MDF or MR MDF?

[PhiLyn]

I've been asked to construct some MDF shelves in a living room. Do I need to use MR MDF or would oridinary MDF suffice. I only ask because my local Travis Perkins tells me that MR MDF is not being used much any more.

Cheers in advance

 

[big-all]

heelloo PhiLyn

shelve unsupported span depth and likely load would be handy for us to tell you if mdf is up to the job

 

[PhiLyn]

That was going to be my next question.... The client would like a 300mm deep shelf with a total span of around 2000mm. They also want a 'chunky' looking shelf which I have found some 50mm think MDF (not MR) for the shelves and I'll use some thinner (and cheaper) for the carcass. I'll support the shelves along their length as often as is necessary (possibly with concealed brackets). They're just planning to put books and DVDs on the shelves (no lead weights0

So that's the plan. Sounds fun doesn't it?!? Is MR MDF the better product to use or given that i'm not in a wet area would normal stuff do?

 

[big-all]

dont use mdf unless you are popye with huge muscles

with mdf you will need support at ideally 650 and 1300mm

if you want chunky scaffold boards old or new are around 40mm thick 9" wide and cost 1-£3 a foot

most book shelves i make are planed pine 9x1 [22mm x 219 ] is more than wide enough for 95% off books

shelves for cds and games are better with 5x1" [22 x119] otherwise they get lost at the back

if its a large area i make from several units top halve narrower

for example 8ft x8ft will be 6 parts floor standing so they can be moved at will

 

[JohnD]

I'm not an MDF enthusiast (though it is easy to paint) and big-all knows more about woodwork.

But for a "chunky" shelf you can fix a "beam" to the front edge of the shelf, it makes the shelf look thicker and adds strength and rigidity. If you wanted, you could put an MDF lip to hide it so the finish matches. It will also help to conceal any intermediate brackets.

The back edge of the shelf can be on some kind of continuous batten as well to reduce bowing.

 

[PhiLyn]

Cheers JohnD. I suggested this as I've done these before but the client didn't like the idea.
Big-all - thanks for the ideas. I'm gonna head to the timber merchant and see what they've got.

I'm still unsure though (for future reference) when to use MR MDF rather than good old MDF?

 

[Burnerman]

Moisture resistant MDF - now thats a bit of a misnomer if ever there was one.....the standard stuff's fine, barring the limitations mentioned above!
John