i've been working on my first fiberglass/mdf project and figured i would share my progress log in case anyone else wanted to do something similar. keep in mind i have never fiberglassed before, and am not a professional fabricator in any way at all. i'm just a joe schmoe with powertools, patience and determination. anyhow, on to the project:


I've been thinking about how I wanted to build an enclosure for my 12" JL 12w6v2 sub in my trunk. My original plan was to utilize the spare tire wheel well, but after much deliberation I decided against it because it would mean raising my entire trunk floor, removing my spare tire, and being a general pain in the butt. It definitely would have been easier to fiberglass there than in the location I decided on, but I think overall, the side was a better choice for me. I care a lot about my trunk space, and I don't really want to be in a situation where I don't have a spare tire. I decided on the driver's side area of the trunk. Both sides of the trunk are similar, but the passenger side has a fuse box located in the hole area, so the driver's side was a better option.



The aluminum stuff you see in the picture is the sound deadening adhesive (eDead) that I used to deaden the vibrations and lower the incoming sound noise through my trunk floor/sides. My main issues I see right away is:


1. I don't want to mess with moving the wires that run along the side of the trunk
2. I also don't want to fiberglass directly on top of them
3. I don't want to fiberglass directly against the tail light
4. I'm going to have to make some sort of pre-fab box in that hole area for the fiberglass to form to


Now, before I continue, let me just state that I have never fiberglassed before or watched anyone do so. I've been reading a lot about it over the past few months, but reading and doing are rarely the same thing. I had a basic understanding of what needed to be done, and the order of things I needed to do, but that was about it. I bought a bunch of crafting supplies I thought may prove useful and just went from there. I'm sure there are better ways of glassing, but this is how I chose to do it.

I had a bunch of poster board that I had intended to use for drawing out the shape that my MDF cover would need to be. Instead, I used it to design a box in the hole area in order to keep the fiberglass away from the tail lights and to create a smooth transition between that hole and the hole I am going to cut in the plastic wall panel (thus avoiding the electrical wires). I just started doing rough measurements and attaching posterboard pieces to each other to create a basic box.



That little flap was necessary because there is a metal bracket thing in the way. Mandatory picture of my 12w6v2:



I continued working on my box fabrication, took it out and closed in the little panel/box area. Then I covered the entire inside with blue painter's tape:





I placed it back in the hole to test fitment, and then folded the edges of the box back so that I could mount it flushly to the car's metal panel body. I used duct tape to secure it. Just as a hindsight note, that little 2"x2" box on the inside of the enclosure was a holy hell to fiberglass. I would definitely have figured out a different way of doing that if I had known, even if it meant losing some enclosure cubic volume. Ah well. Learn from my mistakes. Also, I haven't been able to pop the enclosure out yet, and part of the reason is the duct tape holding in that box. Not sure how else you can do it, but just make sure you use lots of painter's tape and aluminum foil on the inside of your box so that it will pop out as easily as possible.





Next I put on the plastic interior panel that goes over that whole section. I brought my sub over and test fitted it and found that the plastic panel didn't give enough clearance for the magnet on the back end of the sub, so I drew lines of where I needed to cut and cut that area out with some tin snips. I don't have pictures because it was impossible to hold the sub in the air with one hand where it needed to be and take a picture with the other. Use your imagination!




I put the plastic panel back on and tested the fitment again with my sub to make sure there was clearance. You can see the wires there in between the metal car panel and the removable plastic panel. I want to keep it that way so that it doesn't get fiberglassed over and so that I don't have to bother with moving it.




In order to achieve this, I used more poster board to create a "bridge" between the box I made and the plastic panel. This will also make for a smoother and "easier" (lol!) fiberglassing.




Once I had finished creating my bridge, I started covering the entire plastic panel with blue painter's tape. I used a lot of it on this project (2 rolls), as well as a good deal of duct tape, and a roll of masking tape as well. One thing I wish I had done was buy thicker painter's tape (like 2" or 3" inch tape), as it would have sped up the masking process by a lot. I ended up with raw fingertips from applying so much tape.




With the plastic panel and box done, I started designing the outter part of the enclosure. More test fitting ensued. This is a top down view of where the sub is going to end up being as far as how far it sticks out. Keep in mind that this outter wall is going to be made of 3/4" MDF, so it will be all the way straight across. From this picture you can see that it's too far out to mesh into the part of the panel closest to the seat, so more fabrication will be necessary.



Before I got to that, I had one more thing to deal with first. If you look under your trunk carpet, there's a ring on each side of the trunk bolted to the floor close to the seat. I plan on probably using that bolt hole as part of my enclosure's "securing" feature, both so it won't move around and so that someone can't just smash my window and take the entire enclosure. They're gonna need to bring the "Jaws of Life" if they want my sub.

