Bushwalk Australia

Here is my how-to page:

https://bkhome.org/light/treehugger-1p- ... -178g.html

It is "mark 1" and after using it for awhile, will identify where needs improving, and will probably construct a "mark 2".

Thinking ahead to that possible mark-2, I have ordered some 20D silnylon. I built mark-1 with 10D silnylon, which is 31 gsm (grams per square metre), however the 20D is only 36 gsm, not much more. So reckon the little bit of extra weight will be worthwhile, as the tarp will be stronger.

Rough calculation, the 20D will add 21g to the tarp, so total weigh will be pushing 200g.

That 10D fabric seems plenty strong enough though.

Onya Bazza!
Looks good.

If you have some silnylon, and wondering about its "peel strength" when bonded with silicone adhesive, telemarketim would like samples for testing, so that he can build up a comparison table:

viewtopic.php?f=53&t=35134

You would need to know its specs and where you got it from. Ideally, would be good to know what factory it was manufactured.

That's good! Being a Protrail fanboy I like the design as well. I bought some Xenon Sil 1.1 for a poncho and at 37g/m I've been impressed with it's strength and waterproof qualities.
Not saying it's better than other 20D's but worth considering if you have to buy some material https://www.tiergear.com.au/shop/diy-supplies/fabric/xenon-sil-1-1-per-metre

Hi BarryK, What a great detailed series of posts on your project. I have only dreamed of making a glued silnylon tent, but you have done it! Congratulations. May I say that it is a 'bold move' (from Yes Minister) to first try with the sub-optimal glueing silnylon.

Thanks for your mention of my effort to determine silicone rubber glueing properties of tent fabrics (and anything else for MYOG).

Regarding sewing these slippery stretchy tent fabrics. You are probably discovering that, after the glueing, the sewing is relatively easy. I use the big and cheap 300g tubes of silicone, so waste is of no consequence. Consequently, I quickly glue excessively and later squeeze out the excess slowly and steadily. The curing slows once the glue is covered by fabric (as you indicate in your other post). This means that you can easily get 100% cover. The squeezed out excess can be quickly wiped off with turps and a cloth or paper. Spreading the glue around on top and bottom outside surfaces seems to make it easy to sew with a sewing machine.

Regarding tie-outs, I think you could have used a cut ribbon of silnylon fabric that can be rolled and glued and or sewn into a strong tie-out that can be 4, 6 or even 8 layers thick. These can be super light and strong. I have successfully used these on all my tents. They are infinitely strong if there are enough fibres equally sharing the load.

The sockets for the poles can also be made of silnylon tubes (glued or sewn) and glued and or sewn to the ridgeline. An example is shown on the legs of my camp stool in the photo below. Please excuse my crappy sewerist sewing. Ugly, but it works.



Lastly, do you have a photo of how you arrange the 'tree hugger backrest' with this tent. I am missing something?
Thanks again for sharing your experiments. Tim

BarryK wrote:If you have some silnylon, and wondering about its "peel strength" when bonded with silicone adhesive

I'll be sewing for strength and just 'seam sealing', but not in Silnylon. Anyway I have some clothes on the brain at the moment with the arrival of some very nice fabric.
No glueing going on there


Look forward to following your blog, Baz.

Lamont wrote:

BarryK wrote:If you have some silnylon, and wondering about its "peel strength" when bonded with silicone adhesive

I'll be sewing for strength and just 'seam sealing', but not in Silnylon. Anyway I have some clothes on the brain at the moment with the arrival of some very nice fabric.
No glueing going on there

Lamont, Where is your spirit of adventure? You could start a new fashion. Tim

telemarktim wrote:

Lamont wrote:

BarryK wrote:If you have some silnylon, and wondering about its "peel strength" when bonded with silicone adhesive

I'll be sewing for strength and just 'seam sealing', but not in Silnylon. Anyway I have some clothes on the brain at the moment with the arrival of some very nice fabric.
No glueing going on there

Lamont, Where is your spirit of adventure? You could start a new fashion. Tim

Ha ha. Ooooh yeah!

This stuff is not seeing any glue Tim, just the soft and delicate caresses of my sewing machine.

telemarktim wrote:Hi BarryK, What a great detailed series of posts on your project. I have only dreamed of making a glued silnylon tent, but you have done it! Congratulations. May I say that it is a 'bold move' (from Yes Minister) to first try with the sub-optimal glueing silnylon.

Ha ha, I bought 7 metres of it, had to use it. Reckon it will be OK (fingers crossed).

Lastly, do you have a photo of how you arrange the 'tree hugger backrest' with this tent. I am missing something?
Thanks again for sharing your experiments. Tim

I haven't done that part yet. So far only "stage 1", a basic tarp. Next will start adding the bells and whistles. The rest of the design is still in my head.

