Sub in the Tailgate

[ojmagg]

I started out with a carpeted box for a 10" sub in place of the spare tire. I had it ghetto riged with some bungee cords...it was OK...

I want to keep tire and the stock plastic spare cover...so, I made a fiberglass mold of the spare...

I've done some searching...Shawn (psychos2) has some good info/pics...

1. I am wondering about attaching the mold to the MDF...how should I do it? Should I glass the whole thing...or would a few tubes of construction adhesive work?
2. How do I line up the mold and the MDF cover? I'm thinking about placing the mold in the tire, then throwing some construction adhesive on the mold, throw in the MDF, then put the stock spare tire cover back on...
3. How do I get the holes in the MDF and plastic cover to line up perfectly? 4. How should I cut the spare tire cover
5. What is the best sub to use? Pushing about 150 watts RMS...crappy old Dual XPA2100
6. What about a grill gard...how should I attach it...I punctured the last speaker.

[Knigh7s]

ojmagg,

A quick search on google would be your best friend. I was able to find enough info to get you started as many have done this. The major difference would be space and ours being vertical.

1. I am wondering about attaching the mold to the MDF...how should I do it? Should I glass the whole thing...or would a few tubes of construction adhesive work?

IMO, I would suggest to glass them together. The question is, how thick is the mdf you are using going to be. Also, if you are already glassing, why not scrap the MDF and just glass what was supposed to be the mdf section. I'm not sure about clearance with the stock cover when using mdf. IDEA, tape up the stock cover, wax it, glass it, pop it out and glass both molds together?! That will look pretty clean if done right.

2. How do I line up the mold and the MDF cover? I'm thinking about placing the mold in the tire, then throwing some construction adhesive on the mold, throw in the MDF, then put the stock spare tire cover back on...

That would be the easiest way to combine the two together, but I would still glass it after.

3. How do I get the holes in the MDF and plastic cover to line up perfectly?

My answer to question one could eliminate this. But if not, it shouldn't be hard to find the center on the back of the cover (with tire mold), I'd cut the plastic cover first and trace that onto the mdf then cut.

4. How should I cut the spare tire cover

A router and circle jig with the right bit should work, I would definitely cut it a tad smaller and then sand out the rest.

5. What is the best sub to use? Pushing about 150 watts RMS...crappy old Dual XPA2100

This would be a personal preference. You would probably want to look for the slim line subs available today, you might have enough room to countersink the sub. If you look at my blog, you will find the router and circle jig i made as well as the countersink i'm talking about. The subwoofer I am using is the Pioneer Slim Line 12".

6. What about a grill guard...how should I attach it...I punctured the last speaker.

Grill Guard... Maybe someone else can chime in on this. How much protection do you need?

[89Vette]

They may also still make "free-air" subs that don't require a sealed/vented cabinet. If not, I've considering a similar idea but wondered about encasing bolting a flat piece of wood over the entire wheel to and let the whole hatch be the cabinet.

To line up the hole and the speaker, mount the box w/o the hole, install the cover, and drill thru both to get a center hole. If too late for that, cut out a smaller hole (maybe 2" smaller), look inside, and guage which direction you might need to shift to get perfect alignment.

I used a saber saw when cutting Navistar's. Then finish with a semi-round smooth file. When cutting plastic with a saber saw, move briskly. If you go too slow, the plastic get's hotter and "re-fuses" after the cut.

"re-fuze"???? (sp?)

[ojmagg]

ojmagg,

A quick search on google would be your best friend. I was able to find enough info to get you started as many have done this. The major difference would be space and ours being vertical.

Right, if you look at my picture of the glass insert, you'll see I did get this started...I was looking for personal input from users that had experience building these sort of projects on the VX...that being said, I do like your fiberglass idea to replace the MDF. The only thing that would worry me would be the glass-on-plastic rattle. Think that's why some people use 1/2" MDF w speaker carpet. Guess I could carpet the glass...or spray rubber...something to insulate vibration.

89Vette...I do remember the "free-air" subs...I have the trunk Dynomated...but, I think I'm going w the "sealed box" style setup...thanks for the hints on cutting the plastic.

[tom4bren]

They may also still make "free-air" subs that don't require a sealed/vented cabinet. If not, I've considering a similar idea but wondered about encasing bolting a flat piece of wood over the entire wheel to and let the whole hatch be the cabinet.

To line up the hole and the speaker, mount the box w/o the hole, install the cover, and drill thru both to get a center hole. If too late for that, cut out a smaller hole (maybe 2" smaller), look inside, and guage which direction you might need to shift to get perfect alignment.

I used a saber saw when cutting Navistar's. Then finish with a semi-round smooth file. When cutting plastic with a saber saw, move briskly. If you go too slow, the plastic get's hotter and "re-fuses" after the cut.

"re-fuze"???? (sp?)

Re-fuse - Ya got it right the first time.

Also use a variable speed saw at a very low setting. It'll take longer to make the cut but the plastice won't get as hot & re-fuse (or refuse to let go when cut is complete).

[pbkid]

Most of these types of builds are a combination of glass and MDF. Most build as much as possible from the MDF because its more sturdy and makes for easier mounting of the box itself, the sub to the box and any kind of grill. If you decide to glass all of it, make sure to at least give yourself an MDF ring where the sub will be cut in, or your sub will never mount to an entire glass box.

Hint, build yourself a wood 'frame', then glass the spaces in the frame.