Silicone for seam sealing tents

Hi all,

Picked up a tent the other day that I need to seam seal myself. It appears to be a pretty simple process. Everything I have seen about it pushes the use of a 100% silicone sealants, that would then be thinned with a white spirit and applied.

I’m really struggling to find a sealant locally that is 100% silicone, any suggestions would be appreciated. Or maybe that is not as important as I think? Can’t really find any info on if that is the case and if I would be fine with just using a decent clear marine grade silicon sealant.

This is for 20 denier Silicone Polyester fabric.

I’m not sure if it’s 100% silicone, but Coughlan’s makes a seam sealant:

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Hi Jaxz.

The silicone seem sealer isn’t locally available. The water based ones we do get don’t work with silnylon. Don’t even try. I went through the mission earlier this year. DIY is the cheapest and easiest way. Mix CLEAR bathroom silcone (you get the small tubes) with mineral spirits ( I used benzine) and mix well until the mixture has a viscosity of warm honey. The spirits evaporates quite quickly, so just top up with spirits every now and then to keep it nice and runny. Works like a bomb.

There are many youtube vids you can watch too.

Hope you come right.


Here’s a helpful link.


Thanks guys! Luckily the tent came with some fabric patches I can test on, so I will give a couple of things a try.

I think the Coughlans one will work on none coated fabric, silicone seems to only bond with silicone which makes it a bit tricky.

Thanks @Snetrabommi, the tent is also from Six Moon Designs :grin: Just picked up some clear silicone for fishtanks, so hoping that will do the job. But also spotted that the diving shops sell silnet silicone sealant, bit pricey but might give that a try.

Will try remember to report back on what works.

Hi relative to the above discussion re seam sealing I have an old KWay tent good condition the seam seals are coming loose nobody seems keen to re-seam seal the tent what do you suggest?

Hey Chris, do you know what sort of material it is and how it was sealed previously? Likely Nylon with taped interior seams I’m guessing.

Hi that’s correct taped interior seals.

If it is not silicone impregnated and not straight polyester then I think Coghlans Seam Sealer that Arno mentioned should work. The other option would be Seam Grip, bit more expensive but pretty versatile stuff.

My understanding would be that you would have to peel off all of the old tape, then clean the seams with something like Isopropyl alcohol. Afterwards reseal all of the seams from the inside surface.

REI has a nice summary.

Howzit Jaxz, have you had a chance to seal it up yet? I just received my Gatewood Cape from SMD and am now faced with the same challenge. Was going to use the clear aquarium grade silicone with mineral spirits (DIY according to the instructions put out by Tarptent, they seem to prefer this to Seamgrip or similar products). Any feedback would be great.

I can tell you from experience that DIY is the way to go. Super simple, not to mention waaaay cheaper. Good luck.

Hey Colan, I haven’t actually yet :sweat_smile: Haven’t been living somewhere that it is easy to set up and do all at once, so put it off for the moment. I bought some Silnet from Divetek and picked up some odorless mineral spirits from a random stationary shop alongside some sponge brushes. The idea is to dilute the Silnet for the job. Probably not the cheapest way to go about it, as I reckon I’m going to need at least 2 tubes. But I ended upin a deep hole on the backpacking light forum that made me feel that was the safest way forward haha.

But to be honest I’m pretty certain the marine grade and some pnp mineral spirits would work as well.

Let me know how it goes, also how the Gateway turns out. The tarp poncho crossover is a really cool idea, I just always thought it might be a bit too minimalist for me. Did you go for an inner net as well?

I’m going to try and set it up in the garage this weekend and go from there, the Gauteng rain is not making things easy! I have heard that the humidity is great for curing the silicone though?

Damn, guess who’s taking a trip to Divetek tomorrow lol, now that I know the proper stuff is available I’m not going to play around. Cheap is relative when we just had tents shipped half way across the world! Besides, once diluted I’d imagine one tube could very well be enough? This guy’s method seems to use very little and be really neat. Anyway, I’ll keep you updated if I imagine to co-opt the garage for the job.

And as for the Gatewood, I think I’ll still be taking a hardshell along on most trips where any real rain is predicted. At least for now. I thought the dual use would be great for when only light rain is expected or there is a slim chance. The main reason I chose the Gatewood is due to it being the lightest full protection shelter that I could find that wasn’t dyneema and therefore hella expensive. I’m also not the tallest, so after setting it up today (really badly) I’m glad to report it was more than big enough. Will see how it handles wind, etc. etc. For now no inner, I’ve got the Sea to Summit Nano Mosquito Net (82g) if bugs are expected and bought large pieces of polycro and tyvek which I’m going to attempt to build bathtub floors from. We’ll see how far I can push this!

Which tent did you go for?

Thanks, looking forward to hearing how it turns out. Probably have a go at mine in the next week or so. The supplies have been glaring at me from my desk for weeks now :sweat_smile:

Agree, think there is something nice to the idea of the Gatewood for a lot of our weather. Seems like it could be a good fit for something like the Cederberg in summer as a two in one. Got great reviews in general.

Oh nice, where did you find the Tyvek? I could find Polycro, but felt like everywhere I end up in the WC would shred it. May be underestimating how strong it is though.

