What's the best fasteners for subs in enclosures?

[LSN2meBoom916]

Pre-drills and PAN head screws do ok for me.

[Forevrbumpn]

Well, my buddy here on the forums, has used huge 1/4" roofing screws, and caulking, caulking was messy, but damn that speaker wouldnt budge for anything. Eventually the mdf started to break away, and needed to build a new box

[westvan_dude]

I always caulk, but just a very thin bead of silicone so you can pry them out. Does make it a lot more secure.

I'm still thinking of making the mounting face for the subs out of 3/4 or 1inch acrylic plexiglass. Wonder what screws work best for that. You'd want some kind of bolts with a large washer on the inside to distribute the pressure or the acrylic might crack. Any suggestions?

[LSN2meBoom916]

Well, pre-drilling and just using coarse thread, pan head screws works well as long as your woofers have a decent gasket w/ them, otherwise you should cut your own out of rubber/or cork gasket material.

Look at my box(members section)-thats how I mounted my subs directly to the 3/4" plexi.

On the pre-drilling you have to go real slowly and pull back/away from the surface so ur sure to extract the material you're shaving out as you go so it doesn't "bunch up" in the hole and cuase so much tension it cracks/chips the plexi. Heating the bit will help too (plastic=melting as you go)

Otherwise us a a dremmel/rotozip or other HIGH RPM tool that will purely melt the hole you want.

[westvan_dude]

Hey that looks really nice. How did you mount the plexi into the mdf? I'm looking to do something similar. I'm guessing you used some 1/4" fiberboard and wrapped that in vinyl? Hard to tell in the pics. I'm going for a painted smooth exterior so edges of the plexi should form smoothly into the glass/mdf somehow. Inside of your box looks real clean too. Do you have any pics of mounting the plexi in the box?

[LSN2meBoom916]

Hmmm, I'll double check but I'm pretty sure all the actuall "dirty work/build pics" are in the build log as per Steves request for the dirtiest pix avail so the Q's can be answered b4 they're asked.

As for attaching: I used 3/4" plexi AS the front of the box, and thus It was attached the same way you would attach the front of a box if it were 3/4" mdf: I predrilled it all (both plexi and the mdf it got screwed to) then I put a decent amount of Elmers Ultimate Glue (it expands a lil as it dries & is good for joining PLEXI to just about anything, including MDF), then I countersank the screws in the front of the plexi so i could fill the countersinks later w/ Bondo/body-filler and sand it smooth and in those greyish-blue primer pics the screw holes should be invisible due to this procedure+primering. 

So: Predrill everything, countersink everything, glue everything w/ good glue, be carefull when drilling plexi AND while screwing screws INTO those holes as it can still crack/chip, get em good and tight, and I like to "seal" the inside of my boxes the same way you might w/ silicone or caulking but I use resin/bondo milkshake on all inside seams to ensure airtight and STRENGTH in the corners. I have never gone all out like Steve and Used his "45's" But in a high SPL application it'd be a good idea. That box I built also has a piece of 3/4" plexi in the center part of the top section of the box that serves as a VERY STRONG brace and still allows light to travel around inside the box. I taped off THAT center peice of plexi about 1.5" from the edge all the way around and left the edge exposed so when I sprayed it w/ primer, & then white paint, the 1.5" gets covered by paint to hide the SCREWS that hit that otherwise clear piece of plexi. Doing so hides the screws that are needed to secure that plexi to the mdf. Then it is "Milkshaked" all around to seal it for reallies, no exceptions.

Repaint and that's how it looks all seamless inside.

The lil 1/4" plexi windows in the sides of that box are IN-LAID, as in sunken-in 1/4" and glued in place. Then "Milkshaked" and sanded smooth for a seamless look and primered/painted like the rest. They are mounted from INSIDE so the only force on them is still pushing them into place against the left over 1/2" mdf "flange" they are glued to. No way they gonna budge.

Hope that helped and wasn't too ridiculously long winded.