Vac bag pressure

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#1

I have a few wet moulds to envelope bag some will be done in carbon and hopefully a good surface with them. My question is I have read to get a good finish the bag pressure is droped?

I have a regulator so that’s no problem but to what pressure. I’m new to vac baggin never really done it before as only done infusion

Cheers

#2

What do you want to do? Vacuum bagging a wet layup, infusion or prepreg?

#3

I have moulds for wet layup but I thought vacuum bagging would produce better results but it looks like I drew to much resin out of the layup

#4

Nobody can Answer if dropping the pressure is the right thing to do ?

#5

How are you bleeding your part? Your bleeder/breather setup is what will determine how much resin you draw out. You do want some resin bleed so that the air and volatiles can be removed. Wet layup is also partly based on your technique. How much resin do you use? Do you weigh your material? How does your bag look when you’re done? clean pleats with smooth surfaces?

Dropping the vaccuum will reduce the pressure, and possibly reduce the amount of resin drawn out of the laminate but, not necessarily. I think full vac is better. You should control the bleed by how you setup your bleeder.

Do you have pics of the laminate and your setup? And after cure?

Hard to give answers without more info.

#6

I can get pics tonight. My parts are light and strong just not looking the best on the carbon surface I am using 30 micron release film and the bleeder was well and truley wet so maybe I need to dry up the layup abit too.

#7

If your breather if fully saturated and the resin stops flowing, it could cause some of the bubbles to stop migrating. It’s hard to get a good surface from the bag side. The mold side is generally where you’d want the outer surface. I guess you can make a light RTM tool if you wanted a good bag side, but it’s a bit of work. Though probably less work than sanding, coating, or spraying.

#8

Sorry I meant on the mould side I have small bubbles in the weave I meant

#9

You should try a perforated layer. They come in different sizes.