18 replies to this topic

[t1tan]

Hi, ive been a long time reader of this forum but never posted.

But i have a question regarding boric acid and borax. Is it possible to obtain boric acid from the common household Borax (Dri-Pak) brand. I have tried to research this but found no helpful information.

thanks

[portfire]

Hi, ive been a long time reader of this forum but never posted.

But i have a question regarding boric acid and borax. Is it possible to obtain boric acid from the common household Borax (Dri-Pak) brand. I have tried to research this but found no helpful information.

thanks

Hi t1tan and welcome to tne forum. I can't comment on obtaining boric acid from borax, although borax is a salt of boric acid, so i shouldn't see why not.Not sure on the chemistry though...YT2095 ??

It's cheap enough to buy boric acid from http://www.freewebs.com/cooperman435

Edited by portfire, 06 April 2008 - 09:01 AM.

[Arthur Brown]

Only start fabricating chemicals when there isn't a retail or trade supply! It isn't cheap to buy £100 glassware to make £20 of retail chemical.

[phildunford]

The substance called boracic acid is the same as boric acid. It's was easyly obtainable from chemists (it was used as a mild household antiseptic). I would think it's still available from chemists or health food shops so hopefully it's one you don't need to make...

[Mortartube]

Boric acid is getting more difficult to obtain at the chemists. I bought the entire stock 2 years ago at the chemist my cousin works for as the suppliers have taken it off of their books. Buy what you can now is my advice.

[lavenatti]

Try a ceramic supplier. In the U.S. at least, most ceramic suppliers have it for about $2.50 a pound.

[cooperman435]

Boric Acid isn't hard to find at all. It's one of the first and easiest chemicals I obtained. I've loads if you need any.

[t1tan]

Yea i see you have it on your website cooperman.
The main reason i asked was because i wanted to experiment with a al/nitrate comp and it was friday so of course id have to wait for any to be delivered.
Thanks for the info though guys, much appreciated

[portfire]

Yea i see you have it on your website cooperman.
The main reason i asked was because i wanted to experiment with a al/nitrate comp and it was friday so of course id have to wait for any to be delivered.
Thanks for the info though guys, much appreciated

The Al/NO₃ reaction is not really a problem in small quantities, I've made 100g batches of D1 without using boric acid with no problem.I use it now in these sorts of quantities, but just as a safety net. It's when using larger quantities i.e Kg's it becomes a problem.

[Mumbles]

It really doesn't matter batch size if prepared. 100g of cut stars is just as likely to react as 1000g of cut stars. Now if you leave them in a wet pile, yes is is more likely, but no one does that. Comets are much less likely to react than say, cut stars. Less water less chance. I've found that the nitrate Al reaction is generally not a problem if prepared into stars right away. Some comps may exhibit dimished reactivity, D1 being one of the ones most frequently cited. I always use boric acid or gum arabic, so I don't really notice much of anything. Gum arabic is also acidic and will protect against the reaction.

Anyway, borax is sodium tetraborate decahydrate. That is 2 sodium atoms, 4 borate ions, 10 waters. It is pretty easy to prepare boric acid from this salt. The following calulations assume the decahydrate, which is by far the most common salt. Dissolve the product in water. It is reasonably soluble if I remember. For every 381.4g borax, add 231mL of 31.45% HCl and cool to near freezing. The boric acid is soluble in hot water, but not in cold water.


This is the other proceedure I have saved. Please forgive the authors' name.

Boric Acid
Author: Bastard
Preparation: 46.3 g of borax is dissolved in the smallest possible amount of water, and 20.3 ml of concentrated hydrochloric acid is added to the solution. The mixture is cooled down and the precipitated acid filtered out. Use a frit for the filtration, paper will be corroded. The crude acid is dissolved in the smallest possible amount of hot water, then the solution is cooled down in an ice bath and the precipitated acid filtered out. Wash the product with ethanol and dry on a Petri dish (not paper!) Yield: 13.2 g (44% theory).
Properties: White translucent leaflets, only slightly soluble in cold water. Strong heating results in dehydration, yielding boron(III) oxide, or hydrates thereof. The acid is caustic when wet.

[portfire]

You certainly know your stuff Mumbles (chemistry books are coming out ). I should have been more specific (or metioned) in my post that pumped stars are less susceptible to the reaction due to the low water content, where as cut stars need more and thus the reaction is more likely, But I thought that dampening D1 enough to make cut stars might ruin the glitter effect, and also increasing the chance of the reaction taking place. D1 should have no more than 6% water right?

Another thing with regards to boric acid..

MgAl lends it's reactivity from Al (correct me if i'm wrong), and it's adviced to add 1-2% boric acid to the composition, BUT Lancaster says that MgAl is attacked by week acids, like boric acid. Could this make things worse?

NOTE; I'm referring to comps like, meal+ A% of MgAl added.

Dean

[GalFisk]

MgAl is not protected by boric acid. The Mg is more reactive then the Al, though Al has a particular problem with nitrates. I think the only way to really protect MgAl when using water is some kind of coating. Since there's not any AP involved, linseed oil or similar is sufficient.

Edited by GalFisk, 07 April 2008 - 02:04 PM.

[t1tan]

Thank you for the information people, very helpful.
I made some cut stars from the D1 comp and they turned out very well considering they were my first.
The excess water needed to cut them doesnt seem to have had a negative effect on them.
Seeing as i have some borax to use up ill try that way mumbles posted and see wat happens, ill be ordering some boric acid no matter what though.
By the way, i read somewhere boric acid can be prepared from borax with the use of sulphuric acid? is this correct and could it be used in the way mumbles stated or are they mistaken.

T1tan

Edited by t1tan, 07 April 2008 - 03:05 PM.

[portfire]

MgAl is not protected by boric acid. The Mg is more reactive then the Al, though Al has a particular problem with nitrates.

Yes I know, but I read somewhere (might have been on here) that MgAl is similar in reactivity as Al, hence adding the boric acid, but as I said, MgAl is attacked by boric acid. I'm not sure weather this maybe something to do with the Mg side of the alloy ?

[cooperman435]

Not being a chemist I can't add to some of this thread but from experience my Win20 formula now includes +2% boric acid as my firs few batches tended to inflate when made as pumped stars and end up considerably larger when dry than when initially pumped. Adding the boric acid completely stopped this from happening.