Foam and any other Amigas build questions

[AudioSQ]

I feel like I keep starting new threads for this build so while I only have one question, others may follow.

My question now is about the foam. Do I put it on the back three walls and top and bottom? All six sides? Do I put it over braces, just the braces behind the speakers? Do I wrap it around the brace, or do I just put it on one side of the brace (I used the bracing exactly as Paul's build has them) Do I put foam down in the bottom where the stuffing will be or only in the top half where the speakers are? I over think everything.. sorry. Thanks for any wisdom.

I dropped the speakers in the box to make sure the crossovers sound right after solder. The front baffle isn't glued down yet, and the speakers aren't screwed in, but I believe I'm going to like how these sound They sound very promising.

Bruce

[fastbike1]

Look at the link for TRS-80 on Paul's site, that will give you an idea about the lining. Any stuffing you add should be up behind the woofer. I know Paul says he used a wad of stuffing in the lower 1/4" of the cab but it isn't really doing anything there (not enough to absorb any of a standing wave. Either put the crossover on the bottom or put another piece of foam there. You may like the sound with a decent amount of fluffed polyfill up behind the woofer.

[johnastockman]

I feel like I keep starting new threads for this build so while I only have one question, others may follow.

My question now is about the foam. Do I put it on the back three walls and top and bottom? All six sides? Do I put it over braces, just the braces behind the speakers? Do I wrap it around the brace, or do I just put it on one side of the brace (I used the bracing exactly as Paul's build has them) Do I put foam down in the bottom where the stuffing will be or only in the top half where the speakers are? I over think everything.. sorry. Thanks for any wisdom.

I dropped the speakers in the box to make sure the crossovers sound right after solder. The front baffle isn't glued down yet, and the speakers aren't screwed in, but I believe I'm going to like how these sound They sound very promising.

Bruce

Hey, I wonder about these same details, also. What I've done is just line the walls, but don't wrap it around the bracing. Back, sides, top & bottom should be fine. If I have a cabinet that has bracing like the drawing shows, I cut out pieces and put them between the braces so just about all the interior surfaces are covered.


John A.

[AudioSQ]

So I bought some "metal sleeves" (I don't know the real name) to the screws into, so I wouldn't have to worry about stripping the wood if I ever had to take the screws out. Unfortunately when I screwed them in they split the wood a little. None of the splits are on the surface and they're pretty small. I tried to shove some wood glue into them. Is there anything else I should do?

[johnastockman]

So I bought some "metal sleeves" (I don't know the real name) to the screws into, so I wouldn't have to worry about stripping the wood if I ever had to take the screws out. Unfortunately when I screwed them in they split the wood a little. None of the splits are on the surface and they're pretty small. I tried to shove some wood glue into them. Is there anything else I should do?

Do you mean threaded inserts? Not sure if that's it...have some pix? If you get the right coarse-thread on your screws, and you don't crank them down too tight, you can usually remove them a few times before the wood or MDF is bunged up. Drywall-type screws aren't really the right kind. I've used them before when I didn't know any better and I didn't have good results. You want a pan-head style, not a countersink head, like a drywall screw. These are what I've been using when I didn't use a threaded insert with a machine-thread screw:




PE has them, part #081-425, a #8 x 1". #8's work well for woofers and mids, #6's for tweeters and terminal cups. Threaded inserts should be installed from the back so they don't pull out. It's become my favorite method for installing drivers for about 12 years and I've never had one fail or pull out. Wood glue might not work well to hold your sleeves in there if they're metal. I saw a tip once about using a plastic straw that's the correct diameter as a "sleeve", glued in with a little super glue. Something an old woodworker/furniture maker told me. Good luck...post some photos if you can, maybe someone else has a good tip for you. If you've bunged it up, a small hard-wood dowel glued in the old hole, then drilled out with the correct size pilot hole works well also.


John A.

[AudioSQ]

Well its too late to change the screws now :P The threaded inserts are already in. I'll keep those in mind for the screws for the tweeters though. The threaded inserts seem to be in snug. I'm not worried about them pulling out. I didn't put the wood glue around the inserts, but over the small cracks that they caused. The cracks are in the edges of the hole... I'll try to take a photo when I get a minute. Thanks!

