# SDX15 Sonosub Build



## CBMC (Nov 30, 2009)

Ok, I have finally started my SDX-15 Sonosub. I am using 24" Sonotube @ about 385L tuned to 15hz. The ports are 8.15 inch sonotube (actually quik-tube). I have already made my first mistake, I glued the ends together before cutting out the driver and port holes. I am hoping that my router will be able to get thru 2.25 inches of mdf (1.125 because I will cut from both sides using the pilot hole for the circle jig to line up). 

Anyways, to avoid any other "mistakes", I wanted to know a couple of things:

1. I only have a 1/4" shank on my router, thus only have a .5" roundover bit. With the 8.15" port will a .5" port flare be suffice?

2. I have heard people mention liquid glue to attach the endcaps to the Sonotube. Would Gorilla Glue work as well (I thought that the expanding properties of Gorilla Glue would help seal the endcaps) Would also use Silicon to seal.

3. I have heard of people using crutches for the legs on the Sonotube. Is there any readily available product that people use for the legs? I have head dowels, but how are they attached? What are they commonly called? Where do I find them? I am thinking I need about 5"-6" ground clearance based on my sub.

4. Finally, I have read on here that you want a certain type of foam for dampening the inside walls + port walls. What is the most common/cheapest way to obtain such material?

I am sure that many of these questions have been covered somewhere on this forum, but sifting through 1000's of pages of threads just takes so long.

Anyway, forgive a relative newbie for his ignorance.

Thanks in advance.


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## SteveCallas (Apr 29, 2006)

1) Any flare is better than no flare, so while 1/2" isn't ideal, you should still do it.

2) I'm not a fan of using any adhesive between the endcaps and tube myself, just tight tolerances, but if you must use adhesive, I'd use something viscous in fear of the tube absorbing it and getting mushy and weak. The interior of the tube is wrapped in a wax paper to prevent just that, but either way, on large scale projects, better to be safe than sorry.

3) I used large diameter dowel rods, the kind that are meant for handrails or bannisters. I've seen other people use 2" x 4", furniture legs, metal pipe with threaded rod inside, etc. It really doesn't matter what you use as long as it can support the weight and is rigid. If you've already glued your endcaps together, then I would consider using threaded rod through the cap, legs, and baseplate to hold it all together.

4) Polyester batting, fiberglass batting (pink insulation), or open cell foam all work, it's not critical. You can even jam cheap pillows between the top cap and port if you like.


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## CBMC (Nov 30, 2009)

Thanks Steve. So what is the viscous type glue would you recommend. My endcaps sort of stay in the sonotube by themselves, however, I would feel more comfortable with some glue to help hold the on. I have Gorilla Glue, Elmers Wood, and Liquid nails on hand.


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## Mike P. (Apr 6, 2007)

I used Elmers Wood glue on my tubes, it works well. There is a transparent release film on the inside of the tube that glue won't stick to, it peels off easily once you get it started.


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## CBMC (Nov 30, 2009)

Thanks Mike and Steve.


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## CBMC (Nov 30, 2009)

If I were to say buy a 1/2 collet router, along with a roundover bit, what size round over radius would you recommend? 1.5 inch, 1.25, etc. Also, would it be advisable to use flared donut rings on the port intake, if so, what size roundover there?


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