Thursday, May 28, 2009

Intro to using Boric Acid Flux

Make your own flux with Boric Acid and Denatured Alcohol


Boric Acid and Denatured Alcohol make a wonderful flux for preventing firescale on your work. These items can easily be found at your local grocer or hardware store.
Boric acid is also non-toxic for people, making it a great alternative to fluoride based fluxes. (Boric Acid is, however, toxic to insects - so can serve double-duty keeping your studio insect free!) Denatured Alcohol can be toxic if ingested, so do make sure to keep it out of reach of children and pets.

Spoon a little bit of the boric acid powder into a small dish. (It is best to use a dish with a tight fitting lid, such as a baby food jar, as the alcohol will evaporate quickly without.)



Add the alcohol slowly, mixing until a thin paste is made. Add more boric acid powder as needed to thicken. Getting the right consistency can take a bit of trial and error - I tend to prefer my flux a little on the watery side.



Brush on a liberal amount of flux over the entire surface, or, dip the entire piece in flux.


Place on soldering surface, and light with torch to burn off alcohol. It will produce a lovely green flame. Continue soldering and pickling as usual. Due to the flammability of Denatured Alcohol, it is best to store it in a secure area away from your soldering station.

16 comments:

Chelsea Bentley said...

this is what I use and I love it.

DalkullanJewelry said...

I've used borax, twenty mule team, from the supermarket. It's 4 dollars for a big box and worked well on sterling. I'll give the boric acid a try -- maybe it'll help with our springtime ant problem, too. (-:

idreamicanfly said...

Sweet! I'm always looking for natural, non-toxic alternatives. Have you guys tried the vinegar and salt pickle? It works as well as (if not better than) the standard Rio Grande pickle. I have a recipe here:

http://idreamicanflyaway.blogspot.com/2009/01/to-pickle-or-not-to-pickle.html

If anyone has a non-toxic acid for etching, I'd be really interested.

Chrissi Lynn Designs said...

How far away do you need have the flux from your soldering area? I usually keep mine pretty close. I would like to get away from the more toxic version and use the boric acid method.

Can you use water instead of alcohol with the boric acid?

GetSilvered said...

Thanks for this, I'm looking for ways to be "greener" in the studio.

Maggie said...

I keep my small batch of flux right next to my soldering station. There isn't that much alcohol in it to cause that large of fire. It is the large container of denatured alcohol I keep tucked away on a shelf about 8 feet away. It could cause quite a fireball if it was within easy reach of a lit torch!

Maggie said...

thanks for the salt & vinegar pickle recipe! That is one I have not tried.
I am currently using citric acid for pickle, which is also relatively non-toxic.

Roberta said...

So many times I have seen the formula for this on Orchid but one picture is truly worth a thousand words!

Thank you for this!

Ashley said...

Yes Maggie, thanks for posting this. I have been sort of mystified by this process and now it makes more sense.

tinahdee said...

I am going to try this in lieu of the handy flux I have been using. Thanks!

susan said...

why did my boric acid and denatured alcohol put a residue under the jar lid, then when I thought maybe I shouldn't cover it, I put a mesh screen over it and it grew white crystals....scary??!!
SuSu

Beth Cyr said...

Hi Susan! Several etsymetal members that use this say it is normal. The denatured alcohol evaporates so quickly and just leaves the boric acid behind as a residue.

tkmetalarts said...

You can also add more denatured alcohol to the chunkied up boric acid powder. Alcohol evaporates so quickly that you should use a tight lid for the paste. I did ask John Cogswell a couple of weeks ago, the white chunks doesn't take away from the firecoating - just add more alcohol and stir before using.

Also if you accidentally got a flame going in your boric acid/alcohol container, don't panic. Just put the lid back on until the oxygen is depleted, and the flame will die down. Been there, done that. =)

Anonymous said...

Has anyone used Roach Pruf with denatured alcohol? It is 98% boric acid and 2% Other Ingredients. Thanks, ECR, Ohio

SToNZ said...

Yep, Roach Pruf is what I use. It's fine!

Anonymous said...

Very helpful thanks.... Oh and one question Im new to soldering so I hope I don't Sound ignorant by asking this question. I bought 5 ponds of boric acid from a jewelry supply company and on the box it says to mix with methyl alcohol did I buy the wrong type of boric acid or is using denatured alcohol just a greener way and does it work just the same? Thanks

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