After erecting the stage-1 tarp in my lounge room and eye-balling it, I realised that it would be better with a catenary cut on the ridgeline. Making that mod and will update the instructions soon.

telemarktim wrote:I use the big and cheap 300g tubes of silicone, so waste is of no consequence. Consequently, I quickly glue excessively and later squeeze out the excess slowly and steadily. The curing slows once the glue is covered by fabric (as you indicate in your other post). This means that you can easily get 100% cover. The squeezed out excess can be quickly wiped off with turps and a cloth or paper. Spreading the glue around on top and bottom outside surfaces seems to make it easy to sew with a sewing machine.

Tim,
Today I bought one of those 150g mini-tubes and a dispenser gun, from Bunnings:

https://www.bunnings.com.au/monarch-min ... n_p1662108

I am re-doing the ridgeline with a catenary, and wondered if the shorter 150g dispenser might be easier to handle than the 300g.

Yes, quite happy. One thing I noticed, soon as I took fingers off the lever, the flow stopped. With the big dispenser, the flow would keep going a bit, unless I pressed the pressure-release lever. But didn't have to do that, which was nice, gave me very precise control over the dispensing.

Hi Barry,
I have never used the smaller ones. I only use the 300g ones. It is nice to hear that you are not having this problem with the shorter tubes. It is not immediately obvious to me why this would be so. Putting my physicist's hat on, I guess that halving the length of the 'cartridge cradle' leaves it very much less prone to flexing while the trigger is being pulled and leaves negligible flex-back to continue the flow. I can feel that flexing when using the big dispenser. I never use the large formal 'plunger gun' for the reasons you describe.

Instead, I stand the tube on the handle of a kitchen broom and pull the tube downwards when I want more silicone. I Don't get any unwanted flow. I actually get a tiny reverse flow, that is no problem. My method is not so good for long tent seams, It sounds as though you are onto a winner with the stubby dispenser. I will put the idea in my Bowerbird brain for when I try a 100% glued tent!

Did you get an acetic cure silicone rubber in a stubby tube? I would be interested if you could share the product link?

An afterthought, maybe too late. Do you prime the fabric with thinned rubber before the formal glueing? I do. I don't know if it improves the bond strength but in my experience, it seems to make the subsequent spreading of the thick rubber easier soon afterwards. Maybe we should do the glueing with thinned rubber so that we have more 'working time' to get everything just right?

I hope my brain dump makes a little sense.
Thanks for continued sharing of your ideas
Tim

telemarktim wrote:Did you get an acetic cure silicone rubber in a stubby tube? I would be interested if you could share the product link?

An afterthought, maybe too late. Do you prime the fabric with thinned rubber before the formal glueing? I do. I don't know if it improves the bond strength but in my experience, it seems to make the subsequent spreading of the thick rubber easier soon afterwards. Maybe we should do the glueing with thinned rubber so that we have more 'working time' to get everything just right?

Bunnings only has the Monarch brand mini tubes and dispenser guns. That seems to be the only brand selling the mini tubes in Australia.
Monarch sell two types of silicone, for kitchen/bathroom, and for roof/gutters, and both are neutral cure.

I used the kitchen/bathroom silicone:

https://www.bunnings.com.au/monarch-150 ... e_p1662110

Monarch site:

https://monarchpainting.com.au/collection/sealants/

I don't do any kind of surface priming. I vaguely recall reading someone painting the surfaces with a cleaning agent, maybe alcohol, to remove finger marks etc.

I just dispense a bead of silicone, straight from the tube, then run finger down to spread it, then join the two pieces. Hope to get it pretty much right first go. I have had the experience in the past, where have tried to fiddle around with it after making the initial join, and it can become a mess. So I understand why you prime the surfaces beforehand!

However, I am attempting to get it setup such that the two pieces can just "fall together" and be just right. I have just done the catenary curve on the tarp, and used pins, and it worked really well. Will update the tarp instructions soon.

I have modified the Mark-1 tarp, changed from a straight ridgeline to a catenary.

At first, I cut a minimal catenary, after reading advice on some forums about what kind of curve constitutes a "minimal" catenary. Didn't think much of it, so cut again, this time a "deep cut" catenary. Now it is looking good!

Instructions here:

https://bkhome.org/news/202107/treehugg ... y-cut.html

Hi BarryK, That deep cat curve looks great. If the sewn ridge line was straight grain would it work with a shallower curve or no curve at all? Tim

telemarktim wrote:That deep cat curve looks great. If the sewn ridge line was straight grain would it work with a shallower curve or no curve at all? Tim

Yes, eye-balling it here in my lounge room, it does look good.

I don't understand what you mean by "straight grain".

