Say you had three boards cut to form shelves: one each of the
following materials:

1) MDF
2) Plywood (the rough stuff sold at B&Q)
3) Pine

Which will be the least prone to sagging when weight is applied?

Thank you,

Mike W

On Sat, 30 Sep 2006 10:58:17 +0100, Mike W W wrote:


Say you had three boards cut to form shelves: one each of the
following materials:

1) MDF
2) Plywood (the rough stuff sold at B&Q)
3) Pine

Which will be the least prone to sagging when weight is applied?

PS, All three boards being the same size and thickness of course.
Mike W

Mike W W wrote:
Say you had three boards cut to form shelves: one each of the
following materials:

1) MDF
2) Plywood (the rough stuff sold at B&Q)
3) Pine

Which will be the least prone to sagging when weight is applied?

Check out The Sagulator

http://www.woodbin.com/calcs/sagulator.htm



--
Dave
The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257

The message
from Mike W W contains these words:

1) MDF
2) Plywood (the rough stuff sold at B&Q)
3) Pine

Which will be the least prone to sagging when weight is applied?

Assuming the pine has its grain along the shelf then that'll be most
stiff. The ply next, then the MDF.

However, in real applications shelves are often supported with a batten
at the back edge, and that would make ply probably the best bet as it's
cheaper.

MDF can work very well, I've got 2' wide shelves beside me some heavily
loaded (paperbacks all across and three layers deep) and they're not
sagging. They're held up at the ends with shelf wires in slots.

--
Skipweasel
Pay no attention to that man behind the curtain.

Mike W W wrote:
Say you had three boards cut to form shelves: one each of the
following materials:

1) MDF
2) Plywood (the rough stuff sold at B&Q)
3) Pine

Which will be the least prone to sagging when weight is applied?

According to The Sagulator I mentioned earlier the least prone is the pine,
then the ply, then the MDF

Calculation for a 1000mm long x 300mm wide x 18mm thick shelf with a 20 kg
load give the pine & ply sagging by around 2mm with the MDF at 7mm!


--
Dave
The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257

The message
from "The Medway Handyman" contains
these words:

Calculation for a 1000mm long x 300mm wide x 18mm thick shelf with a 20 kg
load give the pine & ply sagging by around 2mm with the MDF at 7mm!

MDF also creeps over time far more than the other two.

--
Skipweasel
Pay no attention to that man behind the curtain.

Guy King wrote:
The message
from "The Medway Handyman" contains
these words:

Calculation for a 1000mm long x 300mm wide x 18mm thick shelf with a 20 kg
load give the pine & ply sagging by around 2mm with the MDF at 7mm!

MDF also creeps over time far more than the other two.


Pineboard (laminated pine) is your man. Same strength but no movement.
Most merchants stock it in a variety of widths

On Sat, 30 Sep 2006 12:20:54 GMT, Stuart Noble
wrote:


Pineboard (laminated pine) is your man. Same strength but no movement.
Most merchants stock it in a variety of widths.

Thanks for confirming that. It's exactly what I ended up buying - and
it was surprisingly inexpensive too. £8.75 per 7ft x 2ft sheet (from
'In Excess').

Thanks to all respondees.

Mike W