Speaker Cabinet Joinery

[Nestor]

I have Festool, including the TS55, tracks, and the parallel guides. It's great for knocking down large panels, but 4 ft crosscuts can be time consuming to line up if you have a lot of them. I have the MFT as well, and it makes dead-square cross-cuts, but it's too small to handle a full sheet.

I have to disagree about tear-out. The TS55 makes clean cuts, but with a zero-clearance insert (or sled) , my table saw can still do better.

IMO, the Domino is superior to biscuits, and it's much faster than fiddling with mortise and tenon joinery, but I would put it at par with dadoes and rabbets for speaker cabinet builds. I think the Domino is geared towards production woodworking where time is money.

MDF isn't really "porous", per se. The reason to use construction adhesive (PL Premium seems to be the glue of choice amongst the speaker crowd) is that it expands considerably, making for air-tight joinery. This also applies if you were to use plywood for your build. Don't use Gorilla Glue. Though it expands, it's too runny to make a good seal like PL Premium.

And to add to Swerd's post about hurricane nuts: add epoxy to the threads before running them into the wood. It will make them more secure and reduce the likelyhood of spin-out.

 

[Swerd]

MDF does not require sealing before gluing with standard polyvinyl acetate (PVA) carpenter's wood glue such as Titebond or Elmer's. Its easy to use, cleans up with water before it cures, and nothing creates a stronger bond with wood. Wood glue works when the joint surfaces fit together well, and requires clamping the joint for a half hour to an hour.

If you want to paint MDF, any cut surfaces do require sealing. A ready and simple way is to use a mixture of equal parts wood glue and water.

The only advantage I see with using a polyurethane glue like Gorilla or PL Premium is if you have wood joints that fit together poorly. Their ability to expand as they cure can fill the gaps, but the glued joint won't be as strong as with wood glue. I don't like using polyurethane glue because cleanup is more difficult, and it stains my hands. Wood glue cleans up with a damp sponge before it cures.

Probably the greatest advantage to DIY is that there are many methods that can work. It often depends on what tools are available and individual preferences.

 

[TheWarrior]

Nestor, I trust you are using some type of dust extraction when you cut? Have you also tried slowing your cuts down to ensure proper 'cleaning'? I'm surprised to hear you say that as I may have had beginners luck, but encountered nothing but perfect cuts except where my inexperienced user errors got the better of me. My first and only experience with this saw was when it arrived, and used a scrap sheet of plywood to make a box with 45 deg bevel joints that I just shot a few brads in to while I was waiting for the Domino. But I very quickly was able to square up the sheet using the track and a fine straight edge. But we are in agreement that table saws will never be made obsolete. Thankfully my dad has one, haha.

The Domino 500 is just an amazing machine. Never intended it for speaker building, but I see where exposed tenons could dress up a veneered cabinet in a unique way while giving rabbets and dado's something extra to lock them in. Completely unnecessary but it will put my kitchen cabinets in a league of their own.

For Nestor and Swerd, thanks for the tips with mdf. I have almost no experience with it, but recall trying to use some type of 'cement' that just kept absorbing in to the board and never joining them, until I allowed the first coat to dry and seal the mdf. My wife very much loves Piano Black style finishes, so yes I will be sure to seal the edges and possibly the whole cabinet so I can give it all a very fine sanding to ensure a flat surface to achieve a mirror finish.

 

[Swerd]

… My wife very much loves Piano Black style finishes, so yes I will be sure to seal the edges and possibly the whole cabinet so I can give it all a very fine sanding to ensure a flat surface to achieve a mirror finish.

If you plan a glossy painted finish, and you can make 45° miter cut joints that fit together well, that is the way to go. That way there is no exposed cut wood at the joints. Exposed cut wood can "telegraph" through paint or veneer.

I've tried painting once, and learned I hated it. In my hands it is much harder to do well than veneering.

To achieve a smooth glossy paint surface, you will have to apply 1 or 2 primer or sealer coats, spray on about 4 coats of black paint, and finally 1 or 2 clear coats. Fine sanding between coats is essential. So is dust control.