With the original straight-cut, it was along the edge of the fabric, so cut at zero degrees angle to the ripstop fabric squares, so stretch along the ridgeline will be minimized.

With the catenary cut, the deeper it is, the more at an angle to the ripstop squares, so the more the ridgeline is liable to stretch.

However, I have glued the ridgeline, 2.5cm overlap, and just tugging on it, it feels very strong and does not noticeably stretch.

I experimented a little with gluing silnylon when I made a tent about ten years ago. The primary load bearing parts of my homemade tent were sewn flat-felled seams. But a number of other parts were glued.

I had just one source of silnylon at that time. But I had several different types of silicone adhesive and I found that there was a big difference between them when it came to how well they glued the pieces together.

I ended up regretting gluing so many parts of my tent. While it simplified some aspects of construction it added significantly to the weight. Sewing and then seam sealing is lighter and stronger. If I had to do it over again I would sew 99% of the tent. That said, while a little homely looking it's still a functioning tent ten years later. The glued parts have held up nicely.

Orion wrote:I had just one source of silnylon at that time. But I had several different types of silicone adhesive and I found that there was a big difference between them when it came to how well they glued the pieces together.

I have wondered whether the different silicone sealants available at hardware stores have different chemical composition, that might affect the glued strength. For my tarp, I have only used these two, neutral cure:

parfix-40g-clear-all-purpose-silicone:
https://www.bunnings.com.au/parfix-40g- ... e_p1230047

monarch-150g-mini-translucent-silicone:
https://www.bunnings.com.au/monarch-150 ... e_p1662110

Orion wrote:I ended up regretting gluing so many parts of my tent. While it simplified some aspects of construction it added significantly to the weight. Sewing and then seam sealing is lighter and stronger.

Yes, when experimenting, I also found that the weight can get out of hand. But, I found it depends how the silicone is applied...

The secret is to spread a very thin film of adhesive, with no wastage out the sides. For doing the hems, I use a short piece of aluminium channel, 15x15x1.6mm. The end is cut at 45 degrees:



A bead of silicone is ejected along the hemline, and this guide is run down, following a line marked by chalk. Index finger is on the end, to hold the guide lightly on the fabric, and a very thin film of silicone is left behind. Nothing spills out the sides, it just piles up inside the guide. The silicone is not thinned.

The hem is folded over, I then run over it with a Uni-Pro 30mm seam roller, also from Bunnings.

The end result is a hem that is extremely light weight.

Orion wrote:I experimented a little with gluing silnylon when I made a tent about ten years ago. The primary load bearing parts of my homemade tent were sewn flat-felled seams. But a number of other parts were glued.

I had just one source of silnylon at that time. But I had several different types of silicone adhesive and I found that there was a big difference between them when it came to how well they glued the pieces together.

I ended up regretting gluing so many parts of my tent. While it simplified some aspects of construction it added significantly to the weight. Sewing and then seam sealing is lighter and stronger. If I had to do it over again I would sew 99% of the tent. That said, while a little homely looking it's still a functioning tent ten years later. The glued parts have held up nicely.

tent.jpg

Hi Orion, Your tent looks great. Regarding the different silicone adhesives that you tried, would you be able to list them and tell us which one worked the best? Tim

telemarktim wrote:Hi Orion, Your tent looks great. Regarding the different silicone adhesives that you tried, would you be able to list them and tell us which one worked the best? Tim

That's a photo of the good side of the tent. :-)

I remember three adhesives in particular. One was McNett's Silnet (now GearAid SilNet). One was GE general purpose silicone glue. And one was DAP All Purpose Aquarium silicone. All three claimed to be "100%" silicone. The first two were some type of neutral cure. The DAP was an acetic acid cure.

The DAP product was far superior in peel tests as compared to those other two.

Orion wrote:I remember three adhesives in particular. One was McNett's Silnet (now GearAid SilNet). One was GE general purpose silicone glue. And one was DAP All Purpose Aquarium silicone. All three claimed to be "100%" silicone. The first two were some type of neutral cure. The DAP was an acetic acid cure.

The DAP product was far superior in peel tests as compared to those other two.

I also have tested GearAid SilNet. It has very poor "grip" and I decided that it is not suitable. It is a "thinned" silicone, very runny compared with the silicone sealants that you buy in hardware stores. It is designed to seep into threads, for seam-sealing a tent.

I have done some comparison tests with neutral-cure and acetic-cure sealant, and not found any difference, with regard to bonding to a silicone surface. I did some comparison tests years ago. Can't recall all the sealants that I tested. I think, Parfix and Selleys brands from Bunnings. I do recall one that I used a lot, years ago:

selleys-310g-401-rtv-engineering-grade-silicone:
https://www.bunnings.com.au/selleys-310 ... e_p1231042

Not sure if I remember correctly, but I think the acetic cure was better at bonding to glass. Both neutral and acetic were poor at bonding to aluminium. Both were superb bonding to existing silicone sealant.

