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Old 12-31-2006, 08:52 PM   #3
Daishi00
Scooby Guru
 
Member#: 78952
Join Date: Jan 2005
Chapter/Region: MAIC
Location: BSG junkie
Vehicle:
2005 WRX
CGM

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Step 1


Mask the area you plan on fiberglassing with masking tape (Pic #1, although I mask the entire area, not just the outline as you will understand soon). Many people have used blue or green painters tape, as well as standard masking tape. In any case make sure to put down two layers of tape overlapping the seams. This will help create a waterproof shield. Also it is imperative to mask out an area quite a bit larger than what you will actually lay the fiberglass on. The reasoning is simply for protection of your car from spills, dripping etc***8230; Once you have the tape placed use some adhesive spray and put aluminum foil overtop (Pic #2 I personally use adhesive spray to hold the foil, clbd39 uses tape as seen in his pic More exposed foil makes it easier to remove the fiberglass). The key here is to make the aluminum foil as smooth as possible and overlap seams (also you can tape that seam down, but I don't bother). Use a roller or plastic spreader to flatten it out. If you tear it either try and patch it with the foil already there, or replace it***8230;don't put down another small piece***8230;it will just create even more seams and possibly move during the fiberglassing step. If you can use the industrial strength stuff found in restaurants, as it'll resist tearing more than the standard stuff in the grocery store.


Step 2


Start with 3/4 oz. Mat cut/tear it into small 2"x2" pieces and use spray adhesive to tack it to the aluminum foil. This will help keep it upright while applying resin. I like to cut it into long strips and then rip it apart as the torn edges work better to conform to corners and by overlapping pieces you will still build up thickness quickly without having to spend precious minutes trying to knock out air bubbles. I would go at least 2-4 inches outside the max area you plan on using. The reason for this is to make sure you get a good thickness at what will be your edge (again, make sure you taped/foiled a large enough area). Once you have a layer of mat "glued" start with the resin. Mixing resin is critical, so if it's your first time on a particular day mix up a small batch to test it's working time, and curing time. If you use too much hardener it will cure to quickly, warp and you're screwed. To little hardener and it may never fully harden or take days and days to do so. If I can get 15-30 minutes of working time from the resin before it begins to gel than I know I have a good resin/hardener ratio. It is best to use the minimum amount of resin needed to soak the mat, as extra resin does not add strength. Resin by itself is extremely brittle and will break easily. Use your brush to tap out any air bubbles that form. Air is your enemy when building up layers as it creates weak points in the fiberglass. Before the first layer has a chance to cure start placing more layers on top. I use a combination of 3/4 oz. and 1 1/2 oz. mat to help build up layers quickly. 3/4 oz. mat is better in corners where you have trouble getting mat to conform. Some people will say it's fine to let each layer of mat cure before putting the next one. I disagree, as I want as many layers to intertwine with each other to increase strength. Also it is key to ONLY use as much resin as needed to soak the mat through. I cannot stress this enough. If you think you might have too much resin down just lay more mat on top and wait a minute or two***8230;if it starts to soak up then you know***8230;if it doesn't, then add a small amount of resin. Continue this until you have at MINIMUM 1/4" thickness. I would try to shoot for 3/8" myself and if you are using a large sub shoot for 1/2" thickness. You need a uniform thickness as well so don't have it 1/8" at one spot and an inch in others. Once you reach the thickness you desire let the mess you've created cure overnight. Pic #3 is a great shot of what this step will look like.


Step 3


Once you've let it cure overnight it's time to pull it out of the vehicle. This should be easy as the aluminum foil will pull right away from the tape and also leave the back of the enclosure nice and smooth. If it's stuck pull carefully until it pops out. This is why all the prep work is the important step. Once you have it removed use a marker and draw the line where you want to cut the excess material off the enclosure. It is VERY helpful to have a saw zaw, an air saw or the very least a dremel with a carbide cutting disk. If you don't have this stuff***8230;go out and buy one of them QUICK (Pic #12). After you have cut off the excess use some sort of power sander with 36 grit (I like an air pressure based orbital sander to make quick work of the sanding) and clean up the edges by rounding them over. Slightly. Also, clean up an inch to two inches of the area near the edges with the sander to remove the waxy-like finish on the fiberglassed material. This will help the next portion of fiberglass bond well to the base. Clean up your enclosure at this point with some alcohol and water and a sponge. Some consider this excessive, but I like to remove as much dust as possible from the inside and clean up the soon to be bonded edges to increase strength even if it is a slight amount. If you are going to just use an MDF board for the rest of the enclosure go to step 4a, if you are going to use fiberglass go to step 4b.
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Last edited by Daishi00; 12-31-2006 at 09:40 PM.
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