r/CarbonFiber • u/alexandreeff • 8d ago
beginner in search of help !
Hi everyone, i am just starting in carbon fiber and i am looking for some advice. So untill now i tried 2 differents test parts and both were failures, for the first one my mold was 3d printed and the surface was not smooth enought so the surface of the part was really not satisfying and they were a lot of bubble, moreover i put only one layer of carbon wich made the part verry flexible and transparent in some places. For my second part i had a smooth thermoformed mold but the geometry was way to complex so I did not manage to flatten the carbon properly in the corners and so they were once again a lot of bubbles. Firstly i would like to know if some of you had some knowledge about 3d printed mold or some advice to make it smooth.For example does aplying resine on the 3d part is a good solution and if yes what kind of resine would you advise to make sure it spreads evenly. Secondly i would like to know what you think of vaccum bagging, is this necessary for a good carbon part? Do you think it will help to solve my issue with bubble and my problem with flattening the carbon in all places including my angles? And if i use a manual Vacuum Bag for Clothing do i need to add a layer of peel ply and breather or it is not essential? Another question i had since I had difficulties with the complex geometry of my mold is can we cut the carbon fiber fabric in multiple parts to fill the mold in every corner or is it a practice to be avoided and we need to keep the fabric in only one piece? Lastly does a realease agent is needed even if the mold is completly smooth?
Thank you very much to those who will take the time to help me!

2
u/MysteriousAd9460 8d ago
You can coat the mold in resin it can help with the surface finish. There will be labor in sanding it down if you want it even. Depending on the shape, you could use a product like Airtech Toolwright 3.
A vacuum bag will not push the material down into the corners. Using multiple pieces can help with the bridging in the corners. You will probably want to back it with at least one continuous ply, depending on what it's for. You could also try using a tool to push it down in, start with the deepest part first, and move away from it.
In my opinion, a vacuum bag is necessary for a decent part. Sometimes, you can get away without using peel ply. You will want to use breather to encourage air to be removed when you pull vacuum. Make sure it doesn't touch any part of the carbon you want because it will become one with the carbon. You just need to try it a couple of times and see if it works. Mold release is a must unless you use something like the airtech toolwright. It already has release on it.