Silnylon Tarp Reinforcements

[Whilly Jo]

I recently made a silnylon tarp.  As I set it up to seam seal, I noticed there was quite a bit of tension on both the ridge line and the four corners.  It was more than I originally thought there would be.  Its not the tightest pitch and on the ridge line tie out some of the stitching is already creating small holes.  Its as if the stitching is tearing apart at the seam.  They are very small holes.  Is this normal?  What is the best way to reinforce the ridge line and corner tie outs?  The pictures aren’t the best but hopefully they show where I am coming from.

[Matthew / BPL]

I can’t speak to what the best technique is for reinforcing corners and ridgelines for silnylon tarps but all of my tarps have had a triangular or semicircular reinforcement at each tie out. Some have had grosgrain edging as well. You can see pictures of these on most of their websites.

Also, this thread might be relevant.

[Jerry Adams]

Are the holes you speak of the holes created by the needle, enlarged under tension?

What silnylon do you have, 1.1 oz/yd2 before coating (30 d)?

[Whilly Jo]

Yes the holes are created by the needle and I believe they are enlarged under tension.  I think it is actually 1.3 oz/yd2.  It seems like the corners are very stretched.  Is this normal?

[Hoosier T]

Looking at the pictured, I don’t see any tie outs down the sides, just on the corners. Is that right? You are probably having to put way more tension than needed on the corner tie outs since you don’t have any on the sides. I would put AT LEAST one in the center of each side ( edge tie out, not mid-panel). That looks to be a fairly large tarp (8×10?) and definitely needs additional tie outs IMHO.

[Jerry Adams]

I have similar fabric and have no reinforcements – I did it just like you

Mine is about the same stretchy, but I don’t really have enlarged needle holes

Yeah, center tie-out probably good

erect tent, put it under a lot of tension, coat the enlarged needle holes and surrounding area with sil-net, mineral spirits:silicone (5:1), or whatever.  Let it dry overnight.  Keep an eye on the needle hole enlargement and if they continue to get bigger, then you should do something more, like gluing on some triangles of fabric with silicone

[R]

Holes enlarge because the load at each stitch is too great for the underlying fabric to support.  To eliminate enlargement, you have to either increase the load the fabric can support by adding layers, or reduce the load by spreading it across more holes.

I recommend removing your guy loops before applying any sealant, then sew on re-enforcement patches and/or use longer strips of grosgrain/webbing to distribute the load across more holes.  If you go with longer webbing, keep it on the edges/seams where there are already several layers of fabric to hold the stitches.

If you want to glue patches on, run some stitches over the existing seams/hems of the tarp afterwards to prevent de-lamination where the loads are highest.  This is what you end up with when you glue patches before sewing.

Example of edge-sewn guy-outs: http://www.heliumhikingequipment.com/store/p47/9x9_Flat_Tarp.html

They’re using a 20d, so you’ll probably be fine w/o patches if you take their approach.

 

[Whilly Jo]

Just to clarify it is 8’x10′ tarp (actually tad bigger as I added a few inches to the overall length and width).  After checking my receipt, I did in fact buy 30d silnylon.  I think it is 1.1oz/yd2 before coating and 1.3oz/yd2 after (the receipt didn’t indicate the weight per area).  There are a total of 8 tie outs: two for the ridge line, one at each corner, and one along each side parallel to the ridge line.

The extra tie outs along the edge are reinforced.  I folded a square of silnylon to form to triangles, sandwiched the tarp between them, and sewed it to the tarp.  So those reinforcements on the edge are sewn to three layers of fabric.  For whatever reason, I did not attach guy line to those tie out and stake them out.  In retrospect, I am thinking that this might have been a problem.  The ridge line tie outs are sewn directly to a flat felled seam. There are a few enlarged needle holes about a 1/4″ away from the flat felled seam/ridge line tie out along the edge of the tarp.  The corner tie outs are sewn on to the rolled edge of the tarp.

It makes sense that the holes are enlarging due to the load being too great at each stitch for the fabric to support.  It sounds like utilizing the extra tie outs will help to spread out the tension.  I think I still need to reinforce certain areas.  I have already seam sealed the flat felled seam.

I am a little confused to whether to remove guy loops first then sew on some patches or to just glue/sew the patches over the guy loops.  Wouldn’t removing then reattaching the guy loops create more unnecessary holes prone to enlargement?  If I glued and sewed patches, would that be enough to disperse the tension?

Thanks for all the feedback.

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