Carbon fiber clouds after baking it...

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Any ideas on why this is or how to stop it?

I've made a few carbon fiber blanks lately but after baking them to cure the PR, they have large nasty cloudy spots right on the carbon fiber.

It's not air bubbles, to be sure, and it is exacerbated by baking it at 150F for 10-30 minutes.
 
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Pics? I'm also confused n why you're baking them. The catalyst should harden them up by itself and leave in the sun a few hours. Baking seems dangerous due to the fumes and pr being flammable (assuming you're using pr).
 
It was just at 150 F. Not enough to do anything such as set them ablaze or melt them.

It was done to harden them, I will add more catalyst next time and try not to cook em!
 
Are you baking the PR just after pouring in order to get it to set up and cure or baking it after it's cured in order to get it to fully harden?
 
Hmmm... That's how I do it, too. How do you glue the carbon fiber to the tubes? Epoxy, thin CA, medium CA, etc? Do you flood the adhesive throughout the carbon fibers or just "spot weld" it?
 
My guess is that there are some microscopic bubbles after casting that you don't notice. But, the heat from the oven causes them to expand slightly... just enough to see them.

Don't know, but it's a guess.

Haven't tried casting carbon fiber without a pressure pot, but I would think that could be the problem. Also, vacuum degassing the resin before pressure casting can help prevent any bubbles in the first place.
 
robertkulp said:
Hmmm... That's how I do it, too. How do you glue the carbon fiber to the tubes? Epoxy, thin CA, medium CA, etc? Do you flood the adhesive throughout the carbon fibers or just "spot weld" it?
Click to expand...


Thin CA.

I've tried very minor "spot welding" with success. However, I don't think I ever baked those.

Recently I have tried applying more thin CA, but I didnt soak it so much that it built up a visible layer.

Oh and to be clear, I am casting the PR at 30-33 PSI.
 
I would imagine it is either moisture or you haven't allowed the CA to fully cure and out gas. I flood my CF blanks with super thin CA to replace all the air in the fibres and allow them to cure for at least 24hrs and if not against a deadline 2 or 3 days in the cupboard where my heating/water boiler is. I then wet sand them and allow to dry for 24hrs again in the boiler cupboard. I cast in PR without any pressure pot. Let that cure for 24/48 hours, remove them from the mould then put them in the boiler cupboard for a couple of days to get rid of the sticky outer. Never had any clouding issues or any air bubble problems at all.
 
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