I'm brand new here. This forum was recommended by a friend. I'm an avid DIY-er but finishes are not my specialty.

The problem:
I built a steam radiator cover (out of red oak) for my 8mth old son's room (turned out great). The minwax oil based fast drying semigloss polyurethane has not dried properly and is giving off a smell as the radiator heats up.. I'm concerned about safety (fumes) so I have removed the cover until I can fix the problem.

The finishing process:
We live in a small 2 bed APT in NYC, so I have less than ideal circumstances for woodworking.

For the first coat I applied the polyurethane directly to the (sanded/wiped clean) surface of the wood. *it it possible that the can was not stirred well enough. * the first coat was possibly thick but had no runs. I sat outside my apt in the sun waiting for the finish to off-gas. After an hour I brought it inside to cure.

After 4 hours the finish seemed cured (the can recommends 3-4hrs). I sanded with 220 and wiped clean with a slightly damp cloth.

For the second coat (around 9pm) I had to change location, so I applied the finish standing inside our apt with the project sitting outside on the fire escape (on a cardboard box to catch drips). It was cold - about 50 degrees. I left it out there to off-gas for an hour, then brought it inside to cute overnight. *Again the can was possibly not stirred well enough.

The next day everything seemed fine other than a slight oily film (like the project had the tiniest film of cooking oil over it). I figured it would harden with heat and time, so I attached the aluminum mesh and installed it.... And now we have the problem.

Thoughts, guys? I'd love to avoid sanding this whole thing back to bare wood (as it will be by hand on my kitchen floor).

wrote in
:

I'm brand new here. This forum was recommended by a friend. I'm an
avid DIY-er but finishes are not my specialty.

The problem:
I built a steam radiator cover (out of red oak) for my 8mth old son's
room (turned out great). The minwax oil based fast drying semigloss
polyurethane has not dried properly and is giving off a smell as the
radiator heats up. I'm concerned about safety (fumes) so I have
removed the cover until I can fix the problem.

In my experience poly smells for a while. It seems that
whatever formula Minwax is using now is worse than it was
10 or so years ago, too.

In any event, my first thought would be to just leave it
awhile - the smell will probably go away in a week or so.

My second thought is, you could try sealing it with shellac.

FWIW, shellac is a non-toxic finish (they coat M&Ms with it),
so if you're making other kid-stuff that needs a finish you
might consider it. Altho toys and things like that are
generally best left bare wood.

John

On Saturday, October 25, 2014 12:12:16 PM UTC-5, John McCoy wrote:

In my experience poly smells for a while. It seems that
whatever formula Minwax is using now is worse than it was
10 or so years ago, too.

The formula was changed to accommodate the newer VOC concerns.

In any event, my first thought would be to just leave it
awhile - the smell will probably go away in a week or so.

I agree with John. Just let it sit a good while.

*First coat applied on raw wood: Some has soaked in, a bit, so it would take longer to dry, than what the can says. Would have been good to let it dry overnight. Despite the short time before recoating, it should cure, properly, after a good week.

So, until then, the penalty assessed is: Your son sleeps with Mom and you sleep on the couch!

Sonny

Thanks, John. I'll definitely look into shellac.

Update: the finish seems fine until I run fingers over it. There is a slight oily residue that comes off on my fingers. This hasn't gone away after a week. Is this normal for poly??

wrote:
Thanks, John. I'll definitely look into shellac.

Update: the finish seems fine until I run fingers over it. There is
a slight oily residue that comes off on my fingers. This hasn't gone
away after a week. Is this normal for poly??

Not in my experience - at all. After 24 hours it should be completely dry
to the touch - no residue, no oily residue. After 24 hours I scuff it down
with a 3M pad and re-coat. Works every time. You absolutely should not get
an oily feel from poly.

--

-Mike-

On 10/25/2014 3:38 PM, wrote:
Thanks, John. I'll definitely look into shellac.

Update: the finish seems fine until I run fingers over it. There is a slight oily residue that comes off on my fingers. This hasn't gone away after a week. Is this normal for poly??

do not apply shellac, it's not very good with heat.
It's a great finish, but it does not like heat.
I would have waited 24 hours before recoating.
Then I would wait a week before putting it to use.

Just wait and see what happens.

I'm not a big poly user, but I don't think you need to stir it.


