Bladder moulding methods

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#1

I am considering doing a pressurised bladder moulding job either with latex or stretchlon bladders (or other?) and was curious about any specific methods for fixing the bladders to the hose etc.

These will be a split alloy mould that has a 50+ mm flange area outside the part.

I was thinking that maybe a rebate could be cut through the mould flange to match the hose dia including the bladder that is wrapped around the hose, then this all clamps into the mould rebate tightly??

Any thoughts on this idea or other methods? Thanks.

#2

You’ll need to seal the bladder to the tooling - as this has to be a tight seal, are you intending on bagging the entire tool or just sealing with sealant tape to the tool?

Also, where is your vac and how are the split halves of the tool sealed?

#3

Justin, I think you misunderstand the process. There is no vacuum, and no bag tapes. Just a pressurised bladder within a closed mould.

It’s a tubular part with a split mould.

Intention is to layup each mould half with pre preg leaving some over lap hanging past the split/flange and then lay in a tubular bladder before closing the moulds. The bladder is connected to a air line and you blow up the bladder while the moulds cook in the oven.

I don’t have to remove the bladders although I will if possible.

Wanted to know how other fix the bladder to the air line hose?? There may be up to 90 psi.

#4

I use a barbed tube connector and put sealant tape around it. That goes into the bladder end, which is then wrapped very tightly with a rubber band.

#5

Ah, gotcha… Interesting approach.

I,ve only ever used bladders with prepregs/autoclave cure where the bladder is part of the vac bag. - whilst inflated with an airline during the bagging stage. - this is replaced with autoclave pressure during the cure cycle.

#6

Here is how I do it: http://www.compositescentral.com/showthread.php?t=7007