Problems with infusion - Helmet


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kosak95
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Hi all, 

I have some questions. I was posting few months back about making wood moulds, and with your help I finally made some type of mould that works. I painted mould with 2K clearcoat and that was final step.
From that moment I started doing helmets with epoxy resin and carbon, and with epoxy resin and fiberglass.
Since then I'm making slow progress on how to make very good helmets. Mostly on helmets I find places where there's no resin. Big problem is around area where resin is entering (middle). And almost on all helmets there are small pinholes.
I'll post some pictures alongside how I make infusion and some examples of problems.
Can you recommend mi what could be the problem and what way is best to put carbon in mould, if that will make any difference. Thanks

There is no more tape and it looks nicer with more tries, this one one of the first ones. I have very strong pump and almost everytime there is 95-99% vacuum.

This one one of the better models. the resin on the top is because of some problems with resin entering, that was first time it happend and later it didn't.
Problem where resin is entering and you can see small pinholes everywhere.
One of the better examples but you can't really see anything because it's fiberglass and it's white.
One of the worst models.

Hope you can give me some advice.
oekmont
oekmont
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At first sight it seems like your bag is to small and bridges in the deep sections of the mould. The pleats should reach to the bottom of the mould to ensure enough bagging film to press against the mould without tension.
Look that the fibres are really pressed against the mould.
It also seems like you are running the resin to fast. Restrict the inlet so that the resin doesn't run so fast. A part of this size should take at least 10-15min (if you aren't degassing).

Chris Rogers
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Its hard to see from the picture, but if that is a wood mold sealed with paint it may not be 100% vacuum-tight which could account for some of these problems.  Can you bag it down to a table or some air-tight surface so the whole mold is enclosed by the bag?  If it is leaking this might help.  Does it drop-test ok?




Fasta
Fasta
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I also thought the same, materials like wood and MDF will leak if not sealed properly.




kosak95
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How do you do a drop test?
Fasta
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kosak95 - 6/29/2020 6:46:53 AM
How do you do a drop test?
If you disconnect your vacuum line the vac bag should hold good pressure, in theory overnight if the bag was perfect. 

For me if it loses a very small amount of vacuum over 1 hour then it is likely good enough to go.






Edited Last Year by Fasta
kosak95
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I'm unable to keep the vacuum inside. I don't hear any air coming out but slowly I can see air is going out. Is there any special way I can put bagging film over the mould that looks like mine?
Warren (Staff)
Warren (Staff)
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Just make a giant envelope bag.  You need plenty big bag to ensure you have enough film to go right down into the helmet mould without any bridging. 

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
Chris Rogers
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What Warren said.   Or find a piece of air tight plastic or metal and use it as a "table" to put your mold on - then bag it down to the table.  Bag on 5 sides, table on the sixth.




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