Have been looking for a 1P single trekking pole tent for a while. Had been eyeing some of the 3F UL stuff on Aliexpress, but I’m over 6ft so didn’t seem smart. Friend was in the US so ordered a Lunar Solo in the end, which seems crazy large on the inside vs how little tent it actually is. First silpoly tent for me, and I’m getting the sense it might have a fiddly setup :face_with_monocle: But excited to give it a try as soon as I can get away! New quilt and lots of fun stuff to try out.

Of course the moment I ordered it SMD updated the tent and 3F UL released a Pro western sized version of the Lanshan 1 :rofl: but that’s how being overly invested in this sort of stuff goes haha

I found ultra-lightweight Tyvek 43gsm from Jessop Industrial Machinery (Pty) Ltd, here in Cape Town. It’s holding up really well. Happy with it. R100 per metre and the rolls are the standard 1.5m width.

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Sorry for the week-long wait for a reply guys.

Went ahead and picked up some Silnet from Divetek (thanks again @Jaxz for the info). It came with a brush but I chose to use one with finer bristles. I mixed the silicone with mineral turpentine until it had an “olive oil” consistency, as had been suggested by many sites and eye balled it by what I’d seen on videos. Set the tent up in the garage, as taught as I could get it (it surprised me how much weigh this actually took! Must’ve been upwards of 10kg per corner!). Went ahead and applied reasonably liberal amounts to all the seams which I felt might leak, wiped the excess off with some TP and left it for a full day to dry.

Anyway, I only ended up testing it out today aaaand… fail. The seams look neat, great, but a few drops got through at the high stress points. Given, I focused pretty much the full blast of the sprinkler at each seam with only a few centimeters clearance (after wetting the entire tent for a few minutes), but even so. If I had to guess where I went wrong it would be as follows:

  1. I was more worried about applying the silicone too thick than too thin, thinking that I could always come back and apply another layer rather than trying to peal nasty thick seals off. I believe my initial mix was too diluted. “Olive oil consistency” is relatively arbitrary a metric.
  2. With the Gatewood, the high stress points are around the hood, as the grommet for the trekking pole is attached via a harness which meets the rest of the tarp in only a few points. These points therefore stretch out a whole lot more than the rest of the peak. On something like the Lunar Solo this would likely not be as much of an issue (the stress from the peak should be evenly distributed to the rest of the material as it is sown all around, rather than only at a few points). As a result, the holes from the stitching were noticeably enlarged at these points. I should likely have applied more/thicker sealing here.

Despite this, the rest of the seams seemed good! I’m off to Mnweni tomorrow to try it out, rain tomorrow night and then dry but probably quite windy for the rest of the weekend. A few drops won’t kill me!

Also, the Tyvek and Polycro were ordered along with the tent. Unfortunately I can’t point you in the right direction in SA for these. Snetrabommi seems to have a good lead for Tyvek though!

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Wow, I’m interested to hear how the cape / tarp Gatewood worked out in the real world! Seems like a very innovative product!

I am wondering why those of you who ordered from overseas didn’t just purchase the Six Moons seam sealing service when you bought your tents. Is the price exorbitant?

Thanks for the feedback Colan, think I should get a chance to seal mine this weekend. So Warm honey instead of olive oil, got it :sweat_smile: Ended up with my Tyvek from SMD as well, which has been going into the wash a lot to soften it up, hard to justify during both a drought and low power though. So my clothes are all being rinsed rather than washed at the moment to allow for it haha.

Ruth I think it was about R400 to have seam sealed, and I’m probably in about R250 with all my messing about. But reckon you could do it for like R150. My main reason was a friend was bringing it back for me and having SMD do it adds like 2 weeks onto the shipping, which I couldn’t do. Also always keen to have fun DIYing.

Finally had a chance to seam seal and get my SMD Lunar Solo out on a hike earlier this month.

Ended up using Silnet diluted with mineral spirits for the job. Worked out in the end, but a bit messy and lots of lessons learnt.

I started off with a square foam craft brush as I had seen them used in various guides. Way too floppy and imprecise for me, messy results. Ended up really liking the circular tipped yellow foam brushes for kids from the art store. Can pick the size you need and allows you to apply a lot of pressure.

I went olive oil consistency, and in retrospect I think it was still a little thick… That was about a 50/50 ratio.

But the main two takeaway were location and thinking things through a bit more :sweat_smile: Turns out my instinct towards hot dry weather for doing this outside was wrong. Humid and mild is apparently what you need. It might very well have been a bad combination of the Silnet being old and the weather, but mine took a solid week to dry to an acceptable level. The issue there being no where to put it inside, and doing this outside in the very dusty and windy west coast. Turns out everything that can stick to drying silicone will, and the tent needed a solid washing afterwards as I didn’t want to pack it with a bunch of abrasive’s attached.

The floor of the tent needed some strips painted on it to stop my pad sliding around on the very slick polyester. Should have started with this in retrospect. Turns out you will get silicone everywhere trying to get into a tent you have just seam sealed.

I haven’t had it in a proper downpour yet, but a solid soaking with a sprinkler seems to show promise. It also dried a lot prettier than I was expecting, having used way more silicone than I now know was necessary.

Probably not the place for a review, but got the tent out for a couple of nights in the Cederberg and rather happy. Bit fiddly to setup, and the lightness of the zips worries me a little. But solid in the wind and shockingly large on the inside for the weight and pack size. Had a lot of critters taking an interest in my pack one night and found it large enough to be spread out in the tent with my pack and most of my gear unpacked around me. Also my first encounter in the Cederberg with a solid gnat storm one morning made me very pleased I wasn’t in a tarp.

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