I've done about 30 of these corner fiberglass boxes. Actually I just did an Audi A4 exactly like that last week haha. I should have shot some photos. For something simple I would prolly charge around 250 for a carpet/vinyl covered box. A color-matched paint job would cost more since it adds much more labor for the bondo/sanding/bondo/sanding/bondo....
I can write up a little how-to for fiberglassing and you can read over it and see if its something you can tackle:
Tools:
These tools are not really listed anywhere, but have provided me a great deal of help. I recommend everyone of them.
Methyl Ethyl Ketone Peroxyide - (diluter for resin - only thing i've found that will remove uncured resin from tools and such)
Bubble Buster - 2" or 4" roller with knobs on it for busting up bubbles in the mat. (bubbles create weakness)
Corner Roller - For getting into corners and working the mat around
TAPE! - tape is your best friend.
Plastic! - Gotta cover anything not to be glassed!
Jasper Jig - For cutting circles with plunge routers (do a search, cheapest i've found it is at Partsexpress.com)
Cabosil filler or Microbeads - filler for polyester resins to thickin the mixture for doing verticle or inclined surfaces. (works amazing! You can create a resin paste if you want)
Dremel Tool - using a general bit, for cutting off extra glass.
Grinder - MUST HAVE
Wood Dowels - For ring mounting 3/8"-1/2" works best
Hot Glue - Sticks to fiberglass VERY well and holds fantastic plus it drys fast.
Fabric - This has been debated many times with some other people who work with fiberglass, alot think that fleece is the best, others think that grill cloth is the best. I however went to my local fabric store and picked out a thin spandexish type material, its poreus and when you stretch it far enough you can pretty much see through it. The key to this fabric is stretchy! The stretchier the better.
Fabrics Cont. - So with fabrics, the general procedure is to saturate the grillcloth or fleece completely with just resin before laying any mat. This works ok but wastes a horrible amount of resin and time. If you use the spandex type material you can stretch it extremely tight and then lay your first layer of mat directly on it! It works incredible and saves SOO much time.
Spray Adhesive - For carpeting if applicable
Body Filler - For getting finished product smooth
Spreaders - for spreading body filler
Sand Paper - 40grit, 80grit, 200grit
Cheese Grater - for cutting down body filler (found at automotive/paint supply stores, actually called a cheese grater)
Sanding Block - For getting it straight
Mold Release - Optional to make removing molded trunk piece easier and cleaner
Rubber Gloves - MUST HAVE!
GoJo - excellent for cleaning sticky hands.
Breathing Masks - A MUST have unless you like breathing fiberglass and body filler dust.
Safety Goggles - Dont grind without them!
Thats it for the tools off the top of my head, if I think of more, I will add them.
The Procedure
1. Remove any loose articles from the vehicle
2. Determine area to be fiberglassed
3. Cover exterior of vehicle, all paint, anywhere that could be wrecked.
4. Lay plastic down on hatch areas not to be glassed, or tape them off
5. Cover entire area looking to glass with tape (if your doing a side enclosure like the ones I built, cover the entire carpet trim piece with tape. EVERY single Square inch, wrap the sides, and about 2" on the back side just to be safe)
6. Use Tinfoil to cover the tape, use larger pieces taping the edges down so no resin will leak through to your "protective" tape barrier.
7. Double check to make sure nothing is uncovered that you do not want glassed
8. Mix your resin (remember more hardner if its cold outside, less if its hot. Too much hardener you'll get extremely hot resin and it will be brittle, not enough hardner and it will never cure completely)
9. Using sheets of Mat about 5" by 5" or larger depending on your level of comfortability start laying them down. Key in this portion is to overlap the pieces by 1/2" to 1" making sure there are no bubbles! Continue this untill entire area is covered. Make sure you go further past the area to be glassed so you can ensure a proper thickness, its easier to cut glass off then to add it on. (if you have trouble getting the mat to stick to the verticle surfaces, use a filler as described in the tools, it will help alot, espeicially if your resin is really runny). Depending on the type of mat (thickness, qaulity etc) repeat this step as nessessary untill you build up a 1/4" - 3/8" thick base. Let Dry untill you can touch it without leaving a fingerprint or having it sticky.
