blotching in hydrocote finish

On Sun, 6 May 2018 13:01:43 -0700 (PDT), Len <[email protected]> wrote:

>I have been trying to finish a couple or doors. Something went wrong in the finish product (I think). Can anybody spot my mistake so I can complete the job? I should add that this technique worked flawlessly on a previous set of doors.
>
>This pair of doors has a (very expensive) molded glass center. So I am finishing only the frame surround, which is a set of 2x6,1-1/2 thick. I do not wish the strong grain to adsorb color and become dominant.
>
>The main colorant is a toner that I made: It is Hydrocote lacquer colored with a premixed water borne dye. The dye was mixed first, cooled, and then poured into the lacquer. The mixture seems to be uniform in color.
>
>
>
>My spray sequence was
>
> 1) Spray the door with a coat of Bullseye shellac and, after drying,
> I lightly sanded it smooth. The idea of the shellac was to prevent the
> grain from becoming too strong in the final product.
>

With some woods this is vital to prevent blotching. Did you over sand
the sealing coat? Was it too thin?

In the back of my mind I sort of remember doing a "water absorption
test" after this step in order to verify an adequate coat.

However, bear in mind that my experience is limited here.

> 2) I then sprayed the water borne lacquer toner on top.
>
>
> 3) If nothing went wrong I would then spray a couple of coats of clear
> Hydrocote and rub out the finish.
>
>I have used this technique before with excellent results. However, this time the result was a blotchy mess. At first I thought it was fisheye. But, after drying, it appears to be smooth. but blotchy. The color is not uniform - even thought the toner seems to be uniform in color and consistency.
>
>Should I:
>
> 1) just keep spraying hoping that it will become uniform with increased
> colorant or should I stop and strip it.
>
> 2) add more color to the hydrocote
>
> 3) try to make a dye mix with significantly less water and add that
> to a new batch of Hydrocote.
>
> 4) strip it and try a whole new approach.
>
>Len

On Sunday, May 6, 2018 at 4:01:46 PM UTC-4, Len wrote:
> I have been trying to finish a couple or doors. Something went wrong in =
the finish product (I think). Can anybody spot my mistake so I can complet=
e the job? I should add that this technique worked flawlessly on a previou=
s set of doors.=20
>=20
> This pair of doors has a (very expensive) molded glass center. So I am f=
inishing only the frame surround, which is a set of 2x6,1-1/2 thick. I do =
not wish the strong grain to adsorb color and become dominant.
>=20
> The main colorant is a toner that I made: It is Hydrocote lacquer colore=
d with a premixed water borne dye. The dye was mixed first, cooled, and th=
en poured into the lacquer. The mixture seems to be uniform in color.=20
>=20
>=20
>=20
> My spray sequence was
>=20
> 1) Spray the door with a coat of Bullseye shellac and, after drying,=
=20
> I lightly sanded it smooth. The idea of the shellac was to preven=
t the
> grain from becoming too strong in the final product.=20
>=20
> 2) I then sprayed the water borne lacquer toner on top. =20
>=20
>=20
> 3) If nothing went wrong I would then spray a couple of coats of cle=
ar
> Hydrocote and rub out the finish.=20
>=20
> I have used this technique before with excellent results. However, this =
time the result was a blotchy mess. At first I thought it was fisheye. Bu=
t, after drying, it appears to be smooth. but blotchy. The color is not un=
iform - even thought the toner seems to be uniform in color and consistency=
.=20
>=20
> Should I:
>=20
> 1) just keep spraying hoping that it will become uniform with incre=
ased=20
> colorant or should I stop and strip it. =20
> =20
> 2) add more color to the hydrocote
>=20
> 3) try to make a dye mix with significantly less water and add that=
=20
> to a new batch of Hydrocote. =20
>=20
> 4) strip it and try a whole new approach.
>=20
> Len

Just a quess Did You fine sand your shellac 220 -320 grit ?
This creates a better surface an etch for the finish applied over it.
Next Temperature and Humidity can be problematic moisture on shellac will j=
ust sit there like condensation .
Make sure it is wiped dry prior to your topcoat of water soluble or solve=
nt based topcoat.
Stripping or scraping it off may be your best alternative.
if it were solvent based You could use acetone or Laq. thinner to remove it=
down to the shellac but since it's water base this stuff is hard to deal w=
ith when dry. If it's not too thick You could try sanding it until your col=
or seems uniform again but that is a crap-shoot.
Having not seen the piece it's hard for me to determine the problem
But I am going to guess it's a blushing layer of moisture between shellac a=
nd topcoat. Or possibly too thick ,too quick on Your topcoat

After agonizing over similar problems in trying to repair such a mess.
I now resort to stripping and starting over in order not spend a lot of ti=
me correcting an inferior finish.

