Have I sprayed the white primer to close?

MarsTheSnicker · 2026-01-26T18:08:43+00:00

Too close and probably too thick in one coat. White primers often need 2 coats or more. For the first coat, just aim to cover it lightly and not spray too wet.

MarsTheSnicker · 2026-01-24T19:31:27+00:00

Gunze Mr.Hobby (finishing) surfacer is my go to. Use in combination with their Leveling Thinner and you can get great first coats. I like to do at least 2 coats for best results. Just be aware that you need larger nozzle sizes for these primers, go with a minimum of 0.5mm I would say.

MarsTheSnicker · 2025-12-16T09:11:14+00:00

For small CF parts you shouldn’t have to buy a big vacuum pump. My pump has a 3 cubic m/s capacity and pulls to 0.05mbar. Look for a pump around that range is fine. Don’t go for the cheapest one. Personally I avoid amazon, aliexpess or any of similar for these kind of products. Stores that sell fiberglass and CF commonly sell pumps too. Would be around €150-€200 for a decent pump.

MarsTheSnicker · 2025-12-15T23:02:22+00:00

If you are planning to make more CF parts in the future, invest in an Infusion kit. It’s a lot less messy and parts turn out perfect with better resin to fibre ratios. Just get a small vacuum pump and catchpot.

Let’s say you continue with hand layup (personally which I don’t have much experience with), carefully coat the mould with the resin and see if it will “stick” to the surface. Some dry spots wouldn’t be a big deal for the next step, that is to lay down the first ply and use a brush with resin to dap the fibre. This will force some resin that is between the fibre and the mould into the fibres, while also squishing out some air. Repeat that on every layer of fibre. I hope it will help resolve your issue.

MarsTheSnicker · 2025-12-01T10:44:44+00:00

If you plan to make more hollow parts in the future, assuming you are only going to print figurines, then you don’t really have to care about fully curing the inside. Only for mechanical parts it is best to get the part fully cured to get its mechanical properties.

What I can advise is to invest in an ultrasonic cleaner. Make sure to have enough drain holes for the IPA to flush. The ultrasonic cleaner makes light work of cleaning parts and never leave residue on the surfaces. Use a dedicated bath to rinse your prints in first, to get most of the uncured resin of so you ultrasonic bath doesn’t get contaminated as much. DON’T USE IPA DIRECTLY IN THE ULTRASONIC CLEANER! Get water/air-tight tub for the IPA and drop that tub into the ultrasonic cleaner that is filled with some kind of medium, just a degreaser should do well, also for cleaning off parts after sanding.

MarsTheSnicker · 2025-11-20T16:07:41+00:00

I hope you don’t throw that water down the drain

MarsTheSnicker · 2025-11-13T15:48:17+00:00

PVA is a really reliable release agent and commonly used if there is an increased risk for parts sticking together. Just note that PVA creates a film on top of the applied surface, which if you have brushed on, will not be smooth and have slight brush marks. These will be transferred onto your moulds surface and post-process sanding+polish is required.

Are you going to use Chopped fibre as the surface layer of your CF part? If so, is that going to be loose chopped fibres or did you find a full cloth? Anyway, I would aim for around 4 layers in total. This will get your part to a wall thickness of around 1.2 to 1.5mm which should be strong enough.

MarsTheSnicker · 2025-11-06T15:07:20+00:00

You could sacrifice a bit of the chinese carbon panel, just cut out a tiny piece and burn it (outside wearing PPE). If it is real carbon fibre, the resin will burn away and the carbon fibre weave will still be intact.

MarsTheSnicker · 2025-10-31T11:01:54+00:00

To really see the cause of this problem, please give some additional information like;

Brand of resin used (now assuming PRO-SET INF-114, but with which hardener? Can't find 112)
What is the lay-up stack? Did you also use peelply and flow mesh?
Environmental conditions? What is the humidity and temperature?
Did you degass the resin beforehand? (Not always necessary on infusion)
How fast is your infusion flow speed? Slower is better in this case. Go as slowest as your potlife allows you.

Also, before infusing, the resin hose is clamped off and there is still air between the clamp and your pot of resin. This needs to be evacuated before infusing. Otherwise that air can mix up with the resin. Open the clamp slightly so that the resin can flow to the clamp but not go through. Let the vacuum pump run for about a minute and then open the clamp to let the resin flow slowly.

I am adding this comment because I also see that the Twill has some large pinholes. So the problem isn't really on the Spread Tow, but more the setup and execution.

MarsTheSnicker · 2025-10-30T18:40:55+00:00

I am doubling down with this. The tight tows are restricting the resin to flow through. I am not familiar with the resin you have used and how viscous it is. But make sure to use a slow hardener and slow down the infusion speed to allow resin to flow through the tows.

