Well, it didn't go quite as well as I'd hoped. I think the bagging was ok as we couldn't find any leaks anywhere, but there was obviously air coming in through the surrounding core as we just couldn't get it to full vacuum and it slowly returned to 0 after turning the pump off.

Let us know how it worked.

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

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.

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

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

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.

thanks for the quick replies.

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

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.