Bruce

[johnastockman]

Well its too late to change the screws now :P The threaded inserts are already in. I'll keep those in mind for the screws for the tweeters though. The threaded inserts seem to be in snug. I'm not worried about them pulling out. I didn't put the wood glue around the inserts, but over the small cracks that they caused. The cracks are in the edges of the hole... I'll try to take a photo when I get a minute. Thanks!

Bruce

Super glue can sometimes work with those cracks, but if you got the wood glue in there, and you're not planning to take the drivers out too often or apply a lot of torque, I'm sure you'll be fine. I have some great tips for threaded inserts I've learned over the years, but only if the cabinet is still in the putting-together stage. Installing them from the back of the baffle has worked very well for me and after some previous issues, the only way to do it for me. I get the special made-for-MDF inserts from either Rockler or McFeely's. They have a coarse serrated deeper thread than the hardwood inserts I've tried. H-nuts can work, too, but some swear by them, others swear at them. I have never had any issues using H-nuts, whether it's spinning or getting cross-threaded. Let me know if you want to use inserts for your next project and I can share some good pix about how I do it and the inserts I use.


John A.

[AudioSQ]

Ok, I took a shot of what I was talking about. This is the worst example. Like I said, I smeared some glue on there to try and go in the crevices, but I don't know how well that worked. Most of them aren't as bad. I also threw in a shot of my foam and poly.. ya'll let me know if anything isn't kosher.

Obviously my wood working skills suck... I like to blame it on the tools. The 30+ year old table saw with out a guide didn't do me any any justice, but even with good tools my skills are still sub par.

[johnastockman]

I see how the MDF split, separating the "layers". You should be fine there. Try to push the glue in there, getting it in the separated layers. If you have a small clamp or a way to clamp that edge, a spring clamp will work. Make sure if you do that, you don't squeeze the glue out with too much clamp pressure. I've had MDF separate like that before and I smooshed some glue inbetween the separations, let it sit for a few minutes and then put some light clamp pressure on it. I have some small spring clamps and they worked great for that situation. I know you don't have a lot of tools, so push some glue in there and let it dry. If your table saw doesn't have a fence, you can use a piece of straight stock clamped to the table (C-clamps work well). A 1" x 4" x 2' piece of hardwood with a nice straight edge works, or a piece of aluminum. If you can find a length of 2 x 4 that has a straight edge, that works, too. Just get it parallel to the blade. Cabinets look great. Some of my first enclosures were made with a straight edge, saw horses and a circular saw.


John A.

[AudioSQ]

I've got several threaded inserts left over from my last build that I want to use on my current build, but I don't what the same issue of the layers splitting as pictured above. Any tips on how to avoid that? How big should I make the pilot holes? Should I make them larger and screw the inserts in with wood glue or gorilla glue? All advice is appreciated.

[fastbike1]

One to avoid the problem is to use plywood. Might not be the answer you wanted, but it will solve the problem. If you're asking a question about the size of the pilot hole, that may be some of your issue. The inserts typically include information on the size of the pilot hole.

I've got several threaded inserts left over from my last build that I want to use on my current build, but I don't what the same issue of the layers splitting as pictured above. Any tips on how to avoid that? How big should I make the pilot holes? Should I make them larger and screw the inserts in with wood glue or gorilla glue? All advice is appreciated.

[AudioSQ]

I think it might have been, I did a couple test runs with one size larger bit and no splitting. It just looks like the hole is too big, and it barely notches the rivets into the wood, but I gave some good tugs and it seems snug so I think it's a go.

[kevin007]

You might want to call or email Erich at DIYsoundgroup. He sells the flat packs for the amiga. Maybe he can sell you just the baffle before you glue the one you have in?

Then just make sure to drill a pilot hole first and use the inserts that are referenced above. Maybe that would work?

Kevin

[AudioSQ]

Sorry, the first part of this thread was from months ago. I've actually had the Amigas in my living room for a few months now. I had planned on getting the flat packs from Eric, but at the time they weren't ready and I wasn't willing to wait. I also drilled the holes today (for a sub, not another set of Amigas) and no splitting. It would have been smart to test the threaded inserts in test holes the first time around. I'm on my 5th or 6th build.. finally starting to figure things out a little.