Last evening, I finished off a storage bag for my folding Sawvivor saw (draw string top, pocket for spare blade, nylon that I treated with silicone spray to waterproof).  Now I'm looking to take on something a bit bigger ... a 10 X 10 Silnylon tarp.  I have some silnylon yardage on order, but I had a question (or ten) about construction. 

My aim is to keep the total tarp weight under 1 lb.  The 1.1 oz (1.3 oz after silicone treatment) silnylon material comes in at about 9 oz.  The plan is to use flat felled seams to join panels and a "rolled" seam for the edges.  Are those the best options?  What seam allowance would you use?  I'm thinking 1 inch.  Do you have a preferred light weight tape material that you would recommend for tie-outs?  Would you "double" the tie-out points with an extra patch? Would you place tie-outs at 2 foot intervals (at least those opposite the ridge-line) or do you prefer 2 1/2 foot?  Would you use nylon or polyester thread (and what weight)?  Other than the ridge-line, would you re-seal sewn areas?

Any other design options you would consider for pitching versatility?

dd

Someone on Solotripping or Waterwalker (now defunct) had posted their experience with exactly this, pictures and everything.  I tried a quick search on solotripping, couldn't find it.

From what I remember, your 1" flat fell & rolled for the edges is what was done.  Taped seams.

Tie down points at the 1/3 marks. 
Three ridge line points that are mirrored on both sides of the tarp - I like to tie a cord under the tarp to hang stuff from.  Dead center & 1/3 points.

Practice your seams.  :D

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DD,

My wife has made three silnylon tarps for me, two 10X10 and one 8X10. The center seams are about 3/8 to 1/2 inch flat felled and the edges are about 3/8 inch rolled. The seams are not taped. The tie outs are 5/8 or 3/4 inch grosgrain ribbon sandwiched between the tarp body and small tabs of silnylon to reinforce the stitching. I bought nylon thread, but it was too heavy for her machine, so she used cotton coated polyester thread. To seal the stitching, I dissolved 100 percent silicone windshield sealant in Coleman fuel and painted it on until the threads were saturated. When the solvent evaporates the silicone is left behind in the thread and needle holes. They have not leaked yet. I don't think you can have too many tie outs so she put on a lot of them. I have even had her add more along the center seam that were not originally there.  They have stood up to those crazy prolonged winds in Quetico on several trips now with no signs of weakness. The attached picture was taken July 2008 on McAree during one of those two day blows. 

Pat

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Pat -

Thanks for the feedback.  That's pretty much what I needed to know.

Nice looking tarps.  What weight silnylon did you use?  What was the total weight of the tarp when finished?

Thx.

dd

dd,

I'm not sure what weight silnylon that is. I found it a few of years ago at Wal-Mart in the discount material bin for $1.00 a yard. It was labeled "unknown synthetic" or something like that. I bought a bunch of it. The 10X10 tarps weigh a pound and a half in the draw string stuff sacks my wife made for them. Just under two pounds with ten stakes included. I use Easton aluminum stakes and aluminum gutter nails. My wife has also made several stuff sacks and a paddle coupler from the material. This picture was taken at the same place the following year. I have used the tarps more as wind breaks than as overhead cover in Quetico. That nylon camo tarp on the right didn't fare nearly as well in the winds as my homemade model.   

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rlageman3 wrote on Nov 17^th, 2011 at 2:00am:

I dissolved 100 percent silicone windshield sealant in Coleman fuel and painted it on until the threads were saturated. When the solvent evaporates the silicone is left behind in the thread and needle holes. They have not leaked yet.

Clever!

Preacher wrote on Nov 17^th, 2011 at 2:46pm:

rlageman3 wrote on Nov 17th, 2011 at 2:00am: I dissolved 100 percent silicone windshield sealant in Coleman fuel and painted it on until the threads were saturated. When the solvent evaporates the silicone is left behind in the thread and needle holes. They have not leaked yet. Clever!

Yes.  This is the way I would probably do it, although there are a variety of solvents suggested for liquefying clear silicone.

Pat -

What ratio did of solvent to silicone did you use.  I've seen rates ranging from 3 to 2 (60/40) to 3 to 1 (one quart solvent to 1 tube silicone).  I would think the thinner mixture would be easier to spread and would more readily seep into the stitching.

