this is the second attempt at this part, same problem each time, seems to have dry ares or air voids.

If your bag is 100% holding vacuum then run more resin into the part at the end of the infusion. If its a small part you might have infused it too quick.  It is quite easy to leave the vacuum pump on too long after clamping the resin feed and hence sucking out loads of resin.

Sorry forgot to say this is just wet lay up then bagged

Wet lay up is always hit and miss, no matter how many times you try.

Wet-layup and then vacuum bagged is notoriously tricky to get rid of all imperfections, it looks to me like those pin-holes are caused by drying out the cloth too much, I would suggest lowering the level of vacuum that you are pulling slightly, you should find that this will reduce the problem.

Paul Statham
Easy Composites / Carbon Mods - Technical

Thats interesting, could you suggest an approx level?
I have tried quite a few experiments lately and always get a dry surface/ pinholes.

http://motoform.blogspot.se

Thats interesting, could you suggest an approx level?I have tried quite a few experiments lately and always get a dry surface/ pinholes.

In our experience, really quite low! - Try 1/2 bar or maybe even lower. You can also reduce the amount of perforation you're using in your release film - to do this you can use an Un-Perforated Release Film and actually then perforate it yourself giving you total control over how perforated it is.

Like everyone's mentioned, vac bagging is a trial and error process on every new part. It can certainly be 'got right' and will produce great results when you find the right balance of resin quantity, perforation and vac level but even for the best of us it's a trial and error process.
                                                    

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Hii morning from Indonesia,

Laying up the epoxy resin before reinforce the fabric, wait until the epoxy resin layer is tacky/little bit hard then you can laying up the fabric (CF) and laminate the layer with resin until you end up with vacum bagging. This way will making sure that the surface is free from dry areas, because the resin on the surface is not absorb to much on fabric (cause the resin is tacky).

see on this video:http://www.youtube.com/watch?v=IAdVO8Rkv6c

All the best

Leon

Hi

this I know and have tried, but firstly it does not make a 100% difference, with the same pressure it gets dry under the toplayer,
I have also tried this with EC´s new polyester based clearcoat with the same result.
Secondly its a messy procedure and the alternative to change for infusion seems better.

http://motoform.blogspot.se

Matt
Thank you, I have started to think in these term and will try it, think I bought unperf last time.

Lets say I switch to infusion, how many layers of CF will it penetrate?
If you remember I make some motorcycle parts and amongst them a self-supporting rear unit,
seat-tank without a rear sub-frame.
In places the thickness will be 5-7 mm, will infusion penetrate all those layers of CF? (some UD fibers in there also.)
I guess the answer is yes with the corrects routing and blocking of the feed,
in that case is that expert stuff that I should practice until perfection, or straight forward?

http://motoform.blogspot.se