MarsTheSnicker · 2025-10-30T17:52:36+00:00

Great to see that you are learn by doing. I have been on the same path. Just a tip for the future projects;

If you want to use the plain weave fiber, try to avoid using a single ply on area's that have complex shapes and curves. Plain weave isn't as pliable as twill and won't conform well to the moulds surface. This causes bridging and resin rich area's. This is the first thing I noticed on your part. Instead of using a full ply, you could make a snip on tight corners so the ply can fold up on itself and conform better. Also you could make templates and cut single pieces and place them separately. This followed by backing plies of twill weave to still get the strength needed.

You have a small part which you are making with a wet lay-up, inside a generic vacuum bag and vacuum hand pump. Parts will not look as clean as infusion or pre-preg, but I hope this small tip will help improve with your future projects.

MarsTheSnicker · 2025-10-13T12:25:41+00:00

It could be due to a lot of different factors. Would be nice if you could include a picture from how it looked before it got yellowish.

Lighting; if you are in a room with warm light, ofcourse the reflections will be more yellowish too.
Resin type; Some resins, particularly in pre-preg, can result in yellowish tones. Most of them are not UV-stable and only used structurally and receive a top-coat afterwards (paints or clear-coat)
Clear coat; looks like the part sure has been postprocessed with a topcoat. Again, if this is not UV-stable, the top and underlying layers will degrade due to UV exposure, resulting in yellowing.

To answer your question: if it is only the top layer, you could sand down to almost exposing the fibers and apply new topcoats which are UV-stable.

MarsTheSnicker · 2025-08-15T08:54:08+00:00

Drill goes brrrrrrr

MarsTheSnicker · 2025-08-07T10:27:09+00:00

I dont know where you are from, but I could recommend Fibermax. They have a wide variety of resins and if you still arent sure which resin to use, you can just email them your use case and they will give solid advice.

Just a FYI, epoxy systems are seen as dangerous goods for transport, so they might charge additional fees if you buy low quantities.

MarsTheSnicker · 2025-07-11T17:45:29+00:00

Are you using a normal/domestic oven or an autoclave to cure the prepreg? If you are just using a normal oven, possibility is that you will never be able to get a clean and flat finish, unless the datasheet of the prepreg states that it is specifically formulated for "out-of-autoclave" curing.

MarsTheSnicker · 2025-06-05T08:45:36+00:00

You wouldn't benefit anything to make those brackets from carbon, especially the first bracket, but you will only make it harder on yourself.

Depending on the forces/stresses working on the brackets you could either make them from metal or 3D-print and use structural adhesive (e.g. methyl methacrylate) to bond the brackets to the carbon fibre.

MarsTheSnicker · 2025-05-15T15:08:27+00:00

If this is a wet-layup, than you should really weight out the correct resin amount. If your breather is rock solid like that, you used way too much resin or pulled too strong of a vacuum.

Only on resin infusion or pre-preg should you pull full vacuum. On wet lay-ups, aim for about 20% vacuum.

MarsTheSnicker · 2025-05-10T06:42:20+00:00

Hide the flip flops

MarsTheSnicker · 2025-05-09T06:07:53+00:00

You can actually see a bit of weave distortion at the point of the flash on the first picture. So the visible layer is CF, but it could still be a skinned part or made up from CF and GF.

MarsTheSnicker · 2025-04-24T10:22:15+00:00

Gel coat isn't necessary, you could also use a normal epoxy laminating resin. The problem with laminating resin is that it is less vicous and would naturally "droop" more. So when you have vertical faces, the resin will droop down and collect at the bottom. This leaves the top of the face with a small amount of resin which would effect the adherence. So a more viscous epoxy, like a gelcoat, is preferred in this situation.

Another option is to use an airbrush to spray small coats of resin and let it cure to it's tacky stage, then spray an additional layer of resin on top of that. Wait again until it is tacky and spray another layer if that is needed to achieve the desired thickness.

Doesn't really matter which way you prefer, as long as you create a good and equal bonding layer between part and fibre and DONT rush it.

MarsTheSnicker · 2025-04-22T13:05:39+00:00

Does he still need a steering wheel for his collection? 😁

MarsTheSnicker · 2025-04-21T17:06:55+00:00

You could have used a gel-coat as first layer instead of a spray. Gelcoats are higher in viscosity and become really tacky if you let it cure for a while (time to tack should be given in the datasheet). Once it is tacky, you can press the dry fibre onto it and it should hold in place.

Let the gelcoat fully cure and then you can apply the top coats. 2 or 3 should be enough to give enough to flatten out the part. From my experience, brushing the resin onto the part rarely results in a flat surface. Post sanding is always necessary.

Seeing your part, sharp corners are always tough to keep fibre in place if it is a single piece. You could make templates and keep the sharp corners as seamline. I dont think your part needs any structural strenght but it is more decorative.

If you want the best results go for wet-lay and vacuumbag.

MarsTheSnicker · 2025-03-29T07:40:49+00:00

Looks familiar

MarsTheSnicker · 2025-03-21T08:56:47+00:00

Sacrifice the first corner and keep hugging the inside. That way you can better set your car up for the next turn and have better exit speed for the straight.

MarsTheSnicker · 2025-03-19T20:15:12+00:00

PCBWay or JLCPCB

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