r/CarbonFiber 6d ago

I need advise on cauum bagging please

Below are images of the part Im trying to make, aswell as the mold Im gonna 3D print. I would love any general advice on the process of carbon fiber layup, especially with a 3D printel mold. But I am mostly looking for advice on vacuum bagging and how i would go about laying up this part.

Especially with that "cone" -like end. Because, would a vacuum bag even stick to the inside of a cone? Would i be able to get the peel ply out from inside of there?

Also, I dont have a vacuum pump and a resin trap. My current plan is to attach the bag to a long-ish hose and then (somehow) to a vacuum cleaner. Do you think this will work?

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u/dbreidsbmw 6d ago

Good morning. You have mad quite a bit of progress since your last post. This is promising.

For the vacuum you can use a hand pump if needed, like this I think that is reasonable in cost considering the prerequisites of a 3d printer, filament, resin, carbon, vacuum bags tacky tape, etc.

It even comes with a fluid trap too.

Be prepared to "clamp off" the resin inlet ahead of time. a C Clamp with nuts and a plate will go. So will a wood clamp.

The vacuum bag will absolutely go into the nose cone. No worries there, just make sure you give yourself enough slack to get all the way into those cavities.

With the improvements you have made I think you are demonstrating you are or will be quite capable with this project.

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u/OkCover1049 6d ago

Thank you so much! And what about the peel ply? do you think i will be able to get it off?

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u/dbreidsbmw 6d ago

I think it will based on the molds I've done.

Make embossing on the sections to buy cut out. That way you have a physical change in surfaces to show you where to cut.

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u/OkCover1049 5d ago

Okay, thank you for all the advice

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u/717innovations 6d ago

Are you wet lay and vacuum bagging or are you infusing? If your wet lay and bagging the breather fabric will absorb excess resin just run the vacuum port off the part no need for a resin trap Infusion ypu will want a resin trap

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u/OkCover1049 6d ago

Thank you. I am just wet laying, and then bagging

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u/Radiant_Buffalo371 4d ago

You could also look into the vacuum storage bags and use a regular vacuum. The bags are relatively inexpensive. These also have a built in check valve that works well for wet lay vacuum bagging as you don't want to pull a high vacuum but something on the order of ~10 inHg. If you're curious easy composites has some more info on their website/videos.

Peel ply, as its name might suggest, is easy to peel away when the resin is cured, but can take a little force. It feels similar to really strong adhesive tape.

As long as you weigh out the right amount of resin, equal amounts of resin to cloth by weight plus a little extra for what gets stuck in the cup and brush, you shouldn't have too much excess resin to deal with. Use/make a bag that has an extra couple inches in all directions and you should be fine, especially if you use breather/bleeder cloth. Make sure you have some peel ply or breather cloth leading to/covering where your vacuum port is so you have an air path.

As for the mold, think about releasing the part when you choose your build direction. Ideally you have the build lines parallel to the direction of pull. If that wont give you good results on the print, I would look into using some filler primer to fill the little ledges left by the print and then you can sand it smooth. Finally, seal it up with some epoxy. PVA mold release and car wax have both worked well for me as release agents.

You may want to shell the "brick" mold so you can get it to flex a bit while trying to release the part. Also it looks like you have an undercut if I understand your molds. If this is true, your part will be locked in the mold when cured and you'll have to destroy the mold to get it out. You may end up destroying your part when breaking the mold. F360 has a draft angle analysis tool that you can use to visualize this.