Surface finish using resin infusion process

[rajasai]

We are having problems with the surface finishes on our fiberglass laminates. The process we are using is resin infusion. Vacuum is set a 0.8 Bar or about 12 PSI.

The problem we are experiencing is print through on the gelcoat and sometimes pinholes. This usually happens on our thinner laminates. Does anyone have any suggestions?

 

[wes616]

Markoff from the tool surface is typically a function of the quality of tool surface itself. Try to improve the tool surface and see if you experience less markoff.

Regarding pinholes. I haven't seen this problem much with infusion processes (Out-of-clave prepregs are notorious for this problem) often it is associated with porosity and poor compaction. I remember seeing some very porous surfaces once, that were infused on a convex tool. I believe that it was a surface tension issue as the resin moved across the tool surface. I honestly can't remember what the corrective action was for this issue, but since you say that this is happening to your thiner laminates, might lead me to believe that something about the tool surface was affecting the resin flow. Additionally it would be interesting to know what type of weave you are using.

Wes C.
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[rajasai]

The weave we are using is a 0 and 90 degree plain weave fiberglass cloth.

We have already found a solution for our print through problem. The solution was to use 2 plies of continuous strand mat in between our gelcoat and woven cloth. This solved the problem by reducing the voids in the laminate and thus leading to less print thru.

I found the answer here

http://www.harveyscomposites.co.za/Information/troubleshooting_table.aspx

Anybody reading this should definitely check out that website. Some really helpful information is available. Thanks for the help though Wes616.

 

[Peter]

Have you tried any of the Lantor products? We have had success on infused parts using Lantor Finishmat against the gelcooat, then a layer of continuous strand mat then a layer of Lantor Soric TF followed by the structural laminate. All those plies go onto the mold in a dry state.