COMPOSITES
I decided to take this activity to begin to study a way to generate a coating for the chair that I have built for the week 8.
I´m not sure if I want to cover just the upper part
… or if I will make a mold to generate another chair, solid, like the 3d with which I used as a main shape to do the wooden chair that I called drop chair; I am sure that this activity can be very helpful to think about it.
I want to utilize the wooden chair as a mold, and for the composite fiber glass, fabric and some other material;
At first I covered the chair with masking tape and polypropylene tape, to generate the shape that I will use as a base for the fiberglass;the idea was to make an experiment directly on the chair, but reading about the process, I realized that will be better to make a test before, to check the possible reaction of the tape in contact with the resin, and testing with different materials, because I never made composites before.
For the test I used a base made with same wood that I used to build the chair, and with a similar structure (I had some pieces …) but smaller.
I prepared the base with different strips with: only masking tape, only polypropylene tape, marking tape, cardboard and leaves (glued with double face tape), masking tape with two different kind of fabric: elastic fabric and a nice japanese cotton.
For the composite I used fiberglass, transparent polyester resin (PP-250); and wax and another film to remove from the base. At first, I putted the wax (it smells horrible!) and a layer of the other film on each strip
The second step was a first layer of resin, specially on the fabrics and finally the first layer of fiberglass; I was worried about this part, because fiberglass is dangerous and not so friendly … but I did it very carefully and it was not so hard …
Is like an art … is a strange mix between working fast and slow at the some time! The resin have to be putted fast because the time of dry is small, but the fiberglass have to be putted slowly because the small “hairs” flies everywhere and they are like needles… but no too slowly … because the composite becomes rigid very fast
Thinking about my chair, I tried to make well the curves … at first was not so easy, but finally I did it; I repeated the process 2 or 3 times for the different strips
when the material was starting to dry, I realized that some excess of resin was accumulating in some parts … because of the shape … I saw too bubbles inside … the double face tape that I used to glue the leaves with the cardboard, is totally impermeable for the resin …
I waited for two hours more or less … observing the material changing colors, texture and hardness …
Finally I decided to remove the pieces from the mold! At first it was not easy because I glued the strips one each others with the resin … but it was possible to remove well all the parts.
Rather than I figured out…the best material for the first base was the polypropylene tape: I was though that maybe it was not very good with the temperature of the resin and probably it could be fused or glued with the fabric and the resin, instead I removed it very fast, easily and the final surface is perfectly clean.
The other surprise is that, otherwise, the masking tape is not a good option: it is glued with the resin … I could remove it but the result is not very clean.
Both fabrics work very well … but the surface is too glossy and I don’t like it so much as final coating for my chair; I like the effect with the leaves, but if I want to use them, maybe I have to put a best base and playing with transparency
If I want to use it for my chair I have to be more clean in order to not damage the wood with the resin …
… well that is what I have for now…
I’m thinking to do a removable coating for my chair that could be used like a final element and used too as a base for a tiny cushion.
…and I think that I could build another complete chair too, maybe in 2 or 3 parts, using the wooden chair as a mold, filled with foam.
I liked this experiment, but I don´t like toxic materials … I think that I will try to do a similar process, but using others materials.
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