Friday, April 12, 2019

An experiment in waterproofing canvas, 10 oz, Kiwi Camp Dry silicone spray

So here the canvas is laid horizontal with a little valley or maybe it's a gully? Anyway after 2 coats of Kiwi Camp Dry Silicone - aka silicon dioxide - it seems to be quite water proof!!

Now this is a $16 canvas (10 oz that is 9' x 12') from Harbor Freight - I had to go to a 2nd store as their 1st store did not restock this item, telling me to goes fast also.

OK so my plan is to use this as a ground "foot print" or ground cloth for the Wilderness Lodge tent.

Part of this canvas I also treated with Linseed Oil - PURE - and no "mineral spirits" (really Naphtha or petroleum spirits) - I've had MORE than enough of that nasty toxic petroleum Octane smell - thanks.

So the linseed oil PURE does not, unlike BOILED linseed oil, have the Cobalt maganese powder as a drying agent - and so supposedly the pure linseed oil never dries. So I have it drying now against the heater - will there are no folds - it's spread out - and so getting a fan blown heat drying.

I tried seeing if the linseed oil held water - and that is linseed oil ON TOP of the silicone spray. Nope - it was WORSE after I treated it with linseed oil.

So the whole point is for the "wax" or silicone or oil - linseed - to get soaked up by the canvas - the HOLLOW cotton fibers. That makes the fibers swell - and if the weave is tight enough then the canvas will repel water but will still also BREATHE.

Now - I got the PURE linseed oil for free from the environmental center free store - run by the county - and I looked up to get more - NOPE. It's not stocked by the local stores. Only the "boiled" (i.e. cobalt-maganese) treated drying agents. But those "powders" are toxic if breathed in. No thanks.

OK that above photo is still holding true!! Yesterday when I poured water on the silicone - it eventually soaked through the canvas. But now that it is dried better - it appears to be holding well as water proofed.

So my guess is the reason the Linseed Oil treated part of the canvas is no longer water proof is because when the canvas dries then the weave SHRINKS but when it's wet then the weave stretches out. A couple claims state:
the oil causes a heating of the textile, resulting in a breaking down of the textile....were caused by linoleic acid in the linseed oil attacking the cellulose fibers.
So when the linseed oil dries out - I'll test it. Actually part of the linseed oil is already pretty dry. I'll try that out.....So the above quote states you need a glue or wax that is FIRST embedded into the canvas before the linseed oil is applied. So good thing I sprayed the silicone in first....
Linseed oil is a slow drying oil that forms into a hard solid with exposure to air. After it dries it will no longer have an oily feel or rub off oil, but it definately does while it is drying!
yeah it's still not dry enough. I have the canvas hanging over a couple chairs.... facing the blown hot air....

The Kiwi Camp Dry spray also does use a Naphtha (petroleum spirits) as the "distillate" - to dry out the silicone and so it sprays spread out. But that smell does seem to evaporate fairly quickly. Also I looked at the Silicone "lubricant" spray to see about using that. It is NOT silicon dioxide (the ingredient used for the Kiwi Camp Dry) but instead the silicone lubricant oil is a polydimethylsiloxane or something like that. I looked it up and it was considered safe when first released but now it's considered toxic and probably carcinogenic. No thanks - it's a longer silicon chain... as a polymer.

OK so it's been a HALF HOUR




So what I did was "roll" the water away from where it had been sitting - again in a "divet" in the canvas - laid horizontal with nothing underneath it. So it could have just soaked through if nothing was stopping it. But NO - instead it mainly just got "wet" and most of the water still "rolled" away.


KIWI® Camp Dry Heavy Duty Water Repellent | KIWI® Products




KIWI® Camp Dry® Heavy Duty Water Repellent offers tough silicone ... Hold can upright and spray entire surface of item from 7 to 10 inches away with a light, ...
I'm not saying it's AS good as the polyester Silicone tarp that I got for $100 - that was 10' x 16' size. (That has NO smell and is completely water proof and very light).... in contrast to the very nasty smelling industrial military canvas that is not water proof and very heavy.

So this is 9' x 12' for $16 but the 2 cans of spray were another $16. So $32 for a tarp that is big enough for a "footprint" - the 10 x 16 is TOO big for a foot print - although I could have just folded it. No - that will go on the roof - since it is very water proof and it won't "stretch" like the nylon stretches (creating divets or gullies or canyons or ravines or valleys for the water to sink in)...

My plan is to put the heavy smelly tarp over the Adobe Cob Beehive hut from the 30,000 year old design.....



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