Peel Ply is either Dacron or Nylon fabric. It is placed in the layup anywhere you want the laminate to separate and or on any surface you want to do secondary bonding to.

It is mainly intended for resins which produce an amine blush.

An example application in the world of kayaks would be:
Where the deck and hull seam is, the peel ply would be layed up on each surface of the seam at the time of glassing. For example on the inside of the deck, after you are completely finished glassing, and before the epoxy starts to set up, you would lay 2" wide Dacron tape along the sheer line, and wet the Dacron out just as if it were fiberglass. You would leave an end about 4" long hanging somewhere where it wouldn't get in your way. While the epoxy is still green, say the next morning, you would apply a filler coat (mainly to the fiberglass because the peel ply doesn't need it).

You would then leave everything as it is on the inside deck while you continue to work on the rest of the kayak, say glassing the inside hull (where you use the peel ply along the sheer line same as on the inside deck).

When it is time to join the deck and hull, most likely the epoxies are completely hardened (no longer green).

Without the peel ply, you would need to use something like a Scotchbrite pad and water and scrub the areas you intend to apply fg tape to like crazy, and then some more, then sand the surfaces with 80 grit paper like crazy, etc. You will never remove 100% of the amine blush from the weave of the cloth (like on the inside deck where you did not totally fill the weave) and when you sand the area you will cut into the fibers of the cloth and weaken the fg. Since you are applying tape over these areas they are likely not left too weak, but still they are not what they could be. This is alot of work and time.

If you used peel ply....

The first thing you do is grab the 4" lengths of Dacron peel ply tape you left hanging on the inside deck and hull and tear the peel ply off the surfaces. This takes about 30 seconds. The virgin surfaces which were under the peel ply are now completely amine blush free, and are rough enough for an exellent mechanical bonding of new resins and glass.

No cleaning of the surfaces to be bonded is necessary!
No sanding of the surfaces is necessary!

This makes you !

Tape (clamp) the deck and hull together and procede to apply fiberglass tape on the sheer joint.

: i wonder if the t.p. would tear up under the heavier wt of one of our yak
: layups. it seems similar to the peel ply idea.

: another question, i wonder if there was some other fabric that could undergo
: major tension that would also do this( would peel ply work? - what is peel
: ply?)like could you do a lay up and put major tension on this outer skin,
: the excess would go thru the pores or be sucked up and you would get a
: thinner laminate w/ more optimal resin content. would it thin out the
: problems w/ those resin rich laminate. like say you had a real simple hull
: shape, could you wet out the layerws of glass and lay on top some fabric
: and hang wts from it all around the perimeter of the yak, scraping up
: excess glass a s it squeezed thru all the time? poor man's and simple mans
: vaccum bag?

: is it possible?

: -mick