Might be a dumb question but, which is better?

Nails or screws when building a MDF 3/4")enclosure?

And if screws, which type? Wood screws or drywall screws? And what would be the recommended size to predrill the hole for these screws?


I know nails can split the MDF if they are too thick..

when i make my boxes i mock up the fitment of them and then pre-drill and countersink.

then i pull them apart. apply lots of wood glue, put the panel on and pin it with an air pinner...then screw it with drywall/flooring screws.

I usually put a screw in every 3 inches give or take with a pin in between each.

the pins and screws actually dont do too much structurally except hold the box in place for the glue to dry

If you have access to compressed air and a brad nailer then it is fine for assembly.

Do not use standard nails and a hammer.

For screws, use decking screws. They are only a little more than drywall and much nicer to use.

^^ Yes you will find with drywall screws that once and a while you will twist the head off trying to tighten them up. For 3/4" MDF I use 1-3/4" wood or deck screws. If you notice with these screws the have 2 little slef sinker bumps on the underside of the head. This will eliminate counter sinking, and speeds things up alot. Also they never break, well maybe once and a while.

What's countersink? What's a deck screw look like? And what are 'pins'?

I know what wood screws look like, almost like metal screws just with a large pitch.

And what's wrong with a nail and hammer? It would distort the panels?

Countersinking is used to make the screw head sit flush with the wood. Deck screws are the same as wood screws, just go and ask for deck screws when buying them to simplify things. Next "pin" is refering to brad nailing the box to gether before screwing it to prevent things from splipping around while screwing. LOL. That came out all wrong. regular nails are thick causing the MDF to spit apart, making it weaker. That is why we use 18 ga brad nails to "pin" our boxes, before screwing. [img]graemlins/laugh.gif[/img]

in other words you gotta pin em down real good so you can screw em the best you can

Personally I avoid screws or nails, and use a minimum amount to hold the box while the glue dries.
Pre-drilling MDF is almost mandatory,depending on the thickness. Drywall screws are a definite no-no. (they are called drywall screws for a reason)

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E.C wuz here

You need a screw with a smooth shank(no threads) for 3/4" under the head of the screw, or it will tighten to the top panel first and never squeeze the pieces together. The screw needs to spin freely in the top piece, while biting into the second. Drywall screws are not suitable for this, thus the breaking of heads.
I use "low root" wood screws, sometimes called particle board screws.
The shaft of the screw is thinner, and the threads deeper, giving more "bite" without the splitting problems.
I always pre-drill with a 7/16 bit, and make two passes in each hole to be sure I've removed enough material to further prevent splitting.
I find that with the right technique, countersinking with these screws is accomplished by just driving them in.

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Charlie Lamble
Sault Ste Marie ON

I'm sure you think you understood what you heard me say, but I hope you realize that what I said is not what I meant

I agree... all you need is a pair per joint to hold the box together untill the glue cures... (the glue is where the real strength is)

Edit: I like to use extra thick yellow carpender's glue...

[ September 21, 2005, 06:56 AM: Message edited by: Haunz ]

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