First infusion has porosity


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Roo2
Roo2
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Hello there,
I've just completed my first infused part. It's a shell for a home made metal detector coil. I'm generally happy with the result but would like to improve the surface finish on future parts.
The part is made with 2 layers of 200gsm fibreglass and a low viscosity epoxy that uses a very slow hardener. It took over 4 hours to start to gel in a warm environment. I'm using a pump that can get down to about -28" and  after I infused the resin it was turned off. No evidence of leaks where seen and the vacuum gauge needle didn't move for the entire cure duration.
If you look at the attached photo of the shell on the scales there are a few areas that appear to have porosity. Small holes between the fibre weave. Could that be caused by using hardener that is too slow and all the resin has been squeezed, drawn out of the very thin laminate? Or is it just evidence of tiny air leaks I couldn't see or measure?
Thanks
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Warren (Staff)
Warren (Staff)
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With a long pot life what you can do is leave the resin to stand for 10 minutes before infusing as most the big bubbles will come out then.  Also when the resin gets to the vacuum feed, allow a bit more resin to flow into the catch pot.  Once you clamp off the vacuum feed, allow the resin feed to stay open another 10 seconds or so.  The extra resin often helps avoid pin holes.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
GO

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