Coating silnylon floor

Often a post like yours brings out a number of coaters who mix silicone caulks with mineral spirits, or stove fuel or the like to thin it. While it does OK as a seam sealer, I haven't found such a mixture yet that will bond well enough with the silicone for the coating to last very long as a DIY silicone floor coating.

Editor Roger Caffin reported on this site that his attempt eventually cracked and peeled. I would not expect a petroleum product to make a good bonding agent, due to the oil content.

You might do better to look for a 1.1 oz nylon that is factory coated to a high degree of waterproofness, especially for a floor, which can be subjected to much higher water pressures than a tent wall. There is a 3500 HH camo one available form LHG: http://www.lightheartgear.com/index.php/fabrics/camo-silnylon
While Thru-Hiker now reps its silnylon only to be ">1000mm" HH, their offering for the last few years has been highly water resistant. You might email them about that, and maybe increase you color choices. I believe a quality factory coated material will last you much longer.

As for which side to coat, the factory coated silnylons are usually coated on both sides, often described as 'impregnated,' which might be questioned by how readily cheaper silnylons are prone to 'wetting out.' But you should be able to check for double coating by inquiring before purchase.

As for slipperiness, it is a problem on both the ground side and the inside. I've seen a number of silnylons, like the Cordura brand, that are less slippery. Unfortunately, they are also less waterproof to a significant degree, according to HH tests Roger Caffin was kind enough to conduct at my request. But I haven't seen a sample of LHG's camo.

One approach to slipperiness is to design the tent to insure that the floor is staked out taut enough so that the material will not slip around on the ground as you move around in the tent, which can be a PITA. Combined with silicone sealer chevrons on the underside of the sleeping mat, that goes a long way to addressing the problem. With those approaches, I've had no slipping problems with silnylon floors.

One last possible option would be to experiment with the many silicone based water repellent sprays on the market to see if any increase friction. Haven't tried that.

I hope this is of some value to you, and please be assured it is based on personal experience, as well as tests reported by Roger and Richard Nisley, not speculation or opinion.

It's not exactly what you asked, but I've been using Lightheart Gear's regular silnylon for floors lately. It's not very slippery and seems plenty waterproof – I've slept on wet ground and snow and have seen no hint of moisture coming through. The material almost feels waxy and typically weighs about 1.5 oz/sqyd.

I just got some of LHG's camo silnylon (3500+ HH). It also weighs approx 1.5 oz/sqyd, maybe a tad less. It feels much different than their Cordura silnylon and is more slippery

Finally, I bought some silnylon from Oware recently. It has a very heavy coating and weighs over 1.6 oz/sqyd. I haven't used it yet and may just try to sell it.

The best solution to silnylon slipperyness is to put silicone dots on the bottom of your sleeping pad. Coating the floor with diluted silicone adds a ton of grip, but it also adds 1-2oz per side, and it makes the floor a dirt magnet. You can't really sweep debris out of your tent if you coated it.

I coated both sides of bivy bottom

The side against the ground peeled after a while

The side I slept against lasted a long time until I replaced it for some other reason

Shield from thru-hiker.com doesn't leak, so all you have to do is worry about slipperyness

Yeah, I have done both sides and one side on my tents. Usually the floors but also a few tarps, hence only one side.

Thinning seems to be the key. It needs to be a good grade of thinner or mineral spirits. The less expensive stuff uses a bit of kerosene and some other things; they are not too fussy with many thinners (since most people use it for cleaning, not for thinning varnish.) The cheap stuff does NOT work well for thinning silicone. Good stuff dries clean in about 15-30 minutes when applied lightly to a paper bag. It will leave no discoloration on the paper, though you might get some leaching stains that look like water got on it. Generally the color won't change. The cheaper stuff will cause it to discolor and stay that way for a long time…maybe four or five hours. This is the stuff to avoid. DO NOT use the environmental stuff!

For floors, I do both sides, brushed in thoroughly. The mix is around 15-20 parts thinner to 1 part calk. Thicker will cause peeling. The fabric should just start picking up a shine from the mix after it dries. Your best bet is to do it in sun on a dryer day. This will cause the solvent to evaporate before the calk sets. If it is damp, the calk will set too fast. If it is too cold, the solvent won't evaporate fast enough. The goal is to leave a very thin coating of calk on the fabric to set. White Gas works, too. But this is reserved for temps around 60F. At 70f it evaporates too fast leaving brush marks and an uneven coat.

For older tarps, where they loose waterproofness due to stretching and wear, I use a thinner mix, 30-50 to one depending on the fabric. For a 9×10 tarp it adds about 2oz total so right around .2oz per yard.

I always tell the sales people at the hardware stores that I want only the good stuff.
They always seem to have plenty of it.

"While thru hiker reps its silnylon only to be …"

Has this been discussed here before? I wasn't aware of the HH downgrade on TH shield product? Is this the same material simply re-evaluated, or is this the rumored EPA standards taking effect and directly impacting silicone coating in the US?

I think that the trick for not having the silicon peeling off is simply to apply a very thin highly diluted mix.
For a start you need 100% silicone (it will labelled as such and translucent) , then mineral spirit (not vegetable not low odour stuff) .
Put a blob of silicone in a jar , add some spirit, mix in and keep adding spirit till it has a consistency of thin oil .
Apply with a cloth or sponge brush . Just one coat.
Try that on a piece of scrap first.

Christopher*,
That is why I suggested the OP contact Paul about the HH posted on the T-H website.

Well I really hope this Thru-Hiker sil HH issue is just a false alarm. I just sewed in this fabric as the floor of my cuben tunnel tent. I relied on the older info found in the HH testing thread and did not even question the fabric when I received it. This may be an other lesson… At least I plan to use a Polycro or a Tyvek ground sheet.
Cheers

I've used thru-hiker shield on bivy bottom for maybe 40 nights? Still waterproof.

Pierre,
Note that the Thru-Hiker site does not say 1000mm HH, it states '>', or over, 1000mm.
If it's any solace, the tent I used for five years until 2012 has a floor of the older solid black silnylon from Thru-Hiker that was sold until around 2011 before T-H began selling the material that was tested by Richard in the 3000mm HH range. The older material never gave me the slightest problem with leakage, and held up very well against abrasion.

You might take a remnant of the material you used, make a pouch of it between your thumb and forefinger, fill partly with water, twist the pouch shut, and see how hard you have to squeeze to drive water drops through it. It was very difficult to force any water through the high HH material I bought from T-H after Richard's post about his tests. Most of the 15 denier sil and PU coated nylons I've been experimenting with that run around 1200-1500mm HH will under strong pressure emit a few small drops at the points of the folds in the pouch, and the older solid black silnylon from T-H did as well.

I think that for a floor, just as important as good HH is the ability of the material and the coating to resist abrasion, and IMO, silnylon is much better at this than PU coated due to its greater elasticity. Try to scrape rubber sheeting with a butter knife.

One of these days I'll finish the HH tester that Roger Caffin was so helpful in advising how to build. All the parts are there, and it's about 75% assembled. These projects would get done much sooner but for all the displacement activity with reading and posting on BPL. For displacement activity, it's not bad though.