js.b1 wrote:
On Sep 25, 11:24 pm, The Natural Philosopher
wrote:
And yet you could sit on it and it din't come off....
THINK about it.
UNDERSTAND moment arms shear force tensile force etc etc..

Oh yes, but pull out strength is important to consider as well. Never
assume plaster is strong or thin on an older house, you can end up
with a plug sitting in mush yet appears fine.

Still think those fibre rawlplugs did a good job, they do not slip out
so easily as their cheap polythene copies.

First of all, the fact that you dont understand the relationship
between moment arm and 'pull out force' is telling.

Secondly, the plastic is as good IF the hole is of the completely
correct diameter.

No screw will hold in mushy plaster, and I never ever put a screw that
is to take any weight at all in plasterboard unsupported. Irresepective
of length diameter or what its made of.

If the plaster is rubbish, it gets the new plaster or car body filler
treatment.

If its plasterboard, it gets cut away and a noggin inserted.