Hello. I would like your opinions on what type of foam should i use for carbon-foam sandwich products. I know that some types are not compatible with epoxy resin. Your suggestions will be greatly appreciated. Thanks!
IMO the best option is structural polyurethane foam. This will give you the ability to use any resin you want (polyester or epoxy) and will also add some structural support to your part. The downside is that it is expensive and usually isn’t available locally so you’ll have to order it. One word of caution is that you should NEVER hot-wire cut urethane foam as it gives off toxic fumes when burned.
If are going to use epoxy resin then you can use polystyrene foam without fear of dissolving it. You can also buy it in pretty much any hardware store around the country. Most people prefer to use the blue insulation sheets that are available in various thicknesses. Apparently it’s slightly stronger than the pink sheets. In either case polystyrene foam is not very high density and has poor structural properties so don’t expect it to add much strength to your part beyond the gains you get from foam sandwich construction alone. Polystyrene foam can be cut with a hot wire but as I said before, only use epoxy resin.
Of course you can also choose one of the more “exotic” core materials like nida-core honeycomb but these are usually out of the price range for a DIY project.
the answer to that is very dependant on what you plan to do with these panels. the end use will dictate the weight (strength) of the foam. will it encounter impact? will there be sheer load? compression? tension?will it encounter high temperature? once you know the answer to all of these you can look for a foam that suits. as a general rule, the more versatile the foam is the more it will cost.
Prob’ a good idea to contact the core manufactures and speak to their technical guys. Nida-Core, Hexcel, Plasticore, etc. I’m sure they can pinpoint a critical core type for your application.
Even if it’s for a laptop table for yourself. At least you will have an idea on what to use 
Need more details.
What manufacturing process will be used?
What reinforcement and matrix will be used?
What’s the application?
I can’t wait to use this Divinicell foam i have here
I do know the yellow urethane foam soaks up plenty of resin, but it’s also strong as heck after full cure.
theoretically with carbon you should use (low weight)balsa or honeycomb. Most foams do not have enough shear strength to be usefull with carbon fiber.
But, I do work often with foam cores and carbon fibre. Every material wich builds up layer thickness, will build up stiffnes.
Even polystyrene or polyurethane foams, but they will fail quickly under pressure, both in compression, as in delamination( in the material itself, it won’t loose bond with the skin.)
I used both PVC(divinycell) and SAN(corecell) with carbon fibre. divinycell as a core material for a 38 foot sailing yacht.
I do not know cores wich aren’t compatible with epoxy, But don’t use *ester resins on (extruded) polystyrene foams.
so, gather some datasheets, and compare, and decide wich one is best for your use in your products.
race yachts use foam cores in the bow, called a crash bow. i worked on a 98ft race yacht and we used airex, its quite a flexible foam, but fit for purpose. the rest of the hull was from memory 75ish kg nomex 35mm thick.
airex is the one that conforms to curves as you heat it with a heat gun , right?
I don’t know if airex does, but the corecell t series does.
yep. means its easier to get it round the pointy end. quite arubbery feeling foam i suppose is a way to describe it.