DCF Shelter Construction

Discussion in 'DIY & MYOG' started by Enzo, May 7, 2020.

  1. Rog Tallbloke

    Rog Tallbloke Thru Hiker

    Yes. There are six long seams on my design. I wish I could think of a way to reduce the total seam length more. ).73 is strong stuff. Just need to think carefully about bias orientation and changes in thickness in key areas.

    Flapping is the biggest risk, as it introduces the most sudden and intense shock loading.
    Last edited: May 8, 2020
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  2. WilliamC

    WilliamC Thru Hiker

    Nice.
    With it pitched that close to the ground, I'm not sure that even a bigger vent would help. On this style of tent, I would think the main ventilation comes from the chimney effect, where you don't want the vent to be too big. You do, though, need air to get in at the ground level.
    Enzo likes this.
  3. Enzo

    Enzo Thru Hiker

    Hadn't thought of that, thanks :)
  4. Rog Tallbloke

    Rog Tallbloke Thru Hiker

    Eight even longer seams on it. Does look lovely though, and yes, panel angles are shallow in an octagon. I've sized my design to:

    A) use all the cloth
    B) Accommodate my Oookworks bignest (or any smaller/larger hex compatible inner)
    C) Use my tried and trusted Hex3 Easton aluminium pole. (max 66". Lighter and stiffer than a pair of trekking poles)
    Last edited: May 8, 2020
  5. Enzo

    Enzo Thru Hiker

    @Rog Tallbloke I can't see your design above, is it a mid? Thought you were planing a hut type shelter, or is that another project.

    For winter think I'd prefer the strength and aerodynamics of an eight sided/seamed shelter, guy out points in seams, seems like a good idea to me. Heavier of course, but it's winter.
  6. Rog Tallbloke

    Rog Tallbloke Thru Hiker

    Hut style will be using my 16 feet of 0.5. The front half of my design is 13 sided and the rear is hex. So 9 main peg points plus 4 at the wide panel mid points. I wish I had enough material to make it a regular 13 sided polygon (Teepee). Maybe I'll do that and make the door out of a piece of 0.5, since I need some of that for reinforcements anyway. With enough pegging points and the strength of 0.7, I don't think it's essential they are on seams anyway because you could simulate one with an extra piece of tape. The key issue is spreading stress away from the tieout as well as possible into the main area of the panels.
    Enzo likes this.
  7. Rog Tallbloke

    Rog Tallbloke Thru Hiker

    I wonder why. It's a TL image URL. Here it is again, freshly uploaded.

    2pteepee.jpg
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  8. cathyjc

    cathyjc Thru Hiker

    I bonded all the seams and stitched only where the zip was attached on my Howff. 1" 3m bonding. The seams haven't budged.
    I think sewing cuben is a 'bad' idea and by sewing you then have to tape over to stop the sewing 'pulling' - making work for nothing IMHO.
    This opinion is for a shelter - other uses ( a pack) might be different.

    Tie outs - my experience -
    I zigzag stitched the loops to a heavyweight semi circle (~) of cuben and bonded that over the seams at hem. I also bonded a slightly larger piece of cuben on the inside at the same place - to help diperse the load.
    After ~50 nights, some of them windy, the bonded cuben hasn't shifted but the stitching is pulling away. I'm debating how/if this needs attention.

    Overall I'd say the bonds will outlast the fabric around them.
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  9. Rog Tallbloke

    Rog Tallbloke Thru Hiker

    Thanks for the input Cathy. An ounce of experience is worth a ton of theory. I'm going to make the tieouts themselves from folded cuben, to make it easier to bond them into the reinforcments and onto the panels. Was thinking of zig-zag stitching to the hem as well, but given your observations, I might just put my faith in the glue and see how it goes.
  10. Rog Tallbloke

    Rog Tallbloke Thru Hiker

    I've just realised (bit slow me sometimes) that there's a MUCH more efficient way to do this which reduces total seam length by 60%.
  11. cathyjc

    cathyjc Thru Hiker

    I made the tie out loops from multiple layers of cuben but stitched them to the reinforcment patches. Not sure I'd bother again - next time I'd just use regular tape/webbing/etc. stitched to the patches. No advantage in cuben and a load more work.

