On 4/28/2012 7:04 PM, Ray wrote:

and it seems to sand and blend ok

Thanks for any opinions

Ray

I just did it recently in my basement with closets. I didn't notice any
moisture issues with the MDF. I used store bought pre-mixed compound
and thinly applied the compound in two stages.- Hide quoted text -

- Show quoted text -

You could blend in a little white/Elmers glue in the first coat of mud
if you are worried about adherence. But then you ned to put it on
very evenly so that the second coat of mud will completely cover it.
Otherwise, you will go thru a lot of sandpaper removing the white glue
mud.



I guess I am thinking more about uneven expansion, and cracking more than
adherence

Ray



I'll find out soon enuf. For adhesion I screwed the mdf into exsisting
studwork/drywall where possible. I wasn't using the mud as adhesion, but
to smooth out things.

I used drywall tape along the seams where mdf met drywall and in
corners I used paper faced metal corner beading. Hopefully it'll keep
for the next 20 years.

I think thinner application of mud prevents worse cracking. Instead of
glopping it all on, spend the time to do multiple thin coats. Also
thinner coats mean the MDF can't swell as much with the moisture.

Also I wonder if paintable silicon to fill in the cracks would prevent
noticeable small cracking. I didn't do it but might be an idea.