Best adhesive to bond silnylon reinforcements to silnyon?

[Monte Masterson]

I didn’t have any Sil-Net on hand so I tried GE Silicone II….failure!  Maybe Sil-Net is the obvious choice, but I thought I’d ask the DIY experts here first. Would Seam-Grip be better?  Thanks

[Franco Darioli]

Ok, GE II will work if…

First you need to clean both bits of fabric with some mineral spirit or white gas .

Next you smear a very thin layer of silicone on both fabrics .

Leave for about 20 minutes then press the two together then put a weight on them.

Wait for 48 hours to cure.

[Monte Masterson]

Thanks Franco, do you use a small brush, fingers or what to coat the silicone onto the materials?

[Franco Darioli]

For a small repair I use a finger. ( I do seam sealing with both a brush and a syringe)

[Ken Thompson]

https://backpackinglight.com/myog-laminating-silicone-impregnated-fabrics/

[Roger Caffin]

Seam Grip is for PU. It will peel off silnylon straight away.

You could try Permatex Flowable Windscreen Sealant (or some name very close).

THIN layer and allow 48 hours for curing. Me, I oversew the edges as well, to prevent any peeling from starting.

Cheers

 

[Ivo Vanmontfort]

I do not think Franco is right.

You need to work fast when bonding with silicon.
I have good results with it.

<span id=”result_box” class=”” lang=”en”>
Same way of working as in next film.
Silicone works well in shear load but not in peel force
http://www.adhesivetest.com/resources/images/clip_image002.jpg

[Franco Darioli]

I do not think Franco is right.
I could be wrong but it has worked for me (the wrong way) several times over the years.
BTW, note that I was talking about pure GE II, not diluted, not Permatex or any other substitutes.

[Monte Masterson]

Franco, so cleaning with mineral spirits won’t hurt the silnylon?

[Franco Darioli]

You only wipe with mineral spirit to make sure there is no dirt or grease on it.
But you only do that for this situation not to clean your tent…

[Roger Caffin]

Footnote to all this:

I do NOT like the stuff in cartridges. It may be cheap … but I don’t think it works very well at all for this task.

Cheers

 

[DAN-Y]

Clean the sil with vinegar and let dry. You wanna be high tech? use acetic acid carefully following all scientific precautions. use acetic acid to thin silicone. caution is advised ;) for geeks only :-) Test results on scraps of sil ;)

[Ivo Vanmontfort]

Franco,

The technique you describe

Leave for about 20 minutes then press the two together then put a weight on them.Wait for 48 hours to cure.

It looks that this is the technique for bonding cubenfiber with aquasure/aquaseal.  (PU glue)

[Franco Darioli]

Ivo,

Applying a thin layer of glue to both surfaces and letting it partially dry for 10-30 min (depending on the glue type) is not all that uncommon.

I came to it with silicone simply by trial and error.

The same way I realised that it is easier to peel off a thick layer of silicone (as in when seam sealing) than a thin one.

 

[Monte Masterson]

Thanks for the input guys. I picked up some odorless mineral spirits at Jo Ann’s and then stopped by Autozone to get some Permatex Silicone Windshield Sealant that Roger recommended. I looked around at a few stores to try and find a rubber brayer, but to no avail. I can order one online, but I’d have to wait of course. I see hard and soft brayers are available. Which is best?

 

[Jerry Adams]

It takes a long time for silicone to dry so waiting 20 minutes wouldn’t hurt

[Hoosier T]

Monte,

How did the permatex work out? As you have seen in the other thread, I have some mods needed for my tarp and will need to glue on some extra reinforcement patches.

[Monte Masterson]

Getting ready to clean the materials with mineral spirits, then tomorrow I’ll  glue on the reinforcements with Permatex. I couldn’t find a rubber brayer anywhere around Gainesville, so I fashioned something that will work. I also bought wax paper to put over the materials for when I press the roller over them. Lastly I’m going to put books over the reinforcements and leave them for about 12 hours,  then pull them away and let everything cure for another 36 hours before I start sewing.

 There are other past threads on the issue such as “Silnylon  Reinforcements” where some of the pros chime in, yet I still couldn’t glean a definitive answer on what works best….that’s  why I started this thread.

You might also check out Ivo’s video. I like the way he scrapes the excess silicone off with a putty knife. One thing all the Daddies stress is to make sure the silicone is put on THIN!

[Franco Darioli]

Odourless mineral spirit may not work as well as the standard stuff..

But I never tried that myself. Vegetable spirit does not work…for me.

[Bill Giles]

I have not had a problem using the least expensive 100% silicone that I could get, usually DAP. I used Odorless Mineral Spirits, but don’t see any reason not to use regular Minweral Spirits other than the odor and I’m doing this outside anyway. I pre-dilute the Silicone one part by volume to three parts of mineral spirits. I paint the diluted Silicone on to both pieces with a throw away foam paint brush and then sandwich the whole thing between two pieces of freezer paper and two pieces of 1/2″ foam rubber. I then weight the whole thing with a gallon water bottle and leave it overnight. I’ve used this method to glue mid panel tie outs to tarps without problems. I sew pieces of 1/2″ Grosgrain to reinforcement patches about 4″ in diameter. The reinforcement patches may be the same material as the tarp or may just be scraps. I usually try to use uncoated fabric for the reinforcement patches. That lets the silicone go right through the fabric. I haven’t had any problems with the silicone gluing my Grosgrain to itself. I tease the tieouts off the silicone as soon as it has taken an initial set. I’ve done this with silnylon and silpoly.

[Jim Colten]

Monte,

Shameless plug here (no further $$ benefit to me though).  If you are a premium member you can see the entire process described here.

One thing to be aware of is that the adhesive cures in the presence of H2O … vapor in the air is more than adequate.  If your locale (Ocala NF) means anything about where you live I would not expect lack of water vapor to be your issue.

I’ve done quite a lot of that with just one failure where the adhesive did not cure (which is the source of the caution early in the article).

The guyout patch shown in the 2nd photo is now nine years old and going strong.  Six years ago I made a slightly trimmed down version of the Jay Hamm tarp where the only sewing was for a zipper in the beak.  Zero glue joint failures, including in a wet snow storm heavy enough to pull well planted stakes out of the ground.  It gets a lot of use.

 

[Sam Farrington]

KT posted the link to the BPL article that is the must read.

IVO’s photo showed the type of reinforcement patch I use. Bonding the patch before sewing makes it unnecessary to sew along the inside circular edges and avoid creating more possibilities for leakage inside the perimeter of fabric.

The silicone caulks work well for sealing. The seals have held up well on the shower stall for decades. But GE makes a silicone GLUE that is much better for bonding. Did not even need to use clamping as the article recommends. The patches will peel with enough force, especially if the glue is old, but no delamination. Did use a roller.
I still sew the patches with seams along the outer edges of the canopy.

High % Isopropyl Alcohol works great for cleaning sil coated fabrics both before and immediately after bonding before the glue sets. Greatly reduced the mess, and is miscible with water, simplifying cleanup. Mineral spirits, not so much on any of these counts. Petroleum products usually contain oil, not great for bonding.

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