Another DIY Tarp

[tight-wad]

Quick, off the top of my head response... Won't be home to give you the exacts for several more days...

I reversed engineered the amount of silicone to use. Commercial sil is advertised as 1.3 oz/sq yard. Wally's ripstop = 1.1 oz / sq yard. Therefore, you need to add 0.2 oz of sil for every square yard you will treat, plus factor in some waste. I overestimated the amount of waste, i.e. there was not as much waste as I thought I would have, i.e. more sil made it into the fabric, i.e. my final result was heavier than 1.3 oz / sq yard. Next time, I'll use less silicone and try to hit the 1.3 target. I seem to remember mine being ~1.4 oz/sq yard.

Long answer, but what you need to do is calculate how much silicone you need to add, then squeeze that much plus a few more drops into your bucket of solvent. I think the ripstop will absorb as much as you want to pump into it (up to some limit), but you only need x amount to do the job. The trick is to just feed it that magic x amount (1.3 oz / sq yard).

I weighed the blob of silicone on a piece of tin foil, then scraped it from there into the bucket.

[speyguy]

TW,
Thanks, sounds like its pretty comparable in weight to commercial sil. I just didn't want to end up with something that was 2 oz / yd.

[Mule]

That really looks good. I forwarded this thread to a good friend who will be doing the same sil operation to his DWR DIY tarp. Mule

[Splinter]

Quick, off the top of my head response... Won't be home to give you the exacts for several more days...

I reversed engineered the amount of silicone to use. Commercial sil is advertised as 1.3 oz/sq yard. Wally's ripstop = 1.1 oz / sq yard. Therefore, you need to add 0.2 oz of sil for every square yard you will treat, plus factor in some waste. I overestimated the amount of waste, i.e. there was not as much waste as I thought I would have, i.e. more sil made it into the fabric, i.e. my final result was heavier than 1.3 oz / sq yard. Next time, I'll use less silicone and try to hit the 1.3 target. I seem to remember mine being ~1.4 oz/sq yard.

Long answer, but what you need to do is calculate how much silicone you need to add, then squeeze that much plus a few more drops into your bucket of solvent. I think the ripstop will absorb as much as you want to pump into it (up to some limit), but you only need x amount to do the job. The trick is to just feed it that magic x amount (1.3 oz / sq yard).

I weighed the blob of silicone on a piece of tin foil, then scraped it from there into the bucket.

What he said...

I won't know the exact weight of the finished project until I can't get a good scale. I do know its going to be subjective and will prob. vary each time. I know the first tarp I made soaked up more sil than the second one that (the gray tarp in the first post) did. I'm going to make another tarp (winter version) here shortly and I will be more diligent about recording weights and amounts

[LostCause]

Sweet looking tarp there.
The craftsmanship looks a lot better than mine.

This may be completely unnecessary but I figured I would throw it out there for others to decide on whether to use this idea or not.
I made a DIY tarp with homemade sil but I soaked the fabric in this product first.
UV-Block by ATSKO.
I washed the wally world $1 fabric with some fabric softener first to remove any coating that may have been on the fabric to begin with (in a front load washer with no agitation), then re-washed the fabric to rid the material of any residue fabric softener. I soaked it in the UV-Block (one of the larger bottles that I bought from there website. they have two sizes available) and let it dry then stuck it in a dryer to cure. I sewed the tarp, then treated it with the sil mixture. I probably used more sil than necessary, but I really wanted my first DIY tarp to work.

The UV-block is supposed to give the fabric an SPF of 50 or so, and also provide a lot protection against UV rot and fading. I can't say if it's all that effective or not. I haven't used my tarp at all yet because shortly after finishing it I had to go back to work. Only a long term test will determine if this treatment is necessary or even useful, but I thought since there was a small recent boom of DIY tarp making going on that I would share this idea. If anyone tries it and deems it successful or a waste of time, be sure to let me know.

[Splinter]

LostCause, I'd be interested to see how the long term part worked. My next tarp is going to be black so I'd worry about the fading issue with it.

My only thoughts/concerns would be does the UV block lessen the amount of sil that the fabric would soak up?

[LostCause]

I wouldn't think so. From what I understand the uv-block is a dye, not a coating. I used an entire 10 oz tube of silicone when I did my tarp. It took it all. I was worried about function instead of weight at that point. My next one will be more exact with measurements and weights.

[Splinter]

... I used an entire 10 oz tube of silicone when I did my tarp.

The tarp didn't turn out "sticky"? On my first tarp, a diamond style, I know I used way too much sil in the mix and the tarp will stick to itself. Its a different fabric weight from the grey tarp, but not by much.

[speyguy]

I just started on my third DIY tarp. The first 2 were made from real sil. This one is from the wally world 1.1 ripstop. My plan is to sew it first and then set it up nice and taught to apply the silicone. Which side do you all think it should be applied to, the inside or outside?

[Splinter]

Just my .02, but I'd sil and then cut and sew, but I put the material into the sil, not brush it on there. If your brushing it on there, I'd prob do the outside first so that the sil will soak (thanks to our friend gravity) downwards. Start at the top and work your way down. Here's the trick...make sure your in a well ventilated area (trust me from personal experience on this one! ), but that is shielded from the wind.

Good luck and let us know how it turns out.