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Helena Campsite and Speedster Stove test

September 10, 2021 — BarryK

Last weekend, went for a hike. Usual stamping ground, Mundaring locality. Caught train then bus to the town of Mundaring, which is in the hills just outside the Perth metropolitan area. Then walked south on the Mundabiddi Trail to the Mundaring Weir Hotel -- as usual, had lunch there. Then walked approximately East, on the Bibbulmun Track, and camped overnight at the Helena Campsite. Next morning, ambled back along old fire trails, to the Mundaring town, then public transport back to Perth.

Lovely Spring weather, a couple of sunny days, though the nights were cold. I was surprised, about 20 people stayed overnight at the Helena Campsite. Some used the internal bedding provision, some, me included, pitched tents. Yeah, we did the sitting-around-the-campfire thing at night. Even somewhat-anti-social-me sat there for awhile.

Here is a photo just after 6.00am, before the sun has appeared on the horizon, but is starting to light the sky:

img1

When I arrived at the campsite on Saturday evening, my legs were knackered, so the walking had degenerated to a slow shamble. Don't have an app for measuring distance, but it would have been about 23km.

Chatted with one young fellow who had run all the way from the Mundaring Weir Discovery Centre, he said it took him about 1 hour. The trail is up and down rocky terrain, and I took about 4 hours to walk that same path. Oh well.

Next morning, followed lovely old fire-trails, here is a photo:

img2

Legs were knackered, but walked slowly and it was very pleasant.

Main reason for this post, is want to report on using the Speedster Stove, and the new "kitchen kit". I used it on the hike, to rehydrate a veggie & couscous packet for the evening meal. Firstly, about the stove, this is it:

https://speedsterstoves.co.uk/30ml-spill-proof-meths/alcohol-burner.html

...oh, the site is currently offline, say they are off backpacking and will be online in 4 days.

Anyway, that's what I bought, 30ml spill-proof methylated-spirit (alcohol) stove, with a matching folding stand. They hardly weigh anything. The stove burns for about 18 minutes. No priming required, immediately usable. It won't spill, just screw on the lid and fuel can be left in the stove.

I had great fun putting together the "kitchen kit". I own a Toaks 1000ml titanium pot, and was able to put everything into the pot, including the meths. Here is the pot, total weight with everything inside is 498g:

k1

Toaks do not sell the 1000ml size any more, they do have a 900ml and a 1200ml. But there are other manufacturers, look on eBay and Aliexpress. Open the lid, everything packed neatly inside:

k2

The bottles are each 50ml, to hold the meths. Some meths can also be held in the stove, so potentially can carry 230ml. The weight that I measured, 498g, was with all bottles filled and the stove partly filled.

The big question is, how many days will 230ml of meths last? Hold that thought, for now, presenting everything packed into the pot:

k3

...on the left is a collapsible silicone cup, a funnel, matches, sponge, folding knife, pill-holder, titanium wind-shield, folding titanium spoon, and the Speedster Stove and folding stand.

All of these items are available on eBay and Aliexpress. The bottles are these:

https://www.aliexpress.com/item/4001079924366.html

They allow precise application of the meths, with a narrow opening, see this photo of the 100ml bottle:

s1

The titanium windshield is readily available also. Mine was originally 110mm wide, but I cut it down slightly so as to fit underneath the pot handles. It is extremely thin and can be cut with scissors. Weight, after cutting, is only 11g. I use a paper-clip to hold it in place around the stove.

The titanium folding spoon is Keith brand, which I chose as it is slightly wider (41mm) than other brands. Got it from Aliexpress.

Here is the stove and stand:

k4

The windshield is absolutely essential. It shelters the flame from breezes, but also acts with the chimney-effect, drawing air from holes at the bottom and focussing the flame onto the pot. With the windshield in place and the pot on the stand, the flame is hardly seen:

k5

If the pot is removed, the flame is quite yellow, and high:

k6

I would never have thought that this is efficient combustion, but it is. With the pot on the stand, there is hardly any tar residue deposited on the pot, and water is boiled remarkably fast.

