Ok I need some help, I have been trying to make a carbon fiber cooling panel for my 350z and have been unsuccessful at making a good carbon part from my mold. I’ve tried both wet lay up a and vaccum bag. I degas the resin using heat. With the wet lay up I brushed a layer of epoxy on, let it tack up and then finished my laminate. I would always have big voids and tiny air bubbles under the first layer of epoxy or “clear coat”. With the vaccum bagging I brushed my layer of epoxy and immediately put my layers for carbon. I pulled 29 inHG the whole time and ended up with tiny pinholes and air bubbles all over the piece. What am I doing wrong? Why are these pesky air bubbles still there? Any help will be appreciated.
Uh-oh, you discovered that going from 1 bar (ambient) pressure to 0,05 bar (-0,95 bar or -29 Hg) only makes air bubbles larger, not smaller.
Instead you want to create airbubbles (or better: not create airbubbles) at 0,05 bar, then raise the pressure to 1 bar (or 0,5 bar, what the heck) which makes the bubbles implode.
This can be done with infusion, and actually the product MTI hose does it automatically for you. See the MTI hose thread on this forum.
Instead you want to create airbubbles (or better: not create airbubbles) at 0,05 bar, then raise the pressure to 1 bar (or 0,5 bar, what the heck) which makes the bubbles implode.
Herman how can you do this
Before you put vacuum we are at 1bar ??
You say that with the vacuum we create airbubbles instead to take them away?
Are you using a per-ply? If not, the bleeder will just wick the resin right out of the laminate leaving voids.
Herman, so the only way to do this is to switch to infusion? I started vac bagging because I thought that was the better way and now I gotta switch to infusion? Wow still so much to learn. So if I already have the supplies for vag bagging what more do I need to switch to infusion? If possible I’d like to get better results with the bagging before starting over with infusion, or is there no other way?
Wyowind, after a little research on this forum it seems that preforated peel ply might be one of my problems. I definitely think its the cause of my pin hole problem but what about the bubbles in the corners where the resin is thick? I’ll try and post some pictures.
here are some pics, notice along the edge of the vent the carbon did not make the corner but instead resin filled with tiny bubbles pooled there. The vac pressure should have pushed the carbon into the edge right? there was excess bag to let it drape into the corner.
It almost looks like your fabric didn’t go down into some of those tight spots.
Did you pleat at all or pay attention to the bag as it was being laid down?
Did you degas your resin as well before hand?
The bubbles may be one issue, but another is that your fabric isn’t laying down into the tight corners so that’s something to look into as well I think.
I did pleat the bag, next time I am going to include more pleats. I also did de gas the resin, but next time I am going to pass a torch over the resin in the mild to make sure the bubbles are popped.
how much advance are you running on that setup? lol
HAHAAHAHA I lol’d at the advance comment. There is a sad distributor out there some where!
Stay at it, Once you pull your first nice part it will all be worth the hard work!
Alot! It took me some time to get the right spring set up to reach 29 inHG. I even bought a crane cams adjustable vacuum advance hoping to make it m ore adjustable.
For the corners, you can slowly work the fabric into the spots with a small amount of vacuum. You have to manually work the fabric in the corners. This goes with peelply, release film, bagging, and distro mesh. Everything has to be evenly compacted by the vacuum bag, else there will be a void, and resin will pool, and air can be trapped.
Yes, vacuum will not move fabrics, and they will not stretch either. You will need to work them in the corners yourself. Whether you use wet bagging, or infusion.
Infuse at -1 bar (or as close as you can get) and after infusion bring the vacuum back to -0,5 bar. (29,5 Hg = 1 bar)
When wet bagging, take extra care for not creating air bubbles.
Not to thread jack here,
Herman: Why drop to .5 bar after infusion is completed? I always thought you let it cure at full (1 bar)
Ok I tried agin with poor results. I degassed the resin, used preforated peel ply and ensured there were a ton of pleats to allow the material to fit into the corners. I still had a few voids, a few pin holes, and micro bubbles. I don’t understand! I degassed, the resin was clear as glass when I brushed it on and in the mold I used a heat gun to pop any bubbles. I think my pinholes and voids near the middle of the panel are due to my vaccum “port” being right over that spot which has different angles (isnt flat). I’m going to move it to a part of the panel that is flat. I’m re trying to make a panel now and I notice that my gel coat parts in little spots I think due to the parting wax. I keep brushing over and over it but it just pulls away. When hitting it with the heat gun it just seems to magnify this effect. I ended up brushing 2 coats of clear to fill in all the voids/open spots, which caused my surface to be uneven which I am sure will be noticeable in the weave. Also this time I’m going to turn down the vac to 22 inHG. I think that on my next try I am going to spray some rattle can clear in the mold and then lay up my part. I think doing is will avoid having a thick part and battling the mold to lay down a gelcoat. Any ideas???
The area that the vaccum port sits right on top of normally.
Void and micro bubbles. This is frustrating. I wish I would of started with something a little smaller!
Also one last question the preforated/peel ply won’t work into corners like weave will. I’m always left with creases filled with resin. Is there no way around this?
I don’t know but you can always save those parts I believe. Just lightly sand, epoxy or resin, cure, sand flat, and clear entire part.
I hope you’re not throwing away your parts…
The first one I skinned, which came out like crap. I got tired of sanding it and its still sitting on my back porch. The second one I injected the voids with resin and sold it (it looked halfway decent). The third one I primed and sold, the fourth one is sitting on the back porch and the fifth one I haven’t pulled out of the mold. So I can clear the air bubbles out?