First Tarp Project . . . 1.1 Silpoly . . . 2 questions

[professrh]

So, I'm getting ready to start my first DIY tarp project. This will be a backup tarp, mostly carried in my day bag for emergency shelter.

It's nothing fancy. Roughly 9'x9' straight-up rectangle. Lots of tie-outs.

Two questions:

1) What are the arguments for and against using 3/8" grosgrain for the tie-outs?

2) Can anyone weigh in with experience-based evidence for or against simply bonding the tie-outs to the tarp (instead of sewing them on), as seen in this video https://www.youtube.com/watch?v=_5yGxdJveZk ?

Huge thank you from The Eternal Noob!

[XJ35S]

3/8ths might be strong enough but difficult to stitch. Gluing with silicone should work but you will probably need 2 or 3 inches of glue length on the top and bottom to hold well (tarp sandwhiched by grosgrain). Make sure you put weight on them as they cure. wax paper will keep any excess from sticking other things to your tarp during that process.

[Cruiser51]

RSBTR actually suggested in a post, that gluing reinforcement patches rather than sewing is preferred with silpoly .... I did that on my first tarp and they held really well.

I wouldn't glue the actual grosgrain tie outs simply because the weave structure of the grosgrain is so coarse (compared to silpoly) it would depend on the physical strength of the "glue" to keep it bonded in place. The bonded silpoly has a lot of surface area, with that thin film between which is almost impossible to separate, while a grosgrain loop would have a smaller area, with no real film, just a bunch of glue .... I would bind the reinforcements and sew the tie out loops for that reason.
If you use 3/8" grosgrain, consider doing a rough strength test to make sure whatever you buy doesn't fall apart. The stuff I have from RSTBTR would be strong enough, but there are many types, I would suggest that if you can break break it by simply pulling on it with your arms, it isn't strong enough, if it doesn't it isn't likely to fail in the field.

To sew those on, I would just use a simple zig-zag stitch, adjusted to fit the loop, if you shorten the stitch length, it starts to approach a bar tack, don't go that far, just lock the stitch top and bottom.
Brian

[dscotthep]

I used 3/8 grosgrain on my first tarp (sewn on) and immediately regretted it. It just looked... so small! However, I've been using it for about 2 years and it has held up great! It hasn't been subjected to a serious storm yet, but has weathered moderate winds (and all my fiddling) with no issues.

I still believe it's the weak point of my tarp, and if it should ever fail, it will be easy to replace (with something bigger). I'll live with it until then.

[Scouter_Ken]

I have done this a couple of ways and all seem to work.

1. Warbonnet method of using some black ribbon (not grosgrain) and sew the ribbon into the rolled hem where you want a tieout and then use some 1/2" grosgrain and a D ring for the tieout.
This seems to work fine and has the advantage of being a light weight option, but I have used this tarp when caught in a heavy wind.

2. Bond a piece of silpoly (same material as tarp) where I want each tieout using silnet seam grip and then add a length of 1/2" grosgrain for the tieouts

3. combine both methods. Add a piece of silpoly and bond using seam grip then add some ribbon in a V shape and attach the 1/2" grosgrain attached to a lineloc 3. (pic of this attached)
This method appears to be totally storm proof. I have 2 tarps with this method and both have been in some big storms with lots of high speed wind gusts and I have not seen any issues.

20191017_141436.jpg

[MikekiM]

All of the tarps I've DIY'd have bonded on reinforcement patches at the ridge, ground corners and side pullouts if equipped. Much cleaner look. No needle holes to have to seam seal and spreads the load over a larger area. I have lots of pictures of bonding in my HF albums.

On my larger tarps I used 3/4 grosgrain. On the asyms and day tarp I used 3/8 without issue.