A guide to vacuum bagging

This short video is a short guide on how to use the vacuum bagging process. It is a follow on from our video showing how to produce a carbon fibre laminate. Vacuum bagging helps to consolodate the laminate, providing a better fabric to resin ratio.
It is a step by step demo that gives you some hints and tips when vac bagging a wet lay-up carbon fibre part. The same process could be used when using standard glass fabric.
John Burn provide training courses - please visit our website.

Category:

Howto & Style

Tags:

• John burn vacumm bagging
• john burns
• john burn
• vac bagging
• vacuum bagging
• vac bag
• epoxy composites
• carbon fibre
• carbon fiber
• epoxy wet lay up
• glass fabric vac bagging
• glass fiber
• grp moulding
• vacuum molds
• vac bag molds
• marine
• DIY
• automotive
• car parts
• boat building
• how to
• how to vacuum bag
• GRP
• sika
• sika biresin
• sika tooling & composites

[gserghiou]

can someone explain the purpose of making the plits in the bag ???

Thanks

[johnburnify]

@gserghiou the pleats in the bag help the bag to mould aorund the shape of the part. If the part is a particularly difficult shape you will need to have some give in the bag to ensure it can cover the area without stretching as the vacuum evacuates the air and causing problems with the component.

[rallyboy88]

beautiful looking part! great job!, just wondering is the resin actually sucked through the peel ply, release film and then the breather fabric?

[johnburnify]

Thanks. Yes, this video starts at he point where we finished laying up the part. The resin we've used has a sufficient pot life (open time) to allow us to draw any excess throught the various layers. When cured the peel ply will allow us to remove everything and leave a nice surface should we need to bond to it.

[rallyboy88]

ahhh i see, so the vacuum totally gets rid of any air bubbles?, its just i notice some laminators use rollers and some don't, so i've been questioning if vacuums are reliable enough to completely get rid of all the air, i was trying wet lay up a while ago but air bubbles were occuring everytime, you pros make it look so easy ha!, but just one more question, how much psi is your system pulling?, thanks

[johnburnify]

There are a number of variables when it comes to reducing air bubbles. Typically depends on type of resin (viscosity), temp and pot life. By vac bagging you should be able to remove 80-90% of bubbles, the rest being so small that they shouldn't be visible with the naked eye. Of course to get the best results you would need to use Pre-Preg with an autoclave, but this route is not normally affordable to most. The PSI is around -0.8 to -1bar for the purpose of our demo. Hope this helps.

[drankfromtoilet]

Nice videos..can you help me find that breaching unit..

[johnburnify]

@openclass1 ...very good. It is just a standard lab coat but in Darth Vader black!

[zdanz25]

im completely new to this and id like to learn how to do. i make foam core skimboards in my garge and theyre all right, they get dents in them fairly easy. I was just wondering where i might find all this material to be able to do this technique. I'd like to make stronger boards, not trying to run a buisness or anything. thank you and bi the way, how does the resin dry if all the air to dry it was sucked out by the vacumm?

[rallyboy88]

@johnburnify okay, yes that helped alot! thanks alot for your help, have a good day sir great stuff!!

Josh