regalman4925

i am planning on building a windscreen for my boat and am thinking about wrapping it in carbon fiber, i just replaced the transon and stringers in my boat so i have worked on glass some. is the carbon fiber harder? it seems pretty similar.... i am making it by making a styrofam mold on the boat, shaping it and laying glass or carbon/both over it

bobsbillets

I could be wrong but I would think that the resin would dissolve the styrofoam

regalman4925

i was told to put foil over the styrofoam and that will prevent it from melting. didnt they use to make stringers on smaller boats from styrofoam?

glassdave

You just need to use a high density poly foam

http://www.fibreglast.com/category/Foam

styrofoam will melt very quickly in poly resins

whats your reason for wanting to use carbon? Most strength properties arent really realized when using CF unless you are using some fairly involved and specific techniques (i.e. bagging, post curing etc)

If it the appearance your after you can just do it as an overlay after your structural part is complete. Somewhere in this section there is a thread i started on some appearance grade carbon parts i did using all poly resins (which make it much easier for the do it yourselfer). I'll try an dig it out for ya.

regalman4925

the carbon fiber is only for appearance. is there any way to use foam that is used for construction? i have access to scrap pieces of it there for keeping my cost lower. im trying to do this myself to avoid dropping a butt load of cash on a new windshield

glassdave

Yes you can still use the Styrofoam, you just need to protect it from the styrenes in the resin. You will need to coat the entire surface with PVA (polyvinylalcohol) its a water based mold release available at fiberglast (or any other supply place really).

http://www.fibreglast.com/product/PV.../Mold_Releases

spray it on in several even coats allowing it to flash in between each. For styrofoam you will need to put on quite a bit and its pretty thin. You will also need to get the shop pretty warm for this process. Once its dried you can go ahead and laminate your part. This stuff is water base so clean up is easy.

For the carbon fiber you will have to do it as an overlay on the final shape and topcoat it with a clear gelcoat. Its a ton of work but is the only way to get the natural carbon look out side the mold.

wjb21ndtown

Dave, would it be worth it to spray the foam with a primer/sealer before putting on the polyvinalalcohol to keep the thin PVA from soaking in so much? Just a thought... I think we use to use shillac for mold release when I worked in tool and die, but that was a release from a clay mold. I'm sure there are different issues involved.

glassdave

no actually the PVA should work fine. Any primer you spray on it will eat the foam as well. It may also be a good idea to start with a single layer of a light cloth on the foam to get the process started. Let that cure out then lay on the bulk of the laminations.

regalman4925

as far as the finish you mentioned clear gel coat. i was watching some how to videos and they were using a resin to build up a nice gloss

glassdave

pretty much the same thing just a higher quality and has UV inhibitors(I think). For appearance grade stuff use clear Silmar 249 resin in the carbon and a clear flake gel for a topcoat.

http://uscomposites.com/polyesters.html