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Testing mk1 tent and wood stove

July 18, 2021 — BarryK

The ultralight (242g) TreeHugger 1P mark-1 tent is described in an earlier post:

https://bkhome.org/news/202107/end-panels-for-treehugger-1p-mark-1-tarp.html

The ultralight (55g) wood stove is described here:

https://bkhome.org/news/202107/wood-burning-stove-weighs-only-55g.html

Firstly, the stove. As reported in the above link, there is a review on Amazon, quoting:

The first burn was only 1/3 full of cedar twigs (not hotter burning hardwood), and before I could put on a small pot the inner supports warped and collapsed into the fire and the outer frame warped into an oval. The outer frame and inner supports are made from very thin titanium, almost identical to what I use for a windscreen with my micro alcohol stoves. The design is quite similar to the small Little Bug stove, which weighs 9 1/2 ounces. This one weighs just under 2 ounces (without the control slider) and is just too fragile to be a usable stove.

Yesterday, I tested it. Here it is, loaded with twigs, ready to go:

img1

Ha ha, I can also confirm, it wasn't long before the pot-rest collapsed! And I didn't even have a pot on top. The titanium just warped and collapsed.

The two side-pieces were still OK. Looking at it today, yes, warped, but still usable. Something stronger is needed for the pot-rest, and something that will help the side-pieces to retain their shape.

Anyway, I boiled water by placing the pot directly onto the wood:

img2

...that smoke is because the wood is damp. Made it hard to start the fire, but once going, OK, except got lots of smoke when added more twigs. The water boiled fast, had soup for lunch.

The tent, well, not much to say, easy to erect, just needed a convenient tree to tie it up in "tree hugger" mode:

img3

And of course, one of the big features is the side entry:

img2

Erection was straightforward -- staked out the four corners, then tied up the high-end to the tree, then inserted the short pole and staked it. Five stakes, but then a sixth for the side -- that sixth stake not essential.

Thinking about the height of the high-end, that was set by the length of my carbon-fibre pole, if it is to be erected without a tree. However, if that constraint was removed, no pole, then the high-end could be higher, which would give more head room inside. Will think about that.

You can see in the above photo, the usefulness of the tree as a back rest while inside the tent. Yes, that was the idea. Or, it could be a wall in a shelter.  

Tags: light

End panels for TreeHugger 1P Mark-1 tarp

July 11, 2021 — BarryK

Continuing the TH1P Mark-1 tarp construction project, this is the previous post:

https://bkhome.org/news/202107/treehugger-1p-mark-1-tarp-deep-catenary-cut.html

By adding end-panels, it has now become a tent:

img1

I won't post the dimensions, as it depends on a user's choice of pole height. It is easy to figure out -- just a triangle, well, almost.

At the front, one side of the triangle is glued to the tarp (left side of above photo) and the other two sides have glued hems, with a tie-out at the bottom corner. The tie-out is just like the others, with an o-ring attached.

The front panel is not quite a triangle, because I cut a bit extra so that the tarp will overlap, to minimize ingress of rain. However, you can see at the bottom, there is still a gap between panel and tarp -- if I had built the inner mesh bivvy, the intention was that would pull-in the front panel slightly, so that gap would disappear.

The tarp has a small hook on the tie-out, so can unhook from the o-ring and fold back over the ridgeline;

img2

In the first photo, you can see an o-ring and a nylon hook beside it. That hook was the one originally attached to the tarp tie-out, however, today replaced it with a smaller one. The o-ring will have a tent stake through it -- I am using triangle-section stakes, so there are gaps for the hook to hook onto the o-ring, but it is better with a smaller hook.

I am intending to take this as it is, and just use one of my ready-made inner mesh bivvies on the next hike. Probably will not construct the Mark-1 tent any further.

The tail-end of the tent has just a simple triangle panel, glued to the tarp on both sides, hem along the bottom.

I have learned a lot from constructing the Mark-1. The tent as you see in the above photo weighs 242g (8.64oz) (not including poles), quite light, but I reckon, from lessons learned, could make it again with less weight, fairly close to 200g. So, rather than take Mark-1 to completion, with inbuilt mesh bivvy, will use it as-is.

I think also, might make the next one a little bit longer, maybe another 100mm, and a little bit wider at the front. The ridgeline has 25mm overlap, but it is such a strong bond, intend to reduce that to 20mm. The successor to Mark-1 will probably be named Mark-3.

