# Typical cost for a fiberglass box?



## naiku (May 28, 2008)

Does anyone know what the typical cost is for a shop to build a custom fiberglass box? I don't need anything fancy, it will literally be a sealed box for a single 10" sub. This is to fit in behind the left trunk door in an A4 Avant. 

I am debating DIY, but have never used fiberglass, and am a little worried about getting it all over the trunk of my car. So trying to figure out an estimate of what it would cost to have a shop build one. 

Thanks.


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## cbrei1023 (Dec 2, 2008)

If you have a shop build it, you will get ripped off. It will look nice, but it will be grossly overpriced. I got quoted 800 for a pair of glassed kick panels from a local shop.


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## Oliver (Jun 25, 2007)

fiberglass subwoofer box, Electronics, eBay Motors items. Great deals on eBay!

Some on ebay [fiberglass subwoofer box]


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## TheDavel (Sep 8, 2006)

average costs should be between $250-$400 depending on finish... carpet/ vinyl ect...


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## Lanson (Jan 9, 2007)

I am actually building 3 sub boxes for fellow Ford Escape / Tribute owners on another forum. I'm charging $370 per. It is a simple, shallow-mount box made to fit a Stereo Integrity BMmkIII under the factory floor level. The materials alone have totaled about $120-150 per box, given the cost of fiberglass mat, quality resin, disposables like gloves, protective gear, carpet, speaker terminal, etc. The rest of the money is my time and tools.

And that seems more than fair, given it takes a whole weekend working very hard to produce a decent product. Not to mention there should be a price for being itchy for a day after you're done.


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## Lanson (Jan 9, 2007)

FYI, you won't get it on your car if you protect the car like you should. That shouldn't be an issue in your decision making. The incessant smell, the time involved, and the mess should definitely be in your decision making, however!


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## naiku (May 28, 2008)

fourthmeal said:


> FYI, you won't get it on your car if you protect the car like you should. That shouldn't be an issue in your decision making. The incessant smell, the time involved, and the mess should definitely be in your decision making, however!


Thanks, is plastic sheeting the best way to protect the car? I have seen people use blue painters tape, and plastic sheeting. Think I will try DIY and see what I can come up with, luckily since it will be behind the trim if it is not perfect it won't be such a big deal.


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## sqshoestring (Jun 19, 2007)

It is a whole lot easier to mold glass instead of shaping it, if you can make or find the shape you need.


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## tinctorus (Oct 5, 2009)

I generally charge people 300 PLUS supplies for a fiberglass box for a single subwoofer


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## naiku (May 28, 2008)

sqshoestring said:


> It is a whole lot easier to mold glass instead of shaping it, if you can make or find the shape you need.


I don't think it will be possible to find/make the shape I need. The space I am working with is almost pyramid shaped with the top cut off. As far as I can tell there is almost 1cf of space (from rough measurements) and I only need 0.5cf sealed. 

Just need to read a few DIY's, and then get on and give it a try really.


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## Oliver (Jun 25, 2007)

Line the space with tape,tinfoil,etc.., apply a release agent , wax, vaseline, something so the fiberglass doesn't stick to it.

Apply glass with resin ... let dry ... remove, add more layers until thick enough and strong enough with your mounting surface imbedded[ wood ring,etc.., ]


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## Lanson (Jan 9, 2007)

a$$hole said:


> Line the space with tape,tinfoil,etc.., apply a release agent , wax, vaseline, something so the fiberglass doesn't stick to it.
> 
> Apply glass with resin ... let dry ... remove, add more layers until thick enough and strong enough with your mounting surface imbedded[ wood ring,etc.., ]


THAT^


Btw, plastic sheeting is great to use, just make sure it is thick enough to avoid a mistake like a hole in the material by accident. 

If you want to do this yourself, go buy this:

lots of quality aluminum foil
lots of masking tape. Blue tape is fine too, but I find it doesn't stick as well.
some carnuba wax, I use my Meguiar's Quick Wax spray, then rub it down.
some chip brushes, 1", and maybe 1.5" or so. 
disposable latex gloves
fresh fiberglass resin. Avoid places that don't have product turnover for this stuff. A gallon is a start. It goes VERY fast. Make sure it has hardener with it.
Good fiberglass mat. If you aren't buying at a specialty store (boat stores come to mind), then you'll need a stack of those 8oz bags of chopped mat. But it DOES work.
mixing cups, 1 quart size. Make sure they are the kind in the paint isle at Home Depot or something, so they don't melt down w/ resin.
if in an enclosed area, a mask or respirator is smart. If working at funny angles, use goggles or eye protection of some sort so you don't flick resin into your eye. 
Keep some acetone on tap for cleanup
A permanent marker can trace a line pretty well through foil and tape, and then it will transfer when you fiberglass on top. Then you can use that line to cut the shape later.


Did I miss anything guys?


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## tinctorus (Oct 5, 2009)

fourthmeal said:


> THAT^
> 
> 
> Btw, plastic sheeting is great to use, just make sure it is thick enough to avoid a mistake like a hole in the material by accident.
> ...


But THAT takes all the fun out of the fumes buzz you get...LOL j/k of course, Or am I?? HAHA


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## nineball (Jan 17, 2008)

Fiberglass Forums - Powered by vBulletin

all of your questions, including the ones you don;t even know to ask yet, have already been answered there. you can also view literally thousands of build logs with step by step pics.


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## GlasSman (Nov 14, 2006)

naiku said:


> I don't think it will be possible to find/make the shape I need. The space I am working with is almost pyramid shaped with the top cut off. As far as I can tell there is almost 1cf of space (from rough measurements) and I only need 0.5cf sealed.
> 
> Just need to read a few DIY's, and then get on and give it a try really.


Well thats what the internet is for.....I can be objective.


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