tt

ted

23/05/2008 1:07 PM

grey shellac effect?

Sometimes when I am coating some wood with warm shellac flakes I get a
patch of greyish finish. If I put more shellac over it, it goes away but
I was wondering what I was doing to contaminate the mixed shellac.
I apply by brush.
Thanks Ted


This topic has 13 replies

tt

ted

in reply to ted on 23/05/2008 1:07 PM

23/05/2008 10:41 PM

B A R R Y wrote:
> On Fri, 23 May 2008 13:07:03 +1000, ted <[email protected]> wrote:
>
>> Sometimes when I am coating some wood with warm shellac flakes I get a
>> patch of greyish finish. If I put more shellac over it, it goes away but
>> I was wondering what I was doing to contaminate the mixed shellac.
>> I apply by brush.
>
> That sounds like moisture, causing "blushing".
>
Could it be when I put brush in water between coats to keep brush from
drying out?
I give it a good wipe before I use it normally.

> Blushing is possible with shellac and lacquer if moisture gets trapped
> under the finish. Just as you've noted, the blush is often easily
> removed by applying more finish. I've removed lacquer blush by
> spraying a very thin "flow coat", which reconstitutes the finish and
> allows the moisture to leave.
>
> Is your alcohol contaminated?
No was new mixture.

>
> If not, maybe the warm finish is attracting moisture on higher
> relative humidity days.
By warm I meant the colour, I should have said "orange flakes"
It was actually 16o C
>
> With lacquer and shellac, I shoot for at least a 15 degree F (20F is
> better) spread between the temperature and dew point.
>
> ---------------------------------------------
> ** http://www.bburke.com/woodworking.html **
> ---------------------------------------------

Thanks,
Ted

tt

ted

in reply to ted on 23/05/2008 1:07 PM

24/05/2008 11:39 AM

ted wrote:
> B A R R Y wrote:
>> On Fri, 23 May 2008 13:07:03 +1000, ted <[email protected]> wrote:
>>
>>> Sometimes when I am coating some wood with warm shellac flakes I get
>>> a patch of greyish finish. If I put more shellac over it, it goes
>>> away but I was wondering what I was doing to contaminate the mixed
>>> shellac.
>>> I apply by brush.
>>
>> That sounds like moisture, causing "blushing".
>>
> Could it be when I put brush in water between coats to keep brush from
> drying out?
> I give it a good wipe before I use it normally.
>
>> Blushing is possible with shellac and lacquer if moisture gets trapped
>> under the finish. Just as you've noted, the blush is often easily
>> removed by applying more finish. I've removed lacquer blush by
>> spraying a very thin "flow coat", which reconstitutes the finish and
>> allows the moisture to leave.
>>
>> Is your alcohol contaminated?
> No was new mixture.
>
>>
>> If not, maybe the warm finish is attracting moisture on higher
>> relative humidity days.
> By warm I meant the colour, I should have said "orange flakes"
> It was actually 16o C
>>
>> With lacquer and shellac, I shoot for at least a 15 degree F (20F is
>> better) spread between the temperature and dew point.
>>
>> ---------------------------------------------
>> ** http://www.bburke.com/woodworking.html **
>> ---------------------------------------------
>
> Thanks,
> Ted

You can probably tell I'm new at this. Want to check on terminology
here. Your comments about alcohol: I use Methylated Spirits to make the
shellac up. Are you calling MS the alcohol or should I be using
something else? I just left a brush out of the water to test the
re-soften hint.
Thanks for all your comments,
Ted.

