Rep Power: 275

i have two 12 innh alpine type s in a q logic box. box is supper heavey.. i want to do fiberglass. i herd it was easy to do just make a mold and yeh.. any one know how or have instructions..??

 
Rep Power: 338

its easy. the basics are:

mask off the work area. the actuall layup location will have to be tight against the part of the car you are moulding. tape and aluminum foil work best here. its allso a good idea to mask off the entire area you are working on. keeps you from getting drips on your bumper. plastic drop cloths used for painting are great for this.

I like to use a wood frame for the top of the mold. this gives me a solid and flat surface to attach a baffle to. This also allows me to take the top off and put a different baffe on if I change subwoofers, want to retune, etc. this frame doesnt have to be larger than the spare tire well opening, but it helps.

after that its glass, glass, glass! the idea is you impregnate the glass matting with the resin (the resin has to actually get in between the fibers, like working shampoo into your hair), then lay it down onto your surface. I like using 2 inch squares of matting (give or take) because it conforms to corners easily.

once the fibers are impregnated, all teh strength comes form fiber. so the key is to use as litte resin in the car as possible after the fact. the greater the fiber:resin ratio is, the stronger (and lighter!) the box is.

make sure that the fiberglass gets well laminated onto your wood frame, its going to be a permanent part of the box!

I like ot do all my layups at once. just layers on layers on layers, till its built up to my desired thickness. Even when the first layer is still wet and curing, ill lay the second layer on top. then the third. This saves me time and air bubbles. the finished surface is going to be very rough, so doing multiple layups at once allows the fibers to be squashed between layers. just makes everything stronger more easily.

once it all cures, youl have your shell you can pull out and clean up. you can now leak check it with water, measure its volume, and construct the baffle.

if you want to lay up glass on a wall (like for kickpanels or for subwoofer enclosures that are moulded to your sidepanels), I find that doing the layups all at once leads to glass slippage while drying. just too much weight for hte sides.

so I like to use glass CLOTH to do the very first layup. it holds its shape very well, doesnt slip down walls when wetted out. I let that cure completely.
Then before I take it out of the car, I lay up all my bulk filler on top of that. it gives me a good surface to get the glass matting to adhere to. Works great.

then I can pull the mold out of the car and clean it up.

 
Rep Power: 275

im so lost!!1 ehhe sorry any pics or english for us dumb people...fiberglassing for dumbys!! haha

 
Rep Power: 338

fiberglass is a composite material:

there are two components. fiberglass cloth, and fiberglass resin. the cloth is literally fibers of glass (glass like your windows!) woven into a cloth. there are several types of cloth. "cloth" usually refers to a weave, just like your t-shirt, your bed sheets, your draperies, etc. "matting" refers to a non-directional chopped mat that is unmistakable when you see it. it'll look, well, non directional! regardless of the type of glass, its going to be a series of small fibers closely packed together.

the resin is just a two part thermoset polymer (thats fancy words for its a liquid hardening plastic, just like superglue!).

the way fiberglass works is by impregnating all those fibers with the resin. the resin seeps into the cloth, and takes up all teh sapce between fibers. then it solidifies, and your composite material is VERY, VERY strong.

Now all we need is a way to actually USE it in the car! and for those directions, you can see my first post. keeping this post in mind, why we do some of the things I recommend in the first post make more sense.

 
Rep Power: 275

ok so where do i get the supplys from?? i need the liquid hardening and just fiber cloth orwhat?

 
Rep Power: 338

home depot will have everything in the paint department, the aisle with the glue. you can get bags of matting or bags of woven cloth in quantities of one square yard a bag, and quarts or gallons of resin.

 
Rep Power: 329

Or you can go to www.selectproducts.com and buy from them (their surfboard resin is the *****, as it's clear) And don't expect too much out of your first attempt. Glassing techinques come from experiance. So the more you do the better you'll get at it. You'll get better at figuring your MEKP (hardener) to resin ration to give you the desired cure time for workability, etc. I'd also like to recommend, as rabbit suggested, to use cloth for your first layer, as you can stretch it as tight as you want and staple it in place. I prefer to go to a fabric store and buy fleece (you can usually find decent sized pieces in the remnant bins for a fraction of the cost). It'll hold a lot of resin and will give you a good solid layer to build upon, as opposed to a t-shirt type material that will eb a thin layer and could sag a bit when you pour the resin to it. If you're using fleece, make sure to pour the resin as opposed to brushing it on, as it'll be both faster and will permeate the fleece much better, and more efficiently. Another thing, when rabbit says tape and use aluminum foil, I'd like to add the best method, especially if you're going in the spare tire well, is to tape everything off, carpet removed, and go outside the area you intend to glass. From there you'll want to use spray glue and spray the tape down with it, then lay the foil on top of it, this will keep the foil in place, and you can roll it down(wallpaper roller) on there to eliminate bumps and imperfections. Then lay up the glass/fleece. You want to use tape and foil as this will make the mold easy to release so you can take the piece(s) out of the car to work on them (once cured). 40 grit sand paper is your friend, buy plenty of it for your sander (or elbow grease). Also, filler is meant to smooth imperfections, not to build up thickness. Strength will come from the fiberglass mat, not resin or filler (bondo). If it's a sub box, I'd recommend going with the thickest mat you can find (builds up quicker) and lay several layers. For 12's, you'll want at least 1/2 inch of thickness, though more is better. More glass mat, not resin.

 
Rep Power: 250

actually fiberglass isnt any lighter than wood.. and in some cases heavier due to the number of layers you have to put in to make sure that it does not flex. fiberglass does save space though depending on the design. or you can make it do some cool stuff if you know how. but prepared to do a shitload of sanding. you will be sanding for hours... your hands will hurt... even with gloves.

 
Rep Power: 338

what I like about surfboard resin are its "thixotropic" properties. what that means is a a resistance to movement, but flows easily when at rest.

(it doesnt make sense, but you can play with the "material property" (so to speak) by mixing cornstarch and water to a paste, then try playing with it like playdough)

Its probably second rung above the bottom of the totem pole for cheap resin, but the workability is far superior to bondo brand resin for that reason. I swear by surfboard resin whenever possible.