Custom Sub box for a Saab 9-5 Aero Wagon

[frestylmotox01]

So I installed my Avic X-920 in to my aero wagon about a week ago, since I bought the wagon about a month ago I knew that I wanted to install my whole setup in there which consisted of the head unit and the amp and single 10 inch sub. The thing is I hate having a box in the rear taking up space. In my previous vehicle (GMC Envoy) I had a stealth box that fit in neatly and didn’t take up much space. Problem is that no one makes one for a saab, of course. I wanted the sub because it was lacking bass, but I didn’t want to pay a shop around 600-1000 I was quoted. So using all of the internet resources I could find, I took it in to my own hands and decided to build my own.

I started by deciding that I wanted to use fiberglass vs MDF because I could make more use of the space and it would fit in better. I researched for a few days on fiber glassing and read till I could read no more. There is a lot of conflicting information out there as to what is better and what you should use (Cloth vs Mat, resin to hardener info, Etc.). I wish I had more pictures but once you get rolling it is hard to stop and photograph things especially when you are wearing gloves and a mask .

First I started by removing the stock unit, then I cut a cardboard template, then taped off the whole area, applied the fiberglass resin and matting. At this point after the first two layers I had actually abandoned the project because it looked so bad and I thought that I really messed up. But a week later I pulled it out of the trash and decided it wasn’t worth throwing away since I had so much money into materials already. I found that I had a lot of air pockets and pieces of mat sticking up, so I went at it with a sander and dremel and smoothed it out. After that I applied more resin and more mat till I had about 7 layers and I was able to stand on it without it flinching (I weigh 200 pounds to it must be strong).

At this point I test fit it in the car and drew an outline of where I was going to cut it. I went to work cutting it and sanding it. Then I placed the sub ring that I bought in to it with the wooden dowels and glued them in. Fleeced it, and then more resin and matting. I applied about 8 layers to the front with resin and mat and it was again strong enough to support me standing on it without flinching and then I decided that I was done adding layers and It was time to trim and sand. After getting it smooth on the rear so there wasn’t any sharp edges I was satisfied and I mounted my sub and wired it up. I still have to carpet it, but I really wanted it in last night so it is 85 percent done.

Thoughts:
This project was a total pain in the ass, knowing what I know now, I still would attempt it, but I would go about things differently.

For example, I’ll recommend the cloth vs the mat, I didn’t have a big selection of places to get things from and was only able to get one thing of cloth which I found easier to work with and also less likely to bubble.

Don’t cheap out and buy two or three quarts instead of gallons, this is not nearly enough and you will spend more doing it this way, I should have just bought two gallons in the first place, instead I bought three quarts and then a gallon after almost running out, I spent more than two gallons would have cost and I used almost all of it.

If you use quarts, don’t pour a whole one and tube of hardener and think you will be able to apply it all before it hardens in the cup, you won’t unless there are two or three of you working.
Buy vinyl gloves, not rubber, they don’t rip as easy and they don’t get as sticky.

Once you start adding layers you can do multiple layers at a time, for me I didn’t figure this out till the end, but after the first two layers you can basically put a layer of resin and mat down, then start cutting the matting or cloth and applying it to the still wet surface dabbing it to soak it and adding resin if it is needed. Theoretically you could do all of the rear and front in about an hour or so plus curing if you are good.

For the first layer, don’t use mat, just apply resin to the tape and let it cure, then go to town with it. I found that using spray adhesive to hold the mat on then applying the resin worked much better. While doing my first layer I panicked and was running around like an idiot cutting mat and dabbing resin. Do all of the cutting ahead of time.

This project will take about 30 hours and between 150-200 dollars depending on what you have for supplies, I had to buy everything and spent at least $200 not including the carpet that I have yet to buy. I also had the sub already, so that isn’t included in the cost. I also did this over three weekends, so it may take more or less time. I worked on it then would do something else till each layer cured.

Patience is a virtue, and I have very little, If I had more my sub would have been oriented a bit more upward and straight, but I got tired of test fitting after a while and just wanted the f’ing thing done. However if you have some this is a worthwhile project that will reward you with more bass and more space.

Resoucrces:
How to Make a Fiberglass Subwoofer Box
Custom Fiberglass Subwoofer

[nordwulf]

That seems like quite project! I'll move to the Tutorials section for future reference. Thanks for the write-up and pictures.

[DrunkieTheBear]

I wish I had the patience you do for something like this. I just had another Infiniti Basslink die on me. I would love to just get a better setup in there.