Peel-ply

Figment · Post by **Figment** » Fri Apr 11, 2003 3:55 pm

Peel-ply is a smooth nylon or polyester fabric that epoxy and (I think) polyester and vinylester resins can't stick to. I got mine with all the rest of my stuff from System Three, but I think it's a fairly common product available wherever cloth and resin are sold, possibly called "release fabric". S3 charges something like $7/yd for 60" wide stock.

Let's just hypothetically say that your task is to apply continuous strips of multi-layer tabbing to a hull/bulkhead joint:

Cut a strip of peel-ply that's larger than your largest strip of glass tape. lay it out flat (preferably in a wet-out box) and drizzle some resin onto the surface, then start layering in your tapes and wetting them out.
You now have your tabbing all ready to lay, and you can just lift it out of the box by grabbing the peel-ply because everything's sorta goo-ed together.
Lay the wet lamination over the joint and take your time rubbing out the runs and air bubbles. You can rub and roll as hard as you want, because you're rubbing on the peel-ply so you can't snag and displace any of the individual fibers underneath.
As the epoxy cures, a little bit seeps through the peel-ply, and this new outer air-exposed surface is where the amine blush forms. Once cured, the Peel-ply lives up to its name, peeling off easily, taking the top layer and amine blush with it.

The remaining surface is smooth and even (because you were able to do such a good job of squeegeeing out runs and air bubbles), but with a slight dull texture leftover from the peel-ply cloth, and the amine blush is gone, so it's instantly ready for the next step of lamination or fairing putty or painting or whatever without the need for any sanding or washing at all.

If it's an ordinary glass job, like say, after recoring the deck.... you just lay it on after all of your glass layers.

Really though I'm told that its value truly shines when doing something like vacuum-bagged cold molding.

Post by **Tim** » Fri Apr 11, 2003 6:20 pm

Peel ply rocks. It works just as Figment mentioned, and really does do all it is advertised to do. It leaves a nice smooth surface ready for finishing or, if necessary, additional fiberglass. It is really nice for making a pleasing finished edge on tabbing and such. Well worth the small additional investment.

Oh, and it works with all resins, too. We used to use it with Polyester and Vinylester at Hinckley.

Tim

Guest · Post by **Guest** » Mon Apr 14, 2003 10:12 am

Ah, a release fabric. I've never used any, but seems like it would be great, especially for the tabbing you mentioned. I'll have to keep it in mind for future glass work...

Post by **dasein668** » Mon Apr 14, 2003 2:56 pm

Anonymous wrote:Ah, a release fabric. I've never used any, but seems like it would be great, especially for the tabbing you mentioned. I'll have to keep it in mind for future glass work...

Ding-dong-dangit! My machine at work seems to be spontaneously eating my forum cookies!

That was me again... Figment: thanks for the Peel-ply info!

Tommy Bahama · Post by **Tommy Bahama** » Sun Feb 06, 2005 3:31 pm

Peel ply is great...we use it in the airplane building world. It's main purpose is to lay-up (as the final ply) over an area that will be worked on again...so you don't have to sand! It is "stippled" on just like any other ply but peels off very easy. The material we use is Dacron...a common fabric for covering wood and fabric airplanes.

Tom

meubcr · Post by **meubcr** » Sun Feb 22, 2009 12:30 pm

Why use peel-ply rather than cheaper, 4 mil plastic sheeting?

Quetzalsailor · Post by **Quetzalsailor** » Sun Feb 22, 2009 2:59 pm

Peel ply weeps air so is just the thing for pulling the air out of a layup when vacuum bagging. It's not supposed to weep epoxy so the bleeder layer, and the bag will remain usable. Its texture leaves the layup ready for subsequent bonding.

I recall Gougeon's book saying that any tight weave Nylon cloth, flag cloth, will be fine for a peel ply. I bought mine at the local fabric ends shop for lots less than it costs at a marine store.

Rachel · Post by **Rachel** » Sun Feb 22, 2009 5:07 pm

I've sometimes used Peel-Ply when squeegeeing out a hand lay-up, and it worked very well. It did three things I liked:

1) It made it easy to squeegee lighter cloth without getting it all ruffled up. Distributing the resin and removing the excess was easy.

2 and 3) When torn off, it left a smooth, yet lightly textured, blush-free surface, just ready to go.

I've never tried plain plastic, but my hunch is it would not work the same.

Rachel

Post by **Tim** » Sun Feb 22, 2009 5:12 pm

They're really not comparable or interchangeable products, and should not ever be construed as such.

meubcr · Post by **meubcr** » Sun Feb 22, 2009 8:53 pm

I'll try peel ply next time, though the plastic is great, cheap stuff for a clean lay-up that allows for squeeging out the air bubbles. After curing it comes right off. I never made the assumption that it would resolve the blush issue (which based on comments posted here, may have proved a wise choice).

Plastic tapes well in places like those overhanging spots in the wee corners of an inaccessible locker or stabilizing cockpit drains...

After curing, it peels right away.