In fact, side-by-side tests with other meths stoves, the Speedster boils the water faster. There are some comparisons on YouTube, such as this one, using the smaller 20ml Speedster:

https://www.youtube.com/watch?v=vTRrt1OltRk

...3 minutes versus 4½ minutes, the Speedster won. Also, the Mini Trangia stove has to be primed, which wastes more fuel and time -- he did not include the priming-time in that 4½ minutes.

As can be seen in the above stove, I set it up on top of my kitchen stove (with ceiling extractor fan running). I also tested the boil time. 400ml took 6 minutes.

My "cooking" on the trail is really just heating up food then eat, such as baked beans, or boil water to rehydrate a meal. And, boil water for coffee. Prolonged cooking is not required, as if required can use my insulated pouch to complete the cooking process. I have one of these, weighs just 43g:

https://bigskyinternational.com/collections/insulite-products/products/big-sky-insulite-insulated-food-pouch-freezer-bag-cooking-cozy

So, back on that question, how many days can I hike with 230ml of meths? According to the Speedster Stoves website, the 30ml stove will burn for 18 minutes. I would probably only need to boil about 600ml per day, which will take 9 minutes -- pour some out for the coffee, the rest to rehydrate a meal. That would mean 15ml per day, so the meths will last for 15 days!

Others might have heavier usage, such as make coffee in the morning, but even if the meths lasts for only 7 days, that is pretty good.

It would be interesting to compare with a gas setup. A 230g gas canister weighs 230g plus the steel container, a small gas screw-on burner is about 75g. They would probably fit in the pot OK. All-up weight is probably going to be higher, plus those gas canisters are not environmentally-friendly.

The motivation behind checking out this meths stove, is previously had used a wood-burning stove, but there are fire restrictions for much of the year here in Western Australia. Gas and meths stoves are allowed all-year round.

EDIT:
A few years ago, I was camping on the South Coast of WA, at a CALM campsite, and was cooking in a camp kitchen. I had a Vargo alcohol stove, and was cooking on a stainless steel bench. This stove:

https://vargooutdoors.com/triad-stove.html

...it is not very stable, and I accidentally tipped it over. Meths ran over the benchtop, and the flame followed it.

The Speedster Stove, on the otherhand, really is spill proof, see this video:

https://www.youtube.com/watch?v=e_K9DxZ-hAk

...he is showing the carbon one, I have the "normal" one, presume that is also just as spill proof.

I was wondering what the weight would be if went for a gas canister solution, instead of a meths stove...

Looked up the calorific value (heating power) of butane gas versus ethanol, and it is about 50Mj/kg versus 29.7Mj/kg. However, that is for 100% ethanol. Methylated Spirits sold in Australia is 95% ethanol and 5% water, with a bittering agent to render it undrinkable. So meths is going to have lower calorific value -- let's estimate around 25Mj/kg.

What that means is half the weight of butane to get the same amount of heating power as meths.

Very roughly then a 100g butane gas canister will be the same heating power as my 200ml bottles of meths.

OK, a 100g gas canister from MacPac weighs 190g, costs AU$10.99. A screw-on burner is $67.46, weighs 72g.
4 litres of methylated spirits from Bunnings is $15.72, which is $1.58 for 200ml.

So from a cost point of view, the meths is far cheaper. What about weight?

My kitchen kit, without the meths parts, packed with a 100g gas canister and screw-on burner, will weigh 488g. This is the base weight of 226g, +190g, +72g

Very similar from a weight perspective. So the choice really comes down to cost and environmental impact. Well, not entirely -- if you are only going hiking for a couple of days, then only one 50ml meths bottle is needed, so can reduce the carrying weight: 498g, take off three bottles at 58g each, the total weight of the kitchen kit becomes 324g.

