DIYbanter - View Single Post - Help! Spar urethane didn't cure right on MDF desk/table

wrote:
Hi all,

I built a work table in my basement (really a kind of desk) out of MDF.
It turned out really nice. I used a helmsman indoor/outdoor spar
urethane to seal the MDF. I applied several thin coats when I noticed
that what I thought was the bottom of the can (gallon) was actually a
hardened translucent layer of material that had settled to the bottom,
it was hard work but I managed to stir it up after that for the
remaining 2 coats.

The problem is that 6 months have gone buy now and the table still
reeks of urethane smell, this can't be good. With the window open
it's ok, but if you put something down on the table for even 5 minutes
and then pick it up, you catch a strong whiff of urethane in the air
and on the object itself.

I'm now prepared to sand this down and restart but it's a HUGE job,
the room is full of stuff that needs to be moved.

Is there anything I can apply to 'post cure' this flawed urethane?
Without having to do a bunch of sanding?

PS. the 'table' is built in, can't be moved. It's 15' long with l
extensions on each end, bolted to the wall.

Thanks,

Zander

contact the manufacturer of the finish for the specifics of the finish
chemistry. I'll bet that there isn't much you can do to it now to cure
the bottom layers, but you might just get lucky. probably you are going
to have to remove what's on there and start over. given the labor
involved and the cost of MDF it might be best to start completely over.

sanding isn't the only way to strip it, should you go the refinish
route. scrapers can be faster and much less dusty than sanding, and
chemical strippers will do a dust free job, though they make fumes of
their own.

when you get to the point of applying a new finish, start with a fresh
can. read and follow the directions printed on the side of the can,
which almost certainly involve stirring frequently during use.....