tt

ted

in reply to ted on 23/05/2008 1:07 PM

24/05/2008 2:25 PM

Kenneth wrote:
> On Sat, 24 May 2008 11:39:05 +1000, ted <[email protected]>
> wrote:
>
>> ted wrote:
>>> B A R R Y wrote:
>>>> On Fri, 23 May 2008 13:07:03 +1000, ted <[email protected]> wrote:
>>>>
>>>>> Sometimes when I am coating some wood with warm shellac flakes I get
>>>>> a patch of greyish finish. If I put more shellac over it, it goes
>>>>> away but I was wondering what I was doing to contaminate the mixed
>>>>> shellac.
>>>>> I apply by brush.
>>>> That sounds like moisture, causing "blushing".
>>>>
>>> Could it be when I put brush in water between coats to keep brush from
>>> drying out?
>>> I give it a good wipe before I use it normally.
>>>
>>>> Blushing is possible with shellac and lacquer if moisture gets trapped
>>>> under the finish. Just as you've noted, the blush is often easily
>>>> removed by applying more finish. I've removed lacquer blush by
>>>> spraying a very thin "flow coat", which reconstitutes the finish and
>>>> allows the moisture to leave.
>>>>
>>>> Is your alcohol contaminated?
>>> No was new mixture.
>>>
>>>> If not, maybe the warm finish is attracting moisture on higher
>>>> relative humidity days.
>>> By warm I meant the colour, I should have said "orange flakes"
>>> It was actually 16o C
>>>> With lacquer and shellac, I shoot for at least a 15 degree F (20F is
>>>> better) spread between the temperature and dew point.
>>>>
>>>> ---------------------------------------------
>>>> ** http://www.bburke.com/woodworking.html **
>>>> ---------------------------------------------
>>> Thanks,
>>> Ted
>> You can probably tell I'm new at this. Want to check on terminology
>> here. Your comments about alcohol: I use Methylated Spirits to make the
>> shellac up. Are you calling MS the alcohol or should I be using
>> something else? I just left a brush out of the water to test the
>> re-soften hint.
>> Thanks for all your comments,
>> Ted.
>
> Hi Ted,
>
> PMJI, but...
>
> The Methylated Spirits is appropriate. (It is simply two
> different types of alcohol mixed. One is ethanol, the other
> methyl alcohol. The latter is poisonous. If they sold pure
> ethanol as a solvent, folks would drink it...)
>
> But please say something more about why you believe that the
> MS was not contaminated.
>
> I ask because such "contamination" can happen more easily
> than you might think. The situation you described does seem
> to indicate "blushing" (as others have said) but that can
> happen in some subtle ways.
>
> Alcohol l-o-v-e-s water, and it is difficult (and therefore
> expensive) to remove water from alcohol. So (virtually) any
> alcohol you can buy will have (some) water in it before you
> open it.
>
> But then, just leaving a container of alcohol open on the
> bench on a humid day can cause problems.
>
> In fact, the tendency of the alcohol to absorb water from
> the air, together with the water on the surface of your work
> on such a humid day, might be enough to cause the "blush."
>
> All the best,

Hi Kenneth,
seems that my habit of popping brush in water seems to be the culprit.
It only happens occasionally so I am presuming it's when I don't dry the
brush properly before I use it again. Saves me a hassle not to have to
dry it so I'm happy.
Thanks for everyones comments, I'll do it properly from now on.
Cheers,
Ted

tt

ted

in reply to ted on 23/05/2008 1:07 PM

25/05/2008 10:57 AM


> But surely it didn't stay soft in WATER,
> did it?

Yep
Ed.

Ku

Kenneth

in reply to ted on 23/05/2008 1:07 PM

24/05/2008 8:04 AM

On Sat, 24 May 2008 14:25:27 +1000, ted <[email protected]>
wrote:

