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<\/a>This is the 16-inch long education layup done to show the strength of a foam\/fiberglass sandwich.<\/p><\/div>\n
You start out by cutting out the piece of foam, tapering the ends, and rounding the top edges so the cloth will conform. Then you lay the bottom 4 layers, first 2 BID and then 2 UNI, on a plastic sheet. The foam core is painted with micro slurry to fill the small holes in the surface and then plunked down on top of the glass.<\/p>\n
The plans don’t say to add dry micro to fill out a radius on the internal corners on the bottom, but this seems like it would be necessary to not get an air gap in the layup. I went half way and did it on one side and left the other bare so I could see the difference. The micro can be seen as the white area around the edges. When making these corners, you plop down micro and then make a radius with the tongue depressor. I found it difficult to do this without scraping micro out onto the glass which is a big no-no. Micro between the glass layers significantly weakens the bond. However, I don’t know what the benchmark is, is a tiny amount of white left over after you’ve scraped the micro off OK or does it have to be absolutely pristine?<\/p>\n
After adding the micro, I laid the same 4 layers of cloth up on top, 2 UNI followed by 2 BID. The cloth conformed well to the curve, but as expected it was impossible to get an entirely air-free corner where I hadn’t radiused with micro.<\/p>\n
After cure, I trimmed the piece to the requisite dimensions with the multitool. The instructions say to cure for at least 4 days before putting it to the test. This piece, which ended up weighing 112g (or 3.95oz) should be able to take a 200-pound bending load when supported in the middle. We put the piece over a broom handle and tried standing on each end. It easily took my ~160 lbs and even managed to handle my friend Greg which “put it significantly past design load”, in his words…<\/p>\n
Some things learned here was:<\/p>\n
- \n
- UND is kind of hard to handle and deforms much easier than BID.<\/span><\/li>\n
- When radiusing inside corners using micro, need to work on the technique to avoid getting it out on the glass.<\/li>\n
- It’s hard to squeegee very non-flat pieces without disturbing the cloth. You tend to get all the contact in a small area and it snags the fibers.<\/li>\n
- This piece also looks like it’s slightly incompletely wetted, just like the previous ones. However, it’s much harder to tell when there’s foam with micro underneath.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"
It’s been a while since I’ve posted on any progress. Partially because I came down with three back-to-back colds starting on Dec 24 (nice Christmas present…) and partially because I just haven’t shot any pictures. Over the holidays, I did make what the education chapter refers to as the “confidence layup”, which is a 16-inch …<\/p>\n