Yet another prepreg question


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fgayford
fgayford
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I am having fun with Easy Composites prepreg. (6 parts so far) The last one is without the vacuum pump running.

The only thing that I need to know is what is the trick to peeling off the plastic coatings? I have enough problems at the grocery store getting the plastic rip off bags opened. There has to be a technic to do this easier. Right now I am using twizzers and a large needle.

So whats the trick guys??????????????Cry

Fred

Even supreme beings don't know it all.
Warren (Staff)
Warren (Staff)
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Finger nails at the edge!!  I sometimes use the edge of a blade.  It's not easy but once youve got a few mm peeled the rest breaks free dead easy.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
fgayford
fgayford
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Well I have made a little discovery. I was in a hurry the last part I layed up with prepreg so the prepreg was not up to room temp, still cool.

The plastic came off dead easy. It still formed in the mold fine at this cooler temp. Just a crazy thought. If it gives me a hard time when it warms up I should have a can of cold spray (like used in electronics) on hand and give the ofending corner a short blast. Once really warm I find it almost impossible to get it started to peel.

Fred
Matthieu Libeert
Matthieu Libeert
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I like your way of thinking fred, I'll remember that when I'll use prepreg soon Smile

Matthieu Libeert
Founder MAT2 Composites X Sports
website:
www.mat2composites.com




fgayford
fgayford
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Well Matt supreme beings think alikeSmile don't they?

I just pulled my 5th perfect prepreg part from my autoclave. I did it without the vacuum pump connected.

So if you can get a perfectly sealed bag as you do in infusion you can do prepreg the same way.

I really like prepreg!!!!

Fred
carboncactus
carboncactus
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Been using prepreg from day 1, never done wetlay really.
Pinholes are the cause of sleepless nights, and are more prone to prepregs since the resin to fiber ratio is much lower, but then again it's what makes prepreg lighter and stronger.
I do leave the pump running overnight, no problem.
You can also leave the pump going for a couple of hours before sticking it in the oven.
If you have an autoclave, that certainly helps, but your bag needs to be perfect, if there's a small leak, the positive pressure will be trying to push air into the bag. You'd be better off just oven curing and leaving the pump on.
As for peeling the film, I keep a Stanley knife at hand, just stab and flick the film, as if you we're scratching it.

http://www.talkcomposites.com/Uploads/Images/db628ad5-e0e7-47b9-873a-3d84.png
Edited 12 Years Ago by carboncactus
Warren (Staff)
Warren (Staff)
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We leave our pre-preg items on the vacuum pump throughout the cure process.  No reason not to really.  With pre-preg if there is a very slight leak you can get away with it if its on the pump.

Generally we dont have many burst bags and even slight leaks usually seal up once in the oven.  Unless you are unlucky and puncture the bag, most leaks are around the gum tape or rarely connector.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
Nick Igoe
Nick Igoe
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Form my F1 days we always had a can of freeze spray on hand, don't forget if your pre-preg is getting a little warm you can always put your mould and materials back into to the freezer whilst you have a coffee etc  to keep it just right, no point in trying to rush a master piece.

As for removing the backing, quick flick at one corner with a pointed scalpel always did the trick for me.

Far UK
GO

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