Canvas treatment?

Just read an article where canvas can be made fire retardant when soaked in mixture of Borax soap and water. After it is dry,soak the canvas once again in a water and Alum mix to make it water repellent.
Anyone heard of this??
I'm gonna try it on some canvas drop pieces and see how it works. If it does WAHOO! If not I'll use the Borax in the wash and the Alum for Momma's homemade pickles. Looks like a win win either way. :thumbsup:

I've seen recipes similar to this.

That said - are you planning to place your canvas close enough to the fire for it to ignite? If not, then it seems to be far more work than is necessary. I've never had canvas ignite (even though it has felt very warm at times) and the canvas we've all heard about catching fire had some sort of accelerant (and stupidity) involved (molten flaming candle wax due to a drunken owner and a candle lantern left burning while on a binge away from camp).

I'm not sure how alum and borax, both being water soluble salts....could produce a water repellent fabric..... :hmm:

Here's a video of a guy burning various fabrics, I jumped ahead to the cotton duck

https://youtu.be/3QbKD6EP9BM?t=5m22s

Homemade oil cloth burn test.

https://youtu.be/etTTtLrPeUw

Spark test
https://youtu.be/VTXjm0no8gw


Another good test.
https://youtu.be/_SAQyRr-O48

The exchange product, aluminum borate, isn't. So, when the alum is added to the borax saturated canvas a chemical reaction could take place, precipitating out aluminum borate in the canvas and making it water resistant.
Disclaimer: I've never done this so this is hypothetical.

Let us know.

I've used alum and borax for tanning a deer hide.....It wasn't waterproof until I oiled it.

Geo.Sears wrote about this.

Bo T said:

So, when the alum is added to the borax saturated canvas a chemical reaction could take place, precipitating out aluminum borate.

Click to expand...

Doubtful...unless you heated it up to about 1200 °c so the crystals could form...

Vomir le Chien said:

Geo.Sears wrote about this.

Click to expand...

 

water­proofing; for which the following receipt will answer very well, and add little or  nothing to the weight: To 10 quarts of water add 10 ounces of lime, and 4 ounces of alum; let  it stand until clear; fold the cloth snugly and put it in another vessel, pour the solution on it,  let it soak for 12 hours; then rinse in luke­warm rain water, stretch and dry in the sun, and  the shanty­tent is ready for use.

Click to expand...

Of course Nessmuk was late 19th century.. :wink:

colorado clyde said:

Bo T said:

So, when the alum is added to the borax saturated canvas a chemical reaction could take place, precipitating out aluminum borate.

Click to expand...

Doubtful...unless you heated it up to about 1200 °c so the crystals could form...

Click to expand...

Different precipitate.

Feel free to enlighten me.

Crystals can be formed in a variety of ways. If you mix aqueous solutions of alum and borax a precipitate should form, at room temperature. Now, I perused a paper on making aluminum borate 'whiskers' which took a much purer form of aluminum borate precipitate (made in a similar manner described above) dried it, heated it above the melting point and made the 'whiskers' form of crystals. This is not necessary for our application. Now our aqueous precipitate is crystalline, just not the 'whiskers' crystal.

And how do we apply/adhere these crystals to the fabric?

The fabric is initially saturated with borax so the addition of alum causes the precipitation to occur between the fibers. The crystals MIGHT be held in place with attractions between the fibers and the crystals. These attractions COULD decrease the attraction between the wetting effect of water and the cotton in the canvas. Again, this is hypothetical as we don't know, yet, if it works. Indeed, it is hypothetical even if it does work.

I wonder how much aluminum borate would precipitate from X amount of borax and alum? Would it be cost effective, something you could do in a 5 gallon bucket.....or would we need an Olympic sized swimming pool to treat a tarp?

Depends on the size of the tarp.
It is easy enough to do a rough calculation for the yield, but let's wait to see Molman comes up with?

:hmm: :thumbsup: :grin:

Good quality canvas is already water-resistant and won't ignite easily (unless you place it into the fire). Cheap canvas (i.e. - canvas drop-cloths) isn't worth treating as there is little that can be done to make inexpensive, loosely-woven canvas water-resistant (short of making it into an oilcloth that rips very easily if placed under strain).

So I repeat my question - Why?

Buy a good heavy-duty canvas tarp (I have 2 from Sherwin-Williams), avoid all the extra work and get the same results.

Might be similar to the reason some buy sun forger fire resistant tents instead of regular canvas tents.