Another consideration: how do you know how much gas is left? You might have to carry a spare canister just in case.

Just remembered something: if you buy the Diggers brand of methylated spirits here in AU, there is a warning on the label not to use it in alcohol stoves. The reason for this is the company is covering themselves legally, see this forum thread:

https://bushwalk.com/forum/viewtopic.php?f=5&t=37593

Interesting topic, gas versus alcohol!    

Tags: light

TreeHugger Mark-3 ridgeline tieouts

August 31, 2021 — BarryK

Continuing the TreeHugger Mark-3 tent project, this is the previous post:

https://bkhome.org/news/202108/treehugger-mark-3-tent-hem-tie-outs.html

As reported, I wasn't happy with how the tie-outs were made. The tie-outs are now glued instead of sewed, and I used a simple rectangle, scrunched-up where passes through the o-ring. See photos in previous post.

At each end of the ridgeline, there will be tie-outs, and I decided to experiment with some kind of more sophisticated design, that spreads the stresses from the tie-out cable to the tents, the forces distributed evenly onto the tent.

I experimented with folding a piece of paper, and this is the design finally used. Firstly, folded the paper in half, lengthwise:

img1

Then folded each end, so as to get "wings":

img2

Then folded the middle, both sides, inward to the centre:

img3

Another view showing the inward-folds:

img4

Showing the wings spread out:

img6

That looked interesting, and I could see how the forces are spread out at the wings. The important point is that the ripstop fabric has least stretch when the fabric squares are not pulled diagonally, which this wing design achieves.

I am not claiming this to be a fantastic design, just something to try.

Doing this with the silnylon though, is tricky, as it won't fold, is very soft and slippery. I managed, by using clips to hold in place:

img7

These clips are used in sewing, readily available via eBay, Aliexpress and Amazon. My local Spotlight store also has them, but very expensive. Then the two inward-folds, glued:

img8

Then, glueing onto the tent was messy, not at all neat like that last paper photo. From the experience, I have some thoughts how folding and glueing can be improved ...next time.

I also glued a silicone cap underneath in the tail-end, for the carbon-fibre tube to slot into. See Mark-1 construction for details.

So, now have a tent ready to test. Not complete, as plan to construct an inner mesh tent, but can put it up to see if it looks OK. Keeping a tally of the weight, it is now 286g, the ridgeline tie-outs and tail-end cap have added 8g.

Good news, my cheap Kmart digital scale is accurate. I purchased a set of 7 weights, totalling 500g, and found the scale to be spot-on.     

Tags: light

TreeHugger Mark-3 tent hem tie-outs

August 29, 2021 — BarryK

Continuing the TreeHugger Mark-3 tent project, this was the previous blog post:

https://bkhome.org/news/202108/glued-ridgeline-of-treehugger-mark-3.html

For the Mark-1 tarp, I sewed the tie-outs, so it wasn't an entirely glued tarp/tent. This time, decided to attempt a totally-glued tent...

For the tie-outs, have not used webbing, instead have folded silnylon, the same fabric used for the tent. I am not an Origami Master, and only did something very basic. Just cut rectangles 24x6cm and threaded an o-ring onto them, like this:

img1

...that is, spread silicone sealant on both sides of the rectangle-piece, around the middle, then threaded the o-ring, then folded the rectangle in half, then scrunched up the fabric near the o-ring and wrapped a strip of cling-wrap. Six with o-ring, the seventh has a hook.

The o-rings are silicone, 28mm OD and 5mm thick, these:

https://www.aliexpress.com/item/1005001460667252.html

The hook is 3.6cm size, these:

https://www.aliexpress.com/item/1005001868137584.html

Looking at my notes, I actually bought the hooks from Amazon, the 3.6cm from here:

https://www.amazon.com.au/gp/product/B08P14TWG1

I glued each tie-out onto the tent like this, a flap glued on each side of the tent:

img2

...which looks OK, but actually is not so good, as when pulled on, the stresses will be at the sides. This may have a tendency to peal off the glued join.

