what can i use for peel ply?

[Mighty Mik]

I have an art supply store nearby, what am i looking for?

[Salto]

I think that polyester suit lining is the same stuff.

Graham.

[Mighty Mik]

I think someone was using drafting mylar, modified by taking a 'woodpecker' for balsa to it... but was it .005 or .003 ... ?

[davidfee]

I think we are talking about two different things here.

Peel Ply is a woven fabric, generally made of nylon or polyester. There are higher-temp types made from teflon-coated fiberglass. It is used to give a bondable surface to a laminate, as well as to wick away slight excesses of epoxy in vacuum bagging operations.

Porous Release Film is generally thin polyethylene or other plastic, with perforations every centimeter or so. The perforations allow air to escape from below the film, which is used as a release barrier in vacuum bagging.

I think polyester suit lining may well work fine as a peel ply. Perforating light Mylar with a "woodpecker" would give an approximation of porous release.

They serve different purposes... what is your application?

-David

[shoe]

I usually just go to my local hobby/sewing supply store and buy a few yards of nylon fabric, whatever I can find cheap. Works good.

[davidfee]

shoe,
I'll have to try that. There's a fabric shop across the street (literally) from my apartment. I have always just ordered the "real stuff" be cause it is convenient and cheap enough. But the shop across the street is arguably more convenient. ;) We'll have to check it out.

-David

[Mighty Mik]

I'm trying to make wings. :) I think we need an overview of a layup here...what goes where?

foam>empregnated cloth>peelply>breather>outer foam bed?

I think we are talking about two different things here.

Peel Ply is a woven fabric, generally made of nylon or polyester. There are higher-temp types made from teflon-coated fiberglass. It is used to give a bondable surface to a laminate, as well as to wick away slight excesses of epoxy in vacuum bagging operations.

Porous Release Film is generally thin polyethylene or other plastic, with perforations every centimeter or so. The perforations allow air to escape from below the film, which is used as a release barrier in vacuum bagging.

I think polyester suit lining may well work fine as a peel ply. Perforating light Mylar with a "woodpecker" would give an approximation of porous release.

They serve different purposes... what is your application?

-David

[davidfee]

For a normal vacuum-bagged composite skinned foam-core wing, check my website for step by step pictures and descriptions: http://members.cox.net/dwfee/VacBagWing.htm

You don't need peel-ply for a normal wing. I do use peel-ply for my skin hinges on foam core wings, however. You use it for a hollow-molded wing, but it doesn't sound like you're talking about that.

-David

[shoe]

I'm trying to make wings. :) I think we need an overview of a layup here...what goes where?

foam>empregnated cloth>peelply>breather>outer foam bed?

It depends on the type of wing. For a small airplane that I'm trying to minimize weight and don't care so much about the LE finish it goes something like this.
Foam>Cloth>Mylar>Nylon Peel Ply>Breather>Bag>Foam Shuck

For a plane where the LE finish is more of a concern
Foam>Cloth>Mylar>Non-porous Release Film>Breather>Bag>Foam Shuck

My "non-porous release film" is simply 4-5mil plastic painters drop cloth from the hardware store.

[Mighty Mik]

see, i'm missing this 'mylar' stage. How this is this mylar? Is drafting film usable here?

[davidfee]

The Mylar molst folks use for giving the smooth, wave-free, surface on a bagged foam-core wing is .014" thick. It's much thicker than normal drafting film. It is apparently used in graphic arts, sign making, etc... but I buy it from a composites supplier such as CST.

[Mighty Mik]

I think i had a crapload of it before i moved here. I'll look around and see what's available.