so I’ve been working on some stuff, have a mold done in poly iso tooling gelcoat/ver. I sanded the mold to 2000 grit as when I laid it up, something happened with the clear coat on the part coming off and just totally screwing with things. Anyway, so I have a nice smooth mold surface. I infuse the part with ver, and when I pop it out, one piece is just super rough, with some air bubbles under the surface a little, and other just has huge chunks missing(obviously huge air bubbles caught between the carbon and the mold surface). Also, the surface of the mold was left all rough and bumpy. I used pva and mold release wax just as I normally do. I’m using a robinair 15600 pump and didn’t have any vacuum loss after letting the mold sit in the bag for 15 minutes or so. Any ideas as to what is going on?
you used clear coat?
just to clarify,you arent spraying clear coat into the mold and laying up on top of that are you??
yeah that is what I was asking, if so that is most likely your problem
well your the one that had the big air pocket you probally had it bridged, but you had to be letting air in or it would of just filled with resin rather then had the pocket. you can have full vacuum and still let air in after it is infused.
I didn’t spray the mold with clear coat… the plug that I made the mold from was sprayed with clear coat… that’s what I was talking about
devildowg, the thread you posted seems to have to do with bagging and not infusion.
the only possible air getting in would be the small bubbles caught in the resin from mixing the catalyst in… should I be degassing my resin before I infuse it?
Do you reduce the vacuum level after it is filled?
I do this to avoid sucking the resin up into the vacuum hoses and it keeps you from sucking your parts dry, (resin poor)!
if you have a smoth mold surface why use pva i bet the rough texture in the mold is the pva still in the mold i personaly have never got a very good finish with pva try cleaninig your mold with water
The problem he is showing and describng is not related to PVA.
The problem is in relation to the void or lack of resin along the peek. It appears in my opinion to be resin starved. I believe the vacuum is draining the part of resin.
I don’t see this as a bubbles getting into the bag during infusion. If bubbles are getting into the bag during infusion, Yu need to do a better check of your seal before beginning an infusion.
You should never infuse unless your bag holds a seal and looses lless than 1 inch of mercury for 5 minutes.
I did have some resin coming out of the part into the vacuum line. Both times I tried to infuse off this mold, there was resin coming out the vacuum line before the entire part was even wetted out. Should I just pile on the flow media some that I’m sure everything is getting wetted out before any resin gets to the vacuum line?
the rough texture isn’t pva… I’ve had to sand the mold out both times to get it off… the pva peels right off
what I do it put the resin line at least 2 inches from any materials in the mold and the peel ply I wrap the vacuum line with, I make sure that touchs nothing as well. This will give the resin no path to follow into the vacuum tube. You could get a little but since doing it this way I have not had a problem yet with resin sucking out of the piece
This is a red flag & bell ringing statement. If your laminate isn’t fully infused and there is resin already plugging up the vacuum line, then you are entrapping air in the laminate. Your resin feed and vacuum lines are not placed properly if this is happening.
Ideally you want a resin flow that begins and flows EVENLY across the laminate. If the flow rushes along an edge or runs through the flow media before all the layers receive resin, then you are going to entrap air that can’t escape. Most people are under the impression that if you pull a vacuum that on a part that there is no more air in that space. In a perfect vacuum that would be correct, but in reality there is still a small amount of air dispersed throughout the laminate. This will remain in the part and create voids if the resin surrounds it with no chance of being pushed out with the flow front. Also do you have a resin break? THis is an area in front of the vacuum line that is usually just peel ply. This dramatically slows down the resin so it can’t rush into the vacuum lines before the laminate layers are fully infused.
Also, have you thought of using fiberglass to develop your process instead of expensive carbon until you can produce acceptable parts?
This is a red flag & bell ringing statement. If your laminate isn’t fully infused and there is resin already plugging up the vacuum line, then you are entrapping air in the laminate. Your resin feed and vacuum lines are not placed properly if this is happening.
Ideally you want a resin flow that begins and flows EVENLY across the laminate. If the flow rushes along an edge or runs through the flow media before all the layers receive resin, then you are going to entrap air that can’t escape. Most people are under the impression that if you pull a vacuum that on a part that there is no more air in that space. In a perfect vacuum that would be correct, but in reality there is still a small amount of air dispersed throughout the laminate. This will remain in the part and create voids if the resin surrounds it with no chance of being pushed out with the flow front. Also do you have a resin break? THis is an area in front of the vacuum line that is usually just peel ply. This dramatically slows down the resin so it can’t rush into the vacuum lines before the laminate layers are fully infused.
Also, have you thought of using fiberglass to develop your process instead of expensive carbon until you can produce acceptable parts?[/quote]
I could have sworn i was setting up the lines how evan showed me when I was down there. placement wise, they’re fine, but I don’t have a resin break, which could be causing the problem.
I don’t see much difference in price when making these parts as they’re only about 2 inches by 6 inches or so… I’ve probably used all of 2 square feet of carbon at best on this part.
This is a red flag & bell ringing statement. If your laminate isn’t fully infused and there is resin already plugging up the vacuum line, then you are entrapping air in the laminate. Your resin feed and vacuum lines are not placed properly if this is happening.
Ideally you want a resin flow that begins and flows EVENLY across the laminate. If the flow rushes along an edge or runs through the flow media before all the layers receive resin, then you are going to entrap air that can’t escape. Most people are under the impression that if you pull a vacuum that on a part that there is no more air in that space. In a perfect vacuum that would be correct, but in reality there is still a small amount of air dispersed throughout the laminate. This will remain in the part and create voids if the resin surrounds it with no chance of being pushed out with the flow front. Also do you have a resin break? THis is an area in front of the vacuum line that is usually just peel ply. This dramatically slows down the resin so it can’t rush into the vacuum lines before the laminate layers are fully infused.
Also, have you thought of using fiberglass to develop your process instead of expensive carbon until you can produce acceptable parts?[/quote]
Devildawg, I agree with you. This is however the first time that information has been produced.
If at any time you have resin racing to the vacuum before the tube is wet out, you have either misplaced your lines or you have multiple wrinkles in the bag that make a beeline to the vacuum. This latter scenario is less likely to be the problem, because these parts are too small to be generating all this much attention. it is difficult at best to judge what you did when you don’t place all the info up front.