Originally Posted by J_P_A
Thanks for the email. Here we go
OK sorry I forgot all about this.
So I was asking what the sealing calk is for?
There can be different strategies for sealing the box joints, versus the woofer, waveguide/CD, and terminals.
For the box sealing- I use PL premium when I construct my boxes. Wood glue isn't trust worth for airtightness. It works, but not quite well enough for me. If I used wood glue I would go back and hit all the interior corners and joints with some simple caulk, like the weatherproofing stuff you buy cheap at the hardware store for the caulk gun. The stuff that is designed to be weatherproof, (I.E water and air sealing.)
Put on a latex glove, and use your finger to push it into the joint and smooth it flat. That's all.
If you use PL premium, do the same thing except you can use the PL premium squeeze out and do not need the caulk. When I glue up my boxes I usually put the PL on a tad heavy, expecting squeeze out. Squeeze out is good, you want that. When possible I put it on heavy on the inside, so the majority of the squeeze out goes inside the box if possible. Not always possible to do it like that though, and I also take a normal glue brush and trim the bristle length in half so they are shorter and stiffer, and spread the PL smooth and butter across the entire surface. I apply the PL to the cut end, or the 3/4" end of the piece, and not to the flat factory surface that would otherwise be part of the 4x8 surface of the sheet. Hopefully that makes sense? The PL adheres fine to either so I don't think it's that sensitive but that's just how I find it works best. When the squeeze out occurs do the same latex glove and finger thing, spreading smooth the PL premium in the joint. When it hardens it's all over, and air tight. There is nothing extra you need to do. It will never leak or break apart.
If you want a picture let me know, but really it's simple:
Shoot PL on the piece, spread it smooth and cover entire surface with a small glue brush, stick it together and either brad nail it in place while it cures, or use a clamp. I like to do both. I brad it first, then after the box is built I clamp up to tighten it up while it dries. The brads allow sufficient rigidity and structure to move the box around before the glue is cured, so I usually build with with brads as permanent clamps, move it to where I want to leave it for 24 hours and then clamp it up nice and tight. I often use gravity to help, if you have a heavy subwoofer, some cast iron tools, gallons of paint, car battery, 5 gallon bucket of sheetrock compound etc... place it on top. There is always something laying around. Then all you need to really clamp is the two sides with horizontal placed clamps, because gravity does the vertical directions for you. Saves you on needing a million clamps if you do multiple boxes on the same day.
That is how I do it. Then sharpen a chisel up really nice so you can shave with it, and run it along the outside squeeze out after it cures, it peels right off perfectly flush and nice looking saving you a lot of finish work. If the PL is fighting you wait another day or so and let it cure better. It should be fairly easy to come right off when you do this.
That should get you air tight boxes. There is a lot of room for error if you do it my way. If the cut is off a tad, or there is a small gap the PL makes up for that. You'll want super identical cuts if you use wood glue. Are you making your own boxes? Like cutting the pieces?
I love the tracks saw, but I find that after they are all cut up setting the fence on the table saw and running every piece through with the identical dimension is still a great idea. Sometimes it only takes off a 1/16th of an inch, occasionally it takes of 1/8th or 1/4" and I say to myself WTF was going on when I marked it? The process takes probably 5 minutes and results in a perfectly square box, and allows me to mentally relax when using the track saw and not have to measure twice, pay attention etc... When I set the track down, I usually do it in the direction it will be slightly over, and not under the line- resulting in a piece that is either perfect or slightly bigger than I needed. Just make sure you put the track down on the right side of the line to do that, and you'll come out fine.
As for woofers- I like the adhesive stick on stuff.
Stick it onto the back of the woofer. It curves nice and is easy to work with. The back of the woofer is usually machine metal and perfectly flat, it should stick right on and not at all be a source of poor seal. The rubberized gasket material then faces the enclosure and will compress when you tighten down the woofer making an air tight seal. This stuff works really good. Sometimes subwoofers or speaker kits might come with some. But this stuff is GOLD. This is also the same stuff you use on the back of the SEOS15 and waveguides. Same idea... stick it directly onto the waveguide.
AE TD15M + SEOS15 + DNA360 (active crossover) Need advice pls... :)
That post had some pics when I did mine. I actually used both.
First the stick on stuff,
Then the putty crap:
The putty strips also work great for speaker terminal plugs: