Ironing Out A Few Details

General Composites Discussions Composites Talk
#1

Hello everyone, I have a project coming up that I want to tackle and I have been doing a lot of research. Onto the details - I will be overlaying a painted interior panel of a car in carbon fiber with a 3k 2x2 twill, and will need to take the part on and off. I don’t want to create a mold or get a vacuum system. I want to use a release wax (of your suggestion) to preserve the interior panel, as the piece will only go on for car shows. Now, I will be practicing multiple times in fiberglass first. Once I get the hang of it, I will use carbon fiber.
The details I can’t figure out are the following:
What resin and hardener can I use that is compatible with both fiberglass and carbon fiber?
What release wax can I use for both of these?
Any tips/tricks?

Thank you, I appreciate the help.

#2

  1. For your application, both polyesters and epoxies will do. I even tend to suggest a polyester, for their better UV resistance. Strength is not the critical factor here.

  2. I would use PVA (hey! I am suggesting PVA!) This creates a chemical resistant barrier between the part and the resin used. In this case, surface quality is not the issue.

Tips: use a very sticky resin. Carbon is so much more stiff, that it is hard to get around corners. A sticky resin, perhaps even already half-curing, can help.

But I am definately not the overlay specialist, and I think (hope) others will jump in.

#3

Are you overlaying a panel permanently or are you looking to create a carbon fiber panel to cover an existing panel that can be removed from car to car and show to show?

If you’re looking to permanently overlay a panel I can throw some tips out, but if you’re looking to make a panel cover that can be removed and snapped into place, others will probably chime in.

#4

Thank you, good info! Any specific PVA you suggest? Also, any specific cost-effective resin/hardener you suggest?

Overlaying a panel that will cover an existing panel, but will be able to take it off when not at a car show. Basically, it will overlay the part you will see but not go in depth. So, your second option. For example, I will partially wrap the inner panel door handle, but will not wrap completely around/behind it. Does that make sense?

#5

I cannot recommend any materials, as I am not familiar with the stuff that is available in the USA. Look for a relatively high viscosity, clear polyester resin, which is UV stable. Perhaps in the surfboard world.

So you want snap-on parts.

#6

Ok. I know what you’re doing then.

I don’t know an easy answer, to tell you the truth I actually was trying to make a panel cover for something that conformed to a certain shape and I had to do it the hard way which was.

  1. PVA surface
  2. Build a fake surface which spanned some gaps
  3. Build up some light layers of fiberglass
  4. Pull plug up
  5. Take the smooth surface and build another plug off of that
  6. Then finish that, fill gaps, drill holes, and do whatever to make it fit the way I wanted it too
  7. Make a mould for resin infusion

If I had to do my item again I may have used large sheets of sheet wax? But I don’t know if it’s even possible to mould off of sheet wax.

I don’t have any suggestions for you other than it may be easier to just make new panels.

#7

Well, it seems straight forward to me. I’ll even say easy, but very easy to mess up the carbon fiber without enough practice. Thus the reason for fiberglass first. Here’s my process:

  1. PVA the entire surface (any good pva suggestions?)
  2. Lay down thin layer of epoxy resin
  3. Wait for it to tack up (~1 hour)
  4. Lay down material
  5. Let cure for 24 hours
  6. Release!
#8

Did I really just read the word “easy” used in a composites forum? :smiley:

#9

Yup! I’m trying to move forward on this project, as this is 4 weeks away now. I need good resin/hardener suggestions and I purchased a release wax last night - Meguiar’s #11 release wax. Supposedly the stuff is phenomenal. We’ll see! So, suggestions?

#10

Spraying PVA onto Meguiar’s stinks. It’s going to bead up like mad. You can do some mist coats to help. I always use Part-all Paste #2 when using PVA. There is no beading.

#11

I won’t be spraying anything though. What would I need to spray?

