Repairing a Speaker Box

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Hi all, wasn't sure if I should post this in the Maint forum or this one but oh well.

I have a 12" sub-woofer bandpass style box in the trunk of my focus. It'd sat for quite a few years when the old, tired 200w Radio Shack amp quit working. So far as I knew the box and subwoofer (a 400w Pioneer) were still good. The year before last, for Christmas, I got a new amp for the sub. Amp is rated at 1100w but was under $100, based on some other things I'd read I figured it would be safe to use with the Pioneer sub, if nothing else at a lower gain. I think the charts and forumulas I'd found led me to believe that it was really maxing out at 400-something watts, based on the fuse size, etc.

Anyway, it seemed to work fine for a while but in the past few months has developed a rattle if I turn it up very much. I thought maybe I'd calculated wrong and actually blown the speaker but there was no sign of any noise at low volume. Today I finally decided to run the subwoofer and poke around and the box and lo and behold I found that the front panel on the box has popped loose on the seam. This box is made of, what I'm assuming is MDF. It's very heavy, dense, particle wood material.

Before I replace the box I'd like to try to fix it.

What's the best adhesive, etc to use to re-join this seam? I'm thinking Liquid Nails and maybe a few shots from the nail gun (18ga 1")

Advice?
 
I would give Gorilla glue a shot. My go to for wood furniture repair. A spritz of water will get it to cure faster and it will swell some to fill voids so clamp it well.
 
Looking down inside the ports in the rear, it does indeed appear to be wood glue.

Regardless of what adhesive I use, I'm not sure how I will clamp it. The front panel and the rear are not parallel in angle. Hopefully I can wedge the whole thing against the back seat while the glue dries.
 
I wouldn't bother with something that needs clamps. I'd go with Liquid Nails/construction adhesive and the nails like you were planning. It won't expand while drying and the thickness will help seal gaps.
 
Try using ratchet straps and blocks etc to get things bound together. Furniture rarely has straight surfaces to clamp to.
 
Originally Posted By: John_VT
A couple nails or screws will hold it while the glue dries.


I feel like screws might split it, nail gun with 18ga may be safe, though.
 
Yeah you would predrill for screws. If you have a finish gun that would be fastest. I like the ratchet strap idea. I would try to spread it open to get what ever glue you use deep in the joint. Smack it together shoot a couple nails. If possible I'd make some right angle triangles to go between the face and side wall glue and nail them
 
To get good grip with screws and also prevent the chance of splitting the wood, you could pre-drill holes for screws. First use a drill bit with a diameter about half way between the outside of the thread and the base of the thread and drill that hole the entire length of the screw. Then drill the first board that the screw goes through to the size of the outside of the thread of the screw.

Dry wall screws work well.
 
I went at it with liquid nails and a nail gun, the nails didn't even get a bite as they were too short but it seems like the glue is holding it well now after I let it dry overnight. If it pops open again I probably need to invest in a new box. I've had this one for nearly 15 years.
 
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Liquid Snails works well,even regular latex caulking works ok just takes a couple days or more to start to dry.gorilla glue is fast I glue my bad shoe soles with gorilla glue and I can wear them in an hour.water loosens them up though.
 
My buddy who did competition audio for YEARS always used drywall screws and the MDF never split. Might be an issue with plywood, but I don't think it is as much of one with MDF.
 
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