I've seen a variety of youtube videos of individuals taking non-treated nylon (and other materials) and dunking it in this mixture to create their own silnylon (etc.), but I've also seen photos of sil tents going up like a torch.  I'm assuming that you would use the least flammable solvent you could get away with (although they all seem to be flammable at some level) and let it evaporate as much as possible.

dd

dd,

I didn't use a specific ratio, but I did make it pretty thin for just the reason you mentioned. I wanted the mixture to saturate the threads and not just cover them. You could apply the silicone directly from the tube and leave a thicker coating, but I don't think you will get good penetraton of the thread and I believe it is suseptible to rubbing off. I stretched the seams pretty good, trying to open the needle holes as much as possible before applying the silicone mixture and let it dry for a couple of days. I used Coleman fuel because it was handy and evaporates quite quickly, but any number of solvents will do the job.   

Pat

Here is a link to a site with a good tutorial on making stuff sacks. The square bottom makes them a lot more useful than just sewing up a sack like a pillowcase. My wife has made several of these for me:

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Pat

I have made several tarps and your ideas and others' suggestions are right on target.  I find if you put a screw eye or hook in the ceiling above your sewing machine you can hang the bulk of the tarp out of the way and then work easily on the perimeter.  You will have to join the two halves first and put in the center ridge tie out to hang the tarp.

IC -

Thanks for the tip about hanging the tarp from the ceiling.  I was wondering how to "manage" that much material.

Pat -
Thanks for the link.  Actually, I made a stuff sack (regular nylon) for my cookset several years ago.  That's when my wife suggested I get my own sewing machine.  (She didn't want me anywhere near HER machine when she found I used a stapler to baste-in the round bottom before stitching it up.)

dd

Questions on the solvent thinned silicone application.

After the solvent evaporates and the silicone cures (let's say a week or whatever) does any silicone transfer to your hands while handling the fly?

How about longevity? Does it flake off - show any visual signs of what, de-lamination?

Does the type of thinner make a difference? Anything better than white gas? If so, why?

db wrote on Nov 21^st, 2011 at 6:21am:

Does the type of thinner make a difference? Anything better than white gas? If so, why?

While I can't answer questions about long term consequences, I've seen mineral spirits and denatured alcohol listed as solvents for diluting silicone.  Of course, I've seen projects use gasoline for the same purpose, but I don't think I'm going there.

A last question (I hope).  I've read that when sewing a tarp that the stitching should not be too tight, leaving a little give in the seam so the tarp can stretch a little when under a load (e.g., wind).  Any suggestions here?  Would a stitch length of perhaps 1/8th inch be suitable for this purpose?  Longer?  Shorter?

dd

db wrote on Nov 21^st, 2011 at 6:21am:

After the solvent evaporates and the silicone cures (let's say a week or whatever) does any silicone transfer to your hands while handling the fly? How about longevity? Does it flake off - show any visual signs of what, de-lamination? Does the type of thinner make a difference? Anything better than white gas? If so, why?

db,

Once the silicone is cured it does not transfer to the hands or stick to itself when the tarp is folded. No signs of delamination or flaking off.

I don't know if there are any long term adverse effects of the solvent, I have not experienced any. I think any solvent that the silicone will dissolve in would work, I just used Coleman fuel because I had it on hand and it evaporates quickly. If I do it again I may try denatured alcohol just to see if it makes any difference.


DentonDoc wrote on Nov 21^st, 2011 at 4:01pm:

A last question (I hope).  I've read that when sewing a tarp that the stitching should not be too tight, leaving a little give in the seam so the tarp can stretch a little when under a load (e.g., wind).  Any suggestions here?  Would a stitch length of perhaps 1/8th inch be suitable for this purpose?  Longer?  Shorter? dd

dd,

My wife said she used a straight stitch, medium length, medium tension. The first one was sewn with cotton coated polyester, but the others were 100% polyester. I have noticed absolutely no difference, but I will go with the 100% poly or nylon in the future. Just seems better for outdoor use, even though it gets the silicone treatment.

These things have been under sustained wind loads and held up with no signs of stress, stretch, rips or tears. I think many tie outs make a difference, spreading the load. I take a lot of 550 cord on my trips to Quetico.

Pat

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Pat -

I noticed from your photo that your tarps don't have any tie-outs along the center line (except at the edges).  Any reason for this?  (Nice trick to use shoes as a tensioning device.  :))

The green tarps looks very much like my Campmor tarps; green with white tie-outs.  They have worked VERY well, but the silnylon tarp should cut the weight about in half.

dd

DentonDoc wrote on Nov 21^st, 2011 at 7:14pm:

Pat - I noticed from your photo that your tarps don't have any tie-outs along the center line (except at the edges).  Any reason for this?  (Nice trick to use shoes as a tensioning device.  :)) The green tarps looks very much like my Campmor tarps; green with white tie-outs.  They have worked VERY well, but the silnylon tarp should cut the weight about in half. dd

dd,

I added a loop dead center on the seam on two of the tarps before my trip this year. I would recommend you put one on yours. You can't have too many tie outs and not putting one on initiallly was an oversight.

The winds kept those lines pretty tight and one of my nephews thought that would be a good place to dry his shoes.

That big green tarp in the background belongs to my nephew and is made by Kondos. The tie outs are actually black. The white that you see is a Klemheist knot made of white cordage used to tension the tarp along that red rope used as a ridgeline. We had a lot of different rope and cord along on that trip. I pretty much stick with 550 cord now.

Here is another pic of that tarp:

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Here is that Kondos tarp again supported by a couple of spare paddles held together by the paddle coupler my wife made with some of the silnylon material:

Pat

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rlageman3 wrote on Nov 22^nd, 2011 at 5:24pm:

paddle coupler

I'm not a fan of poles ... but that's ingenious! Worth a patent application I wonder?

db wrote on Nov 22^nd, 2011 at 9:57pm:
I'm not a fan of poles ... but that's ingenious! Worth a patent application I wonder?

db,

I can't take credit for any of the ideas used to make the tarps or the paddle coupler. All of the ideas came from perusing backpacking and canoeing websites. This is the link to the site where I got the idea for the paddle coupler:

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Pat

db wrote on Nov 22^nd, 2011 at 9:57pm:

rlageman3 wrote on Nov 22nd, 2011 at 5:24pm: paddle coupler I'm not a fan of poles ... but that's ingenious! Worth a patent application I wonder?

Agreed, that's very clever.

Hey DentonDoc, how is the tarp project coming along?

Pat

rlageman3 wrote on Jan 6^th, 2012 at 1:20am:

Hey DentonDoc, how is the tarp project coming along? Pat

Only a couple more things to do.  All the seams are sewn, most of the nylon loops have been added (corners, ridge line).  What I need to do is add two more nylon loops along the edge opposite the ridge line and then decide how many gross grain (intermediate) loops to add.  These have already been folded in half and sewn length-wise, but I haven't decided on actual spacing yet. 

Then the final step will be to "re-sil" the areas where I've stitched.  That may have to wait until warmer weather.

Still this was an interesting little project to spend a bit of time with.  The only "hang up" was working with 10 foot sections of tarp (even with a large flanking work table).  Now that my skills have improved (slightly), I may give it another go.  My new big red sil tarp should work fine.  I'm wondering how it would look in yellow, especially on overcast days when you benefit from more light getting through the tarp.

dd

DentonDoc wrote on Jan 6^th, 2012 at 4:51am:

All the seams are sewn, most of the nylon loops have been added (corners, ridge line).  What I need to do is add two more nylon loops along the edge opposite the ridge line and then decide how many gross grain (intermediate) loops to add.

Are the nylon loops and grosgrain loops the same, or are you using two different materials to make loops?

Pat

DD, My CCS trap is yellow. I like the color. Lets plenty of light through on the gloomy days to see into the bottom of a barrel. Plus it reflexes candle lantern light nicely in the dark to cast a nice glow onto the ground under it.

rlageman3 wrote on Jan 7^th, 2012 at 5:22pm:

Are the nylon loops and grosgrain loops the same, or are you using two different materials to make loops? Pat

The nylon loops are from heavier material than the grosgrain.   Actually I re-purposed a nylon webbing/cam strap I bought from Wally World.  I was a little surprised had how soft and light weight it felt after I opened the package. 

I've already placed one nylon loop on each corner, each end and the middle of the ridge line.  (I actually did a double loop in the middle; one on each side of the tarp ... more backing support that way, I figure, plus it gives me one point to run something like a clothes line under the tarp.  Using a hot knife to cut the nylon webbing was actually a lot of fun.

I'm figuring to use the grosgrain for points where the stress will be somewhat less.  They are half-width since I folded them length-wise and ran stitching down both edges.  We'll see how those hold up ... they seemed super lightweight.

JJ -

Thanks for the tip on yellow tarps.  That was my thinking exactly ... might help to lighten an otherwise gloomy, overcast day.

dd

I like the idea of putting a center loop on both sides of the tarp. I may have the wife add loops to the under side mine.

I haven't used any yellow nylon, but I have an MSR Missing Link tent that is made of orange silnylon and it is VERY bright inside in even low light. I imagine the yellow would be the same.

Pat