Tuesday, February 26, 2013

Vinyl Shingles and Epoxy versus Polyester Resin

The closest thing I found to epoxy shingles was vinyl shingles that were formed like cedar shingles. The grooves were similar to what I was thinking in terms of creating lines for water to run down. In doing some research about epoxy versus polyester the main points were that epoxy absorbs less water than polyester resins when it comes to long term submersion. The cost of the epoxy is significantly more than the polyester resins and it seems that most boats are initially made out of polyester resin versus epoxy resin for that reason. In thinking about vinyl shingles I can see that it would be a more affordable version of the epoxy and since the structural strength of the shingles is not important the use of epoxy shingles may be a bit overboard, literally.

I still find myself thinking about how I would use epoxy and as a medium it is mentioned in all types of high tech construction methods from jets to boat hulls, albeit with the simultaneous use of special core materials, carbon fibers and other strengthening materials including wood. One factor in my ideal project would be that the frames may in fact be the shingle and the structure itself, which will call for a stronger material than vinyl. Vinyl is very resistant to weathering because water does not seem to bother it, but long term exposure to uv may break it down more than epoxy. All materials benefit from a coating of some sort, but I am still imagining a construction method that does not need anything more than what the structure is made out of.

I went into my backyard and picked up prior experiments with frame shingles and epoxy layers that I had made then left out to weather. Some hardened to be stiffer than I thought they should be and were subject to cracking. It appears that if a thin layer of epoxy is applied properly it would provide a great barrier to weather by itself and with as thin a covering as possible. The best feature of my curved framed wall is that I can pick it up myself and move it around to use it somewhere else to block wind and if the frames had an epoxy sheeting on them I don't think it would add as much weight as if I covered the structure with wood. Most of the strength in the structure is from the frames that I have attached to each other, so the wood is a benefit for strength, but not a requirement.

Today I did my most accurate print with epoxy yet. I mixed an iron oxide black pigment into a 2-1 clear epoxy with some filler until I had a very dry feeling paste. I wasn't sure it would print, but I got it to go through a 110 mesh screen and printed on a suspended layer until I built up a print that looked like 1/32nd to 1/16th of an inch thick. The print was the cleanest I have made so far and a line thickness that is about the same 1/32nd on an inch seems to be about the right thickness for printing. My big question is whether or not the suspended print can hold it's shape will drying and if there is too much pigment in the material that it may weaken the epoxy itself. There would be an additional layer of epoxy around this print once it dries, so the idea of the material holding it's shape is the the more important test.

I made some epoxy prints the other day that I let dry longer than I usually do and they held their shape much better than my previous experiments had. I can only assume that if I put a layer of carbon fiber or fiberglass behind these printed layers that I will get a stiff surface that will be even stronger in the sense of holding it's shape under varying conditions of heat and cold. My next job is going to be researching the benefits of printing with epoxy and if it is commonly done. Enamel is a common printing material, but I haven't researched epoxy printing yet.

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