Carbon Fibre

[Robster]

Arnie and all other Carbon Guru's!

 

I have made some wings from wet lay up carbon, but have found that air bubbles will always appear to some degree between the carbon and the gel coat layer. Is is feasable to use Pre Preg at home, can you 'cure' it easily..? Another big problem with wet lay up seems to be that the carbon frays at the edges and for intricate moulds (I have tried to make some wing mirrors) where two pieces is ideal, the fraying looks shoddy. Does Pre preg fray?

 

Any advice would be gratefully received, one year, dozens of failed attempts and lots of air bubbles later I still do not have respectable wings!!!

[EFA]

I'm no expert on wet lay up, but pre-preg can be used and air cured - gives better, but not perfect results. Vacuum forming with carbon or CNC ally tools is the only way to get A1 results.

 

Arnie Webb

The Fat Bloke blush.gif in a Slow Old Vauxhall wink.gif

[Mike Bees]

Robster - are you vacuum bagging? If you don't use any pressurising method then with a wet layup you'll end up with a very heavy (too wet) laminate which will be full of air bubbles. I doubt you'd get pre-pregs to work at all without pressurising.

 

You should be able to homebrew a simple vacuum bag using a vacuum cleaner. Probably.

 

Mike

[Robster]

Mike, Arnie

 

Thanks for your advice. As yet, I have not used vacuum bags, but I will do as soon as the weather warms up enough for the resins not to resemble treacle in the garden shed!

 

Having said that, it is such a messy process that I wanted to use pre-preg. How pliable are the sheets when you get them, do they suffer fraying at the edges like dry weave matt? Do they have to be kept cold? Can you buy proper vacuum bags, or will any large polythene bag do?

 

Thanks again

 

Robin

[Mike Bees]

You might find some useful tips here:

 

http://www.damonrinard.com/carbonqa.htm

http://www.falconhobbies.com/vacbag.html

http://www.sailingsource.com/cherub/bldfoam.htm

http://www.sailingsource.com/cherub/chframe.htm

 

If you're using epoxy resin then protect yourself very carefully and thoroughly - too much contact with results in developing an allergy, and once you've got it you've got it forever. It's not nice - I have a friend who built a boat using epoxy resin, got it all over his hands etc., now has the allergy and the slightest whiff of epoxy brings him out in very itchy red spots (this has nothing to do with any of his other recreational activities).

 

Mike

[Mike Bees]

And:

 

www.spsystems.com - do everything including peel plies, vacuum bagging films etc.

 

Mike