Hey everyone,

I have been infusing parts using a two mould method to reproduce a curved piece with smooth surfaces on both sides. Unfortunately, during my infusion, once the epoxy reaches the vacuum line side and it starts spurting bubbles into the catch pot (see the middle-right circle), small bubbles started to climb back up the resin line, which is connected to the resin feed pot (see bottom circle). I can't seem to get it to stop. During my first infusion of this part it did not have any adverse effects, but it still concerns me that air is:

a) apparently not all the air is moving towards the flow of vacuum - ie. towards the vacuum pump
b) there shouldn't be bubbles in there regardless. The only bubbles I could think of are ones that get mixed in with the epoxy and do not have a chance to off-gas out of the mixture before they are sucked into the part. I realized that a degassing chamber would help fix this, so I am going to build one.



And yes I just realized that you can't read the print so ignore that part of the picture haha.

Anyways, if anyone else has experience this, or knows what it may be, that would be a big help. It is unfortunate that it is a closed mould, as I cannot see the details of where these bubbles are coming from. Any help would be greatly appreciated.

-Mike-

Sorry, for not including the details.

The stack is 2 layers of 200gsm carbon fiber, followed by soric 2mm core, with another 2 layers of 200gsm of carbon on top. There is infusion mesh at both the vacuum side and the resin inlet side, and the soric is roughly 20mm longer on both the vacuum side and resin inlet side so that it touches the infusion mesh (in hopes of getting a good spread of resin and good flow characteristics). The entire composite is 820mm by 650mm.

Vacuum levels are 28inhg (the most I have ever been able to pull in the shop). And the time to infuse is about 45 minutes. I am going to de-mould today so I can provide pictures of it once it comes out. The first piece that came out is already cut into its appropriate shapes.

I was reading elsewhere that when the resin reaches the vacuum tube, it temporarily clogs it, thus slowing the flow of air bubbles out of the laminate, which makes it easier for the other bubbles still in the resin to "float" back up the resin line. I know its a tough explanation and theory, but my camera cannot get good detail of the bubbles that I am talking about. I guess I should wait to see the results before I get worried, but I just have a bad gut feeling about this one.

-Mike-