DIY sonosub end cap questions (1 Viewer)

[Sebastian]

Okay, 16" sonotube, ~44" high including caps/plugs and base.
I am planning on having 1" MDF plugs laminated to 3/4 BB plywood caps.
So I would have 1" of MDF inside of the tube and 3/4 BB outside, cut little bigger so it overhangs the tube a little.

Q1. Are there any issues with gluing MDF to BB?
Q2. The Baltic birch is from home depot and it cost 14.97 for 2'x4' section labeled Baltic Birch HDWD. Looks like it has 13 or 15 plys. Is this the marine grade?
Q3. If not, will it be okay to use it, since I am using the MDF as the plugs?
Q4. I am planning on using the same BB for the base. Is 3/4" base thickness okay to use?
Q5. What should I use, standard wood glue or polyurethane wood glue?
Thanks

 

[Hank Frankenberg]

Sebastian:
1. No issues gluing. Use carpenters glue, use enough and spread it evenly, clamp or lay on flat surface and weight it down with LOTS of weight.
2. & 3. Probably not marine grade, but that doesn't matter.
4. 3/4" base thickness is fine (I assume the same 1" plug)
5. See #1.
Food for thought: Why are you making the top and bottom outside caps with plywood? I made my top parts all MDF - 3/4" plug and 3/4" top cap. My bottom plug is 3/4" MDF with 1/2" plywood glued to the inside side of the plug to give driver screws additional material to "bite" into. My outside bottom cap is 3/4" MDF. If you make your outside end caps from MDF you gain the advantage of easy machinability - You can route a roundover, bullnose, or fancy profile with a router. Also, if paint is your choice of finish, it'll be easier to get smooth coats on MDF.
Have fun

 

[Sebastian]

The reason for MDF plugs is added weight and cheaper.
I would like to use 3/4 Baltic Birch for the end caps so I can stain them maple. I will just use BB edge banding.
If I do decide to go with paint, I will just use MDF all the way through.
Right now, I am planning on,
The bottom end plug/cap will be 3/4 BB, 1" MDF and I am thinking on using 1/4 regular plywood for the T-nuts. That is if I use T-nuts for the driver.
The top plug will be 1" MDF plug and 3/4 BB for the cap.