First attempt at vacuum infusion questions

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#1

hi all… ok so i ve been reading many posts regarding the above and it appears for cosmetic carbon people recomend placing a clear gel coat down first…my question is…planning on using poly infusion resin but i currently use surboard resin for overcoating normal vac bagging bits am i able to use this as a gel coat or better to use actual poly gel coat?

or once last question is it wise to use a little bit of spray adesive on on some carbon fibre if its an awkward mold to lay up ? if i wasnt using gelcoat
many thanks and great website…very helpful

#2

use poly gel coat if using a gel coat… surfboard resin has wax in it that will cause your laminate to fail.

If your going through the trouble of infusing ( higher cost and time involved usually ) why not use epoxy infusion resin, or vinyl ester resin for infusion?

#3

thanks for the advice but just trying it out first so not wanting to go to to much expense with epoxy etc… here in the uk it seems a bit harder getting stuff :(… the parts are purely cosmetic so not bothered about strength etc

#4

I agree with Fastrr’s advice. Surfboard gelcoat has wax in it because they lay up bottom to top, not top to bottom, so use a regular gel coat.

Also you won’t need a spray adhesive for the first layer, the gel coat will provide enough tack for it but you may need it for the subsequent layers.

#5

you really shouldnt need any gelcoat for the surface if you infuse correctly. If it needs to be UV protectant then clear coat it after. The gelcoat will only add weight, no cosmetic advantages.

#6

Clear gel coat will often make the appearance worse! If used for cosmetic effect with carbon, it will distort the look of the material due to the sprayed or brushed on texture. The back of the gelcoat is not as flat/smooth as the surface of the mold.
Clear gel coat is generally intended to be used for in-mold paint jobs of various color gel coats.

#7

mmm now im confused!!!.. i though it i didnt use gel coat then i wounldt get a smooth 3d ish effect on the finished product ?

#8

I’m with needles. If I infuse without a gel coat, which I usually do, I get a very flat carbon look. Examples are the plate I made or the tensile test coupons.

http://compositescentral.net/showthread.php?p=26213#post26213
http://compositescentral.net/showthread.php?t=3817

I understand what Tet is saying though, if you leave the gel coat all wavy it’ll both make the weave wavy and magnify the weave unevenly.

How do you get that nice look with infusion or even vacuum bagging?