That's all I can come up with for You I hope i have shed some light on Your=
problem.

On Monday, May 7, 2018 at 11:00:34 AM UTC-4, Rick the antique guy wrote:
> On Sunday, May 6, 2018 at 4:01:46 PM UTC-4, Len wrote:
> > I have been trying to finish a couple or doors. Something went wrong i=
n the finish product (I think). Can anybody spot my mistake so I can compl=
ete the job? I should add that this technique worked flawlessly on a previ=
ous set of doors.=20
> >=20
> > This pair of doors has a (very expensive) molded glass center. So I am=
finishing only the frame surround, which is a set of 2x6,1-1/2 thick. I d=
o not wish the strong grain to adsorb color and become dominant.
> >=20
> > The main colorant is a toner that I made: It is Hydrocote lacquer colo=
red with a premixed water borne dye. The dye was mixed first, cooled, and =
then poured into the lacquer. The mixture seems to be uniform in color.=20
> >=20
> >=20
> >=20
> > My spray sequence was
> >=20
> > 1) Spray the door with a coat of Bullseye shellac and, after dryin=
g,=20
> > I lightly sanded it smooth. The idea of the shellac was to prev=
ent the
> > grain from becoming too strong in the final product.=20
> >=20
> > 2) I then sprayed the water borne lacquer toner on top. =20
> >=20
> >=20
> > 3) If nothing went wrong I would then spray a couple of coats of c=
lear
> > Hydrocote and rub out the finish.=20
> >=20
> > I have used this technique before with excellent results. However, thi=
s time the result was a blotchy mess. At first I thought it was fisheye. =
But, after drying, it appears to be smooth. but blotchy. The color is not =
uniform - even thought the toner seems to be uniform in color and consisten=
cy.=20
> >=20
> > Should I:
> >=20
> > 1) just keep spraying hoping that it will become uniform with inc=
reased=20
> > colorant or should I stop and strip it. =20
> > =20
> > 2) add more color to the hydrocote
> >=20
> > 3) try to make a dye mix with significantly less water and add th=
at=20
> > to a new batch of Hydrocote. =20
> >=20
> > 4) strip it and try a whole new approach.
> >=20
> > Len
>=20
> Just a quess Did You fine sand your shellac 220 -320 grit ?
> This creates a better surface an etch for the finish applied over it.
> Next Temperature and Humidity can be problematic moisture on shellac will=
just sit there like condensation .
> Make sure it is wiped dry prior to your topcoat of water soluble or sol=
vent based topcoat.
> Stripping or scraping it off may be your best alternative.
> if it were solvent based You could use acetone or Laq. thinner to remove =
it down to the shellac but since it's water base this stuff is hard to deal=
with when dry. If it's not too thick You could try sanding it until your c=
olor seems uniform again but that is a crap-shoot.
> Having not seen the piece it's hard for me to determine the problem
> But I am going to guess it's a blushing layer of moisture between shellac=
and topcoat. Or possibly too thick ,too quick on Your topcoat
>=20
> After agonizing over similar problems in trying to repair such a mess.
> I now resort to stripping and starting over in order not spend a lot of =
time correcting an inferior finish.
>=20
> That's all I can come up with for You I hope i have shed some light on Yo=
ur problem.

Another fine point is: that I rarely color or stain topcoats other than f=
or a repair or touch-up to an existing finish.Sometime if the finish is no=
t subject to wearit is an acceptable choice to darkenor change color hue sl=
ightly.
It's almost a certain disaster when tryiing to go to a lighter shade.

I always prefer to stain or color the wood itself prior to the sealing with=
a shellac or sealer.
This adds depth to the color and it is less likely to chip scrape or scrat=
ch off as it would if it were a colored topcoat.
In most cases let your topcoat be clear not mixed with colors or stains.=20
It's more easily ready for a scratch repair,since you may not have damaged =
the color beneath the sealer
rick B.