Anyhow, I took a paint stir stick and broke it in quarters. I taped two of them side by side and completely wrapped them in masking tape and placed it over the bolt hole. This will allow room for a bracket or whatever I end up using under there. If I had just covered the hole with tape, it would have prevented me from using that bolt hole without lifting up the side of my enclosure. In the last pic, you can see my measurement line of where I plan on having the MDF wall. Note the location of the bolt hole. I'm thinking I will end up using a big metal bracket there and bolting it to the MDF face of the enclosure. We'll see.





Now to the fabrication of the outter side walls. I used more poster board here, creating an extension that followed the curves of the plastic panel so it would flow well when all is said and done. The arching actually strengthens the poster board as opposed to being straight and flimsy. Just make sure you tape it well. I continued with the "roof" part, and then the other side, taping them both to the plastic panel and to each other. I strengthened the roof part with some paint stir sticks broken in half and taped to both the plastic panel and the top side of the poster board "roof". This greatly strengthened the roof part and I had no worries of it being too flimsy to fiberglass on.








I made sure there was plenty of clearance for the trunk hatch to close.




I remeasured again, using an actual ruler, level, and some boards to more accurately depict where my MDF front will end up being and marked my lines all the way around.




All that's left now is to add my layer of tin foil to further prevent resin from seeping through the tape and to make the enclosure pop out more easily (no such luck!). I also cut up some garbage bags and taped them to the edges to prevent me from getting resin on my car. Fiberglassing is VERY VERY messy, so I would seriously reccommend doing everything in your power to protect your car. Most of the first timer fiberglass threads I've read have been full of DIYers with resin/fiberglass everywhere. I just got my car painted, so I was very careful. I also used about 20 disposable latex gloves, and a long sleeve shirt to keep the fiberglass and resin off my arms. I got some on my legs tho cuz I was wearing shorts, and then ended up being very itchy and BURNING! When the resin "sets", the chemical reaction between the resin and the hardener makes it get very hot. If you get any on you, you won't feel it right away. But when it starts to harden, you will have no doubt!

NOTE: I made the mistake of wiping the sweat off my forehead with the back of my latex glove. There was resin on the back of said glove, and about 10 minutes later my forehead felt like someone had pushed my face onto a heated grill. Learn from my mistakes! lol (didn't take pics of my forehead... sorry!)






Now to the actual fiberglassing. I'd say now to the fun part, but it's anything but fun. I have learned that fiberglassing is not something I'd want to have a career in, or really have to mess with ever again. It was a good learning experience and a DIY challenge, but it is not something I enjoyed doing. I'd take wood and a skill saw over laying fiberglass any day!

This first layer of glass was brutal. First, I had no idea what to expect since I had never touched the stuff before. Second, sitting in the car trying to fiberglass was super uncomfortable. And third, that little box area in the back part of the mold was hell on earth trying to fiberglass in (especially having to go upside down to do the top part of it).




Once I finished the first layer, I let it set for a while so that when i layed the second one, it wouldn't be moving around the first layer. Then I started on the second layer. It's hard working against gravity. Trying to paint and stipple the resin on the top (ceiling) areas was difficult and much of it would drip from the brush to the bottom. I tried to mop it back up, but after a while it was just impossible, so the bottom area definitely had a lot more resin on it than the top did.




Here you can see the nightmare area. It was just impossible for me to do a good job in there, so I just tried to get it as best I could and hope it didn't break when I popped the mold out. The whole thing is kind of ugly, but I'm a fiberglassing newbie and I did the best I could. You can see my lines there too that I did on the posterboard in black marker. That's going to be the actual edge of my enclosure, so I fiberglassed a few inches past it to make sure the edge would be strong when I trimmed it down later.



Now I just had to wait for it to cure before I could pop it out.



Unfortuneately, I had a short deployment that left the next morning at like 6 AM. I got up a little early and spent about 10 minutes trying to get it to pop out, but I was getting nowhere and had to just leave it in my car for a week while I was gone. I was afraid it would really stink up my car, but it wasn't all that bad.

On a side note while I was on my deployment, I just thought it was interesting how close the air traffic controller guys were bringing in planes, one after the other. I wonder what happens if one plane rear ends another. Do you get points on your driver's license or your flying license? hmmm...



When I got back home, the first thing I did was get back to popping it out. It didn't come easily, but that was mainly due to the way I had taped that little box over the plastic panel with duct tape. I eventually grabbed a paint stirrer and used it as a shim around the entire thing and slowly worked it out inch by inch. With only 3 layers of glass, it was still pretty brittle, so I couldn't just yank the thing out by force without risking breaking it. It finally came out though, and I was thrilled to get it the hell out of my car.




Honestly, I'm surprised how well it came out as this was my first time glassing. I thought it was just going to crumble into pieces or something, but it was actually quite structurally sound. The little box area needed some serious love tho. I had pulled off most of the tape and foil, but after seeing some bad spots, I retaped and I got some fiberglass filler to patch any weak spots or holes in the area.