#12

This document can help

#13

It would be recommended to spray the PVA. You can wipe it or brush it on but the barrier can be compromised. Spraying it is the most reliable method to create a uniform and complete barrier that blocks chemical reactivity. PVA may or may not be necessary. You should do adequate testing to determine an appropriate release combination.

#14

So I need a special gun for the PVA? I’m really getting short on time, so I need to get everything purchased, arrive at my place, practice, and finish by the first week in April. I need suggestions on whatever resins and hardeners I can use, and what my PVA options are. I need the resin/hardener to work with both CF and fiberglass. Thanks guys/gals

#15

So, after more research, I came up with this:
Clean entire wheel
Use Meguiar’s #8 Release Wax - 5 coats
Put light coat of fiberglass resin (w hardener; use foam brushes)
Wait until tacky, then set fiberglass down
Apply one coat of resin, make sure to get all parts with resin
Let cure for 24 hours. Release with air hose.
Repeat for practice. Once I’ve got it down pat:
West Systems Resin & Hardener
2x2 3k carbon fiber twill
Same process as above. I’ll post back to let everyone know how this goes

#16

Suggest you use Rexco partall coverall film. Water based PVA. Works well on painted surfaces, does not affect painted surfaces. Little trick with it though, if you choose to spray it, spray it at very low pressure small orifice spray gun. Spray it as a mist, not a full film. As it is water based it takes longer to to dry and therefore a full sprayed film will run or curtain on you. Allow it to dry, you will see the mist film self level and give you a nice film to mould off. If you feel you do not have enough on or you may have missed an area, repeat the process. You can also brush or sponge it as well. Also imparts a gloss finish to the part, standard solvent based PVA’s impart a dull finish to the part you mould.

#17

Sorry, to answer a question above re meguiars waxes. Formula 5 very similar. Ensure that the wax is thoroughly buffed and any remnant wax is removed. Ensure you cycle the cloths, wipes, rags etc, through each coat of wax. Also ensure that you leave plenty of time between each coat to ensure wax hardens. You will need to take into consideration your ambient temp for this. One of the main reasons I see with beading of PVA’s is poor wax application, or should I say removal. Rexco coverall film also works well on these waxes, eliminates the beading effect. Not a fan of semi permanents on plugs as in some cases works too well. The chance of pre- release during moulding is higher. You can look at semi permanents that have tailored levels of slip resistance. Zyvax Flex Z is one of them. There may be others. Hope this all helps?

#18

lol… i Read that as well and chuckled…

I am one of those arrogant people and think everything is easy to make. concept wise, composites can seem easy of all the trades and skills i know, composites has to be the most difficult. the know how is fairly simple but there is so much finesse that can not be taught and only gained by experience… I’m no professional but i get by…

PS, what is your skill level? Is this your first project?

did i miss something? I thought you were doing a dash?

#19

I’ve overlaid hundreds of panels in my career. From your basic Honda civic panels to full Audi R8 & Murcielago interiors. I always use polyester and vinyl ester resins.

Basically here is what I do.

Prep my panel by sanding and cleaning.
Mask the back.
Apply thin coat for the tack coat. Let that cure to b stage. B stage is where the resin is sticky but does not come off on your fingers.
Apply the carbon fiber carefully, (flat parts I’ll usually put face down onto carbon fiber I have laid out on the table)
Let that cure 100%. Then add a few layers of resin by brushing it with those pig hair brushes.
Your last coat should be with surfacing wax for sandability so do that.
Sand, re coat a few times, sand, and clear coat.

If you want this permanent, don’t use PVA or wax. If you want to make a removable skin, then use PVA and I’d recommend using two layers of carbon or at least 1 layer of a 4oz woven fiberglass cloth followed by the carbon fiber. If you are going to do multiple layers, allow the first layer to cure fully onto the tacky resin, then apply another tack coat for your carbon fiber.

Sorry if I’m babbling, its 2AM and I’m tired.