West Microlight 410 Data

I've been experimenting with airex foam core hulls, and I'm using MGS 285 epoxy thickened with West Microlight thickener.

So far I've found about 3% by weight is good for filling the surface, but what I'd like to find is some technical data ie. percentage microlight/density figures or increase in volume. Couldn't find anything in the West book. Is there anything people know of on the web?


Matt Turner

 

As a former chemist formulating fillers, puttys and high-build high solids formulas, I'll tell you these main points:
You can deviate as much as you need in percentage (3% by weight microspheres is about as much as I used to use in typical fillerswhich equals about 40% in volume if I remember correctly) based on the the performance you want according to the following tradeoffs:
With much filler and less resin, you get:
- higher viscosity for troweling / buildup ability
- better sanding ability
- less shrinkage (not much anyway with epoxy)
But the downfalls are:
- weaker cohesive and adhesive bond (breaks easier and won't stick as well) although not significant.

Much resin with less filler you get:
- stronger, harder fill
- thinner with a tendency to run and drip
- sanding is a @#$%*!! (technical term)
- heavier, added weight
- waste of expensive epoxy
I'd say to load it as much as possible as long as it doesn't cake up, and then skim coat over with a more resinous mix after sanding. - JB