I have a homemade 58" by 108" rectangular spinnaker tarp. I want to add a tie out in the middle of the tarp to increase the "interior volume" when it is pitched as a lean-to. I am thinking about sewing a piece of grosgrain to a 6" by 6" piece on spinnaker and then attaching the small piece to the tarp with diluted silicone sealant. Has any one tried this before for a tie-out? I know this is the preferred method for patching silnylon and spinnaker but will it hold up to the tension of a guy line?

I want to try doing it this way because I would like to avoid putting needle holes in the middle of the tarp that would compromise strength when pitched as an a-frame.

you may want to consider grip clips. they seems like a good alternative.
http://www.shelter-systems.com/ultra-light-nylon.html

Thanks for the suggestion David. I have used grip clips before on PU coated nylon and they cause a lot of abuse to the fabric plus they distort the fabric too much for my taste. The website you linked did have a good suggestion about using a piece of ballon to keep the grip clip from slipping on silnylon. If end up going the grip clip route I will have to try that.

I dont know if you can avoid sewing a tie-out on? I would glue a double layer of fabric together and sew the tie-out onto that, it will spread out the tension more and the 3layers can be safley sewn on to, as it will be a lot stronger than the single ply spinnaker.

Edited by MAYNARD76 on 10/08/2007 13:24:02 MDT.

i bet a larger sized one wouldn't be as harsh, although the weight adds up

> sewing a piece of grosgrain to a 6" by 6" piece on spinnaker and then attaching the small piece to the tarp with diluted silicone sealant. Has any one tried this before for a tie-out? I know this is the preferred method for patching silnylon and spinnaker but will it hold up to the tension of a guy line?
> I want to try doing it this way because I would like to avoid putting needle holes in the middle of the tarp that would compromise strength when pitched as an a-frame.

Short answer: it won't hold.
Longer answer: it still won't hold, so get sewing. But put the reinforcing on the inside, and then seam-seal with silicon sealant. Search on the forums for several discussions about this. It works fine.

I've successfully glued tieouts on my silnylon tarp. The tieout loop was sewn to 5x5 cm square of silnylon and then glued onto the tarp used silicone sealant (not diluted). I used pea-sized bead of the sealant, spread evenly on the patch using my fingers. After placing the patch on the fabrics, I carefully pressed out all air bubbles, put a load of heavy books on top of it (separated by PE bag) and let it cure overnight.

I didn't needed these tieouts in field yet, but I did some tests before I used this method on my tarp. In case of tieout stitched in the middle of the patch, the tieout will tear from it before the patch will be torn off. I've also tried to peel of a glued patch from side, where it was not glued. It is possible but it requires surprising effort.

I hope it will work well on my tarp. If you're not sure about this method, try it on some scraps beforehand.

Honza

I use glue only on my side pull-outs. However, I have not done this with spinnaker.

I have not had a failure yet with standard 1.35 oz. silnylon. I use Permatex "Flowable 100% silicone Windshield Sealant" because it is thinner than the usual silicone sealant. I stitch the pull-out to a patch of silnylon, then glue the patch on.

Some caveats:
1. You need a lot of glued surface area. I use 6X6 patches oriented in line with the weave of the tarp fabric so the patch doesn't stretch differently from the base fabric.

2. A good glue job starts with a good clean-up job. A thorough scrubbing of both the patch and the tarp with denatured alcohol will remove oils and contaminants. (use gloves!) Then, avoid touching the glue zone - which will deposit skin oil.

3. If you don't scrape the extra sealant off, the patch will be heavy. I use auto-body squeegees to scrape the glue directly, then to squeeze any extra from between the patch and the body. Removing excess sealant is critical to getting a strong bond.

Edited by vickrhines on 10/09/2007 17:29:27 MDT.

All,

Thanks for the suggestions and advice.

Vick,

Good point about orienting the patch to match the tarp fabric that is something I probably not of thought of until I was done.