>Kenneth wrote:
>> On Sat, 24 May 2008 11:39:05 +1000, ted <[email protected]>
>> wrote:
>>
>>> ted wrote:
>>>> B A R R Y wrote:
>>>>> On Fri, 23 May 2008 13:07:03 +1000, ted <[email protected]> wrote:
>>>>>
>>>>>> Sometimes when I am coating some wood with warm shellac flakes I get
>>>>>> a patch of greyish finish. If I put more shellac over it, it goes
>>>>>> away but I was wondering what I was doing to contaminate the mixed
>>>>>> shellac.
>>>>>> I apply by brush.
>>>>> That sounds like moisture, causing "blushing".
>>>>>
>>>> Could it be when I put brush in water between coats to keep brush from
>>>> drying out?
>>>> I give it a good wipe before I use it normally.
>>>>
>>>>> Blushing is possible with shellac and lacquer if moisture gets trapped
>>>>> under the finish. Just as you've noted, the blush is often easily
>>>>> removed by applying more finish. I've removed lacquer blush by
>>>>> spraying a very thin "flow coat", which reconstitutes the finish and
>>>>> allows the moisture to leave.
>>>>>
>>>>> Is your alcohol contaminated?
>>>> No was new mixture.
>>>>
>>>>> If not, maybe the warm finish is attracting moisture on higher
>>>>> relative humidity days.
>>>> By warm I meant the colour, I should have said "orange flakes"
>>>> It was actually 16o C
>>>>> With lacquer and shellac, I shoot for at least a 15 degree F (20F is
>>>>> better) spread between the temperature and dew point.
>>>>>
>>>>> ---------------------------------------------
>>>>> ** http://www.bburke.com/woodworking.html **
>>>>> ---------------------------------------------
>>>> Thanks,
>>>> Ted
>>> You can probably tell I'm new at this. Want to check on terminology
>>> here. Your comments about alcohol: I use Methylated Spirits to make the
>>> shellac up. Are you calling MS the alcohol or should I be using
>>> something else? I just left a brush out of the water to test the
>>> re-soften hint.
>>> Thanks for all your comments,
>>> Ted.
>>
>> Hi Ted,
>>
>> PMJI, but...
>>
>> The Methylated Spirits is appropriate. (It is simply two
>> different types of alcohol mixed. One is ethanol, the other
>> methyl alcohol. The latter is poisonous. If they sold pure
>> ethanol as a solvent, folks would drink it...)
>>
>> But please say something more about why you believe that the
>> MS was not contaminated.
>>
>> I ask because such "contamination" can happen more easily
>> than you might think. The situation you described does seem
>> to indicate "blushing" (as others have said) but that can
>> happen in some subtle ways.
>>
>> Alcohol l-o-v-e-s water, and it is difficult (and therefore
>> expensive) to remove water from alcohol. So (virtually) any
>> alcohol you can buy will have (some) water in it before you
>> open it.
>>
>> But then, just leaving a container of alcohol open on the
>> bench on a humid day can cause problems.
>>
>> In fact, the tendency of the alcohol to absorb water from
>> the air, together with the water on the surface of your work
>> on such a humid day, might be enough to cause the "blush."
>>
>> All the best,
>
>Hi Kenneth,
>seems that my habit of popping brush in water seems to be the culprit.
>It only happens occasionally so I am presuming it's when I don't dry the
>brush properly before I use it again. Saves me a hassle not to have to
>dry it so I'm happy.
>Thanks for everyones comments, I'll do it properly from now on.
>Cheers,
>Ted

Hi Ted,

I read of your "water popping" after I posted... 'sorry.

Yup, that would certainly be the likely source of the
problem.

All the best,
--
Kenneth

If you email... Please remove the "SPAMLESS."

Sk

"Swingman"

in reply to ted on 23/05/2008 1:07 PM

23/05/2008 8:52 AM

"ted" wrote

> Could it be when I put brush in water between coats to keep brush from
> drying out?
> I give it a good wipe before I use it normally.

Don't bother, no need to put a shellac brush in anything... nice thing about
shellac, go ahead and let the brush dry between coats, then stick it back in
the shellac for a few minutes and it'll be ready to use again.

--
www.e-woodshop.net
Last update: 5/14/08
KarlC@ (the obvious)

Rr

RicodJour

in reply to ted on 23/05/2008 1:07 PM

23/05/2008 6:09 AM

On May 23, 8:41 am, ted <[email protected]> wrote:
> B A R R Y wrote:> On Fri, 23 May 2008 13:07:03 +1000, ted <[email protected]> wrote:
>
> >> Sometimes when I am coating some wood with warm shellac flakes I get a
> >> patch of greyish finish. If I put more shellac over it, it goes away but
> >> I was wondering what I was doing to contaminate the mixed shellac.
> >> I apply by brush.
>
> > That sounds like moisture, causing "blushing".
>
> Could it be when I put brush in water between coats to keep brush from
> drying out?
> I give it a good wipe before I use it normally.

