Epoxy Resin Concentrator Manufacturing and Lamination

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nialaz
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Epoxy Resin Concentrator Manufacturing and Lamination




by nialaz » 25/02/09, 00:26

Hi,

I want to make a cylindrical-parabolic concentrator in epoxy resin with mat glass reinforcement.
I made the plaster mold and I am unsure about the implementation of the resin.
In particular, I do not quite understand how the mold release wax is applied and whether it is necessary to use in addition the Coat gel.

Finally, I am finishing the plaster surface of the mold well and I wonder if I shouldn't paint it (acrylic paint)

If anyone can advise me ...!

Thank you
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elephant
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by elephant » 25/02/09, 08:57

I believe that there are excellent books on the subject, on the self-construction of boats: it's a whole profession.

For the little I have seen done:

Your surface will only be worth what your mold is worth: pumice!
The mold release wax is applied to the mold so that the part does not stick to the mold.
The gel coat is applied like a paint on the finished part.

Do not hesitate to take photos: we would like to see!
Good work.
:D
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by gegyx » 25/02/09, 09:36

: roll: I fear mistakes…
I specify that I never made resin on mold. But I was interested in it.

First, the mold must be convex, because the finishing surface is in the hollow of the future dish.

The mold surface must be perfect, as this will reflect the final result of the molding.

To sand fine-grained plaster, this should not be obvious.
Maybe harden it with a fine smoothing coating first (slip).

After, I don't know, if the surface is satisfactory, go to the next step.
But if not, perhaps an impregnation of paint or oily liquid, can help to perfect the surface (with still micropores or fine scratches).
I specify impregnation, and not paint coating, otherwise the wax will not hang in the next step.

Then, wax, as a release agent on plaster should be mandatory.
(On other smooth non-porous substrates, silicone products must do the trick)
Good, the surface is perfect, polished. Okay

This is when we put the gel coat on the wax.
(See how to install it according to the product's instructions for use)
The gel coat is the top coat of the final product. It is resistant resin, impregnated with a dye, which will marry your mold perfectly.

Finally you pass your mat resin and the fiberglass in successive crossed layers (for a sufficient thickness), taking care to impregnate the fiber and removing the bubbles.

Do this outdoors.
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wazaibzh
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by wazaibzh » 25/02/09, 19:41

Hello
I work very (or too often) these materials (resins, fibers ...)
the shape of your mold should not prevent the mold from being released from the mold or you will have to break the mold (with easy plaster)
I advise you to saturate your plaster with a paint to eliminate the porosity of the plaster.
then you will have to wax it. but for the procedure tell me the type of wax you want to use (paste, liquid)
when your mold is waxed, you will apply a fairly thick layer (+ 0.5mn) of gel coat and wait for it to "set". do not wait too long before going to lamination. the best is to wait until the surface is hard but still a little sticky. only wait a week.
for the resin makes a good mixture and in the right proportions (depending on the resin and their types).
if you use glass mat you can cut it into pieces or even tear it by hand and place (in the direction you want it seen type of fiber) the pieces on your mold already coated with resin. the resin will return it "soft" and deformable during the impregnation. do not hesitate to force-feed the fabrics it is very greedy in resin.
example; for a glass mat of 300gr / m2 you need 600gr / m2 of resin
regardless of the tool (brush or roller) which will be used to impregnate the fabric exerts a slight pressure for the air and "compact" the fiber, the best of these is to use a debuller ...
products to be used in a well ventilated place and temperature below 15 ° put on gloves ...
are you sure you use epoxy? because it's a little more complex than
polyester which is cheaper
If you have questions, do not hesitate
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by the middle » 25/02/09, 20:56

Hello,
I found a video which concerns the question (I believe that there are several videos of the "builder")
http://www.youtube.com/watch?v=FZh-CRneIII
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by nialaz » 25/02/09, 22:23

Thanks for advice! : Cheesy:

The video, I had already seen it and it was she who encouraged me to move towards the composite. But when we realize, we always end up asking a lot of questions!

Regarding the surface condition of the mold, I am in the process of making the finishes to reduce the porosity. I can indeed harden and smooth the surface with fairly liquid smoothing plaster. I already did on walls.
Painting I also thought about it. By cons acrylic or glycero?

Regarding the resin, I also called the manufacturer Soloplast today for advice. The technician asked me to send him the project to give me good advice, but he did orient me towards polyester.

wazaibzh,
for wax, I was thinking of a liquid. I saw on the internet that you have to put several layers and polish in each !?
for the gel coat: do we manage to spread it with a uniform thickness? My mold has straight edges as a flange and reinforcement.
Finally after molding I thought I would stick to the mylar composite. Do you think I can just put it in the bottom of the mold before lamination?

Thanks again for your help.
I post some photos.
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nialaz
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by nialaz » 25/02/09, 22:34

Pictures ..

The first mold used to make the plaster mold:

Image

Then the plaster mold made with a first smoothing with the coating

Image


Finally a pdf describing the project
Image
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nialaz
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by nialaz » 25/02/09, 22:36

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by nialaz » 25/02/09, 23:01

To finish describing my essays,

here is how I made the first mold:
1 - realization of the parabolic curve on graph paper
2- making a curve 4 mm from it to take into account the thickness of the depron
3- cutting the paper along the curve
4- a felt tip following the cut on a 2 cm thick extruded polystyrene plate
5- cutting the polystyrene a little above the felt
6- sanding to approach the parabolic shape gently while trying to stay flat on the edge

So I made 3 templates which I then reponce all together to align them.
Erected on a polystyrene plate with a Depron plate on top which follows the shape if pressure is applied to it everywhere.

I assembled the whole with glue for Depron while ensuring the pressure by clamps completed with masses distributed here and there.
Graph paper
Image


Previous and disappointing achievements
: Lol:
Here a plaster molded on a parabolic form (manufacturing similar to what I have just described but using wood instead of polystyrene). Aluminum foil glued (hardly) on it

Image

Here a box in which there are wooden parabolic jigs on which fixed Depron then glued (there also with difficulty) of aluminum

Image
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wazaibzh
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by wazaibzh » 26/02/09, 20:27

quotes:
wazaibzh,
for wax, I was thinking of a liquid. I saw on the internet that you have to put several layers and polish in each !?
for the gel coat: do we manage to spread it with a uniform thickness? My mold has straight edges as a flange and reinforcement.
Finally after molding I thought I would stick to the mylar composite. Do you think I can just put it in the bottom of the mold before lamination?

for the wax I prefer the paste paste (often based on carnauba) and in both cases it is indeed necessary several layer and shine.
yes the manual gel coat (not sprayable) is thick and you can pinch it in a crossed layer or roller if you cannot put the thickness in dry and pass a second layer
I hope that the right edges of your mold will not prevent the release but if you have removed from your preform it should be okay?
for the mylar I would wait to stick it on the part once finished
for the resin and the gel coat takes polyester! even if the smell is disgusting!
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