Or, you can take your cabinets to an auto body shop and ask them how much they charge for a high-gloss black finish. They certainly do a much better job than I could.

 

[TheWarrior]

Swerd I like your optimism that I'll be able to get a mirror finish in 1-2 coats of clear! Question, what type of finish do you prefer with paint? Should I just get some rattle cans of lacquer? I've not done any painting (other than walls) since I worked for a sign shop. I'm like you in that I prefer wood finishes generally and find it easy to work with. But I can't deny my love for a deep flawless black cabinet!

 

[Swerd]

Swerd I like your optimism that I'll be able to get a mirror finish in 1-2 coats of clear! Question, what type of finish do you prefer with paint? Should I just get some rattle cans of lacquer? I've not done any painting (other than walls) since I worked for a sign shop. I'm like you in that I prefer wood finishes generally and find it easy to work with. But I can't deny my love for a deep flawless black cabinet!

Seriously, for paint I prefer to let an auto body shop do the work. They have experience in filling gaps & preparing smooth surfaces, automotive paints, spray booths, dust control, and polishing equipment.

I've also purchased pre-made finished cabinets from Parts Express with excellent glossy black finishes. But I will never (again) try to do a glossy paint job myself.

Run away from that shelf in Home Depot with the rattle cans of lacquer.

 

[Swerd]

But I can't deny my love for a deep flawless black cabinet!

Read this long but helpful build thread. There are lots of good photos.
http://forums.audioholics.com/forums/diy-corner-tips-techniques/68531-new-diy-mtm-towers-designed-dennis-murphy-paul-kittinger.html

This thread should be required reading for any DIY builder who says he wants to finish his speakers with some glossy black paint. You know, nothing complicated like veneer .

The part where skyline_123 begins his glossy black paint job starts on page 7 and continues. Wet sanding appears on page 10 and continues.

Here are his final results (see page 10 for more photos)

 

[TheWarrior]

Challenge Accepted.

And I'll post up the process so there's a current thread!

 

[Nestor]

Nestor, I trust you are using some type of dust extraction when you cut? Have you also tried slowing your cuts down to ensure proper 'cleaning'? I'm surprised to hear you say that as I may have had beginners luck, but encountered nothing but perfect cuts except where my inexperienced user errors got the better of me. My first and only experience with this saw was when it arrived, and used a scrap sheet of plywood to make a box with 45 deg bevel joints that I just shot a few brads in to while I was waiting for the Domino. But I very quickly was able to square up the sheet using the track and a fine straight edge. But we are in agreement that table saws will never be made obsolete. Thankfully my dad has one, haha.

The Domino 500 is just an amazing machine. Never intended it for speaker building, but I see where exposed tenons could dress up a veneered cabinet in a unique way while giving rabbets and dado's something extra to lock them in. Completely unnecessary but it will put my kitchen cabinets in a league of their own.

For Nestor and Swerd, thanks for the tips with mdf. I have almost no experience with it, but recall trying to use some type of 'cement' that just kept absorbing in to the board and never joining them, until I allowed the first coat to dry and seal the mdf. My wife very much loves Piano Black style finishes, so yes I will be sure to seal the edges and possibly the whole cabinet so I can give it all a very fine sanding to ensure a flat surface to achieve a mirror finish.

Yes. I have a CT26 as well.

Don't get me wrong. It makes great cuts; and when compared to a properly set up table saw, you have to look really close to see a difference.

It was only when I got more serious into woodworking that I (ahem) saw the difference.

If you were using a veneer plywood and were trying to hide the edges with mitred joints, the Domino would definitely help. Especially if one doesn't have a table saw to make splined mitres.

 

[TheWarrior]

Next time I'm in Ottawa I'll see if you can show me the difference!

 

[Nestor]

Next time I'm in Ottawa I'll see if you can show me the difference!

Lol. Not sure where you are, but Ottawa is about an 8 hr drive to my place.

 

[TheWarrior]

Are you closer to the YYZ or further West? I haven't been to Ottawa in a long time, but dearly miss my "32nd cousin" and have been wanting to drive my diesel up there to visit. They live right on the river and its just gorgeous!