--
Jeff

woodchucker wrote:


I'm not a big poly user, but I don't think you need to stir it.

Yes Jeff - you do need to stir it. With any poly - not just with satin
finishes, stir slowly and don't shake. You don't want to introduce air
bubbles into poly which will happen when shaking it. That though does not
apply to the OP's question about an oily feel. I can't figure out how he's
getting that - it's just not what one would expect from poly. If I were
him, I'd scuff it down and re-apply with proper stirring.

--

-Mike-

On 10/25/2014 6:24 PM, Mike Marlow wrote:

That though does not
apply to the OP's question about an oily feel. I can't figure out how he's
getting that - it's just not what one would expect from poly. If I were
him, I'd scuff it down and re-apply with proper stirring.


That would be step two. Step one is to put a coat on a scrap of wood
Let it dry, sand, recoat as you did on the original. If it is properly
dried, I'd think operator error on the first try. If it is oily, I'd
think possibly something wrong with the poly. Very odd that would
happen though.

On 10/25/2014 2:38 PM, wrote:
Thanks, John. I'll definitely look into shellac.

Update: the finish seems fine until I run fingers over it. There is a slight oily residue that comes off on my fingers. This hasn't gone away after a week. Is this normal for poly??



Not normal. Is that "new" can of finish?

On 10/26/2014 12:51 PM, Leon wrote:
On 10/25/2014 2:38 PM, wrote:
Thanks, John. I'll definitely look into shellac.

Update: the finish seems fine until I run fingers over it. There is a
slight oily residue that comes off on my fingers. This hasn't gone
away after a week. Is this normal for poly??



Not normal. Is that "new" can of finish?

I find myself especially curious about this so I'd like to recap.

Its seems we have several factors here, and two questions. The first
question: what accounts for this strange result?

Here are (some of the) possibilities:

1. The state of the can of finish.

Do these have date codes? I have seen some pretty un-saleable things
returned to the shelves of Home Depot. What happens to old poly?

2. Insufficient stirring.

The instructions say to mix thoroughly before - and even during -
application. But what happens if we don't? Is it simply that we will
have a more dilute mixture near the top of the can? If so it's hard to
imagine that causing the reported symptom. After all, some of us have
thinned poly on purpose without that result. Or maybe something else
separates out as well?

3. The temperature.

If I remember correctly, poly "dries" by two processes. First the
solvent evaporates, then the "polymerization" reaction occurs over time.
If memory serves, the second reaction at least (the "curing") is
retarded by lower temperatures. But the piece was eventually brought
into a heated space. Would it then cure properly, even if the process
had been slowed by the lower temperature?

4.The timing.

The online instructions say to wait 4-6 hours between coats. So again,
what happens if we don't wait long enough, "long enough" perhaps being
lengthened by the ambient temperature during the first hour outside?
Does the second coat prevent enough oxygen from getting to the first
coat, perhaps?

5. The radiator heat.

But of course, all of the above is to some degree an academic exercise,
with the possible exception of the condition of the can of finish. What
does Tim do now to fix it?

I'm guessing he finished the inside surfaces of the project as well. So
perhaps the first bit of advice would be to try out a repair strategy on
the inside surfaces. If successful, repeat on the surfaces that will show.

Finishing figures prominently among the topics I'm ignorant about, but
if this were my own project I'd be inclined to try removing the oily
residue with a solvent like mineral spirits. If that seemed successful,
I'd probably scuff the finish a little and reapply poly - from a
different can - just to be safe. I'd stir, and watch the temperature,
and wait a whole day before considering any further coats.

One other thing:

Perhaps, given the apartment setting and his infant son, a water-borne
poly would have been a good choice. I thought I read somewhere that
despite being *carried* by water, the poly is still poly. Does this mean
that he could try water-borne poly over what he's got (with some surface
prep, but without sanding down to bare wood)? Or is there perhaps some
other choice that's sufficiently non-hazardous to do entirely inside his
heated apartment?

Sorry for the long-winded questions (my specialty), but I have taken a
special interest in this young man's predicament for some reason.



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Greg Guarino wrote in
:

4.The timing.

The online instructions say to wait 4-6 hours between coats. So again,
what happens if we don't wait long enough, "long enough" perhaps being
lengthened by the ambient temperature during the first hour outside?
Does the second coat prevent enough oxygen from getting to the first
coat, perhaps?

