Possible to use adhesive on “Polycryo”?

Check the GGG thread. There's a small cottage vendor who makes polycryo shelters. There might be some details there.

MYOG

Right, that's the thread ^ that discusses tape. Unless adhesive is in there, and I missed it.

Just occurred to me: that "adhesive" will mean "tape" to some folks. I meant glue. I'll edit the OP.

One of my customers told me they reinforced the hems with super glue. Don't personally know how it works, but it wouldn't be too expensive to try it out.

I'm also interested in gluing sheets together. I sent the question of what adhesive might be used to GG about 5 days ago but have not gotten a reply.

3M's spray adhesives web site has several that list polyolefin (20, 24, 27, 72, 74, 76, 77, 90). Anyone know if any of those work?

I'd imagine that contact cement would do fine. But you would have *zero* margin for error – if you stuck a piece to itself by accident you would never get it apart.

If I were to do that I would spread the pieces out with weights on the ends so they can't stick to themselves, put the cement on, wait the 30 minutes or so for it to be ready, then very carefully put the two pieces together. Maybe cut them bigger than they need to be and trim after glueing to give yourself room to put weights on the ends.

> 3M's spray adhesives web site has several that list polyolefin (20, 24, 27, 72, 74, 76, 77, 90). Anyone know if any of those work?

This would be your best bet. Polyolefin is known to resist adhesives (which is why the tapes don't do the greatest either), so if 3M has made some specifically for it, I'd bet you'll do better with them than your typical contact cement. Make sure it is also UV resistant!

Hm. If trying to make a seam on a hood, I'd have to get that spray adhesive pretty darned accurately onto about 1/2" of material and nowhere else. I can't imagine masking polycryo is fun. I'd wish for a brush application if possible.

Delmar, how about "masking" it with a strip of cardboard? That should give a pretty clean line.

If you do an experiment with various sprays, please post results. Thanks in advance.

I finally got around to trying this out. The local OSH had 3 types of 3M sprays. #90 seemed most appropriate from the verbiage on the can.

The spray can nozzle can be adjusted to spray various widths down to about half an inch. I used a width of about a 1.5". I first tried joining a couple of small pieces, spraying each piece about 3 coats, waiting the advised 2 minutes, then joining and pressing them together. It adhered very well. Over-spray (deliberate) lost tackiness after a few mins. I don't think accidental over-spray will cause pieces to become unintentionally attached later as long as the pieces are dried for a while before folding the sheets. After waiting about 20 mins, I pulled vigorously on the test joint in various directions. This was hardly scientific, but it seemed to be very strong. I tried to unpeel the two layers also, and even that was very difficult.

I then attached two pieces (main ground cloth and vestibule piece) with a joint about 3 feet across. Seems to have formed a more than adequate joint for ground cloth use. I'll be field testing it in a few weeks.

I don't plan to use the glued pieces for a tarp, but given how good the joint is, that may well be feasible. Of course, someone planning to attach two pieces for a tarp will want to do much more rigorous testing (like in thread 59588).

Ah, thanks for the test of the 3M spray. Encouraging.