   P.S. for those unaware of boric acid- it is what professional exterminators use, it gets into an insect's gills and kills it. You save a bunch of money just buying boric acid rather than "roach powders". Same stuff.

[John Archer]

Red Owl...Borax laundry soap is the stuff to use for flux...make sure it is unscented. Boric acid is a different animal altogether although they both contain Boron.

John.