Like you, finishing isn't really my strong suit. But my
understanding is that, if you recoat too soon, you're basically
just creating one very thick coat. Since the solvent has to
evaporate, and that happens very slowly once a skin forms on
the finish, very thick coats are not recommended...

(I note that professional finishers often spray on coats on a
much shorter schedule than 4-6 hours. But they're spraying, so
a much thinner coat to start with).

Perhaps, given the apartment setting and his infant son, a water-borne
poly would have been a good choice. I thought I read somewhere that
despite being *carried* by water, the poly is still poly.

Water-borne poly is just that, regular poly carried by water.
To be specific, it's regular poly in an emulsion in water.
Once the water evaporates, you're left with the normal poly
solvents (just much less of them).

The only non-hazardous finish that comes to mind is shellac.
But as someone pointed out (and I'd forgotten), that's not
such a good choice with the heat from the radiator.

John

"Greg Guarino" wrote in message


I find myself especially curious about this so I'd like to recap.

Its seems we have several factors here, and two questions. The first
question: what accounts for this strange result?

Here are (some of the) possibilities:

1. The state of the can of finish.

Do these have date codes? I have seen some pretty un-saleable things
returned to the shelves of Home Depot. What happens to old poly?

How old is old? I've used stuff that was at least five years old, maybe
ten, without problems.
_______________

2. Insufficient stirring.

The instructions say to mix thoroughly before - and even during -
application. But what happens if we don't? Is it simply that we will
have a more dilute mixture near the top of the can? If so it's hard to
imagine that causing the reported symptom. After all, some of us have
thinned poly on purpose without that result. Or maybe something else
separates out as well?

If I don't use a can of oil paint for some time the linseed oil separates
out and floats on the top. Stirring gets it mixed back in.

If the varnish is non-glossy, one also has to mix in the flatting
agent...the gelatinous goo in the bottom. Takes lots of mixing. Time was
that the flatting material was talc; now I suspect it is fumed silica.
_________________

If I remember correctly, poly "dries" by two processes. First the
solvent evaporates, then the "polymerization" reaction occurs over time.
If memory serves, the second reaction at least (the "curing") is
retarded by lower temperatures. But the piece was eventually brought
into a heated space. Would it then cure properly, even if the process
had been slowed by the lower temperature?

Can't say for sure but I don't see why not. Regardless, the finish should
NOT have an oily film at any time under any conditions.
_____________________

4.The timing.

The online instructions say to wait 4-6 hours between coats. So again,
what happens if we don't wait long enough, "long enough" perhaps being
lengthened by the ambient temperature during the first hour outside?
Does the second coat prevent enough oxygen from getting to the first
coat, perhaps?

All the floors in my house are Saltillo tile top coated with oil poly. I
apply 3-4 coats in one day, waiting between coats until I can walk on it
without sticking. That is usually 3-4 hours.

I mop on the poly so coat thickness varies considerably. The tile is also
a bit curved so in areas where the coat is particularly thick, it will run
to and pool at the corners between tiles. I try to avoid that, I look for
and smooth out any I see, but it is pretty much inevitable that I'll miss
some. In the thickest spots, the poly winds up 1/16" thick - maybe more -
but eventually dries and cures.
_________________

5. The radiator heat.

But of course, all of the above is to some degree an academic exercise,
with the possible exception of the condition of the can of finish. What
does Tim do now to fix it?

I'm guessing he finished the inside surfaces of the project as well. So
perhaps the first bit of advice would be to try out a repair strategy on
the inside surfaces. If successful, repeat on the surfaces that will
show.

Finishing figures prominently among the topics I'm ignorant about, but
if this were my own project I'd be inclined to try removing the oily
residue with a solvent like mineral spirits.

ONLY mineral spirits or other similar (paint thinner, turpentine).

If that seemed successful,
I'd probably scuff the finish a little and reapply poly - from a
different can - just to be safe. I'd stir, and watch the temperature,
and wait a whole day before considering any further coats.

If you wait a day, you have to sand between coats. The "window of
opportunity" for recoating without sanding stops at about eight hours
IIRC.

I would also want to assess the condition of the varnish once/if the oily
residue can be removed.
_________________

One other thing:

Perhaps, given the apartment setting and his infant son, a water-borne
poly would have been a good choice. I thought I read somewhere that
despite being *carried* by water, the poly is still poly.

