2015-07-29 07:54:27

FRP Hand lay up tips

FRP building mold-Hand lay up
FRP products like other plstic products need to preciously meet the size, meachanical and physical properties, and equally important smooth appearance. Let talk about the with details.

Material choosing:
1. Gelcoat, we should pay attention to the mold's temperature resistance, glossiness, crack resistance.Vinly ester is main choice for gelcoat.
2. Surface, Temperature and crack resistance are also problems. Surface veil can improve the causing of crackness possibility. 
3. Core: Key part of the FRP, we should pay attention to the strength, learning reinforcement mechanics distribution,working on prestress of the reinforcement.
4. Back, We should pay attention to the strength, water-tolerant. weather resistance
5. Fills, nanolime carbonate, fiber cab-o-sil can improve the mold's dimension.

Equipment and tools:
Hand lay up is thought as easy and simple process,wool brush is main tool. Trying best to choose good brush with uniform and straight hair.
Disk roller is used to remove the bubbles,not only remove the bubbles but stress close to the reinforcements, squeeze out the needless
resin in the reinforcement.This is a important procedure improving the FRP quality. 

Strictly control the process:
There must do demould treatment on the master mold.Slowly stiring the gelcoat resin avoiding bubbles.Don't need coating to much first time,
just keeping uniform coating the resin on the surface.When gelcoat geting cured,second time coating the resin. The gelcoat resin is toatally about 0.55mm~0.60mm.Calculate the thickness if it is your need.When the two layer of resin cured, finish the last time coating.Gelcoat coating now complete. 

Reinforcement laminating methods:
Batch method
Reduce the shrinkage of resin to minimum range. First we can laminate a layer surface veil or light weight chopped strands mat, then cured
by resin with enough resin. Then begin next laminatings(more layers) and cure until strength requriement meets. Note:Making sure grinding and remove paraffin of the previous layer, or it will delaminate)
RM method
Overlap mat and cloth. Only woven roving laminating has not good shear strength. Only mat, fiber strength can not be concentrating and
waste resin.
Laying method
Fiberglass has good tensile strength, but shortness on the flexbility, twisting.Laying the reinforce cloth in an ideal stress distribution.