Jul 11, 2011 at 5:47 am #1276558
Hi everyone. I’ve been reading these forums for a long time now, and finally, I can submit my own MYOG project. I hope there can be some feedback and discussion, even though this isn’t a new invention, not even an innovation. Rather back to basic I´d say.
But before I start off, I must thank all of you guys that are contributing to this forum, regulars as well as cottage owners (thanks for the sharing Ron). Every time I search the forums I realize just how much knowledge there is here, and how powerful sharing communities. Think about it, I live in Finland… And on starting off, thank you Steve Evans (N2), Dave Chenault and Chris Zimmer (packs), for all the inspiration and good spirits.
I started off ordering some fabrics and accessories from Extremtextil.de. Everything worked great, if I need to order a bigger order again, I’ll definitely use them again. I ordered 3 meters (9.8´) of CT2K.08 cuben fiber, 1 meter of X-Pac VX07 (wonder what that’s for…) and accessories, linelocks, webbings, chords etc. It was Christmas opening the box.
As I work with various CAD software’s professionally I had to make a detailed drawings, as well as 3D ones. First off I cut of a 1000*225 mm (39.3” * 8.9”) strip of the end. I then cut out six circles with 225mm (8.9”) diameter for the tie-outs. That also left me with some “inverted” circle leftovers, witch I used for the extra tie-outs along the edges and internal hanging point reinforcements.
When cutting the cuben I used a IKEA Drälla cutting board and a utility knife. Worked perfectly, even with more demanding curves. I also found that pinning the cuben down with two fingers (peace) while cutting, result in the cleanest cut.
I then proceeded bonding the reinforcement patches. For bonding I used Bison 5 minutes Epoxy. It was as easy as it gets to work with – i.e. me being quite absent-minded, gluing stuff onto my elbows and so on… I was very happy with the end result. At least the latter half of the patches.
Overall, I’m super psyched about the learning curve when working on these projects. I just finished school, and while I’m no idiot, wow if I’d been this excited during my years in the university, my name would be on space stations already.
Um, I’m rambling, yeah. Back on track.
I tried a couple of different approaches while bonding the patches. I started of coating both the tarp and the patch with epoxy, then putting them together. Though I found this to be quite a hassle and resulting in a rather thick reinforcement. Applying masking tape as Steve did in his video was hard as my reinforcements are rounded. I also re-read the epoxy instructions, witch stated you should only coat one surface. I proceeded accordingly. My new tactics was to coat half of the patch, place it and put a weight on it, letting it settle for about half an hour and then do the other side. In the end I left out the intermediate step and just bonded one side, flattening it, doing the same on the other side and then applying weights. This saved me lots of time, the perfect compromise. For weights I just used various household pots and pans, filled with water. Also, baking/wax paper is super as a protecting layer as it won’t stick to the tarp when the epoxy has dried (regular paper do). When working the epoxy I used credit cards cut in half (yeah no need to tell me, it occurred to me later), first spreading it in a thin layer and then placing the patch. Then finalizing it by pressing out air and further thinning the epoxy layer. As I said, I was very happy with the end result, the patches becoming tougher than the surrounding cuben, yet not too hard.
Oh, and also these projects are best conducted while your better half is away, allowing you to redecorate the living room.
When all reinforcements were done, me and my mate (spiritual consultant) called it the day and took a beer on the balcony.
Next day I brought out my mothers sewing machine, witch she had gladly loaned. All the practical skills aside, I also learned that my mother had once wanted to become a crafts teacher but didn’t. Thus, she was excited to learn me all the tricks of the trade. Disclosure, I did the whole tarp single-handedly, mom only gave me tips prior to starting.
I folded the long edges and sewed a double hem, then doing the same with the short ends. I thought about cutting some of the corner away and not getting a 9 layer corner – sturdy but harder to sew – but decided not to. Think it was a good call.
When I ordered the accessories I had apparently had a minor brain malfunction, ordering half a meter of 10 mm (.4”) grosgrain. I should have taken 13+ (.5”) width and a lot more. Luckily I had overestimated the need for 20 mm edge-binding (next project) and used that. Worked even better as it’s softer than grosgrain and thus fit well into the 13 mm linelocks. I’d read a forum article at some point stating that x-box was best suited for cuben tieouts, bartack stitching possibly being to tight. The 10 mm (.4”) grosgrain came in handy for the extra tie-outs, witch I fitted with a twist, making them more ergonomic. I didn’t sew along the perimeter of the reinforcement patches as they seemed solid, I’ll check them after each future trip and correct if needed.
