Fiberglass sealed sub enclouser

This is not a tutorial, if it were, I'd know what the h*ll I'm doing. This is more of a documentary.

I've decided to build a fiberglass sub enclosure. I had the idea, why not mold the enclosure around the underside of the dash? That way the sub is up and out of the way as much as possible. Finding information on fabricating fiberglass on the Internet is limited. So as I venture I thought I'd document the process. At the very least, you might find a good laugh as I end up with a $50 fiberglass rock. Maybe I'll get lucky and it'll work. I know I'll have some issues with fiberglass resonating funny with the sub. I plan to brace the heck out of the box - and probably some sound deadening material. I'm targeting around .75 to 1 cubic foot for this sealed enclosure. It's hard..if not impossible to estimate the volume.. I'm visually measuring 12" x 12" x 12" as I build.. We'll see..

I'm working with an 04 VLX. I've been thinking about this for weeks and this weekend marks the beginning of actual fabrication. - I'll let the pictures do the talking...

Here I'm trying to prove the concept that fiberglass will stick to the bottom of a surface. I used a cardboard box to simulate this. I'll be taping the dash off to protect it from resin.




I thought I might have troubles with the glass sticking, so I reverse glued some duct tape to the box as well. (ultimately didn't need this)



Fiberglass mat - Home Depot or Wal-Mart - Next I'll order it online. At first I didn't think this mat would work well, but it worked better than the cloth.



Fiberglass cloth. It was harder to get this to stick to the bottom of the surface.. So I didn't use this cloth for this application.



Both the mat and the cloth stuck to the bottom of the top of the box.




The glass pulled off the box after about 3 hours. Looks good. I found that a mixture of 70% short strand Bondo and 30% Resin worked best. The bondo thickens up the resin. The bondo gives it that ugly green color. I think regular automotive bondo would be easier to work with. The strands in the bondo make it hard to scoop it up and apply it over your head.




On to destroy my boat.

Here you see the foot rest (bottom left)
tower mounts (three bolts top right)
Battery cables (top, red)
Steering cable (center)
What I've done here is taken Hardware Cloth (small animal cage material) and bent it around to create channels for the cables to run through.



Next, I mask off everything. this way I can lay the fiberglass right on the masking tape and it won't soak through to the carpet (I hope)






I don't have a picture of it, but I've taped drop cloth down to cover all the flooring, drivers seat, side of the boat.. I'd recommend going excessive on drop cloth.. It only takes one drop of resin to screw up the carpet.

time to glass - It's difficult to see, I'm using a squeegee to spread the resin bondo mixture, then I apply fiberglass. and saturate it. I'm looking to simply get a structure at this stage.






I need a better camera. You can see the foot rest on the lower left of the screen. The fiberglass starts at the top of the foot rest and goes away from the drivers seat to the forward wall.. Then up.. On the right you can see where the steering cable ducts behind the glass.


Ok, What have I learned today.

1) use MDF instead of fiberglass

There's a lot of stress in working with fiberglass inside of a new boat. (though it's an 04, I bought it with 1 hour on it from a dealer in sept 05) Resin is messy. It gets every where. on your sleeves, then it tracks.. I'm still hoping the masking tape doesn't saturate through.

Though it doesn't look it, that is about 3.5 hours worth of work. I was moving pretty fast towards the end. The glassing process consumes serious amounts of bondo/resin. I made up about 5 or 6 batches, and every time I had to crawl out of the boat. I'd throw away my gloves each time, so I'd have clean hands to get out of the boat with. Almost dropped the resin once.. I'm not sure this is worth it... I should be done inside the boat. On Tuesday I'll see if this nasty mess comes out.

I found that laying the fiberglass in my hand, then saturating it with Bondo/Resin worked best. It also conserved Bondo/resin as I could squeegee it better.

Having to do it again, I'd remove the drivers seat. You need all the mobility you can get when you have dripping resin over your head.

The path forward looks like this: remove the molded structure, trim it down, brace it up, support a MDF rind to hold the sub, Fleece with resin cover, fiberglass fiberglass fiberglass (ugh), bondo and paint.

Now to go pick resin out of my hair.

and make a chiropractor appointment tomorrow.


(Message edited by yosquire on March 26, 2006)

durrr... I typoed the subject line... Enclosure.

I would recommend using heavy duty aluminum foil with smaller pieces of strategic tape instead of all that tape. once your shell is dry and you have a couple layers on the foil peels right off.

when we did it in my boat we just used straight resin, as the fiberglass cloth we used on the outside layer when wetted stuck right to the foil. we followed this up with 5 layers of chopped mat.

Also a major tip is you can get tons of fiberglass "scraps" on ebay super cheap.

Avoid flat spots unless you build them with other structural material such as wood.

when I get home I'll repost pics, I posted in 2003 when we did it.

I spent all weekend making a sub enclosure to go in the same area of my Supra as you are doing with your VLX. It is a VERY tight space in there. It was tough to figure our how to get the dimensions just right for the amount of volume needed while still allowing enough room for the enclosure to get into the space where it needs to be.

I thought about doing a fiberglass enclosure as well, but opted for an MDF box. I wouldn't have thought such a simple box would have been such an under taking. By the time I filled every little nook and cranny with fiberglass resin to make it air tight, I was beaten down. It's all worth it though. I can't wait to get the system wired up so I can hear how it sounds.

Good luck with your enclosure.

Yeah, please post those pics.

I considered tin-foil, but opted against it as I assumed the glass wouldn't stick to it. Being a smooth surface. Though, I never tested that theory.

I picked up generic tape for $1.18/roll. I used about 3/4 roll of it there.

Timmy Has the right idea with the Aluminim foil. You can get a thicker verson's of foil for this exact application. This is exactley how the mounting or base plates are made for piller or kick pannel speakers, So your on the right track. keep going you will get there and learn a thing or 2 along the way. Yes remove the drivers seet you "Hammer Head". LOL And untill you get used to bending in funky positions and working upside down in them for a few hrs get set up with your chiropractor. Been there done that LOL sorry to laugh.

after you get a couple layers down, you can take the shell out of the boat and finish it, which is great.

Oh, another note, don't work out your shoulders before undertaking a project like this.

With out putting 2 and 2 together, I hit the gym at 9am, worked my shoulders for an hour. Then I came home and laid fiberglass....oh....the burn...

I hope the tape didn't/doesn't give a hard time. When the resin cures it gets real hot and bakes the adhesive into the carpet. I learned the hardway in an older car. granted the box will cover it, but it's still there! Really hope you don't have the same problem.

Other than that, I love this method and props for going this route, it truly is the harder method but the most custom and integrated into the boat.

I used to build kickpanels for cars this way...no better way to form-fit the enclosure to whatever your working with.

don't waste your time with that matt, it's not thick enough to support a sealed box. Go to walmart and buy a couple of cheap sweat shirts and cut them up. Use that as your matt and I would suggest 2 layers. By the time you lay 2 layers and saturate it with resin, it will be as strong as your boat.