Glueing MDF enough?

[protos]

Hi,
I have my first DIY speakers ready to be assembled and glued.They are small size monitors.However my woodwork class teacher told me that mdf doesn't glue very well and I should nail, screw or put dowels. This means either that there will be a cosmetic problem or a lot of extra work (dowels).I see lot of DIYers just glueing and clamping their speakers .
So is just glueing and clamping enough or not?

[Volenti]

Assuming you are using PVA or similar water based glue that will be fine for a set of monitor speakers, you can add small cleats on the inside corners for extra strength.

most of the cheap chinese speaker cabinets I've seen are some kind of MDF held together soley with glue, they seem to hold together ok.

[roddyama]

Originally posted by Volenti
...you can add small cleats on the inside corners for extra strength.

I always use this method when assembling MDF.

[BobEllis]

biscuit joinery is a lot easier than dowels, and an excuse to buy another tool.

I once helped a buddy build cabinets using his brad nailer, with cleats like Roddyama suggests. Boy, was that quick, and more accurate than I've been able to set screws into the cleats. Unfortunately I cannot bring myself to buy a compressor just to use a brad nailer.

[SkinnyBoy]

Originally posted by BobEllis
biscuit joinery is a lot easier than dowels, and an excuse to buy another tool.

you'll want a good quality biscuit cutter... the one I used was a Dewalt.... set you back like $AU300... lol
see my website for my boxes.. website.. website.. hmm.. lol

[x. onasis]

With small cabs, glues work just fine.

A biscuit (or plate) joiner is very handy. It adds some strength but mainly makes it easier to allign panels during assembly.

You can make a servicable plate joiner out of a router and a slot cutting bit, and make your own biscuits, (from the same stock if working with hardwoods) it's the accuracy of cutting the slot that's essential.

You could also use this slot cutter for spline joints, partial, or full length. (This can also be done on a table saw)

BobEllis- You've used the tool. I suggest looking at the package deals at the hardware warehouse. You can often get a brad or finish nailer and a small compressor for a reasonable price. Then you become an easy person to buy gifts for, as there are many reasonably priced pneumatic tools worth having on hand.

The speed factor of pneumatics is even dwarfed by it's handiness, when you consider both one-handed assembly, and the willingness to assemble those jigs that would make the job go much easier.

[jackinnj]

Originally posted by BobEllis
biscuit joinery is a lot easier than dowels, and an excuse to buy another tool.

I once helped a buddy build cabinets using his brad nailer, with cleats like Roddyama suggests. Boy, was that quick, and more accurate than I've been able to set screws into the cleats. Unfortunately I cannot bring myself to buy a compressor just to use a brad nailer.

I have used a friend's biscuit cutter (Fried) and it is excellent for cabinetry where there will not be a lot of stress -- it makes assembling cabinet doors a breeze. If the cabinet has to carry a load, however, the biscuits don't provide any strength -- use battens. Fine Woodworking did an article which reached the same conclusion -- about 2 years ago.

I would use screws and battens (I rip 1X4 into 1X1's) for speakers, just make sure to adjust your volume calculations for the added materials.

[Izrun]

A great place for air tools is Harbor Freight. You can get them for really cheap. I'm not sure on the quality, but what do you expect for a $14 brad nailer!

[Therac]

Like the guys said.... Glue works just fine. I use a speciel glue that "expands" when getting dry, so all small "cracks" are being filled and the box gets air tight.
Unfourtunately i don't know what the glue is called on English but on Danish it's called POLYUHRETAN glue! Does anybody else use this kind of glue? I don't know if PVC glue expands, cause i newer really use it?!?

Therac

[roddyama]

Glue joints holds just fine on MDF. The problem is that the glue joint is much stronger then the MDF. When you glue a butt jointit provides a lot of leverage against the joint and if you're not careful the MDF will split.