Want to make my own Alpacka-esk pack raft, but don't want to fork out that much $$$.

And, DIY is always a lot funner (and suits my purposes better).

Anyone have any suggestions on a worthwhile fabric?

I was thinking:
http://www.rockywoods.com/Fabrics-Hardware-Patterns-Kits/Heat-Sealable-Nylon-Fabrics/Heat-Sealable-70-Denier-Nylon-Taffeta


ohh... and does anyone have an idea of how big samples are from rockywoods or seattle fabrics?

Edited by uncoolperson on 05/06/2009 21:34:59 MDT.

Can't help you with the rest of it, but while sample sizes vary 2-3" on a side is typical for rockywoods.

Good luck, sounds like a fun project.

I had a similar idea some time ago (simple kayak rather than packraft). I played a bit with samples of the heat sealable fabrics and now I'm not sure if it would work. My key findings are:

- the coating can be welded only to itself, a weld with the other side of the fabrics is weak

- PU glue (aquaseal) does not stick to the heat sealable coating

That means one would have to design the boat in a way that uses only the proper way of sealing the fabrics. Although it seems to be possible, it won't be easy. I'd really prefer the possibility to use a glue when needed to join whatever face of the fabrics I want.

I've gotten some input from someone that used to semi-mass produce something similar, and it was a slightly heavier and old school fabric (might have to go that route).

the engineer in me and some beer in me says I have to construct some tests.

so,
strength of various seams (atleast two types of sealants combine with sewing and a heavy nylon strip and heat sealable)

air permeability of fabric and above described seams
pvc tube with pressure gauge on it, fabric/seam on end screwed on (air tight) with a balloon over to collect air seeped through.

if someone has a better idea or things I should test for please share.

some visual basic and excel spread sheets (ratios of what can be lost where under what pressure... only fishing for a few hours) later I should be able to come up with a suitable combo.

if I do this data should be able to be used to make super duper light weight waiters in the future (even the commercial breathable ones are too heavy and bulky).

because this is an economy job (can't make 4 to see what works, test a few things and make one, heck today I lucked out and instead of being part of the 10% laid off I was part of the 90% getting a 5% pay cut), if someone has some sizable scraps/materials they can donate it'd be appreciated (I figure yard square should do it)


materials to be tested so far:
http://www.rockywoods.com/Ripstop-Nylon
http://www.rockywoods.com/210-Denier-Doublewall-Ripstop
http://www.rockywoods.com/Heat-Sealable-70-Denier-Nylon-Taffeta
http://www.rockywoods.com/Ultra-Sil-Silicone-Ripstop-Nylon-Fabric

http://www.rockywoods.com/Fabrics-Hardware-Patterns-Kits/Nylon-and-Poly-Webbing-Fabrics/2-Polypropylene-Webbing-Black
http://www.rockywoods.com/Tenacious-Tape-Sealing-Repair-Tape
http://www.rockywoods.com/Fabrics-Hardware-Patterns-Kits/Seam-Sealers-Seam-Tapes/Aquaseal-Urethane-Sealant

If I pull this off I'll share my findings.

any input appreciated, anecdotal included.

Edited by uncoolperson on 05/15/2009 18:26:57 MDT.

Hi Andy,
Looking at the list of fabrics you want to try, the ordinary ripstop nylon and silnylon will definitely be air permeable. For making something inflatable, we have to look for fabrics that has really thick layer of quality coating. The common coated nylon is unlikely to be airtight, especially after some use.

So far, the only material of this kind that would be easy to get is the heat sealable fabrics, with the disadvantages I mentioned in my previous post.

Other option would be look for some PU coated fabrics with very high pressure rating, such as the ones used in bombproof tents or tent floors. I had a tent with floor made of something what would be perfect here. The common PU coating, unlike the thermoplastic version, can be glued quite well or it can be sewn and then taped.

Finally, some light fabrics with good vinyl coating will work too and could be cheaper. Vinyl is also easy to glue and the glue is easy to find. I have swatch set of vinyl coated fabrics from Seattle Fabrics, the lightest they have is 10 oz (http://www.seattlefabrics.com/vinyl.html).

Check this for what can be done with vinyl coated fabrics:
http://www.yostwerks.com/InflatableMain.html

Cuben Fiber is air tight. One use is inflatable kites for
surfboards.

That's something I've been looking at, if I go that route I gotta rework by design to something more economical.

Contact Stephenson/Warmlite and ask what they use for the DAM.
It's not very sophisticated construction and it seems to work.

from the catalog looks to be heat sealable coated nylon taffeta.

You might consider using separate inner bladders. Then you could make the outer shell using standard cut'n stitch techniques and construct the bladders of readily available vinyl or polyurethane film. If you make the bladders oversized, they could be quite thin since the shell would support them. The shell could be the lightest uncoated fabric you think you can get away with in light of projected use.

I was playing around with that idea today, the only problem I've come up with is that I'm still stuck finding lightweight and cheapish (a few yards required, off hand don't remember just the tube part), heck I even tried my hand at sealing some painters plastic sheeting I had lying around (my skills at that apparently are poor).

If i can get myself up to the level plastic sheeting with ripstop nylon outer would make for a nifty raft.


I'd really like to find the same stuff that they use to make the wx tex bags.

Edited by uncoolperson on 05/09/2009 17:50:39 MDT.

anyone have ideas behind aquaseal durability when creating seams between sheets of cuben fiber?


iron turned way up on the heat sealable stuff I linked to with sealable side to nonsealable side seems pretty strong (two 6x6 squares overlapped about an inch and a half don't want to tear apart by hand).


numbers to come once testing aparatus is figured out.



Edit: still pealed apart though.

Edited by uncoolperson on 05/15/2009 18:27:38 MDT.

Cuben fiber at the linked to specs sealed with aquaseal is not air tight (or atleast not at 3-5 psi), also does not pass the screw driver punched into it test (attempt to recreate a stick punched into it).

think I'm going to go with that heat sealable nylon.

little bit of math and geometry to go.

Edited by uncoolperson on 05/14/2009 19:26:54 MDT.

Well, I think I'm going to give up for the summer. Time to start fishing and stop playing with my project. Perhaps wait until winter (after deer, pheasant, and duck season of course)

Lessons learned
Alpca, well worth it... costs lots (to me anyway) but an at home build costs some too.

I'm in easy 40+ hours (design/build/fix)
materials were $100, add 40 for aquaseal
$40 R&D materials, 6-pack of beer for R&D
4x take out dinner
additional 4 6packs of beer

add another my guess easy $100 materials and 20 hours build time plus $50-$100 hardware for the next build.

Lessons learned, think through and maybe non permanent mock up the build prior to building... make sure my methods will work.
This proved a problem working out the seal that turns all the flat pieces into tubes, I connected everything together hoping to fold then seal up.... that didn't work had to make those seals in tension rather than shear (I was warned about the seal style, but i was stuck).(mine were shaped like { )

Work out a better idea than a piece of wood and a clothing iron, didn't seal the pieces together nicely, fought with that for way too long.

Figure out supply of aquaseal and the fancy accelerator, sure the company's headquarters are in my town.... but they're closed on weekends.
Also, get more brushes, nothing gets it off the one brush in the package.

Edited by uncoolperson on 06/10/2009 07:26:59 MDT.