You can't remove all of the water with a wipe. Use alcohol to keep
the brush from drying out or stick it in a zip loc bag.

R

BA

B A R R Y

in reply to ted on 23/05/2008 1:07 PM

23/05/2008 11:03 AM

On Fri, 23 May 2008 06:09:54 -0700 (PDT), RicodJour
<[email protected]> wrote:
>
>You can't remove all of the water with a wipe. Use alcohol to keep
>the brush from drying out or stick it in a zip loc bag.
>
>R

Or just let it dry and soak it in alcohol before the next use. Shellac
will totally redissolve when alcohol is reintroduced.

I don't clean my shellac brushes at all.

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

Ft

Fred the Red Shirt

in reply to ted on 23/05/2008 1:07 PM

24/05/2008 9:21 AM

On May 23, 9:39 pm, ted <[email protected]> wrote:
> ted wrote:
> > B A R R Y wrote:
> >> On Fri, 23 May 2008 13:07:03 +1000, ted <[email protected]> wrote:
>
> >>> Sometimes when I am coating some wood with warm shellac flakes I get
> >>> a patch of greyish finish. If I put more shellac over it, it goes
> >>> away but I was wondering what I was doing to contaminate the mixed
> >>> shellac.
> >>> I apply by brush.
>
> >> That sounds like moisture, causing "blushing".
>
> > Could it be when I put brush in water between coats to keep brush from
> > drying out?
> > I give it a good wipe before I use it normally.
>
> >> Blushing is possible with shellac and lacquer if moisture gets trapped
> >> under the finish. Just as you've noted, the blush is often easily
> >> removed by applying more finish. I've removed lacquer blush by
> >> spraying a very thin "flow coat", which reconstitutes the finish and
> >> allows the moisture to leave.
>
> >> Is your alcohol contaminated?
> > No was new mixture.
>
> >> If not, maybe the warm finish is attracting moisture on higher
> >> relative humidity days.
> > By warm I meant the colour, I should have said "orange flakes"
> > It was actually 16o C
>
> >> With lacquer and shellac, I shoot for at least a 15 degree F (20F is
> >> better) spread between the temperature and dew point.
>
> >> ---------------------------------------------
> >> **http://www.bburke.com/woodworking.html **
> >> ---------------------------------------------
>
> > Thanks,
> > Ted
>
> You can probably tell I'm new at this. Want to check on terminology
> here. Your comments about alcohol: I use Methylated Spirits to make the
> shellac up. Are you calling MS the alcohol or should I be using
> something else? I just left a brush out of the water to test the
> re-soften hint.
> Thanks for all your comments,
> Ted.

But surely it didn't stay soft in WATER,
did it?

--

FF

Ft

Fred the Red Shirt

in reply to ted on 23/05/2008 1:07 PM

23/05/2008 7:55 AM

On May 23, 8:41 am, ted <[email protected]> wrote:
> B A R R Y wrote:> On Fri, 23 May 2008 13:07:03 +1000, ted <[email protected]> wrote:
>
> >> Sometimes when I am coating some wood with warm shellac flakes I get a
> >> patch of greyish finish. If I put more shellac over it, it goes away but
> >> I was wondering what I was doing to contaminate the mixed shellac.
> >> I apply by brush.
>
> > That sounds like moisture, causing "blushing".
>
> Could it be when I put brush in water between coats to keep brush from
> drying out?
> I give it a good wipe before I use it normally.
>

Shellac is insoluble in water. If you put the brush into
water the water will dilute the alcohol and the shellac
will immediately harden on the brush. If that isn't
happening to you then either you're not using
shellac, or you're not putting the brush into
water.

I use a ladle to transfer shellac from the can to
the pot where it's diluted for use. That way
the rim of the can stays lean. I tried cleaning
the ladle with water *once*.