    The bonding adhesive is strong in 'sheer' but weak in 'peal' - take that into account when you design.

    Very little stress in the hem so 1\2" turn over and bonded with adhesive (cheaper stuff from Paul).

    Also - because cuben has no stretch and is more like 'paper' than 'fabric' - there is effectively no warp/weft or bias.
    Which way you lay the pieces is irrelevant (IMHO) and if you need to patch 2 bits together to get the size piece you need - that's fine (I did it)
    - tho' maybe not so pretty, but who cares :whistling:.
    Chiseller likes this.
  12. WilliamC

    WilliamC Thru Hiker

    A vague memory so I may be wrong, but I seem to remember that the types of cuben used in tents etc has the dyneema laid in two directions (this part is clearly true when you look at it), which means that rotating it 90 degrees has no effect on strength but rotating it 45 degrees does (this may be where I'm wrong but it makes sense to a layman).
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  13. Enzo

    Enzo Thru Hiker

    I would use the cuben so one of the dyneema strands is perpendicular to the load.
    Recently heard of a TT li shelter whose zip panel has apparently stretched, I'd assume stitching on the zip but dunno.
  14. Rog Tallbloke

    Rog Tallbloke Thru Hiker

    Here's the new cutting plan. Much simpler. A single 12'6" seam, a short zip at the back, and a long zip at the front. My 24' of material gives me a 115" diameter 66" high teepee (69" with a 3" air gap) covering 73.4 sq ft .

    20200508_175256.jpg
    Last edited: May 8, 2020
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  15. gixer

    gixer Thru Hiker

    It was my request mate

    Figured if .75 tore then 1oz would be better
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  16. Rog Tallbloke

    Rog Tallbloke Thru Hiker

    @gixer What did the replacement weigh?
  17. gixer

    gixer Thru Hiker

    627g = .74oz
    740g = 1oz

    1oz doesn't pack as small though
    Rog Tallbloke likes this.
  18. Rog Tallbloke

    Rog Tallbloke Thru Hiker

    1oz. It's like leather. Lol. You still got it?
  19. Enzo

    Enzo Thru Hiker

    Good for stuff sacks :)
  20. cathyjc

    cathyjc Thru Hiker

    I'm going to have to 'amend' the above statement - I just tried to alter a internal tab on my Howff.
    I tried pulling a piece of cuben off the surface of the fly and torn the mylar away from the dyneemer threads !!! - easily repaired but shows that even in 'peal' the bonding is stronger that the mylar/dyneemer matrix. The piece had been bonded in place ~3 yrs.
  21. Rog Tallbloke

    Rog Tallbloke Thru Hiker

    How hard were you pulling it Cathy?
  22. cathyjc

    cathyjc Thru Hiker

    I was trying to peal it off and as it was quite firmly attached pulling quite hard.
    Previous experience had shown me that if the piece has been attached for only a short while it is possible to peal the bonded piece off - but not in this case.
    Again the bonding is stronger than the 'fabric' :):thumbsup:.
  23. Rog Tallbloke

    Rog Tallbloke Thru Hiker

    This was bonded using the 3M tape, yes? Have you got the numerical identifier of it?
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  24. cathyjc

    cathyjc Thru Hiker

    Mmmh cannot remember. By the final stages of construction I was using both 3M and Venture tape.
    @paul thinks the Venture tape as good as the 3M IIRC ??
  25. Mole

    Mole Thru Hiker

    Really this is useful builders info, and should have its own thread in the myog forum?

    Mods?
    Tartanferret and cathyjc like this.

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