Sort of. It is polycarbonate + acrylic. Oil poly is polycarbonate +
(probably) alkyd, could be phenolic but not likely.

Water base stuff has two useful features: 1., it doesn't color the wood
and 2., it washes out of applicators. When you get those you give up
hardness, durability and longevity.
________________

Does this mean
that he could try water-borne poly over what he's got (with some surface
prep, but without sanding down to bare wood)? Or is there perhaps some
other choice that's sufficiently non-hazardous to do entirely inside his
heated apartment?

Once cured, you can put water poly over oil poly and vice versa.
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On Sat, 25 Oct 2014 08:35:19 -0700 (PDT),
wrote:

I'm brand new here. This forum was recommended by a friend. I'm an avid DIY-er but finishes are not my specialty.

The problem:
I built a steam radiator cover (out of red oak) for my 8mth old son's room (turned out great). The minwax oil based fast drying semigloss polyurethane has not dried properly and is giving off a smell as the radiator heats up. I'm concerned about safety (fumes) so I have removed the cover until I can fix the problem.

The finishing process:
We live in a small 2 bed APT in NYC, so I have less than ideal circumstances for woodworking.

For the first coat I applied the polyurethane directly to the (sanded/wiped clean) surface of the wood. *it it possible that the can was not stirred well enough. * the first coat was possibly thick but had no runs. I sat outside my apt in the sun waiting for the finish to off-gas. After an hour I brought it inside to cure.

After 4 hours the finish seemed cured (the can recommends 3-4hrs). I sanded with 220 and wiped clean with a slightly damp cloth.

For the second coat (around 9pm) I had to change location, so I applied the finish standing inside our apt with the project sitting outside on the fire escape (on a cardboard box to catch drips). It was cold - about 50 degrees. I left it out there to off-gas for an hour, then brought it inside to cute overnight. *Again the can was possibly not stirred well enough.

The next day everything seemed fine other than a slight oily film (like the project had the tiniest film of cooking oil over it). I figured it would harden with heat and time, so I attached the aluminum mesh and installed it... And now we have the problem.

Thoughts, guys? I'd love to avoid sanding this whole thing back to bare wood (as it will be by hand on my kitchen floor).

Your concern about not stirring the polyurethane well enough is
unwarranted. The thicker contents at the bottom of the can that needs
stirring will only effect the sheen. That contents is not present in
the clear gloss polyurethane and that is why that polyurethane is
glossy.

Don't be too concerned about the smell unless it really bothers you or
your son. It will stop soon. When polyurethane is curing it gives off
those fumes. The off-gassing is exacerbated when it is heated such as
being near a radiator.

wrote in message


After 4 hours the finish seemed cured (the can recommends 3-4hrs). I
sanded with 220 and wiped clean with a slightly damp cloth.

It may be dry to the touch but it won't be cured for at least two weeks,
month is closer.

I hope you dried it after wiping with before the damp cloth before
applying coat #2.
____________

For the second coat (around 9pm) I had to change location, so I applied
the finish standing inside our apt with the project sitting outside on
the fire escape (on a cardboard box to catch drips). It was cold - about
50 degrees. I left it out there to off-gas for an hour, then brought it
inside to cute overnight. *Again the can was possibly not stirred well
enough.

The next day everything seemed fine other than a slight oily film (like
the project had the tiniest film of cooking oil over it). I figured it
would harden with heat and time, so I attached the aluminum mesh and
installed it... And now we have the problem.

If it had an oily film, regardless of how slight, you didn't stir it
enough. The 50 degree weather didn't help either.
__________________

Thoughts, guys? I'd love to avoid sanding this whole thing back to bare
wood (as it will be by hand on my kitchen floor).

Try wiping it down well with paint thinner. If the oily film goes away,
scuff sand and apply another coat after stirring well. "Well" = twice
what you think it needs.

--

dadiOH
____________________________

Winters getting colder? Tired of the rat race?
Taxes out of hand? Maybe just ready for a change?
Check it out... http://www.floridaloghouse.net

On 10/25/2014 4:44 PM, dadiOH wrote:

I hope you dried it after wiping with before the damp cloth before
applying coat #2.

I wondered about that possibility as well. Any one else have thoughts on
this?

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