Fiberglassing Trunk??

So you want to venture into the world of fiberglass molding.  First of all, let me suggest that you talk to a professional installer in your area.  Most good ones will be willing to take five minutes (but don't expect much more) to look at the vehicle with you and give opinions, advice, etc.  Based on the questions that you are asking, I'm guessing that you probably do not have a lot of experience with this type of install, and if the installer can't talk you out of it, at least maybe he can point you in the right direction.  Personally I would absolutely recommend AGAINST you taking this on at your current experience level.  However, with that said...

1.  Sound deadening and lots of it...  Dynamat extreme (foil covered stuff) works wonders.  If you want to go with a spray-in deadener, more power to ya.  Look at SelectProducts.com for sound deading tips & tricks.  Don't even think about wasting time with fiberglass or building until this is done or you will be very unhappy with your results.

2. Measure, measure, measure and measure some more.  When you're done compare with the manufacturer's specs for subwoofer airspace and the dimensions of the amps.  Now measure some more.  A little hard thought here will save you hours of wasted work.  (I recommend sealed encloures only for this type of work.  A ported enclosure is simply too hard to build accurately with this type of construction, unless you really know what you're doing.)

3.  Build your basic frame out of wood.  (Amp rack, Subwoofer mounting rings, etc.)  Use a basic frame to give yourself an idea of positioning.  You NEVER, EVER have as much space to work with as you think, so build the frame in the trunk to see how everything fits.  Use wood to stilt your mounting rings in place.  Wood should form the floor of your enclosure if possible, unless you are using the spare tire well for the sub.  Also, incorporate as much heavy MDF into the walls (back, sides) as possible.  The more dense the construction is, the higher its rigidity, hence better damping and a better sounding enclosure.  Leave channels in the frame for wires to run through.

4.  Glass work.  Mold the backside into the contours of the trunk and stretch the cloth for the part that shows.  Make sure to layer it up thick once you've got the basic shape..  If you need more info than this for fiberglass molding, don't do it.

5.  Finish work.  Sand, starting with 60 grit to get rid of the big nasty stuff, and work your way down to 600 grit.  Use body filler to fill small imperfections.  Do NOT try to use it to thicken up your fiberglass for strength... it won't work that way.  Paint, vinyl, Carpet, whatever you like to heart's desire.

This is a big project.  It would require MANY work hours for even the best professionals.  If not done right, it can come out looking bad, or worse (and more likely) sounding awful and either way making your friend upset with you.  Before investing all the time and money in this, ask yourself if you are really ready for this type of project.  Try a practice encloure outside of the vehicle just to get the hang of it.  And remember, there's no shame in admitting to your friend that this type of project is beyond your CURRENT skill level.  There's a reason professionals get paid what they do for custom fiberglass work.  Who knows, maybe you could find a shop that would do the work at a reasonable price and allow you to spend some time watching and observing the work in progress so that you could develop your installation skills for future projects. 

Whatever you decide to do, good luck and godspeed

TT_Raider

Well bub....Welcome to the world of 'Glassin'

Like TT_Raider said...Talk to installers,  preferrably ones that have done projects like Trunks before.  most will be willing to take the time and talk to you about this stuff, heck you might even be able to find one to teach you how to 'glass...dont' hold your breath on that....I know I've done it a few times....but not every installer is like me....

Also, if you haven't ever done a 'glass project before...take time to do a lot of research, and mess around with small stuff like door build-outs, kicks, a-pillars, etc.  Before taking on a trunk.  Also be sure your buddy knows...it's gonna take a few days atleast...before he'll have his car back.  or atleast 24 hours, if you intend on having the enclosure be able to come out of the trunk. 

Sound deaden the trunk.....

Make a framework......check for clearance of all moving parts in the trunk...make sure there is access to such things as fuel shut-off, etc...remember on frameworks you can use, MDF, Masonite, Footing tubes ( the cardboard rolls you get at like home Depot for putting footings in the ground ).  And Remember MEASURE like your life depends on it, and also double check, than triple check, that quadruple check.  roughly estimate the enclosure dimensions to make sure you are within spec. 

Also make sure you use some type of mold release agent.  so the enclosure can come out at sometime.

use as much MDF as you can....leave channels to run your wires....  if you can't use a lot of MDF...remember you'll have to use a lot more mat and resin to strengthen  the enclosure.   Once you think you got it all....start matting and resining....( follow the instructions exactly when it comes to mixing Resin )....Use Latex Gloves, disposable brushes and mixing containers.  ALSO you might wanna wear a respirator..the fumes, smell bad, and prolonged exposure..has some really nasty side effects.  if you don't have one...buy atleast those cheapo dust masks, and do it outside, or in a well ventilated area....like a tent with the sides up...also when sanding the enclosure...wear the dust masks, at the very least, and in a well ventilated area.

A few tips when it comes to the first coat of glass....if you have a lot of curves in the design...you can always use Nylon or fleece for the first initial coat to get the shape.and the curves. 

When you sand....and you get little bumps....throw a thin layer of Bondo over it, to fill it in....do not use more resin....you could end up makin the glass sag. 

Like Raider said.....there's a reason shops and installers make a lotta $$$$$ for fiberglass work...it takes a lot of time, a lot of patience, a lot of time ( i know I said it twice ), it's a danger to your health.  not trying to discourage you man....just want you to know what you're getting into....

Goodluck