Next step, use it on a hike, one or two nights.

EDIT 2021-07-12:
Here is the Mark-1 tent rolled up:

img3

That's great, really small! Dimensions are about 175mm long and 80mm diameter.   

Tags: light

Wonderful quilt from undercling-mike

July 07, 2021 — BarryK

I posted about sleeping bags versus quilts for camping and hiking, back on March 20, 2021:

https://bkhome.org/news/202103/sleeping-bag-versus-quilt.html

Here is a photo from that post:

img1

In that post, I didn't reveal who makes them. Will do so now. His name is Michael, known as "undercling-mike" on the Aussie Bushwalking forum. This is the thread where you can find out all about them:

http://bushwalk.com/forum/viewtopic.php?f=27&t=24995

Mike started making these in 2017, I think as a hobby, presume that he has a day job. Unfortunately for Mike, news got around how nice these quilts are, and the orders flooded in. The manufacturing delay got longer, then in December 2020, Mike declared a hiatus, he wanted to rest awhile.

But people still kept requesting them, myself included. I placed my order on March 11, and received it just over 3 and half months later. Despite the hiatus, Mike has kept making them, just very slowly. In his last communication with me, he indicated that he probably won't accept any more orders for awhile.

Anyway, what I have is this:

-8 degrees C rating, regular-length, wide-width, 950 HyperDRY down (ethically sourced), 10D burnt-orange taffetta fabric inner and outer, straps and 5L stuff sack.

Weight, in the stuff sack and including the straps, is 633g.

Dori is a lass who lives here in Western Australia, and she acquired her quilt from Mike in November 2020, and has posted a video:

https://www.youtube.com/watch?v=PtA7wT56ppQ

Hers is a little bit heavier, as she went for the 850-loft down and 15D fabric.

Mine would have been 594g if had also chosen regular-width, but was enticed by the possibilities of that little bit extra width. In the above photo, you can see the gap underneath. The wide-width fills that gap, which makes it, I think, more usable without straps, saving about 20g -- so, my pack weight will be 613g.

Here is a photo of a wide-width, you can see how the gap has been filled:

img2

When mine arrived, I threw all the blankets off the bed and slept under the quilt. Lovely! So light and warm.
And so beautifully made -- as a beginner sewer, I marvel at the perfect stitching.
One thing I like about the burnt-orange 10D taffetta fabric is that it is translucent, and I can see how the down is distributed -- yep, it is spread everywhere.

If you are a camper/hiker and are drooling over these photos, unfortunately you cannot currently place an order. I have had feedback from a couple of people that Mike has not responded to their inquiry. That's because, as I stated above, he has taken a break from making them. He will of course complete the ones that he has accepted an order for, but be patient. He indicated to me that he will do a reset and resume making them, so probably best to just wait until he announces that on the forum.   

Tags: light

Wood burning stove weighs only 55g

July 06, 2021 — BarryK

I posted about tiny wood-burning stoves for hiking and camping a few days ago:

https://bkhome.org/news/202106/ultralight-wood-burning-stove-for-hiking.html

Had one on order, it arrived today, this one:

https://www.aliexpress.com/item/4000556939038.html

Weight is advertised as 100g, very interesting design, though puzzling. Packs flat, which is what I want:

img1

...26x12.7mm, a good size that will fit in my lumbar pack.

What you see in the above photo is 4 pieces, titanium, weighing 55g, but it also has something else, called a "dampener", thicker titanium, that weighs 44g:

img2

This dampener and the size and placement of holes is perplexing. It seems from this photo that the fire is above the dampener:

img3

...but, there isn't much room for a wood fire above the dampener.

I saw on a YouTube video, a guy stating that a Lixada folding stove is a cheap Chinese knock-off of a USA-made stove. Which got me wondering about this one. I came across this very concerning review on Amazon:

"It collapsed 5 minutes into the first burn"
https://www.amazon.com/gp/customer-reviews/R1ISBTNKDTUIC5/ref=cm_cr_dp_d_rvw_ttl

That review mentioned that the Lixada stove is a copy of this one, made in the USA:

https://littlbug.com/littlbug-junior-stove/, and

https://www.raymears.com/Bushcraft_Product/1091-Littlbug-Junior-Camping-Stove/

img5

...weighs 145g and made of stainless steel, lots of good reviews. Note, doesn't have that dampener. Of course, a lot more expensive. Ah, there is a video review of the Littlebug Junior:

Part 1: https://www.youtube.com/watch?v=DDasLCTBWg8

Part 2: https://www.youtube.com/watch?v=UOhpVkkknE8

Part 3: https://www.youtube.com/watch?v=ysSfOmE_KnY

So, the Lixada stove is a cheap knock-off, and apparently not a good one. There is that mysterious dampener, and a report that it collapses. Cannot find any more reviews. Ha, I see that the Littlebug design is patented, which may be why Lixada added that dampener thing, and an extra cutout at the top to feed in wood, to make it different. The review posted on Amazon doesn't bode well, but will take it on the next hike and attempt to use it.

