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Random1010
02-13-2008, 01:44 AM
Ive been inspired to try making a fiberglass box. so im making one around 2.5 cu ft at 32hz. i just wanted to make sure im set before i start buying and constructing.
so 1. i need fiberglass mat which is the actual fabric of the fiberglass construct?
2. Resin and hardener? mix the 2 like in bondo and paint it onto the mat until clear to form a hard surface. 3. whats a good material for stretching over the frame?
4. whats the best way to make the cutouts? i have no access to a router for 2 weeks so could a compass and a steady jigsaw hand make do?

and lastly does anyone have any really creative ideas in terms of design? im struggling.

thanks

fo0manchu
02-13-2008, 02:11 AM
1. yes you'll need fiberglass mat
2. yes get resin and hardener and mix as per instructions. I suggest doing like half a quart mixing at a time until you get used to the kicking times. If you mix a lot at once you might use half of it before the rest hardens up. Apply with a brush, brush resin on surface first then tear up the mat and put it on and apply more resin.
3. Fleece is good to stretch over the frame, held on by staples or glue gun.
4. Best way is a router with a some kind of jig. But jig saw will do if you have a steady hand.

as for designs, look some pictures up on google or around the forums. good luck!

Random1010
02-13-2008, 02:35 AM
1. yes you'll need fiberglass mat
2. yes get resin and hardener and mix as per instructions. I suggest doing like half a quart mixing at a time until you get used to the kicking times. If you mix a lot at once you might use half of it before the rest hardens up. Apply with a brush, brush resin on surface first then tear up the mat and put it on and apply more resin.
3. Fleece is good to stretch over the frame, held on by staples or glue gun.
4. Best way is a router with a some kind of jig. But jig saw will do if you have a steady hand.

as for designs, look some pictures up on google or around the forums. good luck!

thanks man! only thing is..when i think of fleece i think of north face jackets, which arent stretchy. can anyone link me to an example?

mrbomb
02-13-2008, 11:35 PM
something like this

http://www.joann.com/joann/catalog.jsp?CATID=cat3098&PRODID=prd18849#select

Random1010
02-13-2008, 11:36 PM
thanks. now im just trying to decide how i want it setup.

mrbomb
02-13-2008, 11:38 PM
whats it going in?

Random1010
02-13-2008, 11:39 PM
1999 bmw 740i
i would do 2 12"s ported facing back but i really hate trunk rattle so i was thinking of doing 2 facing the seats with the ports in the middle facing the ski hatch..
any input?

mrbomb
02-13-2008, 11:44 PM
get a pic up of the trunk where its going so we can get a better idea of what your working with

Random1010
02-13-2008, 11:49 PM
unfortunately i dont have my digital working. its your standard big trunk car. nothing special. i need 4 cu ft net at 31hz. however i cant decide how to face it and any design i want.

mrbomb
02-13-2008, 11:53 PM
would you want it to be an amp rack also?
with some nice curvy lines? painted? maybe some lighting?

Random1010
02-13-2008, 11:55 PM
ya its gonna be as wide as the trunk is and have the 2 subs on the sides and the amp in between. curvy yes and painted. however if i face the seats i lose the aesthetic appeal. and i cant think of anything nice to do on the trunk side that would look good. so im torn.

dannyz122001
02-14-2008, 12:03 AM
are you willing to sacrifice sufficient trunk space or do you still want it to be functional?

dannyz122001
02-14-2008, 12:04 AM
I have a good idea of a setup I did in my old mustang I always recieved compliments from my buddies on how clean looking the set up was.

Random1010
02-14-2008, 12:05 AM
well its a big trunk so 4 cu ft shouldnt take up more than half. i want to be able to throw stuff in there but just like a backpack or a keg. im down to do something creative if i have suggestions though/.

dannyz122001
02-14-2008, 12:10 AM
the design Im thinking of kinda limits some areas. You could fit a bookbag and all, but im not so sure about a keg. I was kinda thinking about doing 2 seperate boxes, on the left and right sides of the trunk (where I think BMW has small storage slots) and then an amp rack set back into the trunk (near the back of the seats). You wont be able to fit anything huge, but should still have access to the spare tire and all of that. It would look pretty **** good, show off your work and all while still maximizing the given area. Throw in a few neon strips and your good to go.I s it convertible or sedan?

