question about construction of enclosures

[uraberg]

When constructing an enclosure with simple butt joints, do you use screws and glue, or glue only? I plan on veneering the box (with formica), so the screws would be hidden.

I'm only hesitant because i don't want to risk delaminating or splitting the joints. The enclosure is made of 3/4 MDF, and I've had bad luck combining screws with MDF. These would be used in home.

 

[SpeakerBob]

When I do mine I drill pilot holes to stop the mdf from splitting. I use screws to hold the panels together while the glue sets then remove and fill the holes with car body filler (bondo) and sand.

Also the screws just need tightening enough to squeeze the glue out. Don't force them.

Rob.

 

[nigelwright7557]

I use two methods of construction depending on box.
1/ Screws and corner battons.
2/ Glue only.

The screws through battons works well but does leave screw heads showing so I usually cover the box in thin carpet.
The glue method works well too but needs very accurate sawing to ensure no gaps.
Advantage is now screw hears showing.

 

[planet10]

All of our boxes used just glue.

And MDF is not a good material for building a sub.

dave

 

[wirewiggler]

I am relatively new but I rabbit 3/4 Baltic birch plywood pin/glue/clamp. For glue I use polyurethane glue (Gorilla) and wet the surfaces with a rag before applying glue. The glue will foam up and expand and help fill any voids, however the box must be clamped securely or they will push apart. Be sure to scrape the excess off before the glue completely cures or you will be sanding for the rest of your life.

Bill

 

[tmuikku]

Only glue for final product, screws for fast prototypes.
Rabbet joints are nice and easy. Flush trim the edges with a router after all gluing done. Also a bit easier to assemble than with simple butt joint. Downside, requires a router + time for routing

 

[bob4]

Downside, requires a router + time for routing

or a rabbet plane

 

[uraberg]

For now the box is glued with butt joints, and I will just leave well enough alone. If it ever breaks, then that'll be a good reason to try some of these fancy joints.

Thanks for the replies.

 

[djn]

When you install good bracing, the butt joint is fine.

 

[phivates]

If you must use mdf, make your pilot holes for screws longer than the fastener. That is into the edge of the panel. Screws into the face are fine, if not re-used too many times. Weird stuff. It looked like the answer to our dreams at first.

 

[GM]

When constructing an enclosure with simple butt joints, do you use screws and glue, or glue only? I plan on veneering the box (with formica), so the screws would be hidden.

Fasteners weaken joints, so if used as clamps, then ideally remove them and use a glue/sawdust paste to back fill.

FWIW I normally drill a pilot hole for insetting paneling nails, then back filled. Too small in diameter to be a structural issue and never loosen due to being ribbed.

GM

 

[mashaffer]

I have often considered making a psuedo-rabbet by laminating two thinner pieces of stock since I have no router or table saw.

 

[Disco-Pete]

Fasteners weaken joints, so if used as clamps, then ideally remove them and use a glue/sawdust paste to back fill.

FWIW I normally drill a pilot hole for insetting paneling nails, then back filled. Too small in diameter to be a structural issue and never loosen due to being ribbed.

GM

How do fasteners weaken joints?

 

[GM]

Loss of material density/integrity, causing 'hot' [brittle] spots. If you want fasteners anyway, then use large glue/screw blocks cross pinned away from the joint to reinforce it.

GM

 

[ILikeFoodz]

I use the rabbets and flush trim as well. Did butt joints on my first build, and I will never use them again because of how difficult it was to get the edges lined up flush. With rabbets and flush trim, it all just fits together and supports itself, making glue up and clamping super easy.

 

[paulys55]

I used butt joints (no screws) on a sealed enclosure (MDF) for a Stereo Integrity HST-18d2. I did brace it fairly well. If you are not familiar with the driver, let me say it can move some air and I'm sure the pressures inside the enclosure are not trivial. It has held up fine so far but it was my first real enclosure build and if I were to do it again I would probably use Baltic Birch and some fancier joints.

 

[academia50]

When I built my DTQWTII I used dowels, the whole construction does not have a single screw, but if I made a new box, in a simple way and together, I would use screws, they put the panels in their exact place, like a guide. Then you take them out and drill with a wick of a diameter slightly inferior to the dowell. Finally they are trimmed flush and they remain aesthetically very well.
I did not use that technique because the upper joints were made at 45 degrees, a real pain if you do not have a carpentry cutting table.



DTQWTII from Argentina

 

[Cal Weldon]

How you do it depends on your tools and skill level. For many joints including butts, I use corner blocking and an air nailer. If you are limited, then screws are fine, it's just a very slow method.

 

[badman]

I generally just glue, the stock fails before the joints unless you did a sloppy cut job.