TB

Tom B

14/05/2008 3:06 PM

"Curing" Shellac sealer coat?

I've searched a bit and read a lot (Jewitt, etc.) but can't find a
direct answer to the following question:

If I use a 1# cut of dewaxed shellac padded on as a seal coat (over a
stain or even raw wood) is there some rule of thumb about how long it
should dry before I overcoat it with an oil based finish (varnish,
BLO, etc.)?

It's always seemed to me that once shellac is dry to the touch (maybe
15 - 30 minutes with a 1# cut), it's done its thing, but I see and
hear references to "curing" it before overcoating, hence the question.

Regards.

Tom


This topic has 6 replies

BA

B A R R Y

in reply to Tom B on 14/05/2008 3:06 PM

14/05/2008 7:42 PM

On Wed, 14 May 2008 15:26:18 -0700 (PDT), "nailshooter41@aol.com"
<nailshooter41@aol.com> wrote:

>On May 14, 3:06 pm, Tom B <xlean...@nospam.mail.airmail.net> wrote:
>
>SNIP
>
>> It's always seemed to me that once shellac is dry to the touch (maybe
>> 15 - 30 minutes with a 1# cut), it's done its thing, but I see and
>> hear references to "curing" it before overcoating, hence the question.
>>
>> Regards.
>>
>> Tom
>
>You can recoat with shellac in as little as 20 - 30 minutes depending
>on the environment in which you are working.

It also matters what is going over it.

I let Seal Coat dry overnight under water base. For other stuff, I
just make sure it's not sticky any more.

---------------------------------------------
** http://www.bburke.com/woodworking.html **
---------------------------------------------

Rn

RF

in reply to Tom B on 14/05/2008 3:06 PM

17/05/2008 7:14 PM

Tom B wrote:
> I've searched a bit and read a lot (Jewitt, etc.) but can't find a
> direct answer to the following question:
>
> If I use a 1# cut of dewaxed shellac padded on as a seal coat (over a
> stain or even raw wood) is there some rule of thumb about how long it
> should dry before I overcoat it with an oil based finish (varnish,
> BLO, etc.)?
>
> It's always seemed to me that once shellac is dry to the touch (maybe
> 15 - 30 minutes with a 1# cut), it's done its thing, but I see and
> hear references to "curing" it before overcoating, hence the question.
>
> Regards.
>
> Tom
You are right in your information, a !# cut is very thin and 30 minutes
would be fine for a drying time.

nn

"nailshooter41@aol.com"

in reply to Tom B on 14/05/2008 3:06 PM

14/05/2008 3:26 PM

On May 14, 3:06 pm, Tom B <xlean...@nospam.mail.airmail.net> wrote:

SNIP

> It's always seemed to me that once shellac is dry to the touch (maybe
> 15 - 30 minutes with a 1# cut), it's done its thing, but I see and
> hear references to "curing" it before overcoating, hence the question.
>
> Regards.
>
> Tom

You can recoat with shellac in as little as 20 - 30 minutes depending
on the environment in which you are working.

I wouldn't put a final coat of finish on until the last coat was on
for a couple of hours.

Robert

LH

"Lew Hodgett"

in reply to Tom B on 14/05/2008 3:06 PM

15/05/2008 3:07 AM

"Tom B" wrote:

> I've searched a bit and read a lot (Jewitt, etc.) but can't find a
> direct answer to the following question:
>
> If I use a 1# cut of dewaxed shellac padded on as a seal coat (over
> a
> stain or even raw wood) is there some rule of thumb about how long
> it
> should dry before I overcoat it with an oil based finish (varnish,
> BLO, etc.)?

I know diddly-doo about finishes, but why rush it?

When I use shellac, allow it to cure at least a week before taking
next step.

YMMV.

Lew

Nn

Nova

in reply to Tom B on 14/05/2008 3:06 PM

15/05/2008 12:45 AM

Tom B wrote:
> I've searched a bit and read a lot (Jewitt, etc.) but can't find a
> direct answer to the following question:
>
> If I use a 1# cut of dewaxed shellac padded on as a seal coat (over a
> stain or even raw wood) is there some rule of thumb about how long it
> should dry before I overcoat it with an oil based finish (varnish,
> BLO, etc.)?
>
> It's always seemed to me that once shellac is dry to the touch (maybe
> 15 - 30 minutes with a 1# cut), it's done its thing, but I see and
> hear references to "curing" it before overcoating, hence the question.
>
> Regards.
>
> Tom

Shellac doesn't actually need to cure as it's an evaporative finish.
What can happen is that when several coats are applied too quickly the
outer coat can seal the pervious layers slowing the drying process.
This will cause a soft finish until given enough time for the underlying
coats to "cure" (dry).

--
Jack Novak
Buffalo, NY - USA
novasys@verizon.net

EP

"Edwin Pawlowski"

in reply to Tom B on 14/05/2008 3:06 PM

14/05/2008 10:18 PM


"Tom B" <xleanone@nospam.mail.airmail.net> wrote in message
news:2ugm24ducnir1pl9ho9fvqq2b457pr8b85@4ax.com...
> I've searched a bit and read a lot (Jewitt, etc.) but can't find a
> direct answer to the following question:
>
> If I use a 1# cut of dewaxed shellac padded on as a seal coat (over a
> stain or even raw wood) is there some rule of thumb about how long it
> should dry before I overcoat it with an oil based finish (varnish,
> BLO, etc.)?
>
> It's always seemed to me that once shellac is dry to the touch (maybe
> 15 - 30 minutes with a 1# cut), it's done its thing, but I see and
> hear references to "curing" it before overcoating, hence the question.
>
> Regards.
>
> Tom

Finishes dry to the touch in a short time, but full hardness can take day,
even weeks for polyurethane to reach maximum hardness. Shellac is dried as
the alcohol evaporates, but I'd still give it a few hours or even overnight
before putting another material on top. But that would be my practice with
no scientific research to back it up.


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