Fiberglass introduction

[fbi90909 5,000+ posts]

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 10+ year member]

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?

 

[terra 5,000+ posts]

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 10+ year member]

got ya. Ill throw something together and see if you like it

 

[dannyz122001 10+ year member]

how big are the demensions of the reccessed area? is that where your looking to put it?

 

[terra 5,000+ posts]

ya. not sure of the dimensions. i wouldnt go above 17 tall and 30 wide.

 

[dannyz122001 10+ year member]

you're looking to do 15's right?

 

[dannyz122001 10+ year member]

my bad, i just saw you said 12's. sorry

 

[terra 5,000+ posts]

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.

 

[terra 5,000+ posts]

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?

 

[terra 5,000+ posts]

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 5,000+ posts]

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

 

[terra 5,000+ posts]

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 10+ year member]

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)?

 

[terra 5,000+ posts]

what do i do for paint? after bondo ill do primer obviously but what are some good paints over that? automotive?