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My First Speaker Build

Alien, what gap are you trying to close? The rear removable panel gap? Believe it or not I struggled with the same dilema recently. I bought some 3/8" weather stripping and if squeezed tight enough it will shrink down to 1/16th of an inch which was perfect. The stuff is a beast to conform but once it's there, the stresses of getting it there are no more. Post some photos of your problem area.
 
StevenZ said:
Alien, what gap are you trying to close? The rear removable panel gap? Believe it or not I struggled with the same dilema recently. I bought some 3/8" weather stripping and if squeezed tight enough it will shrink down to 1/16th of an inch which was perfect. The stuff is a beast to conform but once it's there, the stresses of getting it there are no more. Post some photos of your problem area.
Click to expand...

That sounds like my problem. I will just go with it and see how much I can squeeze it. I will also paint it to match the rest of the speaker.
 
Yeah, just sink some screws in it and hope you used enough glue and nails. :) I can't wait to read your impressions. I've cut out all my pieces and am ready to CNC the openings tomorrow. I'm so excited! :)
 
Well, this project has quickly gone downhill. I put on the weather stripping, used straps and secured the back to the body, and drilled holes for the screws. When I screwed them in, the MDF cracked on the edge, no matter how far from it I placed the screws. On top of the cracks, one of the holes is already stripped.

How can I fix the first speaker? How should I proceed with the second speaker and what size of screws should I use to secure the back to the body?
 
Did you go with the 1/2" or 3/4"?

When using screws in MDF I use coarse thread drywall screws and pre drill a hole just about the size of the screw shaft. Usually I just glue and clamp. The joint comes out stronger than the MDF around it, however that won't leave you a removable back.

As for repair, fill the holes with wood putty and start over in a new location with slightly bigger holes. MDF is finicky stuff with screws.
 
I learned the hard way too... that you can't screw into an edge on MDF or it will split every time. Fortunately, glue alone holds MDF amazingly well, even edge glued joints in MDF are quite strong. And if you have a table saw, you can rabbit the edges so that the pieces self-align for glue-up. Another trick for aligning pieces for gluing is to drill small pilot holes and insert tooth picks.
 
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RayW said:
Did you go with the 1/2" or 3/4"?

When using screws in MDF I use coarse thread drywall screws and pre drill a hole just about the size of the screw shaft. Usually I just glue and clamp. The joint comes out stronger than the MDF around it, however that won't leave you a removable back.

As for repair, fill the holes with wood putty and start over in a new location with slightly bigger holes. MDF is finicky stuff with screws.
Click to expand...

I went with the 3/4" MDF. I want the back to be removable in case I need to fix or mess with the stuffing.
 
Then your best bet is to glue and/or screw solid wood cleats (basically just blocks) that you can screw into without splitting. It'll take up some interior volume though. You can glue them to the sides, top, and bottom flush with the back edge, put the weather stripping around the enclosure walls, and then screw into the cleats.
 
You should've made the removable back a flush inset type. Where you'd put cleats in the back of the cabinet about 13/16" from the edge so whenever you apply your weather stipping and put the back in, it will be flush. Another good idea would have been to use a combination of plywood and MDF. When building cabinets with removable backs, I make the back panel and the cleats of plywood for this very reason. MDF strips easily but can but can be fixed with wood glue and/or bondo.

Another idea would be to use hurricane nuts to secure the back down, wing nuts, or just plain ol' silicone. Though if you use silicone or any other gasket/sealant type, make sure everything is properly connected and working before you seal it up. You can always take out the woofers if you need to add or remove stuffing. Get some wood glue, smear it in as far as you can into the crack, put some masking tape over it, and clamp the sucker. This should fix the splitting material. Good luck, and post some pictures if you need more assistance.
 
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My guess is that you are trying to compress 3/8" weatherstripping to invisibility and the excess torque on the fasteners is what's causing the problem with cracking.
If you have a router, you could either cut a channel in the back edges to accept a "D" profile weatherstrip or cut a rabbet to accept flat weatherstrip. Either of these methods will remove the necesity of torquing the fasteners beyond tight.
Ray's idea of the cleats is also good. MDF is not really that good for frequent unfastening and fastening. If you are only making provision for future access, fastening into the MDF will be OK.

This is a picture of installing the "D' profile butyl rubber strip in a panel:

IMG_0004.jpg
 
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westend said:
My guess is that you are trying to compress 3/8" weatherstripping to invisibility and the excess torque on the fasteners is what's causing the problem with cracking.
If you have a router, you could either cut a channel in the back edges to accept a "D" profile weatherstrip or cut a rabbet to accept flat weatherstrip. Either of these methods will remove the necesity of torquing the fasteners beyond tight.
Ray's idea of the cleats is also good. MDF is not really that good for frequent unfastening and fastening. If you are only making provision for future access, fastening into the MDF will be OK.

This is a picture of installing the "D' profile butyl rubber strip in a panel:

IMG_0004.jpg
Click to expand...

Nice work, did you cut that groove with a router?

Russellc
 
Hm, I do not have access to a router. I think I will go the route of gluing the back on and just removing a woofer if I need to adjust the stuffing.

What order do you recommend I paint, put in the crossovers, woofers/tweeters, and glue the backs on?
 
Install the crossovers, seal up the back, tape the openings and paint away. Obviously leave long enough leads for you to reach in and grab so you can solder them to the drivers after you uncover the holes.
 
Don't forget to install and tape up your binding posts or terminal cups as well before painting. Good luck! Double check and triple check the crossovers for proper execution. Once they're sealed up, it will be next to impossible to modify/alter them in any way.
 
I usually make crossovers that fit through the woofer hole. I finish out the box (glue, sand, paint/stain/veneer) then install the crossovers through the woofer hole, then install the drivers.
 
Keep in mind that the woofer cutout is only 3-5/8". Not much room to get a hot melt gun in there to fasten down the XO when it's done.
 
I like to use masonite (clipboards work great) as a base for the XO, put some spacers on the corners, and screw it into the back of the enclosure from the inside. I've got a monster long phillips screwdriver just for that. If something goes wrong with the XO it's easily removed and fixed.

edit: looking back at the OP's crossovers, they probably won't fit so it's a moot point.
 
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