EC! Laminate Sample #9:
- Reinforcement: 9oz 7781 style e-glass, 12oz biaxial e-glass
- Resin: Proset 114LV/210 Epoxy
- Core: 1/2″ 9.5lb Baltek End-Grain Balsa Core
Panel weight: 16.5oz per square foot / 5kg per square meter.
Thickness 0.53in / 13.5mm.
Overview:
This panel was just a way to throw some balsa into the mix and compare infusing balsa with foam. End grain balsa gets a bad reputation from the wet core found in thousands of old open molded items – especially boats. Core was often poorly bedded and there was room for water to run from block to block and turn it into a “two week old tuna salad” looking mess. Unfortunately balsa is often overlooked despite it’s price and really good compression properties. It is heavy though, and because it’s made of trees, there is variability from sheet to sheet in terms of weight – but manufacturers can supply it in fairly tight density bands.
Balsa soaks up a lot of resin, and because it’s porosity isn’t “closed-cell” like foam, it takes a while for air, moisture and other fun stuff to work its way out of the cells of the wood. You will want to have a way to store balsa in a low-humidity environment (my basement isn’t this!) and that will help. I drilled holes for resin flow here because in a flat panel, the kerfs are closed and its hard for resin to flow from the top skin to the bottom.
Things to Improve:
The air in this laminate is the major problem. This could be improved by letting the dry material sit under the bag longer at full vacuum. It could also be improved by letting the resin feed more slowly. It could also be improved, especially near the edges where there were some dry spots – buy running the flow media closer to the edge of the part. There is some value to running it over the edge of a panel like this and down onto the peel-ply break area – but some drawbacks too!
Video:
Laminate Schedule:
