Cloudy Patch between gel and cloth

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#1

Hi,

Hoping for some help, this is my first post and I have been successfully infusing Carbon Fibre flat panels but have recently started working on moulds with more complex radius and there are cloudy patches appearing mostly on the radius, this is not bridging.

The way we have been doing this is to spray the moulds with clear polyester spray gel, I understand the the spray gel has got to be thick enough so this is not an issue, it is then left overnight to cure and then the following day are laying up and then infusing with synalite 1967 resin. We know the process and materials work for a large company that sent out thousands of products, but we are having issues. Can anyone point us in the right direction… It looks like a slight crazing in the gel and only appears on raduis’s.

I have attached a picture and would really welcome some advice as this is costing me a lots of time and money in materials and time! Ignore the cut out rectangle this is supposed to be there…

Thanks

#2

Sorry to bump this but no one has any ideas?

#3

If I flip the part over and view it as it would be placed in the mould might it be some kind of compaction issue related to pressing your vac bag into the bottom radi whist under vacuum which then causes the fabric as it passes over the top radi to be vey compacted and under tension which could inhibit resin flow and vacuum to those areas affected.

#4

Have you tried to layup without a full cure of the gel coat? As in where you can touch the gel coat and the gel coat won’t come off but it’s still a little tacky.

Are you spraying anything between the gel coat and carbon fiber to hold the cloth in place?

Are you using vacuum infusion or what’s your process. It might help us understand more where the problem is.

#5

As Wightmarine said, you probably have some tensions on this area.
Your bubble is between 2 edges and you probably don’t put correctly your vacuum bag. For your next attempt, try to put a larger vacuum bag and make more plies and take your time to apply it correctly before infuse.

#6

You have pinholes under the gel coat! The tensions are not your problem.

Have you degased your resin?
What ist your vac level?
Which bagging film do you use?
How did you place the Flow media?
How big is your brake zone? Do you use MTI hose ( I guess not)
Which temperature do you infuse?

If you answer these questions we can help you.