An Origami Master could probably have told me how the fabric could have been folded such that stress is spread evenly to the tent.

Anyway, will see how it holds up. If do decide to do something different, easy enough to cut off the tie-outs and glue something else on.

I am recording the weight at each step of the Mark-3 project. In the last blog post, after having glued the ridgeline, the weight was 251g. Now, having glued on the hem tie-outs, the weight is now 278g, an increase of 27g. Still looking good!   

Tags: light

Glued ridgeline of TreeHugger Mark-3

August 19, 2021 — BarryK

Continuing the Mark-3 glued-tent project, here is the previous post:

https://bkhome.org/news/202108/finished-glueing-hems-for-treehugger-mark-3-tent.html

Next-up is to glue the ridgeline of the tent. This joins the two pieces, with 2cm overlap. That 2cm is nominal. I used a spreader tool, an approximately 14cm long aluminium channel, 2cm outside-width with 1.5mm wall thickness:

img1

...so only spreads the sealant as a thin film 1.7cm wide. So I overlap the two pieces of silnylon a tad under 2cm. Anyway, when the seam roller is run over the join, the sealant spreads a little bit.

The ridgeline is curved, so the two pieces need to be arranged so that the ridgelines are straight, with 2cm overlap. So when I glue, both pieces will already be in place, and the top piece will just flop down into the required position. I used concrete blocks to hold the ends firmly in place:

img4

Glued along the ridgeline, just doing about 20cm at a time, and it came together OK. One point to note, I made chalk marks about 20cm apart beforehand, as a guide to how far to glue. So, apply glue, spread, let the top piece fall onto the bottom piece. There was of course a chalkline running the entire length of the bottom piece, 2cm from the edge.

Because of those blocks on each end, had to wait until the ridgeline glue had cured, then glued the ends.

An important detail: in the above photo, you can see that I used a wood plank. What I also did was place cling-wrap the full length. This is because some sealant will bleed out of the overlap underneath. Silicone sealant does not stick to cling-wrap.

Now for some advice on what not to do...

I thought that it would make glueing easier if I constructed a frame for the tail end, this thing:

img2

The tail-end of the tent has two flaps that have to be glued together, which I did, using the cardboard-box-thing to hold everything in place:

img3

So far, ok, then cutout the reinforcing for the tail-end:

img6

And glued it on:

img7

...which is where things went a bit wrong. Ended up with some wrinkles, on both sides.

Glueing on the reinforcing pieces is tricky enough when doing it on a flat horizontal surface. The cardboard-box-thing made it very difficult.

So, if I had to do it again, I would glue on a flat horizontal surface. Glueing the two end-flaps together could have been left to last. Lesson learned.

At the high-end of the ridgeline, glued another piece of reinforcing:

img8

I have been keeping a tally of the weight as the project progressed. The previous weight, having glued the hems and reinforcing on the hems, is 229gm.

I filed the 2cm spreader tool so as to spread a slightly thicker film of glue, compared with the 1.5cm spreader used for the hems. I reasoned that the ridgeline is going to be subject to most stress, so be generous with the glueing.

The weight, having glued the ridgeline and reinforcing on each end, is now 251g, up by 22g.

The next step will be to attach the tie-out webbing. However, instead of sewing on webbing as I did for Mark-1, I am thinking of going for an entirely glued tent, no sewing at all. Up until now, I thought that the high stresses at the webbing would require sewing, but rethinking it... anyway, stay tuned.   