I began adding more layers of mat, and started getting fairly good at it. It was so much easier working with the mold out of the car vs. it being in the car. Any bumps or rough spots I would sand down before laying the next layer. I talked to a professional fiberglasser online and he gave me some pointers that really helped me. All I can say is get yourself a little 2 or 3 inch paint roller. It makes things 10x easier and better looking than trying to just use a brush.



Over the next few days I would add a couple layers and then let it cure. I think I ended up with about 8 total layers. There isn't much flex to it at all any more, so I figured that was a good point to stop.



Now that I was done fiberglassing (THANK THE LORD!), I needed to trim it back to where my initial black lines were. I used a dremmel to cut with, and it went through fairly smoothly. Make sure you wear a fiberglass mask, eye protection and long pants/shirt because the fiberglass dust will be everywhere and is bad bad bad.




I can't tell you how happy I was to be done with fiberglassing. Now it was time to move on to the wood working part of the project, something I'm much more comfortable doing (although not necessarily any better at!). My wood front is going to set inside the actual fiberglass part, so I used some posterboard and got a tracing of the inside. Then I took the posterboard and put it on my 3/4" MDF sheet and traced the outline onto it and used a skillsaw to cut it out.





Next I did some test fitment to figure out where the hole needed to be. My initial plan was to have the sub mounted right to this board, but after some research and contemplation, I decided that it's not going to give me the angle I want to project off the hatchback glass, so I would need to build sort of a wedge to give myself an angle. Therefore this hole is just to allow the sub to pass through. You'll see what I'm talking about later. I used a router with a circle making attachment to cut out the circle. Worked pretty well.




Now, my front MDF cut out was a little too large to fit into the fiberglass, so I began the tedious process of slowly filing/sanding it down until it was a nice, snug fit. I made my brother hold the board while I filed, as I am the elder and I didn't want all that sawdust getting all over me!






My original plan was to fiberglass the board in, but after my time spent glassing, I decided to just liquid nail the hell out of it instead. This stuff is awesome. I just gooped it on generously in a zig zag pattern and slid the board into the fiberglass enclosure. Then I went back over the seams like you would normally caulk something and smoothed a line with my finger to make sure it was good and in there.





Next came building my angled wedge. I spent a few hours testing placement and doing the math, sketched up what I wanted and made the pieces out of posterboard. Then I used the posterboard pieces to trace the shapes onto my MDF board, and used a table saw to cut them out.






After all that hard work, I figured it was time for a break, and what better nutritional food than graham crackers and milk. I myself am a half dipper. I dunk the first half, eat said half, and then dunk the remaining half. I find this to be the most efficient way of eating graham crackers. Make sure you don't hold the dunk too long or you'll end up with graham mush as you're trying to get it to your mouth. (I'm losing my mind at this point)





So here's what my angle wedge is going to look like. I need to do some angled cuts on some of the pieces to match with the slant of the sides.




I noticed now that my top piece of the box needs some angled cuts as well to make it look right with the support pieces. I didn't have any way of making accurate angled cuts, so I had to freehand it as best I could. Once everything was cut, I set the box up on the enclosure and got an idea of where I would mount it, and I used my router again to make a hole through the top of the wedge piece.





More test fitment ensued, this time with my sub in place. I wanted to make sure I had all the clearance I needed and that everything was fitting right before I started putting it all together.




Everything looked good, so I got out my trusty tube of liquid nails and went at it. I started with the base pieces and glued them together so that everything was flush. I used the clamps to aid in positioning everything perfectly, not for holding the thing together while it set. With liqiud nails, you don't even really need clamps, as it's adhesive enough from the get go to do it on it's own. Next I put more liquid nails on the top of the based. I felt like I was building a gingerbread house (note: don't eat liquid nails). I put on the "lid" and caulked all the seams of the entire box, in and out and then let it set overnight.






Obviously, I needed some sort of terminal or outlet somewhere on my enclosure for connecting the amp wires to the sub wires. I found a nice little banana plug terminal at radio shack in one of those misc. drawers in the back. I mounted it on what will be the underside of the wedge box so that all my wiring will be invisible. It took a little fabricating to get it to work with the 3/4" MDF, but I eventually got it mounted and attached my speaker wire to the inside.





The last thing to do to complete the enclosure was to attach the wedge box, so I grabbed my liquid nails and went to down again, icing it like a cake and setting it onto the main enclosure. I let it set overnight and then it was ready to go (and super strong).





I attached the sub and put it in my car (damn thing is heavy with the sub in it). I know it's not all pretty right now, but I was just itching to get it in my car finally after weeks and weeks of working on it. Once I have some more free time, I'm going to take it back out and sand it down and either carpet it or put vinyl over it. I havent decided yet. You can't see any wiring in the pic, but my sub is actually fully connected with my amp in the tire well. Not sure what I'm going to do with the 2 amps and 2 crossovers I'll be running, but that's how it's gonna stay for the time being.

And without further ado: