Your carbon fibre/fiber tips please!

[kjorn]

Do you do all the layers at once? Or do them over multiple sessions? For both vacuum bagging and hand layup.

[Denisesewa]

Do you do all the layers at once? Or do them over multiple sessions? For both vacuum bagging and hand layup.

I do hand layup one at a time to insure proper wet-out and adhesion without getting the fabric to resin ratio too out of wack, vacuum bagging can be done in multiple layers.
other people may do it differently.

[gbleck]

If you do hand layup you can use a top layer of peal ply. It helps to drive out extra resin and allows you to add layers in multiple steps while maintaining good bonding and keeps the part clean till you pull it off. Scaled composite kits used hand layup with peal ply for years. The biggest advantage is keeping the part uncontaminated between layers and before you finish.

[foam-n-fibre]

If you are doing a hand layup and have complicated shapes where parts meet, consider using spray adhesive to hold the dry carbon in place before you wet it out. I've made some SUP paddles and use the adhesive for my final wrap of twill cloth around the shaft, as well as for the complicated 3D handle shape. A light spray of 3M Super77 on the cloth and then you can form it into all kinds of complex areas, and make sure it is perfect before you wet it out.

I expect that in a stress test the adhesive may interfere with the bond somewhat, but I have not had an issue with it, and its commonly used. If you are concerned with the strength, add an extra layer. Considering that some are made of Aluminum, adding an extra layer in places should not be too big an issue. Also doing the hand layup will also not give the perfect ratio but that's not a huge deal.

If you want to vacuum bag, you can do it with a shop vac. If you want to removed lots of resin and really dry it out stronger vacuum is needed, but it will clamp things down quite well. I've done it many times.

Peter

[tahoedirk]

Hey there Kjorn. I wet each layer separately and either clamp or bag my mold . Using 20oz uni and 20 oz 2x2 twill on a bias, my masts are currently about 20 layers(15mm) and wings are 12 layers (10mm)at their thickest point. I feel a little extra epoxy is not so bad. No voids or delam is a good thing and 20 oz fabric is quite dense , but 60 layers of 6oz sounds really labor intensive. Get a sharp rotary cutter, and a big smooth work table for cutting, plan on spending some hours cutting your cloth ahead of time. I use thin, slow or medium slow resin and layup all at once. Whatever you do, try not to leave too much sanding, sanding sucks. I'll say it again, sanding carbon sucks.

Also, once cut, cloth cut on a bias is really quite handy since you can stretch or compress it to an exact dimension.
Enjoy!

[kjorn]

For the nuts and bolts... do I layer the carbon on first, then drill holes through it and embed the nuts. Or embed the nuts first then carbon around them?

Same question with the holes through the wings. Carbon, then drill through. Or make the holes first, then carbon?

Are there any issue with the stainless steel touching the carbon fibre? I know on my carbon kiteboard, the bolts have rusted away to almost nothing.

[davesails7]

If you are doing a hand layup and have complicated shapes where parts meet, consider using spray adhesive to hold the dry carbon in place before you wet it out. I've made some SUP paddles and use the adhesive for my final wrap of twill cloth around the shaft, as well as for the complicated 3D handle shape. A light spray of 3M Super77 on the cloth and then you can form it into all kinds of complex areas, and make sure it is perfect before you wet it out.

This seems kinda sketchy. I've never heard of using adhesive to hold carbon on before you wet it out, won't that mess with the resin? Also, why are you putting the cloth on dry? If you put it on dry how can you tell you're getting the resin through to the down side?

[kjorn]

When vacuum bagging, can I just keep the vacuum up for an hour or so while the epoxy goes off, then leave it dry without the vacuum over night?

How long is it recommended to keep the vacuum pump on for?

[FrederikS]

Spray is pretty standard for vacuum infusion but make sure to use stuff that is intended for it some of the sprays have components in them which degrade the fiber to matrix adhesion severely. Infutac or the Zywax equivalent works great but is not recommendable for hand lay-up.

Usually you apply vacuum for the bleed and once it is complete you dial back the vacuum to compress the remaining bubbles and then just clamp it off if mold and bag is any good.

[Bille]

If you do hand layup you can use a top layer of peal ply. It helps to drive out extra resin and allows you to add layers in multiple steps while maintaining good bonding and keeps the part clean till you pull it off. Scaled composite kits used hand layup with peal ply for years.

The biggest advantage is keeping the part uncontaminated between layers and before you finish.

Good advise on the peal ply , and also saves a Bunch of sanding ---
however
do NOT use the peal-ply that has the silicone release agent , it will contaminate
your lamination's.

Also --- if peal-ply is used for a textured finish between lamination's ; get the
one that leaves the grittiest finish , after it is pulled off your part.

An example for peal-ply with and without the silicone , (this is a reputable co.) :

https://www.freemansupply.com/AirtechReleaseFabr.htm

Bille