I have used 3M 77 (which is the industrial strength stuff) I think it is too much. It sticks very well of course, but it leaves a residue on the surface of the part. It is hard work getting that off and this is in no way ideal if you want perfect parts right out of the mould.

I now use Zyvax StayZ, way way better, seems to interlink with the epoxy as described, yet the surface is also not 100 % so some post work will have to be done. Also it is constantly out of stock and hard to get.

As for the 3M 77, maybe i used way too much, because most people are always stressing how little spray glue is actually needed. i use it to bond the peelply as that does not remain in the laminate. The rest of the layers are bonded with StayZ.

You can use the 3M 77 but i think its too much, yet my mould was so complex i didnt want to risk the cloth not staying down. As an alternative i could suggest using a lower strength (more standard) type of spray adhesive, using very small quantities.

I will possibly also look into the hairspray idea. For now, the Stayz seems to be working best, and it lets me not worry about the structural integrity of the laminate.

Thanks a lot for your feedback ! 

I've heard the hairspray idea before, never tried it myself but tempted to soon

The one thing I have learned in composites is this. Listen and if it makes sense test it yourself. The smoke and mirrors soon disappear. Its a proof is in the pudding sort of thing. I now test everything before I commit to a project.

Thanks to Matt and the guys I have proven to my self the following.

1. A perfectly sealed bag is possible. (I have had 14 in a row)

2. Clamping off the bag produces pin hole free surfaces. (who would ever have thought of turning off the pump?)

3. Those clamp off devices are the greatest thing since toast. I used to use vice grips and all other type of devices. The thing I like the best about them is the light weight. If you use vicegrip plyers or such, they are so heavy and add so much torgue and twist that they can easily cause a leak.

I infuse and then clamp off the two lines within an inch of the entry point of the bag. I then cut the tubes off an inch above them and then put a bit of resin in each tube. In this way I can see if the clamps are really clamping off the lines. If the resin level drops I know it needs a bit more clamping pressure.  The whole mold is now easy to move without restrictions so I can put it in my hot box oven and infuse the next mold and so on.

4. I ordered some soric from them and it arrived here in Canada as promised in about a week. I tested it as a flow media. One 6k carbon in the mold then a layer of soric and then another layer of 6k carbon. Then the vacuum bag. (not stretchelon. but regular bagging so it doesn't stick) It infused perfectly and produced a pin hole free part.

Right now I am testing the carbon skinning method....

Fred

you are right!
StayZ is the best, but it is very hard to find especially in italy!!!

 have find another spray, Nu-Tack made in usa but it is impossible from italy to contact the factory.
I have sent a lot of e-mail but no answers till now...

Yeah star.ace, it seems Zyvax have serious production issue, from what I've heard recently.

I use Stayz from Zyvax as it is epoxy compatiable. Should be available from Composites One and others. Most spray adhesives discussed in the posts on this topic will have a negative effect on the cured resin but Stayz is epoxy and will blend into the epoxy used to make the part and not effect the mechanical properties of the cured resin. Airtec makes a similar product just for ester resins.