Thread: A question of strength

the oval profile is the stronger of the two

Steel is stiffer than ally, but I don't think either is big enough for 1290 span

I guess 25mm or 32 mm chrome tube (shower curtain rail ) is out of the question ? It can be purchased at most hardwares with the support fittings including a centre support bracket.

Thanks. They are both the same profile (oval & 30x15 x1.5) and both available through Hafele at about $16 for 3.6m for al and less for steel

Hi FlatOutBEn,

Steel is around 3 times the strength of Aluminium, but also around 3 times the mass. The trick that is normally used is to go the aluminium option, but make it 3 times thicker, which gives the same mass, but 3 times the stiffness.

Having said all of that, in your case (given no option of thickness), go the steel.

Steel is about 3 times the stiffness as aluminium (not necessarily the strength, though; depends on the alloys). Even so, the rule of thumb for preliminary bridge design is to make the span 24 times the depth of the girder. 24 x 30 is only 720mm. Why do you need to make the lower rail span the full length? Standard practice here is to use a triangular bracket at midpoint, attached to the back wall of the closet/wardrobe. If the back wall is too weak, you could suspend the lower rail from the upper one at its mid-span attachment.

Joe (retired SE)

Thanks Joe
However it only has to hang shirts! I ordered the aluminium rail this arve. Maybe I can make up a wall bracket just in case. I will attach a photo when its complete. Darryl