Tags: light

Finished glueing hems for TreeHugger Mark-3 tent

August 15, 2021 — BarryK

Continuing the Mark-3 project, this is the previous blog post:

https://bkhome.org/news/202108/glueing-hems-for-treehugger-mark-3-tent.html

I have glued the hems on both pieces of silnylon. This is the smaller piece:

img1

...the hems are folded on what will be the inside of the tent. In the above photo, you can see 3 sides have hems. Starting from the left, bottom of tail-end flap, bottom of side of tent, and the edge rising to the peak at the high-end. Here is the other, larger, piece:

img2

...this has a flap at the high-end, for enclosing the tent. For this piece, there are 4 hems. Starting from left, the edge of the flap, the bottom of the flap, the bottom of the side of tent, and bottom of the tail-end flap.

I am recording the weight as each step is completed. As reported in the previous blog post, the weight of the fabric, the 2 pieces, is 182g. With the glued hems, the weight is now 217g. An increase of 29g.

The next step was to glue reinforcing where tie-outs are going to be sewed on. I used two bowls, 15.2cm diameter and 20.6cm diameter, as templates to cut out circles. Here is the reinforcing glued onto the small piece:

img3

...also glued onto what will become the inside of the tent. I used the larger diameter reinforcing at the corners, the smaller in the middle.

The larger piece has 4 reinforcings, due to the flap at the high-end.

I have posted how to glue and apply the pieces of reinforcing, in the Mark-1 instructions. It is tricky, to not end up with wrinkles. I extrude parallel beads of sealant onto the piece of reinforcing, then spread it with a finger (wearing gloves), then dip the fingers into the mineral turpentine to remove stickiness, then lift up the reinforcing and lower it in place, trying to get it exactly in place, so don't have to push it around. If some pushing around is required, it is necessary to check that wrinkles have not developed on the other side.

The weight has now climbed to 229g, a jump of 12g.

The next step will be to glue the ridgeline, perhaps tomorrow.

Note, I have appended to this blog post, a speculation why some silnylon has poor peel strength:

https://bkhome.org/news/202108/testing-peel-strength-of-10d-orange-silnylon.html      

Tags: light

Glueing hems for TreeHugger Mark-3 tent

August 12, 2021 — BarryK

Continuing the Mark-3 tent construction. It started with a design in SolveSpace, reported here:

https://bkhome.org/news/202107/more-tweaks-for-treehugger-mark-3-tent.html

I am using 10D "burnt-orange" silnylon ripstop fabric. Yesterday conducted tests on the "peel strength" with silicone adhesive:

https://bkhome.org/news/202108/testing-peel-strength-of-10d-orange-silnylon.html

I have cut out the two pieces, and together they weigh 182g, so it is going to be very interesting to find out how much weight the glueing will add to that.

In yesterday's blog post, I tested both neutral-cure and acetic-cure silicone sealant, and today started to use the Selleys 401 Engineering Grade silicone. Did two hems, then realised a couple of disadvantages of the acetic-cure...

For the neutral-cure, I am using the Monarch compact applicator gun, this one:

https://www.bunnings.com.au/monarch-mini-compact-caulking-gun_p1662108

Monarch do not make an acetic-cure silicone, so I had to use the full-size applicator gun. This has a disadvantage, apart from being a bigger and heavier thing to wield, when the fingers are taken off the trigger, silicone still oozes out of the nozzle. Even after pressing the relief-trigger, it still oozes out.

However, the design of the Monarch compact applicator is such that when the fingers are taken off the lever, the flow stops immediately. This precise control makes application so much easier. And, it is smaller and lighter.

The second disadvantage is that acetic-cure silicone skins quickly. This is not just an issue with applying, but I found it also gunked-up my spreader tool. I have this special spreader tool, introduced here:

https://bkhome.org/news/202106/refinements-to-glueing-tarp.html

img0

When glueing the hems, I run the applicator gun along for about 30 - 40cm, then use the spreader tool, then fold over the hem. I am concerned about the rapid skinning of the surface. It seemed OK, but might be an issue if I tried a longer run and/or was very slow to fold over the hem.

