Need help; terminal cup in a fiberglass enclosure leaking air, what now?

[philrab]

Title says it all. Have a fiberglass stealthbox custom made for my car I picked up used off another owner. Spent today chasing a few air leaks, and got them all we'll sorted EXCEPT the leaking terminal cup. Seams as though air is leaking directly through the center, like where the speaker leads attach rather than from around the edge.

1. What's the best way to deal with this? Was thinking pack it with epoxy to seal the bastard up, any other opinions. I don't have the fiberglass skills to be comfortable removing it and fixing the resulting hole.

2. Seams the preferred method is either direct leads out the box or bolts to act as studs. Any potential issue drilling through fiberglass, cracking or splintering?

Any advice would be appreciated. Sooner or later, I'm going to but up and learn to do fiberglass work, but right now I'm trying to fix the mess I found.

[timc31610]

To see if it is worth fixing just cover the backside of the cup with hot glue. It is removable where as epoxy isn't. At least not without a saw.

[mbdblue]

fiberglass doesn't really split or crack, but it can splinter. If you decide on direct leads, I'd use a metal drill bit so it's cleaner. I'm guessing the terminal cup is plastic so I'd use some CA glue to seal it up depending on the size of the hole.

[Jhunt94]

have you thought about some kind of foam ring on the backside to help seal it up when you tightened the screws down? If it would work for you it would be a lot less messy than gluing it down, in the event that you have to remove it in the future.

Never mind, didn't read it properly. Thought air was leaking around the cup.

[philrab]

Nope, air leaking right through the damned wire connections. Never using another terminal cup after this (not like I built this enclosure to begin with.

What I'm thinking is the following. Feel free to jump in and stop me if I'm being a knucklehead about it.

The fix: Take some spare bolts, and drill right through the terminal cup. Crimp ring terminals onto speaker wire inside the enclosure, and run the bolts through from inside out.

Pack the outside of the terminal cup full of epoxy and thread a nut onto the outside. Once dry, secure speaker leads using another set of nuts to run to the amp. Should be solid, epoxy should stop the leaks, I can always use a dab of silicone in the drilled holes for extra insurance.

Any of that sound way off base???

[Chris Hammer]

I vote hot glue first..

[timc31610]

The terminal cup is likely the weakest part of your enclosure. If you are going to go through all of that it would probably be better to do as you said in your opening post and just glass it over and use bolts. Can you hear the air leaking out? is it so bad that is is affecting your output?

[philrab]

The terminal cup is likely the weakest part of your enclosure. If you are going to go through all of that it would probably be better to do as you said in your opening post and just glass it over and use bolts. Can you hear the air leaking out? is it so bad that is is affecting your output?

A. I've never fiberglassed before. Epoxy I can do.

B. I can actually hear the air whistling out on lower bass notes. It's nowhere near as bad now that I sealed up a few other leaks, but I'm a perfectionist and it's pissing me off.

It's debatable whether or not it's affecting output. This is a really small enclosure (.22 cu ft.) so even that little woofer (Image Dynamics ID8, 0.2 - 0.4 cu ft. sealed) is really loading the Hell out of it.

While I'm screwing with the enclosure. I had it packed with 0.3 lbs (1.5 lbs per cu ft.) of polyfill. Hard to tell by ear, but the bass sounded a little fuller and perhaps drove deeper, but on the other hand it sounded slightly muffled. Any opinions on polyfill? Perhaps I had it packed too tightly, and should have only had 1lb/cu ft. Currently running without it, bass sound a little hollow (best word I can think for it).

[Skullz]

Get a small square piece of 3/4" mdf and drill a small hole in the middle of it and feed the wire from the back through it and glue it to the box, viola no more air leak.

If the terminal extends past the wood inside the box, just use a hole drill and bore it out till it fits the side of the box with no gaps.

[_paralyzed_]

Is the cup removable? I'd remove it and goop the hell out of the back with clear silicone and then reinstall it. Put some silicone around the cup's lip while you're at it so that is for sure sealed too.