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TreeHugger Mark-3 ridgeline tieouts

August 31, 2021 — BarryK

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

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:


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


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


Another view showing the inward-folds:


Showing the wings spread out:


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:


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:


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 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:

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:


...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:

The hook is 3.6cm size, these:

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

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


...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:

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 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:


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:


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:


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


And glued it on:


...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:


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:

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


...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:


...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:


...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:      

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:

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

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:

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:


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:


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):


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:

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., 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:

...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:

...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:


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:

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

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

...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:

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:

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:


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:

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:

...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

More tweaks for TreeHugger Mark-3 tent

July 31, 2021 — BarryK

I have been using SolveSpace to design TreeHugger 1P Mark-3 tent. Here is the previous blog post:

While waiting for the 10D silnylon to arrive from China, I keep playing with the design. The latest iteration is have made the floor-width at the tail-end a bit wider, 70cm, up from 60cm. Just gives a little bit more foot room inside.

Also tweaked the catenary a little bit, and have put it directly onto the 2-dimensional plans. Here are the SolveSpace 3.0 files, gzipped:



Here are the cutout plans, the pink lines represent the usable fabric width of 151cm:


And the other side:


And as shown in the previous post, I have inverted one side so as to minimize the length of cloth required. In the latest design, as the foot-end is wider, the required length of fabric will be longer, about 5.22 metres.     

Tags: light

Plans for TreeHugger 1P tent Mark-3

July 20, 2021 — BarryK

The TreeHugger 1P tarp/tent Mark-1 project is documented here:

I started a Mark-2 design, with spreader-bar for head-space, but abandoned it:

Thought about the design a lot more, and decided, rather than have a spreader-bar, will make the high-end higher. This means will do away with the constraint of using a carbon-fibre or trekking pole to hold up the high-end. The high-end will be held up by tying to a tree trunk or branch -- unless can use an extra-long pole.

With Mark-1, I first constructed a tarp, and then added end-panels to turn it into a tent,as shown here:


I was going to construct a built-in mesh bivvy for the Mark-1, but now jumping to Mark-3, based on Mark-1, with lessons learned, higher high-end, slightly longer, and end-panels included in the original cutout.

What I mean is, instead of adding the end-panels afterward, plan to include them in the fabric cutout. This will simplify construction. So, there won't be an intermediate tarp, the tent will be constructed directly.

Here are the SolveSpace 3.0 files, gzipped:


SolveSpace is a "parametric 2D/3D CAD" application, for Linux, Windows and OSX, described here:

Here are the dimensions for each side. The outer lines include the hems and ridgeline overlap, the inner lines will be the actual dimensions after the hems are folded over and the ridgeline overlap glued together:


The other side includes the panel on the high-end:


Those 1.5cm measurements are hems, that will be folded over. The 2.0cm measurements are the ridgeline, and the two sides will be glued together at the ridgeline, by 2.0cm overlap.

Here are the two pieces put together, to show the length of fabric that will be required:


...based on the fabric having usable width of 1.51 metres, and the length required is 5.75 metres.

If we want to go for a deep catenary cut, as I did for the mark-1, here is a possibility:


...the left side is the high-end of the tent. Measure down 90cm and draw a line to the ridgeline on the low-end. Then plot the points as shown. This will be slightly less deeper than the Mark-1.

So, after cutting out the two sides, cut the ridgelines as per the above curve. Then join them, with 2cm overlap.

I am keen to get going on this, however, currently only have 20D fabric, and really want to use 10D, as aiming for lightest possible weight. Have placed an order for 10D, but it is coming by China Post, and my experience is will have to wait about 2 months. Aaargh! Will have to find something else to do in the meantime.

According to SolveSpace, the area of the two pieces is 2.537 plus 3.540, which is 6.077 metre squared. If the 10D silnylon is 31gsm, the weight of the fabric will be 186 grams. A bit less than that if there is a catenary cut.

EDIT 2021-07-21:
I discovered that the panel at the high-end actually requires the fabric roll to be wider than it is. My 10D silnylon has a usable width of 1.51 metres, same for the 20D silnylon. However, found by careful rotation of the cutout, can get the cutout width to be 1.518 metres, that is, 151.8cm.

Also, the two pieces can be cut out so as to use less fabric length, 5.112 metres, compared with 5.75 metres above:


...the brown lines represent the usable fabric width. The first piece is flipped vertically, so ridgeline is on the bottom. The second piece, on the right of the above drawing, is rotated slightly, to minimize the cutout going over the usable width. Even so, the bottom hem-line of the high-end panel is about 0.8cm over the usable width, going into the edge of the fabric that is not silicone-impregnated.

I can live with that. The bottom hem-line of the high-end panel will be folded over by 1.5cm, and the little 0.8cm un-impregnated will end up impregnated when the hem is glued.

Sure have designed this to the limit, maximum height that can be achieved at the high-end. Sitting inside, the height at the peak point will be just on 1.51 metres, but of course this drops rapidly on each side. That 1.51m is based on about 2.5cm air gap at the bottom of the tent. Then, as planning to construct an inner mesh bivvy, the final peak height will be lower. 

EDIT 2021-07-21:
I have played with the dimensions, now the second piece fits nicely within the 151cm usable width of the fabric, and without having to rotate it. Here are the updated SolveSpace 3.0 files, gzipped:


And here are the dimensions for cutting the pieces out of the fabric:


...required length of fabric now just a tad over 5.07 metres. 

EDIT 2021-07-25:
I think that when construct the Mark-3 tent, will reduce the depth of the catenary cut a little bit:


...same thing, measure down 80cm from the top-peak of the high-end of the piece. having cut the catenary on one piece, suggest use that as a template for the second piece. Depth measurement is 18.07cm from the straight-cut ridgeline, compared with 20.9cm for the previous "90cm" catenary cut shown higher on this page. Not much different, but the ridgeline will rise from the foot-end at a slightly steeper angle, which I prefer. 

EDIT 2021-07-31:
The plans for Mark-3 have been tweaked again, see later post:     

Tags: light