EDIT:
I found an early video, made in 2015:

https://www.youtube.com/watch?v=qywFv8RRzx8

...and the original design does have that dampener. Interesting that they did away with it in the latest version.

EDIT 20210718:
This stove has its first test, report here:

https://bkhome.org/news/202107/testing-mk1-tent-and-wood-stove.html

...so, apart from the collapsing pot stand, it is usable. That will be an interesting project, to design an alternative pot stand that will not collapse and will assist the side pieces to stay circular and not warp.   

Tags: light

TreeHugger 1P Mark-1 tarp deep catenary cut

July 04, 2021 — BarryK

On June 5, 2021, I posted instructions for a glued tarp, straight-cut, that weighs only 178g:

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

After that, I speculated about a catenary-cut on the ridgeline, to try and get rid of looseness of the fabric along the ridgeline:

https://bkhome.org/news/202106/catenary-cut-for-tarp-ridgeline.html

...and cut a minimal catenary curve along the ridgeline.

However, the fabric along the ridgeline was still very floppy, so decided to experiment with a much more aggressive catenary cut.

To this end, I thought about what the curve shape should look like. It seemed to me that the curve of a boat mooring line looks "good", as calculated here:

http://abc-moorings.weebly.com/catenary-calculator.html

I can't say that this is the mathematically best shape for the deep-cut ridgeline, but it intuitively looks "right". I downloaded the spreadsheet file, and gzipped it, uploaded here:

Catenary-Mooring-Line-Shape-Tool.xlsx.gz

Here is a table that I got from that spreadsheet:

img1

...you enter "77" for the "d" parameter, and "205" for the "X" parameter. "X" is whatever the actual horizontal distance is, as shown in the sketch. Transfer the table to the fabric, gives the green line.

This will be done on both pieces of fabric (the first can be used as a template to mark out the second), and when the two ridgelines are brought together, to be glued, there will be an overlap of 2.5cm, and it is necessary to mark a line on the fabric that will be underneath the overlap.

The ridgelines are now curved, and have to be pulled straight, so as to be glued. I did that by placing them overlapped and held down at each end with concrete blocks:

img3

...so, in theory, I can run adhesive along the underneath fabric, and the top piece should just about flop back into the correct overlap position. The main problem with this plan, is couldn't lift the fabric at the ends, because of the blocks, so had to start further in. But that is OK, glued the ends afterward.

In the above photo you can see newspaper underneath. One layer of newspaper, with cling-wrap over that. The cling-wrap is important, because silicone adhesive does not stick to it. When I ran the seam roller over the overlap, a tiny bit of sealant bleeded out underneath, which is OK -- it will simply be flattened by the roller and won't stick to the cling-wrap.

I have posted about this before, but reiterating here, this is the roller I use:

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

Glueing worked reasonably well. I used the 25.4x25.4x1.6mm spreader tool that I discussed in an earlier post:

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

img4

...that worked really well. Using the applicator gun, ejected the silicone adhesive in a zig-zag pattern, fairly generously as the spreader tool will catch any excess glue -- it just piles up inside.

Here is the ridgeline after glueing, with one side pulled out flat, so you can see the curve:

img5

...and as you can see in the photo, the tie-out webbing has been sewn on. It is best to wait several days after glueing, before sewing, to avoid gunking up the sewing machine. Here is close-up of the short end:

img5

And here is close-up of the high end:

img6

In the original straight-cut ridgeline, I experimented with "sockets" to hold the carbon-fibre poles. What I have done as shown above is very simple, just silicone end-caps glued to the webbing. These, 7.7cm ID:

https://www.aliexpress.com/item/1005001609758449.html

I have experimented with this, and found it to be very strong. Silicone adhesive bonds to the silicone end-caps very strongly -- so strong, that it can't be separated. The weak point is the bond with the webbing -- I used the applicator gun pressed firmly onto the webbing and forced silicone adhesive as much into the webbing fibres as possible. Then used my finger (wearing disposable gloves) to press the adhesive firmly to try and force it into the fibres even more.

