Jayhovah's fiberglass sub box build log
 

I have been brainstorming on what to do for a sub box for over a year... I originally had my heart set on a ported 8" setup.... At first I thought I might try and build an ultra light foam core box but it was going to take up way too much space... then I thought maybe I could stack fab an MDF box into the cavity under the floor in front of the shock towers, but sinking an 8" sub into that area was just going to be too tight for me(have seen others fit 8" in that area though)....

I finally decided to stop fiddling about and just make a simple sealed box for the Alpine Type R 8" that has been sitting on the shelf for many months. I absolutely hate working with fiberglass but you just can't beat it when it comes to weight and fitting things into odd/tight spaces. This will be my 5th fiberglass car audio project, so hopefully there will be some benefit from the experience.

Got started today - on to the pics!

http://www.the370z.com/members/jayho...masked-off.jpg

All masked off, used modeling clay to fill voids or round off sharp bends.

http://www.the370z.com/members/jayho...9-layed-up.jpg

Got the glass layed up...

http://www.the370z.com/members/jayho...popped-out.jpg

Here it is popped out. God I hate fiberglass.

Tomorrow I'll trim it up, make the baffle, and hopefully glass up the rest of it.

Looking forward to seeing the finished product. Make a second one to use as a mold in case I like it, you can make me one. :woot:

...
I'd say the chances of that are pretty slim... :tup:

Finished cleaning up my mess from the day and decided to mark up the mold for trimming so another small update before tomorrow...

http://www.the370z.com/members/jayho...t-fit-mold.jpg

Quick test fit and I realized I've already made a mistake... I made the mold with the top trunk mat out thinking with the weight of the sub should squash down into place when it's reinstalled and the box was finished... this was not entirely true and there is a little bit of a gap around the box towards the inside of the car (on the outside the contours of the panel hold it down in place). I think this will be OK though, as I plan to add some foam on the outside to decouple the box from the interior panels.. hopefully it will keep it fitting tight. In the worst case Ill have my trunk mat modified to remove the area under the box (and put a cut in the under-mat there)... that would suck, but it also carries the benefit of being able to access the spare without removing the sub (which would also allow me to screw the box in place). Not a huge deal and somewhat of a tradeoff.

http://www.the370z.com/members/jayho...trim-lines.jpg

I want to use a flat plywood piece for the baffle so I used a laser level here to mark the horizontal trim line... this way it all stays on plane.

http://www.the370z.com/members/jayho...trim-lines.jpg

Marked the vertical cut as long as I had the laser out...

http://www.the370z.com/members/jayho...dy-cutting.jpg

Ready for trimming!

Oops, I thought you said you love working with fiberglass. ;)

the use of the laser level is genius.......

Small update...

http://www.the370z.com/members/jayho...trimmed-up.jpg

Trimmed up the mold..

At first I thought I would do an all plywood baffle... but it would have to be double layer so I could flush mount the sub and would be difficult to glass in and probably a little heavy.. Instead I decided to do a mounting ring and glass it in.

http://www.the370z.com/members/jayho...-out-rings.jpg

http://www.the370z.com/members/jayho...jig-set-up.jpg

Cutting out rings with a jig saw is much faster than setting up a router and jasper jig..but there is something so sweet about perfect circles.

http://www.the370z.com/members/jayho...wood-rings.jpg

http://www.the370z.com/members/jayho...gs-cut-out.jpg

http://www.the370z.com/members/jayho...s-ready-go.jpg

http://www.the370z.com/members/jayho...ffle-rings.jpg

Set up with some wood glue and brad nails..

http://www.the370z.com/members/jayho...ir-bubbles.jpg

While waiting for that to dry and I ground out some of the really bad air bubbles in the mold and patched them over with a few layers of cloth.

Will see about glassing in the baffle tonight after my girl goes to bed... what do you guys think so far?

I think you should have made two (just kidding). Looks good so far. Hurry up and finish it so I can give you crap for not making me one. :stirthepot: :D

You might get lucky! I did a similar one in my 350z and decided I wasn't happy with it, ended up selling it to someone following that build thread!

I do the same thing. I build something and if it doesn't turn out exactly as I imagined I scrap it and start over. It took me three times before I was happy with the cubby gauge pod I fabricated. If it doesn't work for you we can talk. If I get my car back from Specialty Z next week I'm hoping to to have close to 600 supercharged horses to listen to for a while. :tup:

I see that you're finally getting to finish this project!

So jealous that you're able to work on your car at this time of the year. Every time I think of messing with my interior/fuel system, the weather motivates me not to (-5F currently)

It's gonna be redonkulous!!!! Looking forward to seeing your results!!

LOL that would be a deterrent!! temperatures dropped pretty sharply over the last couple of a days and its a brisk 55 degrees outside... Just took the car to walmart for some late night supplies and it always surprises me with the power on cold days.

The cooler weather is also giving me a lot more work time with the polyester resin...

You need a heater in your shop!!! If I had my car stored for the winter I'd want to do all sorts of stuff!

glassed in the top and started adhering the baffle. Taped off the surface of a table and used it to mold the top flat. I went ahead and glassed up one side of the baffle (the one closest to the opening)... I will see how well stuck the ring is and decide if I need to glass in the other side as well (which will be awkward).

http://www.the370z.com/members/jayho...p-baffle-1.jpg

http://www.the370z.com/members/jayho...p-baffle-2.jpg

http://www.the370z.com/members/jayho...p-baffle-3.jpg

http://www.the370z.com/members/jayho...p-baffle-4.jpg

In for the pics. Looking nice. I need to get one of those laser thing-a-ma-doodles. Very handy.