I did two hems, then decided to go back to neutral-cure and the Monarch applicator gun. I did comment yesterday that perhaps the peel strength of the acetic-cure join might be a "tad" stronger, however, that really might have been my imagination -- they are both strong.

Regarding glueing of the hems, here is a photo showing the hem on the tail-end flap, ready to be glued:

img1

Each piece of fabric has a flap at the tail-end of the tent, that will be joined together, to enclose the tail-end. The hems are 1.5cm, so there is a chalk line marked 3cm from the edge. I run the silicone along, following the chalk line, then fold over the fabric. Pretty simple. The photo shows the bottom-side of the tent already folded.

Note, for those who haven't read through the Mark-1 construction posts, after applying the sealant, then the spreader tool, then folding over the hem, I then use a "seam roller", shown in this photo from the Mark-1 project (the cup has mineral turpentine):

img3

You could do it with your fingers, but the roller makes it easier to roll-out the bubbles. The fabric is incredibly stretchy, so the roller has to be rolled backwards and forwards over only a couple of inches, progressing down the hem -- just rolling straight down the hem results in warping of the fabric.

The roller is from Bunnings:

https://www.bunnings.com.au/uni-pro-30mm-seam-roller_p1662302

Another little detail, for anyone reading this who is interested in giving it a go. Silicone banks up inside the spreader tool, and obviously this is going to start to skin. So, what I do is clean it out with a tissue after doing each hem line. And another detail: when ejecting the sealant from the tube, apply it with a slight zigzag, which might help the spreader tool to create a nice even film output.

A comment about glueing versus sewing: there is a misconception, that I have read often on forums, that glueing makes the tarp/tent much heavier than if sewed. Not so. It is a matter of doing it "properly", only using enough glue and no more. My spreader tool ensures that.

In fact, a sewed tent may end up being heavier, as it has to to be seam-sealed, probably using as much sealant as I use. Furthermore, hems and ridges/joins have two (or more) folds when sewed, requiring extra cloth, whereas I have just one on hems and no fold on ridgelines/joins.

I might as well also add, another misconception, that a glued tent is not as strong as a sewn tent. Not so. In fact, the glued tent is likely to be stronger. There are some places on the glued tent that do still need to be sewn, such as attaching tie-out points.

...so, my little plug in favour of glued tarp/tent. Onward ho, will glue the hems on the other piece tomorrow.   

Tags: light

Testing peel strength of 10D orange silnylon

August 11, 2021 — BarryK

I have made a tarp/tent by mostly glueing instead of sewing, and it has been a success story.  Search this blog for earlier reports -- suggest click on "light" category link at bottom of this post to quickly find them.

The fabric used is silnylon, which is nylon ripstop weave impregnated with silicone -- so there is silicone on both sides. When two pieces are overlaid and glued together, the join has been found to be very strong. However, there are two forces to be tested -- "longitudinal" strength, and "peel" strength.

There is a chap (Samuel) who made a video testing glued strength of silnylon, linked from an earlier blog post:

https://bkhome.org/news/202105/glueing-silnylon-fabric-versus-sewing.html

...the blue 10 denier silnylon purchased from Adventure Expert is what I used in the TreeHugger 1P Mark-1 tarp/tent. Here is a direct link to the video:

https://www.youtube.com/watch?v=_5yGxdJveZk

...Samuel uses the term "lateral" the same as my "longitudinal", and the term "perpendicular" same as my "peel" strength.

The longitudinal strength is fantastic, photo taken from the video:

img1

What is not so good is the peel strength, that is, when try to pull the two pieces apart. In the above photo, the two pieces are glued together, but if you were able to lift up one edge and pull on it, that would be testing the peel strength.

If there is glue right to the edge, then there is no opportunity for peel strength to be a concern. However, with a tent flapping in the wind, there could be a weak spot, maybe at the end of a join, that might start to peel apart.

I did subjective tests on the blue 10D silnylon from Adventure Expert, and found peel strength to be far less than longitudinal strength.