The end-cap is glued right on top of where the webbing loop is sewn together, so it is, I think, a pretty strong end-result.

I have mentioned in an earlier post, reiterating here, I now use a mini-applicator gun, that takes 150g tubes of silicone sealant:

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

...I find this easier to wield while glueing hems and ridgeline, and also, unlike the full-size gun, the flow stops immediately I take my fingers off the lever -- I like that very precise control.

The black webbing is this, nylon 12mm wide, and 1mm thick:

https://www.aliexpress.com/item/4000126877988.html

The blue webbing at the high end is for when want to erect the tarp in "tree hugger" mode, tied around a tree trunk. That is much lighter, nylon 10mm wide, 0.5mm thick:

https://www.aliexpress.com/item/1005001666741572.html

Oh, and that cord-tensioner on the black webbing is from here:

https://www.aliexpress.com/item/1005002198346631.html

Here is the final weight of the Mark-1 deep-cut tarp: 183g (6.46oz)

Photo erected:

img7

...yes, very good, the sides are fairly taut.

Of course, you do lose head-height, but it still looks OK. When erected in "tree hugger" mode, I will be sitting at the very end, leaning against the tree trunk (or wall inside a shelter), so my head will be at the highest point of the tarp. And yes, there will need to be rain protection to make that feasible, will get onto that stage of construction soon.

Actually, the weight is a little bit higher than it could have been. I cut the ridgeline open twice, going from a straight-cut, to a slight catenary curve, then a deep-cut curve. This resulted in a mess at the ends of the ridgeline and had to glue extra layers of reinforcing fabric to rejoin the ends of the ridgeline. Even so, 183g is pretty good.

Next instalment coming soon!     

Tags: light

Ultralight wood-burning stove for hiking

June 29, 2021 — BarryK

Years ago, I bought a few different metholated-spirits-burning stoves, aiming for extreme light weight. I was reminded of this today, reading this post:

http://bushwalk.com/forum/viewtopic.php?f=53&t=36046

...forum member 'crollsurf' has a really light setup, stove and windshield:

https://www.ebay.com.au/itm/324185702933

img2

https://www.ebay.com.au/itm/144062317171

img3

...total 42g. But may also need a metal disk under the stove, to insulate from the ground. And of course a small pot.

I also have this kind of gear. Of course, meths has to be carried, lets say a 100ml bottle for a multi-day hike. So, at least another 100g, and the bottle has to be carried such that it doesn't leak.

lately, I have been exploring the option of a wood-burning stove. It certainly does appeal -- just using fuel from the forest floor, no need to carry fuel. Even in the most arid wilderness, there are going to be leaves and twigs lying around on the ground.

These little wood-burning stoves are in a grey area, in places where open fires are banned. Here in Western Australia, many hiking trails allow fires within designated fire-pits, and in some places even on open ground, but usually only over Autumn - Winter - Spring. In the hot dry season, only a gas or meths stove may be allowed.

It is an interesting question, whether any tiny wood stove could have its combustible material so constrained as to be considered equivalent to a gas or meths stove.

Anyway, here is a comparison of many of the choices:

https://www.youtube.com/watch?v=ajPCW41YWOU

...some fantastic wood stoves!

But, are any of those suitable for the ultralight hiker? Like, under 100g? Yes, he reviews one, the Emberlit Fireant:

https://emberlit.com/products/fireant-titanium-multifuel-ultralight-backpacking-stove

img1

...weighs 85g (3oz).

There are plenty of others like this on Aliexpress, Amazon and eBay, but not this light. If you want to research what is out there, go to these sites and search for "wood stove folding ultralight" ...or similar words... cast the net a bit wider: "wood stove hiking".

The Emberlit Fireant can also hold a meths burner.

Thinking about burning wood, it is not really constrained. You would insert twigs in the side, so there is always the possibility of burning wood to fall outside of the stove body.

The Emberlit is fascinating, but I have ordered a different kind of wood-burning stove, that weighs 100g (and much cheaper). It is also titanium and folds flat for easy carrying. Will post a report after it arrives and have tested it.

