Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - fiberglass door panels, dash, center console, sub enclosure, amp rack
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Old 08-04-2007, 10:57 PM
splitsurferjeff splitsurferjeff is offline
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Helpful Hints/tips/walkthrough For Custom Glasswork

Okay, there's some stuff i kinda want to bring up about some of this advice. I haven't fiberglassed a whole lot of car stuff, and I've never done anything that needed to be brought to a sandable paintable finish, however....I do shape a lot of surfboards and do a lot of board repairs, and this idea of just soaking fleece with resin doesn't sound sufficient. RESIN IS WEAK. All of the strength comes from the resin hardening into the hollow fiberglass filaments and keeping them rigid. That being said, fiberglass is prettttttty weak in a straight line, its gets much more strength from geometric shapes where there are angles of pressure balancing each other out. Case in point, on a surfboard the deck will crush after prolonged use, but the rails of the board which are rounded hardly ever get dings or dents. What I would suggest that you do if you're planning on such extensive glasswork is to find an online wholesaler and buy some light to medium weight chopped fiberglass mat. Also buy SEVERAL gallons of polyester resin and catalyst. By several I'm gonna say you probably need north of 10 gallons for your sub box center console and dashboard. As far as retaining stock mounting points you really just need to accurately measure where your mounting points are and make flanges which you can then drill holes through to mount your pieces. Now, as for fabrication: Use masking tape and cover your entire dash and center console areas and your sub box area where they will be against the floor/firewall/whatever . Use A LOT of masking tape then cover with Tin Foil (for a release agent)so you don't leak resin all over your car. Then tear, not cut pieces of glass mat off and soak them in resin and fit into place. Do this for a couple of layers 'til your pieces are nice and thick and have no air bubbles in them. Let them dry and then remove them from the car. Keep adding layers two at a time until there is enough glass to keep the structure rigid. This is especially important for the sub box since it's going to have speakers causing heavy vibration in it. This is when you use the fleece and resin. Stretch fleece over your glass using wooden dowels glued with a hot melt glue gun to create the nice sweeping curves wherever you need them for your pieces. At this point you should have a glass shell for a backing with fleece stretched over what will be the visible parts (if that makes sense...hard to explain without a picture). This is when you soak the fleece completely and then use the same process of dabbing glass mat into place. Make sure there are no air bubbles and that all the fleece is saturated. Let that dry to rigid then repeat the steps of adding more layers until you are confident that your pieces are thick enough to not crack. This is probably a good time to check if your flanges that you've fabbed are thick enough before bondo-ing. Then you can take regular ol' bondo and fill in everthing until sandable and finally sand down with fine grit sand paper until smooth. Then prime and paint. For the sub box you need speaker rings of some MDF board to make your own. Your best bet if it's an under the seat box is actually an MDF (medium density fiberboard) box with a fiberglass back/bottom. If you want to do full fiberglass it's going to be the same as the dash/console only you're going to use a jig saw to cut rings the minimum diameter of your basket clearance (inside of ring measurement) +1" (outside of ring) and "float them from the fiberglass shell using wooden dowels then stretch the fleece over and do the same glassing technique then using a saw to cut out the speaker hole. If you want a flush mounted speaker you need to make a second speaker ring out of MDF the size of the speaker (full mount area) on the inside +1" for the outside measurement. Then glue the two together with woodglue so that when you sit the speaker in the rings that fabric will be bonded to the larger ring with the speaker sitting on the recessed ring thus making it flush with the outside of the box. If you go for MDF enclosures with the glass back just resin the glass back to the side pieces of of your fabbed box and for top mount speaker holes just cut to the min basket clearance. If you want flush mounts cut holes the size of the speaker in the top piece of the box and mount the smaller ring on the back of the "lid". Make sure to use a good sealing caulk on all seams and wood glue and finish nail/screw the MDF together to keep it air tight. Also keep in mind that you need to either run the wire through the box somewhere which needs to be caulked air tight or you need to install a lead plate on the box somewhere which needs to be screwed and caulked. As far as displacement testing a very easy method is to use packing peanuts or even sand if you cant find any...frozen peas really (peanuts are just the least messy and most convienent) and use a 1cf box and just fill it up and dump it in to your box to check if your box has the desired volume. I would suggest carpeting an under the seat box as little or none of it is going to be showing so paint is just wasted time and effort. For a really professional stealth install go to the salvage yard and rip the carpet out of your same make and model vehicle that way when you carpet your box it will match your OEM carpet exactly. Sorry for the HUGE post but I had to search EVERYWHERE for good info for my projects just thought I'd share.

Creativity, design talent and just TAKING YOUR TIME AND THINKING IT THROUGH will really help you with this project.
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