In an earlier contribution to this discussion, Lobster
wrote:
I'm in the midst of installing a large stone resin shower tray; it's
going in an existing alcove where it will be a snug fit on three
sides; the alcove being as deep as the tray is wide (760mm). I've
built the required platform for it to sit on, topped with 0.75"
marine ply, and now just need to lay the tray down on a bed of mortar
as per instructions.

Trouble is, this thing is obviously very heavy and I can't get access
to anything but the front edge to lower it down flat, ie parallel to
the floor. Having tried several 'dry runs', the best I can do is
stand in front of the tray, standing up on it's front edge, and then
lower the high (ie back) edge away from me till it reaches the deck.
If there'd been mortar in situ, it would have squeezed out the front
all over my feet.... The tray is now 3 or 4 inches away from the back
of the alcove, and has to be slid back into place (which would bugger
up the mortar bed still further).

Anyone done this before? I can't think of an easy way to do it,
certainly not without crippling nyself. How critical is the
integrity of the mortar bed - am I worrying too much about it? I
sure as hell want it to be right, though; I don't plan on replacing
this tray in the forseeable future!

Thanks
David

You could try this - it might work, but I've never done it!
Obtain 2 strips of wood, about 1/2" x 1" and a bit longer than the width of
the tray. Lay them flat across the alcove, a few inches from each end. Apply
mortar all over, level with the top of the wooden strips.
Slide the tray in, with the back edge supported by the strips, and the front
edge slightly raised. Lower the front edge. [The wooden srtips will stop the
tray from disturbing the mortar too much].
Finally, pull the strips out, allowing the tray to settle onto the mortar.
Mortar should flow into the spaces vacated by the strips - and even if it
doesn't, the tray will be adequately supported.
You will have to decide in advance how the pull the strips out - maybe
drilling a hole for a rope or hook in each before laying it.

HTH.

--
Cheers,
Set Square