The silicone sealant that I now use, for tent construction, I do not thin. Especially after I discovered how poor Silnet is for glueing.
Maybe a contentious point, perhaps a little bit of thinning is OK.

Ah ha, found an old blog post, not that old, 2019, where I tested the Selleys 401 sealant:

https://bkhome.org/news/201905/testing- ... alant.html

Found also a reference to the neutral cure sealant that I used:
Parfix "Roof, Gutter and Concrete" silicone sealant.

...at the time, was building a prototype solar water distiller.

BarryK wrote:

Orion wrote:I remember three adhesives in particular. One was McNett's Silnet (now GearAid SilNet). One was GE general purpose silicone glue. And one was DAP All Purpose Aquarium silicone. All three claimed to be "100%" silicone. The first two were some type of neutral cure. The DAP was an acetic acid cure.

The DAP product was far superior in peel tests as compared to those other two.

I also have tested GearAid SilNet. It has very poor "grip" and I decided that it is not suitable. It is a "thinned" silicone, very runny compared with the silicone sealants that you buy in hardware stores. It is designed to seep into threads, for seam-sealing a tent.

I have done some comparison tests with neutral-cure and acetic-cure sealant, and not found any difference, with regard to bonding to a silicone surface. I did some comparison tests years ago. Can't recall all the sealants that I tested. I think, Parfix and Selleys brands from Bunnings. I do recall one that I used a lot, years ago:

selleys-310g-401-rtv-engineering-grade-silicone:
https://www.bunnings.com.au/selleys-310 ... e_p1231042

Not sure if I remember correctly, but I think the acetic cure was better at bonding to glass. Both neutral and acetic were poor at bonding to aluminium. Both were superb bonding to existing silicone sealant.

The silicone sealant that I now use, for tent construction, I do not thin. Especially after I discovered how poor Silnet is for glueing.
Maybe a contentious point, perhaps a little bit of thinning is OK.

Hi BarryK and other silfabric-gluers, I don't think what you are saying is contentious for glueing silicone coated fabrics. The thick pure silicone rubber is needed. ( I prime fabrics that are not already factory silicone coated, but that is a separate matter and the subsequent glueing is with thick glue.)

1.Your (BarryKs) glued sample of silnylon (sent to me), was it glued with your neutral cure RTV silicone rubber? It has excellent peel strength, by my assessment. So that is a tick for thick and neutral cure????.
2.Smellypaddler has just sent me another glued sample of silpoly glued with Prosil 20 100% acetic RTV silicone rubber. It has an impressively thin layer of glue (He was 'not happy' with the seal, but I think it also has excellent peel strength. So there is a tick for the thick acetic cure.
3. Orion Found that DAP100% acetic cure silicone rubber was superior to other non-acetic cure silicone rubbers. His tent is holding together 10 years later,(even if it has an ugly side! Another tick for thick acetic cure RTV.
4. Lastly, I have only used acetic cure RTV silicones of many brands, but always insist on acetic cure. They have always been capable of forming strong peel resistant bonds with compatible fabrics. These silicone rubbers have always bonded well with aluminium, stainless steel. titanium and copper. This seems to be at odds with BarryK observation about his acetic cure RTV not sticking well to aluminium. Have I got this correct Barry?

I know an acetic cure is not recommended for galvanized or zinc alum plumbing for reasons of the corrosive nature of the solvent. I have never taken any notice of this and it has never been a problem. I think it evaporates and gets neuralized just so quickly that it only does good! However, from a chemistry point of view, I like the corrosive nature of the glue as it can easily clean organic contaminants on surfaces, including metals. I still sand metal surfaces to remove oxides and provide scratches for improved keying.

Lastly, as a chemist, of all the solvents for RTV silicone rubber, acetic acid is a bit nasty smelling, but by far the safest. Acetate is part of life and we have evolved with it, unlike the other recent nasty creations of chemists that are used as solvents. I think this is why it is used for making fish tanks?

The evidence in support of acetic cure seems to be stacking up, although some neutral cure silicones could be an exception).
Thanks for your ideas, samples and help. Tim

Tim,
Yes, that glued sample I sent you, was the Monarch neutral cure.

Yes, both neutral-cure and acetic-cure were disappointing on sheet aluminium and aluminium extrusion. I don't recall if there was a difference, but I think that used a flat screwdriver blade and was able to peel both off.
...just read my old blog post from 2019, the Selleys 401 acetic cure, was able to scrape it off the aluminium with my fingernail!