Peel ply

General Composites Discussions Composites Talk
#1

I’ve seen peel ply used for the vacuum infusion process. Is it a good idea to use peel ply when doing wet layups without vacuum and oven cure?

#2

not really, peel ply is only used as an intermediary between the vac bag and/or excess resin trap cloths.

#3

When doing contact molding (ie without vacuum) I use peel ply all the time. I do a lot of race car body repairs and very often it is almost impossible to use vacuum, so I place peel ply over the last layer of fabric and add resin until the peel ply is completly covered and the weave is no longer showing. This does two things, first it helps hold down the fabric and secondly it creates a smooth finish which makes it easier to prepare for paint.

#4

So you’re peel ply on those race car bodies becomes part of the composite? Is it totally clear after resin saturation? Or is peel ply as the name suggests, it peels off after the part cures?

Ok so let me test my best interpretation of how to set up for vacuum infusion in a female mold. Please correct me where i am wrong.

  1. spray your pva or use just wax release on the mold surfaces.

  2. spray in clear gel coat OR brush/roll some epoxy ( i’m hooked on epoxy lol )into the female mold. let it gel and cure enough that it is just to the tacky point but touchable.

  3. Lay down the first layer of nice carbon fiber cloth. Work out all the wrinkles and what-not so it lays nice and flat.

4 lay in your remaining layers of carbon cloth and or kevlar cloth.

  1. cut up and lay in the flow media

  2. cover that with a full single sheet of bleeder ply.

  3. cover that with a layer of peel ply.

  4. cover with vacuum bag.

#5

[QUOTE=Fastrr]So you’re peel ply on those race car bodies becomes part of the composite? Is it totally clear after resin saturation? Or is peel ply as the name suggests, it peels off after the part cures?

Ok so let me test my best interpretation of how to set up for vacuum infusion in a female mold. Please correct me where i am wrong.

  1. spray your pva or use just wax release on the mold surfaces.

  2. spray in clear gel coat OR brush/roll some epoxy ( i’m hooked on epoxy lol )into the female mold. let it gel and cure enough that it is just to the tacky point but touchable.

  3. Lay down the first layer of nice carbon fiber cloth. Work out all the wrinkles and what-not so it lays nice and flat.

4 lay in your remaining layers of carbon cloth and or kevlar cloth.

  1. cut up and lay in the flow media

  2. cover that with a full single sheet of bleeder ply.

  3. cover that with a layer of peel ply.

  4. cover with vacuum bag.[/QUOTE

The peel ply gets peeled off after curing leaving a smooth, matt finish ready for secondary bondin etc. I’m not an expert on VIP, but I think the peel ply should lay in after the carbon/kevlar and before the flow media. Maybe someone else could clarify that one. Is peel ply typically used in VIP?

#6

I have also used Peel Ply with open hand lay up and just recently.

I had a mold that I had sprayed gel coat on it 4 months ago (to protect the surface during moving) and it started to self releasing (All my molds get semi-perm release with wax too) and I just finished laying it up. I then use peel ply to lay in on the top, then clear PE film and then a sand bag (used for hammer forming steel and alum panels) to hold or compress the gel coat back to the mold.

It came out perfect!

NEVER leave Peel Ply in a composite product! A guy came over last weekend to buy some peel ply and he told me a guy had failed to peel out his peel ply and the airplane wing delaminated! :eek:

A tip here, if you are using white peel ply (turns clear with resins), take a Sharpie marker and add lines to it to remind you to remove it after curing.

#7

I ordered a few yards of release ply “B” from Fiberlay last week. They called me and said they would have to substitute another product that costs more. What costs more than $8 per yard release ply “B”? I hope it works really well, for $9-11 per yard.

#8

…well look for my deal for members on here for peel ply in the for sale section…duh!:rolleyes:

#9

Your right. Otherwise you will have a very smooth sheet of cotton stuck to your part.

Step 7 needs to go before 5, and you can leave 6 out of the processs as it would be a waste of resin. Its not needed with VIP.

Also…Richmond Aircafts green peel ply. Highly conformable. Expands more than others. Very fine. Its the junk!

#10

Peel Ply bump… :slight_smile:

Can you experts tell us why there are non-perforated peel ply and then perforated peel ply?

I think i’m going to infuse a part and want to make sure i use the right stuff. I believe perforated is the correct peel ply for that?

So, non perforated would be a good use for say one of those race car body repair jobs?

#11

Im no expert.

But, heres the break down.

Peel ply is meant for secondary bodning. Its to create a rough surface that mimics a sanded surface. It just happens to be the perfect release material for resin infusion because its very permeable.

Peel ply is what you want for resin infusion. Not release film.

The perferated and non-perferated release plys pretain to pre-preg, and wet lay-up vacuum bagging.

The release films that major manufacturers use are chemically treated films, not cloths. Perferated films are used to control the amount of resin bleed. With perferated films you have to be aware of the resin content to want to bleed. Everything is weighed, measured, and calculated. So you use as little bleeder as you think you can get away with to acheive that result.

Non perferated release films are for when very little bleed is needed. Basically a very calculated, air free lay up.