EDIT:
Here is another interesting comparison of wood-burning stoves for hiking:

https://www.youtube.com/watch?v=P28PK5m4Gjw

And if you would like to see something really creative, here is a no-drill gasifier tomato-juice-can wood stove:

https://www.youtube.com/watch?v=8he7txE6uLw 

EDIT 2021-0630:
I received an email from ally, with links to very light stoves. For an alcohol-fuel stove, you can't get any lighter than this spill-proof stove and folding frame:

https://speedsterstoves.co.uk/20ml-spill-proof-mehs/alcohol-burner.html

https://speedsterstoves.co.uk/utralight-mini-pot-stand-for-cups-mugs.html

...8g plus 4g, great for making a quick coffee on the trail!

He also posted a link to a tiny ultralight titanium wood-burning stove, Firebox Nano, 4oz (113g):

https://www.fireboxstove.com/folding-firebox?product_id=337

...including its case, weight is 6oz.    


  

Tags: light

Refinements to glueing tarp

June 26, 2021 — BarryK

Continuing TreeHugger 1P Mark-2 project, previous post:

https://bkhome.org/news/202106/treehugger-1p-tarp-mark-2.html

Some issues have been identified, and solutions...

Glueing reinforcements

I have glued on the tie-out reinforcements, and it has, in some of them, been unsatisfactory. These reinforcements are at the tie-out points, where webbing is to be sewed on, to spread the tension. They are just pieces of the same fabric glued onto the tarp.

The procedure is to spread silicone adhesive on a reinforcement, using the fingers, then lift it up and place it onto the appropriate place on the tarp. Getting it to lay nice and flat, and in the right place, no ridges and no bubbles, is a challenge.

There is a video on YouTube where a guy shows how to do this, that I have linked to in an earlier blog post. However, I have concluded that his method is not suitable for me. Where is that video? Ah, here:

https://www.youtube.com/watch?v=Ec8YhQffRj8

He might have got away with it using heavier fabric, however, 10D silnylon is incredibly stretchy. Using the fingers to smooth out the piece of reinforcing, and push out bubbles, stretches it -- and here is the thing -- the underneath fabric does not stretch, or will stretch less. So, after attempting to smooth the piece of reinforcing, ridges can form in the underneath tarp. You might then battle to stretch the tarp to remove those ridges.

One factor though, in support of his method, he is using Gear Aid Seam Grip seam sealer.  In his case, the surface is PU, but for silicone surface, as for silnylon, Gear Aid have "Silnet", also known as "Seam Grip + Sil", which is a thinned silicone adhesive. Seam sealer, being thinned, is quite runny -- it is designed to seep into the sewn threads.
Silnet is far more runny that straight silicone adhesive from the tube, that you buy in a hardware store. The runny seam sealer has much less "grip" between the two surfaces, so you are more easily able to push the reinforcing around after placing it on the tarp.

Note, I have experimented with that Silnet. You buy it from camping stores, it is for seam-sealing tents. It is very runny. Also, it is much less "sticky". I found when folding the hem, that it was somewhat reluctant to stay down. The straight silicone, you fold the hem, and that's it, it is stuck.

So, using straight silicone adhesive and pushing the reinforcing around with the fingers, what you end up with is a weirdly distorted reinforcing.

Extra notes about the video:
Do not use bare fingers, as he has done in the video. Exposure to harsh chemicals may not have an immediate effect, but in the long term the body will react.
Also, I think the way that he has spread the seam sealer is inefficient -- dribble beads over the entire surface first, in roughly parallel lines, then simple sweeps with side of a finger can spread it.
Also, with care, the piece of reinforcing can be laid pretty much in the correct place, without all the wrinkles requiring to be pushed out as he has done.
He used a soldering iron and comments that it cauterizes the edge so won't fray -- however, as the reinforcing is glued to the tarp, there won't be any fraying -- besides, ripstop doesn't fray. Cauterizing will cause lots of little melted lumps -- notice, later in the video he trims some of them off. OK to cut out the circles with scissors.

I used this finger method on a few of the reinforcing pieces, then remembered that with Mark-1 I only used the fingers a little bit, then used the Uni-Pro seam roller. See photo of the seam roller here:

https://bkhome.org/news/202105/tarp-glueing-hems-and-ridgeline.html

Yes, this is the way to do it. Hopefully, lay the piece of reinforcing down accurately, so you don't have to pull it around, then run over with the seam roller.

So, some of the reinforcing tie-out points look good, some look crappy.

