bed sheet tarp

[roesso]

im going to start my bed sheet tarp this weekend and was just woundering if any of you all had anything they would have done different when making there's

[Canadian Woodsman]

I'd say make sure your grommets or tie out points are heavily reenforced, there's nothing more annoying than pulling a guy line too tight and ripping out a grommet! Also, it's better to have too many tie out points than too few. Good luck, be sure to post pics of how it turns out!

[MohaveGreen]

Just curious - do you plan to waterproof it, and if so, how?

[16ga]

Just curious - do you plan to waterproof it, and if so, how?

There are a few threads about them, I actually did a how to write up last year. I water proofed mine with silicone and mineral spirits

[Pappy Frank]

be sure to keep us informed. The same thing is on my to-do list. Thanks

[Bockster13]

There are a few threads about them, I actually did a how to write up last year. I water proofed mine with silicone and mineral spirits

would that also make it FIREPROOF!?

[roesso]

im taking pics of it and my knife i will post them up as soon as i get it done

[Todd Bradshaw]

No, it won't make it fireproof and a lot of substances will actually make it more dangerous if it catches fire.

In terms of just making it water resistant, if you want the best, in my opinion it would be to soak it well with 303 Fabric Guard. I build sails for antique boats and canoes for a living and some of them are high quality cotton about bedsheet weight. I've been doing it for about 33 years now. This is a hunk of 600 thread-count Egyptian Cotton. The sample on the left is untreated, the sample on the right was treated with 303 Fabric Guard. They were wet down about fifteen minutes before the photo was taken. The untreated sample was completely saturated in about thirty seconds as it sucked up the water. Most of the water on the treated sample just rolled off of the surface and the rest is beading up. When dry, the treatment is invisible and can't be felt. There is no goo to come off on on you or other equipment and it's also one of the best UV blockers you can buy to keep the sun from eventually rotting your cotton. The 303 isn't exactly cheap, but it will outperform anything else you can find on fabrics like Egyptian, Ventile or other high-end lightweight cottons and do it without reducing the breathability in dry conditions. I also use it on acrylic sailcovers, boatcovers and even the convertible top on our T-Bird, as it is the waterproofer/ UV-shield suggested by the companies that make those fabrics.

303-test-002a.jpg

[Woro90]

How densely woven must the bed sheet be to make waterproofing it possible? It looks like a good way to get hold of an old-school cotton tarp for little money. I'm thinking along the ways of ironing some wax in, then giving it a good bath in a solution of alumjust to be sure: http://lesnizelva.blog.cz/1206/impre...ztokem-kamence

[Todd Bradshaw]

The tighter the weave, the better in general, though there are a lot of factors involved. Ideally, you would look for a "percale" weave. This is a typical, "over/under/over/under" way of weaving fabric. It tends to yield the strongest and densest cloth with the smallest holes between yarns. For high-quality bed sheets, manufacturers will often use a "satin weave" instead, because it looks classy. It gives a shiny surface (usually more so on one side than the other) and it is done by yarns passing over more than one of the cross yarns (like over three, under one, over three, under one, etc.). While this sort of weave may look great on your bed, it's not as good for our outdoor uses as a plain percale weave. The way you tell is generally by reading the label carefully and then examining both sides of the fabric to see that they look the same. Really good cotton will be firm and will have a slight sheen to it, but it will look basically the same on both sides.

Thread-count - The best cotton cloth is woven from what is called "ELS cotton". ELS stands for "Extremely Long Staple" - meaning that the raw cotton fibers from that particular variety of cotton plant are much longer than most. Long fibers can be spun into thinner, stronger yarns and those yarns then woven into a tighter weave, yielding more strength and more resistance to wind and rain with less weight and smaller spaces between the yarns. A thread count in the range of 400-700 will generally indicate this kind of high quality cloth. You may even see fabrics which boast a thread-count of 1,000-1,200 though this is rather deceptive. In reality, they're taking two strands of 500-600 and weaving it "two over, two under" and adding up both strands to get the high number as a marketing ploy. You're generally better off sticking with the simple percale weave and a more realistic thread count.

Egyptian Cotton - Theoretically the best - but - Technically, any cotton grown in Egypt is labeled Egyptian Cotton, and only a small percentage of it is actually the really good, ELS cotton. The high-quality Egyptian Cotton is a hybrid and fairly recent (100-150 years or so). A true ELS cotton species that once grew in the Caribbean and was later wiped out by disease was cross-bred with a local Egyptian variety to produce the tough ELS product that became the famous Egyptian Cotton. In the USA, we also have "Pima Cotton" which is the same basic stuff. It was started with a government program in the southwest with the help of the Pima Indian tribe. Pima Cotton growers actually have an organization that has guidelines to regulate the product's high quality and it is always good stuff. Ventile cotton in Europe is another one that is a similar ELS cotton fabric.

So if we have a very tight, plain weave with a high thread-count and long staple fiber, that's about as good as it gets for cotton outdoor products. They will be pretty windproof and when wet, the fibers will swell, plugging the small spaces between them and give us a good start toward rain protection. This can be enhanced in two ways. We can slather it with wax, oils or other thick goo, or we can simply treat the fibers themselves with something that makes them water repellent without plugging the spaces between them. The drawback to the wax/oil/goo scenario is that the treatment severely reduces the fabrics natural breathability - and it's that way all the time. You may gain a bit more heavy-duty rain protection for some gear, but lose a lot of breathability. The method that basically treats just the fibers may not be quite as waterproof, but if you need the stuff to breathe, it may be a lot more comfortable.

A tarp, for example, might be great with the wax treatment, since tarp shelters tend to be pretty open. An enclosed, single-wall cotton tent, on the other hand, might do better with the more breathable approach to help prevent interior condensation problems. A raincoat might be better waxed, but a full-time wind/rain/everyday coat would probably be more comfortable with just the fibers treated and the tiny spaces between them left open (like your basic Ventile anorack).

That's probably more than you will ever need to know about cotton (and that's just the quickie, nut-shell version) but hopefully it will help decipher the labeling on bed sheets when you're buying one for outdoor use. As to just how good it needs to be for waxing, it's hard to say, but obviously it's going to be easier and more reliable to plug small spaces between the yarns with wax than big spaces - and a higher-quality fabric will probably be worth hunting for.

I suppose the other thing we need to mention is that when you saturate cotton cloth with wax, you are essentially making a really big candle. This is always worth keeping in mind when you're around and close to fires.