Talk Composites - The Forum for Advanced Composites

Double bagging / chamber ?

http://www.talkcomposites.com/Topic32246.aspx

By 8900120d - 3/6/2019 9:28:24 AM

Hi guys, 
im quite new resin infusion, im having some trouble getting the bag to stay sealed! ive tried everything! 
key points:
- the mold and layup is inside an envelope bag
- all equipment and consumables used is from Easy composites and made for resin infusion
- masking tape the edges of the infusion mesh to avoid small holes in the bag
- wrapped the edges and underside of the mold with breather cloth to avoid getting holes in the bag
- peel ply ontop of the spiral hoses
- checked the hose connectors and sealed them with bagging tape
- tested to make sure the catchpot is not leaking
- tested to make sure the pump isnt leaking
- used a stethoscope to listen for leaks - no leaks found!

ideas:
1) i have read that double bagging could help? putting the whole thing into a second envelope bag, then pressurizing the second bag? is this the right process? 

2) its a small part so instead of double bagging, maybe i can put the whole thing into a vacuum chamber? (my degassing chamber, with the addition of extra ports for infusion)

3) has anyone tried doing a smoke test to find leaks? using some kind of smoke which is sucked in from the feed line?

thanks Smile
By matthieutje65 - 3/7/2019 11:24:19 AM

8900120d - 3/7/2019 10:03:27 AM
Matthieu Libeert - 3/6/2019 1:29:26 PM
sahil mohmed - 3/6/2019 9:28:24 AM
Hi guys, 
im quite new resin infusion, im having some trouble getting the bag to stay sealed! ive tried everything! 
key points:
- the mold and layup is inside an envelope bag
- all equipment and consumables used is from Easy composites and made for resin infusion
- masking tape the edges of the infusion mesh to avoid small holes in the bag
- wrapped the edges and underside of the mold with breather cloth to avoid getting holes in the bag
- peel ply ontop of the spiral hoses
- checked the hose connectors and sealed them with bagging tape
- tested to make sure the catchpot is not leaking
- tested to make sure the pump isnt leaking
- used a stethoscope to listen for leaks - no leaks found!

ideas:
1) i have read that double bagging could help? putting the whole thing into a second envelope bag, then pressurizing the second bag? is this the right process? 

2) its a small part so instead of double bagging, maybe i can put the whole thing into a vacuum chamber? (my degassing chamber, with the addition of extra ports for infusion)

3) has anyone tried doing a smoke test to find leaks? using some kind of smoke which is sucked in from the feed line?

thanks Smile

normally there shouldn't be any need to double bag... are you sure you didn't start with a punctured piece of film? the simple rule for me is that if your not able to find the leak within 45 min, you just start with a new piece of bagging film Smile it's close to impossible to find a leak on the bag. 
Most common problems are dust or fibers on the tackytape, pleads in the bag where you tape it or leaking moulds (if your sure your tape is well applied on the flange. As your talking about envelope bagging, might it be that the backing of your mould is a bit rough? sometimes sharp spots on the back of your mould might puncture the bag, or the corners of your mould. As I read you are talking about a small mould so I would suggest you to keep trying until you get it right Smile  

Thanks alot for your reply!
tried again, but this time i bagged it in another room which is dust free (no stray fibers laying around) and i managed to get a seal for the first time! 


Well done! Just need to take your time for bagging. Rushing things will even make you lose more time Smile