fbi90909
02-14-2008, 12:11 AM
get LOTS of gloves, get a respirator, and get eye protection. safety first!
w/e you do do not buy bondo resin.
get Chop mat. 1-2oz.
get lots of 2" cheap paint brushes.
get painters tape
get mixing cups or cups to use while working with the resin
use a spandex like fleece for a stretching material. or polar fleece. the fleeces are thin which when properly stretched can save you on resin when soaking the material. using a thick fleece will eat up resin like a mofo.(plus the fleece has basically no strenght for the enclosure)
get some sissors, a hot glue gun, a staple gun.
lots of sandpaper. get some really rough grit so that in between layers you can quickly sand down sticking/standing hairs
do not paint on the resin. you should stab it in. when you mix up a batch of resin just take a 2" paint brush and dip it 1/4" deep into the resin. with your chop mat in place just stab it into the mat. you do not need a thick layer of resin, as long as the fiberglass is wet it will be fine.
do 2 layers of glass at a time. allow for the resin to sit for an hour or 2 to harden up and begin on another 2 layers.

glassing is easy man. the key is patience. take your time. read up on how to and get all your materials cause if not you'll be running around looking for supplies while in the middle of glassing liek i did. :/

dannyz122001
02-14-2008, 12:13 AM
i'll try to throw a sketch together from my girlfriend's beemer and send it over to you to see what ya think. what amp and subs are you using? and do you have an amp for mids?

Random1010
02-14-2008, 12:14 AM
the design Im thinking of kinda limits some areas. You could fit a bookbag and all, but im not so sure about a keg. I was kinda thinking about doing 2 seperate boxes, on the left and right sides of the trunk (where I think BMW has small storage slots) and then an amp rack set back into the trunk (near the back of the seats). You wont be able to fit anything huge, but should still have access to the spare tire and all of that. It would look pretty **** good, show off your work and all while still maximizing the given area. Throw in a few neon strips and your good to go.I s it convertible or sedan?

its a sedan. as far as i know they never made 7 series convertibles. anyways i want 1 box for simplicity and time. im on a schedule and want to make it as easy as posible while looking nice

dannyz122001
02-14-2008, 12:15 AM
got ya. Ill throw something together and see if you like it

dannyz122001
02-14-2008, 12:16 AM
how big are the demensions of the reccessed area? is that where your looking to put it?

Random1010
02-14-2008, 12:30 AM
ya. not sure of the dimensions. i wouldnt go above 17 tall and 30 wide.

dannyz122001
02-14-2008, 12:38 AM
you're looking to do 15's right?

dannyz122001
02-14-2008, 12:39 AM
my bad, i just saw you said 12's. sorry

Random1010
02-14-2008, 12:41 AM
mmhmm..if i do subs facing the trunk ill do a mdf frame/box for 3 sides and just make the front(side that actually shows) out of crazy glass. but if i face them towards the seats im not sure how id do it but id prefer this option.

Random1010
02-14-2008, 01:01 AM
ideally id like both the subs pointed at the ski hatch with the ports out the back and the amp mounted on back. u designing something?

Random1010
02-14-2008, 08:45 PM
how do i figure out volume of a design before i actually build? there are way too many curves and angles for me to figure it out. or how would i figure it out after i build?

fbi90909
02-15-2008, 12:14 AM
basically since you plan on doing a 5 sided box with a face of FG you would want to calculate it as a normal 6 sided box. when you get your dimensions you will have a set air space that you know will be in the box. by removing the baffle and fiberglassing it you will most likely have the subs being pulled out of the face to give the enclosure some curves which will add a little more air space to the enclosure.
well.. after you have the face of the enclosure fiberglassed solid take some cardboard and line it up onto the position where the baffle should have been to separate the set air space you already calculated and leave you with the front air space. like making a paper wall. well after you have the 2 air spaces separated take some of those mini foam pellets found in bean bags and fill up the front portion of the enclosure(the new air space). when filled find a 12x12x12 cardboard box which is 1cuft air space and dump the foam pellets fromt he air space into the box. mark your line of where the foam settled inside the box and then measure up the air space it's taking in that 1cuft box.
when you add the new air space to the existing air space you will get a pretty close estimation as to where the air space of the entire enclosure is w/o counting displacement.
now, if you over shoot your air space goals just take slabs of MDF, measure the pieces to calculate how much air space the slab is taking up and just place them on the walls of the enclosure or where ever.
I'd recommend you build the port last or use aero ports for your enclosure. cause with aero ports you will be able to adjust the port even after the box is complete with the estimated air space of the enclosure.
i hope i didn't confuse you. lol

Random1010
02-16-2008, 10:18 PM
nah i got you. now im waiting on a couple things. if i sell my car im doing 1 12" in a fb box. if i keep my car im doing 3 18"s in a sealed fb box.

banhammer
02-18-2008, 05:54 PM
my options for brands of resin, hardner, and fb mat are bondo brand or Elmers. which should i go with? also do i want fiberglass cloth(looks like clear carbon fiber weave) or fb mat(sheet of stringy fb)?

Random1010
02-27-2008, 07:38 PM
what do i do for paint? after bondo ill do primer obviously but what are some good paints over that? automotive?