Spreading adhesive

I posted about a problem with spreading the adhesive for hems and ridgeline. A dribble of adhesive along the line to be joined, then use side of a finger to spread it. But of course the adhesive will spread out, and the problem I had was the chalk mark getting erased. I posted about this problem, with a suggested workaround to draw arrows:

https://bkhome.org/news/202106/treehugger-1p-tarp-mark-2.html

However, today I devised another solution. Bought 16x16x1.5mm aluminium channel from Bunnings, cut it at 45 degrees, and very carefully filed the tip so that (hopefully) a thin film of adhesive will be spread, only 13mm wide:

img1
img2

I filed so that an extremely thin film of adhesive will slide through. The channel is held with the index finger pressing lightly so that the sloped end slides over the fabric, following the marked chalk line, the sides keep the adhesive from spreading out. Adhesive still needs to be dribbled down the line-to-be-joined beforehand.

Length is non-critical, I cut off 14cm of channel, which fits nicely in the hand. Cut at 45 degrees because my hacksaw-jig thingy only does 22.5, 45, or 90 degrees. Perhaps a steeper angle would be even better.

A little bit of experimenting, and it works well. The great thing about this is two-fold. Firstly, the chalk line is still there, so can see where to fold the hem, or overlap the ridgeline. Secondly, no glue is wasted.

That second point is very important. I have found when constructing Mark-1 and Mark-2, that the glue can very quickly become a significant part of the weight of the tarp. I would even say, that if you apply it liberally, you could even double the weight of the tarp-sans-glue.

A little thought about the weight compared to sewn tents. They need seam-sealer, such as Silnet, and you can very easily use up a 50g tube on one tent. My glued tent does not need seam-sealing, except where the tie-outs are sewed on, and the amount of glue used could be similar to, or less, than that used to seam-seal a sewn tent. As long as there is no excessive glue applied.

The 16x16x1.5mm (13mm inside width) channel is OK for the hems. For the ridgeline, need wider channel, but the biggest that Bunnings sell is 20x20x1.5mm (so 17mm inside width). Actually, the 3cm overlap that I have done so far for the ridgeline, is probably more than needed. Will think about that. Might shop around, see if can find slightly bigger channel.

Chalk marking

I have posted about using a fabric marking pencil. Still not happy about it. It is some kind of "chalk", but is too hard, and I have to press harder on the fabric than I would like.

What I am using now is a chalk bar, designed for use on fabric:

img3

https://www.spotlightstores.com/sewing-fabrics/scissors-dyes-accessories/sewing-tools-accessories/fabric-markers/birch-tailors-chalk-pack/BP80054557

https://www.spotlightstores.com/sewing-fabrics/scissors-dyes-accessories/sewing-tools-accessories/fabric-markers/birch-tailors-chalk-sharpener/BP80054555

...I bought the second one, because the first is out of stock at my local Spotlight. The inbuilt "sharpener" is a joke -- just use a blade, or any sharp edge.

I also bought some chalk from the kid's section in Kmart, but found it to be unsuitable -- too crumbly. It tends to come off in chunks rather than a nice line on the fabric. Maybe it is just the cheap brand -- "Anko", which is Kmart's own brand.

EDIT:
Bought 25.4x25.4x1.2mm, 0.45m long, "Connect It" rectangular aluminium extrusion from Bunnings. So that is about 23mm inside width. Cut it at 45 degrees. Here it is:

img4

Not yet tested. I think that it would be necessary to dispense the adhesive in a zig-zag pattern along the line to be joined, to optimize even spreading.   

Tags: light

TreeHugger 1P tarp Mark-2

June 21, 2021 — BarryK

Complete instructions for Mark-1 tarp are here:

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

Mark-1 was a learning experience, and hopefully Mark-2 will be pretty much what I want as the final product.

The original concept was to have a 25mm carbon fibre spreader-bar just above head-height, to give more head room. I was a bit nervous about how that would complicate the design and how the sides would hang, so Mark-1 does not have the spreader-bar.

With Mark-2, decided to "go for it" and construct as per the original concept, even though haven't quite figured out some details for affixing the spreader-bar.

This time, I am using 10D silnylon purchased via Aliexpress, from Rex Outdoors:

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

Rex Outdoors only ships by China Post, which is very slow. Not sure, think that it took about 2 months to reach my doorstep in Australia.