 

[lsiberian]

Dado is about the only thing the TS 55 and TS 75 can't do. But that is even more easily accomplished with a Festool router as it can utilize the track in the same way the saw does.

Repeatable cuts, such as rips from a 4x8 are accomplished with the Parallel Guide. Larger pieces can be cut with a jig and the track saw fixed on a Festool work table, or a DIY one with the rear bracket to lock the track on to. The track is then able to pivot vertically, so that it lifts out of the way, a new piece can be situated and then you just drop the track back down, place the saw and cut!

I think the biggest advantage over a table saw are the flawless, glue ready cuts that are made. Zero tear out, even on a bevel cut. But for me, what these tools provide are the elimination of the big stationary machines used for cabinetry as I will be switching gears this winter and will build up an inventory of kitchen cabinets to be sold online next year. So there in lies how I justified the cost. And then of course a couple speakers might get built too...

Back to construction adhesive, that makes perfect sense even more today now that I consider how porous mdf is, it would need to be sealed to use wood glue. I trust the construction adhesive eliminates this?

It makes sure there is no leak between boards so for my reference builds I tend to use it instead of titebond. I don't use it for lower level projects because it's a lot of work to deal with as Swerd points out. Believe me it wasn't an easy choice for me to go table saw I went back and forth for months, but for Speakers the precision needed on cuts is higher than normal construction. I probably won't be buying tools again until I get a house though.

 

[ARES24]

One more hint. I've tried Hurricane nuts and T nuts in the past. I hate them, especially with MDF. I've had much better results with threaded inserts like this:

Don't use this kind (they work in hardwood but not MDF or plywood):

And frankly, for those 7" drivers in the Thor, I would skip the threaded inserts and screw directly into the 1" thick front panel with #8 black pan-head screws with a coarse thread like these:

I don't have a drill press, and when I used threaded inserts, I found it difficult to drill 6 perfectly perpendicular holes for the inserts. When I drove in the bolts, the last one in never lined up correctly. With wood screws, you have a little more latitude, and they are plenty strong for a 7" woofer. I use the threaded inserts for heavy woofers bigger than 8".

Edit:
When I mount woofers or tweeters, I pre-drill holes for the screws. I would never trust myself power driving screws. One slip and you buy a new woofer. I also try to always use screws that can accept a square drive tip. Again, it's too easy to slip with a flat blade or Phillips head screw driver and punch a hole in the speaker cone.

I like this style of screw. I take the washers off and then it is impossible to slip off and damage the cones or cabinet.

They also come in spiffy colours!!!!

 

[TheWarrior]

It makes sure there is no leak between boards so for my reference builds I tend to use it instead of titebond. I don't use it for lower level projects because it's a lot of work to deal with as Swerd points out. Believe me it wasn't an easy choice for me to go table saw I went back and forth for months, but for Speakers the precision needed on cuts is higher than normal construction. I probably won't be buying tools again until I get a house though.

Thank you and everyone else for educating me on adhesives. I am currently sourcing 1" mdf to compare the price to what gluing two pieces of 1/2" would run. In learning more about how Transmission Line speakers work, I acknowledge the need for that cabinet to be as rigid as possible and that 3/4" simply won't cut it. As I do not yet have routers, I am going to start with the other 3 sides. My goal is to work occasional weekends piecing the cabinet together so that by Xmas (when I believe Madisound did some holiday pricing last year) I'll nab the drivers etc. and bring the Thor to life!

ARES I believe Madisound normally includes hex heads in their kits, but if not I will request either those or the square drive for the driver mounts. Because the Thor is supposed to have a removable base that houses the crossover, I will make the baffle permanently affixed to the cabinet, which also would be necessary for the piano gloss paint job I plan to do. Call me crazy, guess I'm just a glutton for punishment! (really just want to know if I can even do it!)

 

[Nestor]

Are you closer to the YYZ or further West? I haven't been to Ottawa in a long time, but dearly miss my "32nd cousin" and have been wanting to drive my diesel up there to visit. They live right on the river and its just gorgeous!

I live near the Lake Huron shore.