just recieved our rather huge order for some repairs we need to do. initially we were going to try infusion so we didnt order any release film, but now feel we're better off sticking to wet lay and vac bag.

It depends a bit on the shape of what you are repairing, as the difficulty in removing peel ply comes from the fact that it goes very stiff once the resin has cured (so no, I don't believe a second layer of ply would do anything but use more resin). If you've got quite complex shapes, then it can become very difficult to remove the peel ply. If your area is relatively flat, then it is generally quite easy to remove. 

The release film is perforated to control the amount of resin drawn out when under vacuum so you risk pulling out too much resin if you do not use the film, try a small practice piece first.

As Chris says, without the release film, the peel ply and breather will soak up the resin trying to become part of the laminate. The release film will prevent this

thanks for the quick replies.

There are many videos on youtube etc. where people do vac bagging without release film.
If you think you really need it and can't wait for the release film make your own. Take a trash bag and put a bunch of holes in it with a nail or wire. If you need larger amounts of release film, put a bunch of thin nails through a thin wooden board in the desired pattern and push it onto the trash bag to perforate it. Simple, cheap and fast. The resin will not adhere to PE or PP or whatever material trashbags are made of.

that sounds like a plan. we just happen to have a roll of bin bags on the boat.

Like said above, the perforated film will make sure there is not to much resin being drawn out of the repair... If you dont use it with vacuumbagging you will have dry spots, a bad finish and probably bad fix... The trashbag idea sounds good, you can also use some vacuumbagging material its mostly selfreleasing as well! If you have the time its mostly better to wait a bit and make sure you have the right materials to work with. It's a lesson I've learned in the past trying to use cheaper materials bought in my local DIY store not being made for composites work and 9 out of 10 times that project failed

Matthieu Libeert
Founder MAT2 Composites X Sports
website: www.mat2composites.com

Trashbags and similar cheap plastic films work fine for many purposes.
I have seen aircraft and sailplane manufacturers use them in production (vacuum bagging, sealed with acrylic bathroom caulk), and the first time I saw the nailboard idea was a composite aircraft repair shop.

well, the first two patches are done with some bin bag. i started with the smaller bits just in case anything horrible happens.