How to fix plaster vent to wall?

longwalks1

We've bought 2 plaster/cast ornate vents and need to fix them to the wall above the doors where out washing machine/dryer are, they look like this:

https://www.google.co.uk/search?q=plaster+vents&espv=2&source=lnms&tbm=isch&sa=X&ved=0ahUKEwim9tCSuvbSAhWJDcAKHUXkDKQQ_AUIBygC&biw=1366&bih=662#imgrc=IK_kHAVlZRilzM:

They're very light in weight, but cast from something. How do we fit them? I was assuming adhesive, so used some 'Sticks Like Sh*t' (its real name, used it on skirting boards previously) but even after holding the vent in place for 20 minutes, arms aching it still slides down the wall :mad::mad::mad:

Any pointers greatly appreciated people :T

Rain_Shadow

Your Sticks like Sh*t appears to have a case of the runs.

Hasbeen

Would try a couple of small panel pins nailed proud underneath to allow set, then pull out pins.

http://www.toolstation.com/shop/p19015?mkwid=sn5vPdnbD_dc&pcrid=175042720940&pkw=&pmt=&product=19015&gclid=CjwKEAjw8OLGBRCklJalqKHzjQ0SJACP