I'm with ya though... working with glass sucks.

Highly recommend it! It was a Harbor Freight impulse buy (~$45) and I am constantly finding uses for it.

Does your Z stink now?

It's already subsiding. I left the hatch open for several hours while the mold was curing to keep it ventilated.. and any time I am working in the garage I'll walk over and open the windows and hatch to continue letting it air out. I will probably still smell it faintly for a while but it will go away eventually.

Popped the top off the table and it came out great!

http://www.the370z.com/members/jayho...ffle-cured.jpg

Will just need a light coat of filler to smooth out the tape lines before upholstery.

http://www.the370z.com/members/jayho...p-trimming.jpg

Here it is all marked up for trimming... I didn't try to coordinate the curves on the top and bottom since it would be impossible to get perfect... I figure a little twist in that side will give it some flair and make the glass stiffer.

Tonight I'll get it all trimmed up and also add some glass to the other side of the baffle and also add to the larger flat spot in the top as it has a little flex in it. Hopefully tomorrow or Monday I can start closing it in!

looking great so far! can't wait to see how it turns out.

David Hasselhoff would approve.

Do you ever do the Bondo milkshake on your fiberglass interior?

Interesting project. Sub'd.

Eh? What's that?

Take half Bondo and half fiberglass resin mixed until it's the consistency of a milkshake. Then add a little hardener and slosh it around in the interior of your enclosure to seal up any little pin holes, smooth it out and to give it a little more structural rigidity.

Sounds effective! I wonder if it would add much weight. I usually just fill the enclosure with water to check for leaks.

Starting to come together, look'n good.

Didn't seem to add much to mine.
https://uploads.tapatalk-cdn.com/201...09829050d2.jpg

Right on... I may give it a shot! Thanks for the tip

I added some layers to the weak spot and more around the baffle on that side... I cut the handle off of a small brush and had to reach in do it blindly... It didn't turn out that great as I can see a lot of air bubbles though the other side but hopefully it will provide enough support. Not much to see really so I didn't bother snapping a picture.

Didn't get around to any trimming today...perhaps tomorrow!

Trimmed and ground away the excess...

http://www.the370z.com/members/jayho...trimming-1.jpg

Started with the jig saw on the open end since its easier to cut smooth lines and makes much less dust..

http://www.the370z.com/members/jayho...trimming-2.jpg

Then moved on to the dremel with cutoff wheel..

http://www.the370z.com/members/jayho...immed-up-1.jpg

http://www.the370z.com/members/jayho...immed-up-2.jpg

Trimmed up with some light sanding..

http://www.the370z.com/members/jayho...sticks-mat.jpg

Experimenting here to see if resin will stick to this IKEA cutting mat.. it's just about the right size and stiffness to help me mold the last side. I tried taping it up first but the tape wrinkles as it curves so hopefully I can keep it bare.

Polyester resin does not stick to the Ikea chopping mat! I will try to give it a shot for setting up the last side. I think I will try to do it similarly to the top..will set up a few layers on the mat and wet it out, then try to form it over the side and hold it in place to cure... If I can secure everything in the right position Ill glass as much as I can on the inside of the box through the sub cut-out and figure out the rest later.

http://www.the370z.com/members/jayho...ting-board.jpg

impatiently waiting for final results lol :stirthepot:

Well I got the side molded and glassed up.. sort of. It did not go very well.

http://www.the370z.com/members/jayho...ide-mold-2.jpg

http://www.the370z.com/members/jayho...ide-mold-1.jpg

http://www.the370z.com/members/jayho...eady-glass.jpg

Here is the mock up of how I wanted it to work... Ikea chopping mat supported by modeling clay and a wheel chock (only because I didn't have enough clay).

Looked good at this point.. so I unstrapped the enclosure and laid down 4 layers of 6oz cloth then replaced the enclosure and strapped it back down.. Started laying down cloth patches on the inside to secure it... Things were going so well! But then disaster struck.. The clay started to soften and sag on me from the heat of the curing process... so I tried to push it back into place and the whole enclosure slipped on the wet mat.

I unstrapped the enclosure and pulled out all the wet cloth patching on the inside, straightened out the large pieces of cloth on the chopping board, and secured the enclosure again as best I could while the resin was gelling on me... mixed up a fresh batch of resin and started repatching everything back into place. I only got one layer on the lid side where I had to glass it in blind,

I will definitely have to use BoneZ's filler-shake trick to ensure a good seal I think.

http://www.the370z.com/members/jayho...et-up-cure.jpg

So here it is curing... you can see the enclosure walked quite a bit and is a little off the board in a few places.. luckily fiberglass can be forgiving with needing to patch and repair spots... it just sucks cutting, grinding, and sanding it so I always try to get things right the first time.

Can I cancel my order? :rofl2:

Lol

like you said......it IS a very forgiving medium to work with. Im sure youll get it squared away.

Not as bad as I initially thought!

It finally finished curing so I popped it off the mold and it actually turned out OK. If I have time tonight I'll add a couple of more layers onto that side and a few more small patches inside.. I go back to work this week though so progress may stall until next weekend.

http://www.the370z.com/members/jayho...side-place.jpg

I'm on the opposite side... I'm off this week, and will be starting on my fiberglass sail panels.... as well as beefing up the soundproofing in the door panels. the new SI MkV's are midbass monsters!

Went a similar route, but with a pair of 10's.

That looks like an emergency hatch release mechanism.