spare tire well box.

turbovdub

whats the best way to seal this?

i was told by a local tweeter around me layers on some dynamat, puts the face board on top and reaches in and seales with the hardening foam. they have had awesome results...

any other ideas? thanks

turbovdub

bump...for some help

Custom Jim

Can you use a caulk around the outside edges to seal it up ?. I've attached flat boards to back walls of vehicles or to floors and I have taken liquid nail and layed it thick enough to where when the board is set against the metal the glue fills the valleys and the gaps between the board and the metal surface. I stick the board down and then pull it away to see if it has made 100% contact and if so stick it down like I want it but if it's not in 100% contact I add more caulk and try it again until I get 100% contact.
I've also mixed up a weak mixture of body filler (a tad less than usual amount of hardener to increase my working and application times) and then laid a bead of this filler in the gap and then layed down the board squeezing out the excess and then before it hardens use a knife to cut away the excess filler that has oozed out to make it look nice.
Be careful with any glue or expanding foam and let it cure and allow the vapors to disipate so that if there is a spark the fumes do not ignite and blow things up.
I've used expanding and hardening foam before but I have not seen how long it actually lasts. I do know you want a low amount of expansion and with the foam you need some way to lock the board down so it stays put while the foam expands and cures.

Jim

turbovdub

wow... that was an awesome write up. thanks for the input.

i am going to try and use as much mdf as possible. if you have any other input... please pass your knowledge along.

thanks again

if anyone else can add on some more info, please do..

Custom Jim

Thinking about some more input you may see how flexible the well is. Most panels are stamped steel and some will have reinforcing ribs stamped into them to help with the rigidity but the flat bottom of the well may flex or some other portion of metal could flex reducing the output. Try pushing down or up from the underside of the well and see how solid it is or isn't. If it flexes fairly easily take a 1x2 or some strips of 3/4" material and then after marking it, use a jig saw to trim the one edge to fit snug against the contour of the area. Try and make the strip long enough to reach over to area's that do not flex to lock it all together. Once the reinforcing strips are made, clean the area so glue will stick and what I've used through the years is more liquid nail. Apply a good bead to the edge of the strip and stick it into place. If it's a spot that the strip wants to move, stick it hard to the surface to squeeze out the excess glue and then pull it away from the surface. Wait until the glue skins over and then place it back up against the surface and it should stay put. By pulling it apart and letting it skin over it acts more like a contact glue even though it's not fully cured. If it wants to move on you, run some tape over it to hold it down and then come back a day or so later, remove the tape and it should be pretty solidly stuck.
I've used a fair amount of liquid nails attaching wood strips or panels to sections of cars because I hate drilling through the metal and having to deal with mig welding holes shut later should the design change or a person wants to return it to stock. Also holes in the metal invite rust problems and even if you mig weld the hole shut, now both sides of the panel have to be refinished. With glued on strips or panels you can get them off with some work and there may be some residue left but this can be sanded off, the area prepped and then reshot with some paint and then what was there is no longer has any traces of it even being there.
The reason I said before to watch the fumes is I did hear of an installer years ago make a sealed enclosure and there were fumes inside the box and the tinsel leads on the speaker became real close to each other and an arc occured and the fumes then ignited. Years ago I was adding some expanding foam under a floor shelf to hold up the washer and dryer downstairs and I was going to town filling the void and then it went poof as the water heaters pilot light being close by caught the fumes on fire. Gotta be careful and think ahead.

If the main board is fairly large, add some furring strips to the backside to strengthen it and maybe too flush mount the sub or recess it to where a protective grill could be added and then covered with a large piece of acoustical carpet and it would be completely hidden from sight.

Jim

turbovdub

thanks again jim. when i go into work tonight, i am going to go over your plan with the other installer working on my car.

lpreston

I did a single 12 in the spare well on a Neon years ago. I went under the car with 1/4" thick strips of steel and bolted them to the bottom of the well. Then I sprayed the crap out of it with sound deadener (can't remember which one tho). Full layer of Dynamat in the inside of the well. Sealed it with UV7700 which is like steel when it hardens. Car ended up with first in class and best of show at the only competition I entered it in...beat 3 of the best local installers using Hafler mids, Magnadyne tweeters, Clarion amps/head unit & eq.

bknauss

Fiberglass the well.

[Deleted User]

Your mom fiberglasses.

bknauss

Josh wrote:

Your mom fiberglasses.

You and my mom have something in common!

PoweredByDodge

1" x 1" foam rubber insulation... bolt the **** down until it's squished to 1" x 0.125". done properly, you can get away with something along the lines of a 400 - 500 watt 12" sub. that kind of 'seal' likely won't hold up to anything massive, but it'll surely do the job for a moderate speaker.