Liquid nails good enough to hold endplates on sonotube sub?

[GuyPanico]

For my first DIY project, i'm going to be making a sonotube sub. My question is regarding my method of attaching the endplates. My idea was to cut a .125" wide, .5" deep circle in each end cap so the sonotube will slide in. Would liquid nails alone keep the endcaps secure? I know from past uses for car boxes, liquid nails is just about as good as screws. I just want to run it by you guys first for approval

Also since i'm on the subject...i'm going to be firing the sub downward, and the ports upward. How much clearance should I give the driver (12") and the floor (or base plate if I do it that way) on the sub? 3" or so?

Thanks guys!

[GuyPanico]

The enclosure is approximately 12.5" (tube) x 52" (overall). The ports are 2.5x15.5 (may do a single 5x31" tube for simplicity). I dont know the exact inner diamter of the sonotube since I havn't bought it yet. So my final dimensions are as of yet only estimates. I think the final finish will be done in that textured, stone looking spray paint. I staggered the ports because I think it might look cool, and might disperse sound better (maybe?).

[mrlots2do]

Your WinISD response graph could go much lower. The 2.6 cu ft volume seems much to small for this driver. I have an 8.3 cu ft sonosub, ACI SV12 driver, down firing, 3 ports down firing. double thick end caps (1/2 inside tube), end caps bolted together with 3 pieces 3/8" all thread, base plate with 4" risers below driver.

Had one construction failure, I think the sonotube had shrunk, came loose or I blow the end cap off.

Phil

[mrlots2do]

Your WinISD has several important parameters missing.

[pinkmouse]

On the topic of glueing, a few finish nails or long staples would give more strength, and hold things together whilst the glue sets.

Make sure also that the glue has two or three days to set off before you put the driver in, no-nails has some pretty wicked solvents in it that may damage the driver.

[Volenti]

I wouldn't recomend liquid nails, in had some of my older enclosures that used liquid nails it went hard and brittle and lost adhesion (one enclosure I removed all the screws, test dropped it from a modest height (2') and it fell completly apart)

I only use PVA wood glue for my enclosures now.

[zobsky]

liquid nails will work, .. if it worked, in one case, to hold a 16 ft sonotube transmission line to a 3/4" circular endplate

however, i think your method is not optimal, .. get hold of a plunge router and route out something that can fit snugly inside the sonotube eg. http://www.diyaudio.com/forums/attac...amp=1089125144

also, take some sandpaper and roughen up the sonotube as it is usually coated with some sort of waxy mould-release compound which doesn't support adhesion.

another alternative is (PL brand) polyurethane construction adhesive which expands somewhat when curing to fill any gaps

i used that when building the EBS sonotube enclosure for my shiva (driver currently on sale - shameless plug )

good luck

[GuyPanico]

Thanks guys. I'll use PVA and finishing nails.

As for my curve, i'm not really sure where to make the compromise between volume, tuning frequency, and sound quality. This sub will be used for 80% music, 20% HT. So i'm wanting to keep it musical. I unfortunantly dont have the rest of the T/S specs for my driver, as much as i've tried. I entered fake numbers to fill in the empty variables for WinISD, and it didn't effect my curve or tune. What are the other specs used for?

Thanks again guys.

[GuyPanico]

With the ~12"x48" tube I was planning on using, after taking into account driver/endcap/port displacement, I should have about 3.1cuft of air to make use of.

Here is my original 2.6cuft cabinet vs. 4.7cuft vs 3.1cuft. (sorry for large pic.)

[Collo]

I use PVA glue to stick endcaps on. I like to make the caps from 2 layers of MDF and use a router to cut down the sides for an exact fit. I stop just past the join, which gives plenty of surface area for the glue.
After drying, I use a flush trim bit to make the visible MDF the same diameter as the tube, and then use a rollover bit on the edge.

This picture is from a project that required an extra thickness, which explains the extra layer and port, but you get the idea...