Concrete panel with fiber glass (Experience 3)
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According to the assignment, one of the process that wasn´t covered and I want to introduce in my final project is Composites or similar. With this I can reinforce and seal the wood of the structure of the cube which is the module of the project and that need to be ready to be outside I contact with the element in order to collect resources like water, energy and food.
· CNC router
· Brush
· Gloves
· Mask
· Cutter
· Vcarve
· Rhinoceros
· Resin
· Catalizator
· Glass fiber sheet
The first try on composites was in the assignment of Molding and Casting where I poured concrete reinforced with rebar
In this assignment I will reinforce the wood with glass fiber.
1. Buy the materials
2. The guy in the store told me to mix the resin with the catalyst. 300 ml of resin with 100 drops of catalyst.
3. He said I don´t need gloves of anything and that if a drop falls into my arm I should remove it with thinner. Anyway I will use all the equipment. I have the resin since yesterday in my room and it stinks with that smell. I have the bag in the window to keep the room ventilated.
4. Now I will cut the cube in the router again
5. Unfortunately I couldn´t get the piece on time.
6. Anyway I will experiment with the material. I took some pieces of wood of a little Emosilla
7. The resins have to be in a ventilated place, because it generates gases. I hang it in the window while brought it to the lab
8. I read this tutorial about applying fiber glass. Cómo utilizar un kit de fibra de vidrio
9. Mix the resin with the catalyst. It gets hard and unusable in 30 minutes approximately So be fast
10. Apply the resin to the wood , put the fiber and apply resin again. Put plastic (could be bag) and apply presure, so the fiber + resin becomes one with the wood.
11. I cut the fiber bigger than the piece to cut it after.
12. I use press to keep everything together while drying
13. After it was ready and hard enough I cut the extra fiber with the cutter
The previous experience wasn´t enough to complete the assignment. So I will repeat it again but with some pieces of my structure of my final project. Debating about what I was doing. Probably I shouldn’t call it composite because a composite does not necessarily mean straightening and sealing a material with the glass fiber. I don´t know exactly the name of the process I used, but I not only to seal the wood against the environmental elements, I also want to reinforce it, because the cubes will carry a minimum of 45cm3 of soil and 20kg of water and maximum more than the triple of these amounts. The Fiber glass is perfect for that because in my previous test I could prove how though the 3mm wood gets in the combination with the resin and the catalyst.
I will reinforce a couple of joints to hold the next cube in cantilever. In the future
The pieces were cut in the CNC router. But before I did the Gcode in Vcarve (software)
I asked again to one of the guy of the lab, who know about doing this techniche and the made me some recomendations I will do this time. I used the same fiber glass I used before, but another resin and catalist the Fab Lab brough. I measure the quantities with the weight measurer. The portions are for each 100 of resin you have to use 1 of catalist. That means that if I poured 50gr in the plastic glass of resin I poured half gram of catalist in it. In reality it was a little but hard to get that relation because it is difficult to control how much you poured, but if you miss a couple of grams in your mix is not that bad, It will just dry faster of slower than usual. It is better to work in small amounts, and do the mix a copuple of times to do the job, because if the mix gets wrong of dries to fast only a small portio of material o mix will be damage.
The resin used is polyester, •RESINA PP-7010-14 TIX
Safety first
I put tape on the areas I didn´t want to have fiber, because it will increase the thickness of the material 2mm at least, and then the press fit won´t work as ow it deigned now. The fiber will not stick to that piece, because the fiber only sticks into materials where the resin can penetrate like the wood, but not in plastic or duct tape. I also covered the two pieces of wood I will use as press with plastic.
I cut the fiber the same size of the wood
With the brush impregned in the resin applyed it on the fibe which is on to of the wood. Make sure the whole fiber has the resin and looks more transparent than before. The press with clamps the face where I applied the resin + fiber for 20 minutes at least. Then remove the excess of fiber with a cutter and a san paper machine to remove the hairy edges.
The result. The pices mounted on my final project and holdind another cube on cantiliver.
I wanted to develop a little bit further the first experience with the concrete. I do work with this material often in my projects. This time I will add two things. 1. Modell a 3d pattern in rhinoceros. 2. Reinforcement with fiber glass. This is a composite, where compression and tension is assumed by the concrete and fiberglass respectively. Normally the concrete is done with cement and rebar, but kinds of fiber is also used. The result is a thinner concrete and less net weight.
After that I made the gcode in the Vcarve (Aspire), but this time is not about cutting. It is carving a piece of foam
The foam was carved in the router. The frame for as casting was also cut with the router. It is a simple press fit frame. I fixed the frame and the foam piece to a wood and secure it with screws. Applied a un molding wax before pouring the concrete mix and cut the glass fiber the same size of the square.
I divided the mix in 3 types. First only concrete which is the finishing in contact with the foam. After that comes a sheet of fiber and then the second mix which contains sand. Finally the third mix with concrete, sand and stone to give better streght at the bottom, and before puring is another sheet of fiber placed.
After 12 hours I removed the foam. And after 24 hours I removed the frame. Looks good. In 48 hours it will have the final streght
· I would like to continue experimenting with the fiber to make my final project more durable. The wood though enough to resist the outside condition and allow the pieces to carry weight if needed
· I have to be in a more controlled environment when using this material, because I was in a hotel room when I did it.
· The difference of the wood with and without fiber is very big. I can make my structure thinner and reinforce it with the fiber.
· Next time I will use a syringe to control how much resin and catalyst I am pouring.
· Next tie in the future of my project, I need to count with the increase of the thickness of the material and I can do the press fit bigger to tolerate this change of thickness