Thread: Starting Fiberglass sub box!

it seems lowes has resin for 31$ a gallon and 9sq ft of matt for like 5-7$. I figure 1ft cube box is 6 sq ft so lets say I did 8 layers I would need 8 sq ft per side. which means I need 6 packages of the 9sq ft of mat. looks like everything I need cept for the material to stretch, I can find at lowes and there happens to be a jo ann fabrics across the street. Tomorrow I am getting up early and hitting up lowes to get the supplys and hopefully finish this project before it gets dark!

Yesterday I finally got around to getting all the things I needed to begin my fiberglass box. It decided to rain as soon as I got home so I had to wait till this morning to start it. It was a bit tricky at first but I think it turned out well so far. I have it about 50% complete right now and hope to finish it off tomorrow and bolt it in my car. Here are the pics from the work I did today.

My trunk before the fiberglass box, this is my 4-5 year old bandpass box which sounds nice but takes up half my trunk and slides around all the time.



Here are most of the materials I used. Resin, Fiberglass mat, some mixing stuff, blue tape, gloves etc.



The first thing I did was tape off the area to be fiberglassed



Then I put some tinfoil over the taped area (light portions on the blue tape) and proceded to cover the tape with apoxy and fiberglass. It was tricky at first and doing it inside the car didn't make it easier.



After about 2 hours it was completly cured and flexable enough for me to pop out of the trunk easily.



After it was out I began to layer more fiberglass and apoxy ontop of the first 2 layers. This is after 4 layers.



This shot is when I finished with the 7th layer. I also happened to run out of fiberglass so I guess 7 layers is good enough. The piece is much larger than it needs to be to account for weakness around the edges. Trimming the edges will make it look neater and it will be much stronger.



Before I cut the box I filled a 1'x1'x1' box with packing peanuts. My 10" sub needs 1' cubed amount of volume but it is really hard to measure the strange shape of the box. The solution is to create a box of known dimensions then pour the packing peanuts into the box. As you can see I have more than enough room which is great because I will be trimming off the edges.



I marked and cut the edges of the box so that they best fit the flow of the inside of the car and the volume I needed. The actual sub should not protrude much beyond the current width of the box. I can always cut more though if I need to. We will see how it all goes together tomorrow!

well i'm impressed if that is your first box! looks good and you work pretty fast.

Originally Posted by scott_fx

well i'm impressed if that is your first box! looks good and you work pretty fast.

Thanks guys. It is my first time working with fiberglass let alone making a sub box. I tried to make the second half today but it was raining all day! and I ran out of hot glue and fiberglass anyway so I had to hit up lowes again and restock.

I made the mounting ring out of mdf board after stopping at both a car audio store and a lumber store to have someone else make me one. The car audio store wanted 50-90$ for the ring and were just going to cut it with a saber saw. the lumber store wanted me to wait a few days and didnt know the price. So I bought some mdf from the lumber store and took a wack at it my self. The ring came out ok due to my 20 year old jig saw I am using but hey it will work well enough once I get it coated with fiberglass.

So I made the whole tripod setup with the ring and some dowels and hot glue. It was a lot harder than I thought it would be but it got done. I put it in my car to test fit it. Good thing I did because the trunk arm hits it or comes really close to hitting it when I close the trunk. I may need to trim more off of the top and left side of the box so that it will clear the trunk arm. The ring will be mounted in the lower right corner and away from the box just enough to create a gental curve to give strength.

I am going to have to play with it tomorrow to get it to look good and fit nicely in the trunk but once it does I should have no problem laying down the remaining fiberglass and finishing up the box just in time for a huge outdoor party tomorrow night. The perfect place to show off my ride and new system!

Very nice job on your box! Well done! That is a lot of work.

I thought you might enjoy seeing some pics of the box I just finished for my Dodge Ram. I have one 12" sub on the passenger's side and on the driver's side I built a locking storage compartment. I coated the storage area with herculiner, which is a bedliner like Rhino lining. The photo shows it being pretty dusty but I have since cleaned it up and its a nice, shiny, black now. The idea behind the herculiner is that I can toss my ball hitch in there and it will hold up to the abuse.

ok so I have trimmed my box more around the edges to make sure it clears the trunk arm. I then took my mdf ring that I made yesterday and remounted it and stretched some dark cotton/polester fabric over the whole thing and glued it down. I then coated it in apoxy and waited for it to harden.

After that I put down 2 layers of fiberglass then waited for that to harden

I just finished putting down a second 2 layers of fiberglass now and its looking pretty sweet.

I do have a ? though. I did 7 layers on the first half of the box and I currently have 4 layers on the front half. How many layers should I do on this top half?

i think general rule of thumb is that you should be able to stand on the piece with out breaking it. I would at least put a couple more layers on to avoid having it sound 'loose'