sticking mosaic tiles to mdf

[moonstoneblue]

I am making mirror borders and am sticking tiles around a mirror onto mdf. I have used pva to stick them on but I now need to grout inbetween the tiles. Some of the grout will therefore go directly on top of the dry pva. Will it stay or should I use something else? I used pva as I assumed that grout would not stick directly onto mdf. Can anyone help please?

[andy01]

i've done something similar in the past, but i used mastic to stick the tiles on some plywood boxing around a pipe. used normal white grout, which is still there now so its must hve been ok?