Ed Pawlowski wrote:
On 8/10/2017 2:33 PM, William Ahern wrote:
snip
My question is, what's the quickest way to seal the hardboard? I was
thinking Modge Podge or triple-thick water-based polyurethane. Both Modge
Podge and polyurethane can take weeks to fully cure. How much time should I
wait before putting the sealed hardboard back under the mattress?

Shellac. Dries in minutes. Zinsser brand is readily available.

Thank you. And to -MIKE-, too. It worked great. It's been a few days since I
put the hardboard back in place, and no hint of a smell. And I loved the
ease of applying and cleaning up the shellac.

I used oil-based polyurethane to refinish the inside of our cupboards when
we moved into our house a few years ago, but that stuff was a nightmare to
clean up and not something I'd want to revisit unless I had a 52 gallon
barrel of mineral spirits to store my brushes. I used water-based
polyurethane to finish our dining room chairs and table (a kit from Shaker
Workshop), which was much more convenient, but that's partly because I
purchased a huge box of disposable foam brushes.

The shellac is just incredibly convenient. I have half a mind to try it on
some other project that might see some wear & tear, like a side table. The
way my kid is destroying the finish on our furniture and floors, I'm
attracted to the thought of being able to easily touch things up. OTOH, I'm
still a real novice at finishing. I end up have to sand away alot of
mistakes. The shellac seems like it might gum up sandpaper. The oil poly did
that, too, but probably it hadn't yet even fully dried--I was racing to get
3 coats on everything ASAP so my wife could setup the kitchen. Instead of
sanding, is it common to use thinner to even out a damaged or poorly applied
shellac surface before touching it up?

OTOH, I never had an odor from hardboard. Are you sure it is not from
the mattress?

Absolutely, positively sure. It was the same smell as when I was cutting it
to size in the garage--cardboard + resin. Initially I thought it was just
the dust, but after vacumming and airing the room out it would always come
back within a couple of days. After 6 weeks there was just no denying the
persistence of the problem. (Also, latex mattresses don't usually have any
smell whatsoever, not even up close. And the brand we got, sleeponlatex.com,
seems one of the most reputable.)

FWIW, the boards were perforated S2S from Decorative Panels International,
purchased at Lowes and supposedly manufactured in the US, according to
decpanels.com. I don't think they were defective or counterfeit, but what do
I know. The only time I'd ever handled hardboard before was when removing
the panels on console TVs and radios when I was kid. The edges of the
perforations on these panels were pretty rough, though; not like the old
perforated panels I remember. Probably that was a contributory factor.
American manufacturing isn't what it used to be.