First infusion has porosity

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First infusion has porosity

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Roo2	Roo2 posted 8 Years Ago HOT Topic Details
Group: Forum Members Posts: 8, Visits: 31	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 Attachments IMG_2461.JPG (580 views, 1.00 MB) IMG_2463.JPG (485 views, 2.00 MB)
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Warren (Staff)	Warren (Staff) posted 8 Years Ago HOT Post Details
Group: Administrators Posts: 2.5K, Visits: 8.5K	Also remember there will be some small amount of air in the fabric that comes out during the infusion process. You always introduce a little bit through the resin feed line initially. Warren Penalver Easy Composites / Carbon Mods - Technical Support Assistant
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First infusion has porosity

Roo2 - 8 Years Ago

Did you degas your resin? If not, that will very likely cause the problems.

oekmont - 8 Years Ago

Hmm. No I didn't degas. The resin I used was quite runny and I didn't stir it vigorously. I didn't...

Roo2 - 8 Years Ago

With a long pot life what you can do is leave the resin to stand for 10 minutes before infusing as...

Warren (Staff) - 8 Years Ago

In my opinion a really perfect finish could only be achieved with a properly degassed resin. During...

oekmont - 8 Years Ago

Degassing is totally unnecessary for a perfect cosmetic finish, I do it day in day out and never...

Hanaldo - 8 Years Ago

I can definitely say that degassing could be a very important part of the infusion process. Maybe it...

oekmont - 8 Years Ago

I guess degassing may depend on the resin and how you stir it up- if you trap a lot of air. I...

polaraligned - 8 Years Ago

Thanks for all the feedback. I'll try both allowing the resin to stand and degassing in the resin...

Roo2 - 8 Years Ago

If you're mould was porous, you'd definitely see evidence of air ingress during the infusion As...

MarkMK - 8 Years Ago

If you do a corret degassing (proper chamber, full vacuum) you'll notice that even a crystal clear...

oekmont - 8 Years Ago

Well water at a molecular level is a product of oxygen and hydrogen, so of course there will always...

Hanaldo - 8 Years Ago

Thanks all. I have a small fiddly part to infuse this weekend. I'll use my runny slow cure resin and...

Roo2 - 8 Years Ago

The mentioned effect has nothing to do with the oxygen bound in the water molecules. Although water...

oekmont - 8 Years Ago

I used my resin trap to degas a small batch of resin in a cup. It formed a nice frothy head that...

Roo2 - 8 Years Ago

Also remember there will be some small amount of air in the fabric that comes out during the...

Warren (Staff) - 8 Years Ago

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