I am having some problems, I am bagging a part and having some wierd bubbles. I am using a robinair 15600 pump that is pumping at 25.5hg
Here is pictures of what it is doing. Can Anyone give some suggestions on what is going wrong???
I think it is wierd. Please if anyone can help, I am taking pics of the mold so you can see what it looks like
Here is a pic of the mold, It is not cleaned off from last bag but every part comes out with these bubbles.
Here is my layup
Clear Gel
Carbon Fiber
2 Layers of 1.5oz mat
Peel Ply
2 Layers of Breather
Then the bag
We compress it to the corners as much as we can and it looks like it is completly compressing to the contours. We let off the vacuum probaly 10 times and press into the corners and resuction. The second stage of the pump is kicking and it keeps full vacuum on the piece. I pull the pump off about an hour and a half later. I am using poly resins and all air-tech materials for the bagging.
if you can see around the big bubbles are thousands of tiny small bubbles
same problem as i had,havent done another part yet but i think the gelcoat is too thick as it naturally collects in th ecorners and curves,are you brushing it on? pic of my part here with some ideas- http://www.icancomposites.com/forum/viewtopic.php?t=411
no my gel coat is sprayed in
are there any bubbles on the large flat part?
the flat surface is mostly fine, but the first picture is a rather flat surface. Could I not be putting vacuum on it long enough
why wont your pump pull 29hg? im not sure what the answer is,we will have to wait for the experts to help,i need to find out what it is though also!
i know what they will say though lol,do the part with infusion :idea:
My comment is maybe it is gelling before you can get the bag on it in time. That is why you use epoxy as it has a longer (can be ordered that way) working time than PER.
the bubbles appear to be in the gelcoat though??
the gel coat is fine, it is in the laminate. I know I have a faulty vacuum gauge and I have got a new one coming because I have 2 Robinair pumps and it says they are both pulling the same amount of vacuum and the second pump I just got yesterday. It might be gelling before I can get the bag on it. but it is still sucking into the breather. I can’t use epoxy or I would, I am using fiberglass mat in it plus it is going to be a pure cosmetic piece.
from the look of the picture when it is all bagged could it maybe the breather is too saturated and that causing the air not to travel through it? Could I be taking the vacuum off it too soon?
can you put too much breather in it?
The radius on the far edge in the picture looks to be very tight. Some of the pictures appear to show a line of bubbles in the sharpest turn of the radius. Also, the fiber orientation shows is running at 0-90, with the 90 perpendicular to the sharp radius.
Have you tried orienting the fabric on a bias (+45/-45) so it will conform better to the sharper turns. My 1st wild ass guess (WAG) is that your cloth can’t conform to the sharp curve and is “bridging” even though you have adequate vacuum, & that’s what leaving the voids in those areas.
The flatter area(s) maybe just voids caused by the resin curing before you could get adequate vacuum applied.
I would try doing a hand layup with fiberglass (cuz it’s a lot cheaper to experiment with)., and orient the fibers 45/45 to your sharp radius sides and see if it improves. Then try it again using the vacuum system. Keep trying with fiberglass until the kinks are ironed out. Then start using the carbon fabric.
wow, doing a 45 degree laydown is better? how so?
interesting… could you possibly do us some basic diagrams to explain this?
because of how the fabric is woven, it’ll wrap around tight curves better
so if we are cutting 3 pieces of carbon for a part then we do it like this???
sorry,pic isnt working?
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