Construction proceeded as per the Mark-1, this time with slightly different dimensions:

img1

4.8 metres of fabric is required, and the 2 pieces can be cutout efficiently like this:

img2

So, had 2 pieces, and together they weigh 133g. It will be very interesting to calculate the weight of the fabric in grams per square metre. From SolveSpace, the bottom-left angle is 87.3 degrees and top-right is 74.96 degrees, on the top image above. Then can calculate the area:

https://keisan.casio.com/exec/system/1322718508

Gives the 2 pieces 4.08 metre squared, which calculates to 32.6gsm.

Very interesting! The photo on the Rex Outdoor page states 28gsm, then further down they have 30gsm.

I really do need a reference weight to test the accuracy of my digital scale. It is only a cheap one from Kmart.

Note, I suspect that the manufacturer and vendor are just stretching the truth a little bit, by including the border of the fabric in the area calculation. Only suspect, not verified! There is roughly 1 inch along both sides of the fabric that are not silicone-impregnated, thus lighter. That's why, in the photo below, you can see the ridgeline of the first piece placed about 1 inch from edge of the fabric, because that is going to be cut off.

Marking out this fabric has proved to be even more of a challenge than the previous fabric used in the Mark-1 tarp. This stuff is very translucent. Here is a photo showing the first cutout laid on the fabric to use as a template to mark-out the second piece:

img3

For Mark-1, I used these fabric-marking pencils:

https://www.spotlightstores.com/sewing-fabrics/scissors-dyes-accessories/sewing-tools-accessories/fabric-markers/semco-fabric-pencils/BP80401344

However, with this green fabric it is difficult to see the line. With Mark-1, I was pressing the pencil a bit too firmly onto the fabric and I was worried that it might be damaging the delicate fabric.

I have experimented with other markers. On the forums, the Sharpie metallic silver permanent marker pen is highly recommended. However, I think that it is unsuitable for a couple of reasons.
Firstly, it remains highly visible through the translucent fabric. Secondly, it may compromise the silicone glueing -- I have no idea how well the silicone adhesive will stick to it.

I also tried chalk, but when ran a bead of adhesive along with the finger, while glueing a hem, it also erased the chalk line. So I could not see where to fold the hem over to, and had to estimate it visually , which was not satisfactory.

Actually, I did use the Sharpie pen to mark-out the two pieces, as the marked line was outside where cut with the scissors.

WARNING: At first, I bought Anko brand metallic marker pens from Kmart, as the Sharpie brand was out of stock. This is Kmart's own brand. Useless, they kept on blocking up. Initially, after some effort, they did flow OK for awhile, but they rapidly degenerated, and after a few uses they were unusable. Later, I bought Sharpie metallic pens from Woolworths, a set of three including silver -- they work great!
Note, the Sharpie pens I bought are fine-point, which are OK, but apparently there are ultra-fine available, which would be even better I reckon (Woolworths only stock the fine point).

For the hems, I went back to the Semco pencils. To make the line more visible, needed something dark underneath. This was the only dark fabric I had available:

img4

...the photo shows a length of wood being used as a ruler for the marker pencil. I took care to press the pencil lightly.

Running a bead of adhesive along with the finger does still partly erase the marked line, but enough remained for me to just make out where to fold the hem.

EDIT 2021-06-22:
Hmmm, no, not so good. Sometimes the marked line is completely gone. As had pressed lightly with the pencil, it gets erased when spread the adhesive with the finger. I think that it is chalk-based, and the particles get swept away.

Struggled through with the hems, but when got to the ridgeline, tried this...

I don't need a continuous line, just periodic visual cues showing where the other piece of fabric is to be pulled onto overlap the underneath piece. To achieve this, I drew arrows, about every 6 inches:

img5

Yes, this works. Even if the tip of the arrow gets swept away, I can still see where it is pointing to. In the photo, you can see the other piece of fabric at the bottom, the edge of which has to be pulled up to the marked line. Overlap is 3cm.

EDIT 2021-07-25:
For the record, appending this extra note about marking-out and glueing. I am now using a chalk bar (purchased at Spotlight) to do the line marking, and aluminium channel to spread the adhesive. This spreads without wiping out the marked line, so the above suggestion to use arrows is not required. This technique with aluminium channel spreader is described in a later blog post:

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

img10

...an extra note to add, is now overlapping the ridgeline by only 20mm, and for that using a spreader made from 20x20x1.5mm aluminium channel.    

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