Peel ply and secondary bonding with polyester

[nickyp]

I've used peel ply/release fabric with epoxy lay ups, repairs, and vacuum bagging.
I have recently been doing more glasswork so have used it to get a smooth finish on various jobs using polyester.
My question is this: after peeling it off, can I glass straight to the surface without sanding, or is it best to sand as well?

 

[nickyp]

I'm bumping this one, as I really want to know the answer.
I'm still sanding, but the peel ply makes that a lot faster.
Lotta glass guys on here. Please chime in

 

[MDI45]

Nickyp,are you using a general purpose polyester.....if so it has wax in it ..so you must sand it

 

[nickyp]

Yup, waxed polyester.
I was just wondering if when I peel the release fabric off, it pulls the wax off. It certainly seems like it has. The surface is dull, and It sands so easily and powdery.
Sanding after, is not a big deal, and is very quick. I've been doing it as a better safe than sorry thing, but it would just be nice to know the facts.
I know that the peel ply removes the amine blush from epoxy.

 

[MDI45]

I have read that it doesn't need any sanding....but I would do a small test patch with your choice of finish and see what happens

 

[nickyp]

Thanks,
I think I will test the bond with and without sanding, and see if there is any difference

 

[pyrofan]

Yup, waxed polyester.
I was just wondering if when I peel the release fabric off, it pulls the wax off. It certainly seems like it has. The surface is dull, and It sands so easily and powdery.
Sanding after, is not a big deal, and is very quick. I've been doing it as a better safe than sorry thing, but it would just be nice to know the facts.
I know that the peel ply removes the amine blush from epoxy.

If it sands easily an does not gum up your paper the wax has risen to the top of the surface. When using a resin with wax added,if your do not sand the surface completely, in my experience you will not get a good bond.

 

[nickyp]

If it sands easily an does not gum up your paper the wax has risen to the top of the surface. When using a resin with wax added,if your do not sand the surface completely, in my experience you will not get a good bond.

Not to keep beating the same drum or sound rude, because that is not my intention, I will reiterate. I am a competent fiberglasser, and realize that laminating resin is unwaxed and therefore stays sticky, so you can go ahead and glass right over it. I know that the wax in waxed resin floats to the surface, blocking the resin from the air, thereby allowing it to cure.

My question pertains to the use of peel ply over waxed resin, and weather it traps the wax, leaving an unwaxed and ready to glass surface after peeling.
I think it does, but that is only my feeling. After communicating with MDI, I plan to do a few test runs and put this tp bed once and for all, because it seems no one knows for sure or don't feel like saying.
I will let everyone know once and for all

 

[pyrofan]

I wasn't trying do imply you didn't know what you where doing, just trying to tell you that if you could sand easily and it didn't gum up your paper that the wax had done the job it was intended to do.

I have tried the peel and release fabric with laminating resin to try and get a smoother surface before smoothing off with a filler. For me it was not worth the effort.

 

[nickyp]

It's all good pyro. Appreciate it
I don't know, I must have been on the rag yesterday.