Planning for Mark-2 tent, I ordered 20D olive silnylon from Extrem Textil:

https://www.extremtextil.de/en/ripstop-nylon-tentfabric-silicone-coated-20den-36g-sqm.html

...I found peel strength to be very poor.

I also purchased 10D light-green silnylon from Rex Outdoors:

https://www.aliexpress.com/item/32625219053.html

...found peel strength to be very good.

These tests are only subjective, me just pulling on the fabric with my hands. I used neutral-cure silicone sealant, this stuff:

https://www.bunnings.com.au/monarch-150g-mini-translucent-silicone_p1662110

I don't have enough of that light-green silnylon to construct the planned Mark-3. Unfortunately, Rex Outdoors have sold out of that color, so purchased their pantone-orange color -- I would describe it as "burnt-orange".

It arrived a week ago, and I cut off two pieces to perform peel tests. One piece, used the Monarch neutral-cure, and the other piece used Selleys RTV Engineering Grade acetic-cure, this one:

https://www.bunnings.com.au/selleys-310g-401-rtv-engineering-grade-silicone_p1231042

Left them for a week, so today is the big day, the peel tests. Here are the two pieces, propped up with clips for the photo-shoot:

img2

I wanted to find out if there is any difference in peel strength on each side, hence you can see in the above photo, glued both sides.

Result: just like the green fabric, very strong. Takes considerable strength to peel them. Not quite sure, as this is very subjective, but the acetic cure might be a tad stronger. Both sides seem to be equally strong.

I wonder why the 20D silnylon from Extrem Textil has such poor peel strength? This is wild speculation, but it could be due to the manufacturing process, how the silicone is applied. With the 10D silnylon from Rex Outdoors, the silicone seems to be impregnated right through. However, what if the the 20D silnylon has separate coating of silicone on each side, not impregnated right through?  -- that would account for the poor peel strength. Or, it could be that the silicone on the silnylon is a different chemical composition, that does not bond well with silicone sealant.

Lesson here, for anyone thinking of constructing a tarp/tent by glueing: test the peel strength first.

EDIT 2021-08-15:
I have discovered a possible reason why some silnylon has poor peal strength. I was browsing through the offerings at RipstopByTheRoll, and saw that their 1.1oz 20D silnylon is described as:

Sil/PU (silicone/polyurethane) double coated 1.1 oz ripstop nylon (silnylon). This fabric is coated with a sil/PU layer on each side and is non-breathable.

I contacted them, and they explained that actually the coating is a blend of silicone and PU, to achieve higher waterproofness.

As far as I can see, only their 7D silnylon has pure silicone. It seems that this is a trend, to coat the nylon fabric with a silicone/PU blend. I am wondering if some vendors don't bother to inform of that fact.

This is interesting, a sil/PU coated silnylon becoming sticky:

https://www.trek-lite.com/index.php?threads/sticky-sil.2343/

Something else that has puzzled me: I have read, again and again, that silnylon will stretch when wet, and this is given as a big disadvantage. However, I asked myself, the silicone is permeating the nylon fibres, so how can they get wet?

What people are actually referring to is fabric that has silicone coating on the outside and PU on the inside. Probably most tents have this fabric. Yes, moisture will get into the fibres and it will stretch. Really, the only good thing about this fabric is that the manufacturer is able to seam seal it by applying tape on the inside. Sealing of silicone coated silnylon has to be painted on manually, not something that most tent makers want to do.

To obtain an appreciation of why silnylon, with pure silicone coating both sides, is superior, read this:

https://www.slingfin.com/blogs/the-beta/fabric-coatings-101-pu-vs-pe-vs-silicone

...his reference to Sil/PU coating is silicone on the outside and PU on the inside. We now have a new trend, a mix, or, blend, of silicone and PU, coated on both sides.

I have a suspicion that this sil/PU blend is the cause of the poor peel strength.       

Tags: light