--

FF

Ku

Kenneth

in reply to ted on 23/05/2008 1:07 PM

23/05/2008 10:34 PM

On Sat, 24 May 2008 11:39:05 +1000, ted <[email protected]>
wrote:

>ted wrote:
>> B A R R Y wrote:
>>> On Fri, 23 May 2008 13:07:03 +1000, ted <[email protected]> wrote:
>>>
>>>> Sometimes when I am coating some wood with warm shellac flakes I get
>>>> a patch of greyish finish. If I put more shellac over it, it goes
>>>> away but I was wondering what I was doing to contaminate the mixed
>>>> shellac.
>>>> I apply by brush.
>>>
>>> That sounds like moisture, causing "blushing".
>>>
>> Could it be when I put brush in water between coats to keep brush from
>> drying out?
>> I give it a good wipe before I use it normally.
>>
>>> Blushing is possible with shellac and lacquer if moisture gets trapped
>>> under the finish. Just as you've noted, the blush is often easily
>>> removed by applying more finish. I've removed lacquer blush by
>>> spraying a very thin "flow coat", which reconstitutes the finish and
>>> allows the moisture to leave.
>>>
>>> Is your alcohol contaminated?
>> No was new mixture.
>>
>>>
>>> If not, maybe the warm finish is attracting moisture on higher
>>> relative humidity days.
>> By warm I meant the colour, I should have said "orange flakes"
>> It was actually 16o C
>>>
>>> With lacquer and shellac, I shoot for at least a 15 degree F (20F is
>>> better) spread between the temperature and dew point.
>>>
>>> ---------------------------------------------
>>> ** http://www.bburke.com/woodworking.html **
>>> ---------------------------------------------
>>
>> Thanks,
>> Ted
>
>You can probably tell I'm new at this. Want to check on terminology
>here. Your comments about alcohol: I use Methylated Spirits to make the
>shellac up. Are you calling MS the alcohol or should I be using
>something else? I just left a brush out of the water to test the
>re-soften hint.
>Thanks for all your comments,
>Ted.

Hi Ted,

PMJI, but...

The Methylated Spirits is appropriate. (It is simply two
different types of alcohol mixed. One is ethanol, the other
methyl alcohol. The latter is poisonous. If they sold pure
ethanol as a solvent, folks would drink it...)

But please say something more about why you believe that the
MS was not contaminated.

I ask because such "contamination" can happen more easily
than you might think. The situation you described does seem
to indicate "blushing" (as others have said) but that can
happen in some subtle ways.

Alcohol l-o-v-e-s water, and it is difficult (and therefore
expensive) to remove water from alcohol. So (virtually) any
alcohol you can buy will have (some) water in it before you
open it.

But then, just leaving a container of alcohol open on the
bench on a humid day can cause problems.

In fact, the tendency of the alcohol to absorb water from
the air, together with the water on the surface of your work
on such a humid day, might be enough to cause the "blush."

All the best,
--
Kenneth

If you email... Please remove the "SPAMLESS."

BA

B A R R Y

in reply to ted on 23/05/2008 1:07 PM

23/05/2008 6:39 AM

On Fri, 23 May 2008 13:07:03 +1000, ted <[email protected]> wrote:

>Sometimes when I am coating some wood with warm shellac flakes I get a
>patch of greyish finish. If I put more shellac over it, it goes away but
>I was wondering what I was doing to contaminate the mixed shellac.
>I apply by brush.

That sounds like moisture, causing "blushing".

Blushing is possible with shellac and lacquer if moisture gets trapped
under the finish. Just as you've noted, the blush is often easily
removed by applying more finish. I've removed lacquer blush by
spraying a very thin "flow coat", which reconstitutes the finish and
allows the moisture to leave.

Is your alcohol contaminated?

If not, maybe the warm finish is attracting moisture on higher
relative humidity days.

With lacquer and shellac, I shoot for at least a 15 degree F (20F is
better) spread between the temperature and dew point.

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

LB

Larry Blanchard

in reply to ted on 23/05/2008 1:07 PM

23/05/2008 10:06 AM

On Fri, 23 May 2008 22:41:48 +1000, ted wrote:

> Could it be when I put brush in water between coats to keep brush from
> drying out?
> I give it a good wipe before I use it normally.

Ouch! Don't do that! Shellac and water are not a good combination.
Store the brush in alcohol. Or better yet, put the shellac on with a pad
and toss the brush.


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