And suddenly. When the church bells rang midnight of the third day. It was done.
Last weekend I went home to my parents. Brought out the almighty judge. You’ve read this far…
Scale tipping at 145 grams (5.1 oz), including linelocks. The 3mm (.1”) ( spectra chord (4*1m + 4*2m) weighing 80 grams (2.8 oz). Totaling 225 grams (7.9 oz). Personally I was happy with the result, I didn’t have another goal than “light”, ~sub 250 grams (~9 oz). Size, it’s about 1.30 m wide and 2.8 m long (4.2’ * 9’). Eight tough tie-outs with linelocks and four smaller ones. On linelocks and 3 mm (.1”) chords, I had to be very exact while melting the chords, or else they wouldn’t pass through the linelocks. As far as durability goes, I’m reckon the sewing thread is the weakest link.
Later I went out to my parents summer cottage to set it up. I just had time to put it up as a low a-frame and a modified lean to, before my camera shut down. The A-frame came out a bit too low and flat in the middle, but I really liked the modified lean to. I do think catenary cut tarps are beautiful, but it’s something basic, primitive about flat tarps that appeals to me. One thing I’d still like to ad is a pair of lifters. Mosquito netting will also be necessary during the summer.
On reinforcements patches. I’ve concluded that almost everyone makes triangle shaped reinforcements, except for HMG and me. I was happy when I saw them doing it, yet once again paranoiac, as I thought of it first*. For all I know about mechanical engineering, one of the basic rules is that you don’t ever design sharp corners. Sharp corners will always create a focus stress point.
*verification not needed
Besides my mother being interested in traditional crafts. I also learned that my grandfather and grand grandfather both worked as shoemakers. I wonder if I got a bit of their spirit in me while working on this project; at least, I now know that MYOG is great fun and highly addictive.
Now. You comment.
Thanks for reading.
FinlandJul 11, 2011 at 5:50 am #1758002
Great write-up of the process and its a good looking tarp. Keep us posted on how it works in the field and what you learn from using it!Jul 11, 2011 at 9:21 am #1758041
@owareLocale: Steptoe Butte
Let us know how the epoxy works. It would be nice not to have to use contact cement.
For reinforcements some sail makers use two layers with one a semi circle and one a triangle.
Round edges on the reinforcement can be stronger for a given distance from the tie out. On Cuben Fiber, which has little stretch, the stress is tends to be transmitted inline with the tie out. A lighter compromise shape to save weight over a full semi-circle might be a triangle with the tip rounded to at least the width of the tie out.Jul 11, 2011 at 11:43 pm #1758353
I'll try to get out during the following weekends and get some more experience and pictures. Don't have any mosquito net yet though, so it'll be interesting. :DJul 12, 2011 at 4:07 am #1758372
Wow, great job. and nice timing as this is on my to-do list before my fall trips. Thanks for all of the detail and tips.
Hmm, linelocs on the tie outs, might have to look at that idea. Sure would make for a fast pitch.
Glue down reinforcement patches to distribute the stress, got that one written down. How did you determine the size of the patches?
I just love this site.
Let us know how it works out for you as you get a couple of trips under it.
DaveJul 12, 2011 at 4:31 am #1758375
Ah, great if it can help you. I'm no expert – yet – but just fire away if you have any questions at all. I find the flat tarp highly recommended as a first project, it's really not that hard, no catenary ridgelines etc.
I opted for the linelocks, one can always cut em off later if they're excessive. I think they save some nerves while pitching. Fixed lenght is fine on flat ground but require adjusting on uneven terrain. As I´m an active scout, I have no fears for chords and knots, still, linelocks wins when the wind is howling.
On the tie-out reinforcement patches. I started doing some, alot of, research here at BPL – read, hours at work. Then I used AutoCAD to plan the whole thing. As the cuben width is 1.36 meters, that's where I started off. Then it was just a matter of dividing the width with number of tie-outs I wanted (six circles in my case) and plotting the result. Holding a full-size piece in the hand to truly get a perception of the thing.
DanielJul 12, 2011 at 4:43 am #1758377
I'll get back to you how the epoxy's holding on. One key reason to the triangles is of course less unused fabric and a alot less time consuming process. But the circles are so stylish…
The sail maker info was new to me, thanks. I've actually played with the thought of visiting a sail makers company near my parents. A discussion with them could prove to be really revarding. Why reinvent the wheel. There's also been alot of people asking for their input on these forums.
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