10. Pull the piece you have just created out of the vehicle, using a grinder, grind off any of the mat hairs sticking up and any overhanging sharp pieces or points.
11. Place the piece back into the vehicle and using a sharpie marker, mark on the fiberglass where you should cut it to size. (for the tiburon I usually use the line in the bottom carpet base where the spare tire cover sits, so you can still remove the spare tire cover without removing the enclosure).
12. Using a dremel tool, or grinder, whichever you feel more comfortable with, cut along the line you just drew.
13. Test fit the piece again and make sure it fits what your trying to accomplish
14. Take the piece back out and cut your ring out of MDF board using the Jasper Jig and a plunge router (If you dont have access to a router and jig, use a jigsaw, but I can't guarantee a good sub fittment)
15. Using the wood dowels cut accordingy and hotglue, mount the ring to the fiberglass piece in the finished postion you would like. (keep in mind the dimensions of your subwoofer to allow adequate clearance) Place a bunch of these dowels holding the ring to the enclosure, you should have enough attatched to be able to pick up the entire peice by the ring without budging the ring, then you know its strong enough. (Do not place the dowels too far out where they will cause trouble with the fabric going to be stretched) Test Fit in the vehicle to ensure clearance from hatch etc.
16. This is the tricky part Stretching the fabric, The fabric cannot extend over the edges of the enclosure, you must leave 1/4"-1/2" of exposed glass in order for the front layer to create a good seal. (leaking air sucks) Also, you cannot cover the front face of the ring with the fabric, hotglue the fabric to 1/4 of the ring again leaving 1/4" exposed on the front (face) side of the ring, then attach the fabric to the outside portion. Complete the next 1/4 of the ring and repeat till finished. You will end up with a whole lot of extra material bunched up in a certain position on the enclosure, this is ok, just cut and hotglue seam it together.
17. TAPE off the outer face of the ring right to the edge. (this is to protect the ring from any stray fiberglass or resin, its very important to keep this area flat or the sub will not seal)
18. Glass the front of the enclosure with the same procedure as the first glassing you did. As you get better at it, use larger pieces and don't overlap them, just butt them against eachother and just be sure to seam the next layer over the seam of the first to create the best seal as possible. Repeat untill roughly 1/4" - 3/8" thick. Dont be afraid to overhang the glass over the edges of the enclosure, you can always cut it off.
19. After letting dry, grind off any over hanging pieces, or hairs, grind off any large "bumps" in the surface that may make smoothing a challenge later.
20. Test Fit the enclosure to ensure everything fits ok.
21. Get out the Body filler, using a spreader, apply generously on the entire enclosure (besides the face of the ring! which still should be taped). You will be able to visually see and "ups and downs" in the face of the enclosure.
22. When you get the body filler spread and its halfway hardened, use the cheese grater to remove any high spots that would cause headaches for sanding. (TIP: Cheese grater works great for making a surface straight also)
23. Sand with 40grit sandpaper on a sanding block (ALWAYS use the block unless in really tight quarters) changing directions often. This will ensure a straight finish.
TIP: There is a huge difference between SMOOTH and STRAIGHT surfaces, it may feel smooth, but its not straight, use a bare hand and run your fingers across the surface, feel those slight ups and downs? ya, fill those in/sand them out or it will stick out like a sore thumb if painted (if not painted, dont be so anal about it)
24. Continue laying layers of Body filler on the surface untill every area is to your standards.. or DAMN straight if you ask me
25. Drill a hole, wire the enclosure and caulk the hole with liquid nails, or cut a terminal to fit if applicable - Let dry overnight
25. Test Fit the enclosure
26. Remove the tape from the ring
27. Use spray adhesive and carpet the enclosure, or continue on to paint.
28. Mount and wire sub
29. install into the vehicle using Velcro on the factory carpet. (only use the grippy side, it grabs the stock carpet VERY well, I've autoX'ed with my enclosures in, no probs.)
30. Crack a beer and Enjoy!
This is my own general procedure for creating an enclosure, you may change/add/remove steps as you need. This is a very good general idea on how to create a enclosure yourself. If you have any questions feel free to send me a PM and I will happily respond.
I spent about 20 minutes typing this up, so I probably left something out. Ask if theres anything that confuses you.
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