I'm having a problem that is driving me nuts. I've been using qualalac
and it is cracking. I mean lots of cracks. When I first noticed it I
thought it was the wood but the cracks are in the finish. Moisture
content in the wood is not an issue as the pieces that this is
happening to are quite dry at about 6%. I'm mixing the lacquer with
lacquer thinner 50% as per the directions. I'm using a small hvlp
sprayer.
I used to use nitrocellulose and never had a problem. I can't find it
anymore or I would still be using it.
Has anyone had this problem with qualalack or know what is causing
this?
TIA, Bob

http://outofcontrol-woodturning.com

wrote:
I'm having a problem that is driving me nuts. I've been using qualalac
and it is cracking. I mean lots of cracks. When I first noticed it I
thought it was the wood but the cracks are in the finish. Moisture
content in the wood is not an issue as the pieces that this is
happening to are quite dry at about 6%. I'm mixing the lacquer with
lacquer thinner 50% as per the directions. I'm using a small hvlp
sprayer.
I used to use nitrocellulose and never had a problem. I can't find it
anymore or I would still be using it.
Has anyone had this problem with qualalack or know what is causing
this?
TIA, Bob

http://outofcontrol-woodturning.com


From Behlen's product catalog:

"Qualalacq™ Thinner are recommended to be used in conjunction with this
product."

http://www.hbehlen.com/Behlen_Catalog2006.pdf

--
Jack Novak
Buffalo, NY - USA

Very nice work on your site.

Steven Raphael
Ithaca Mi
http://www.geocities.com/steven_raph...turnings1.html
wrote in message
oups.com...
I'm having a problem that is driving me nuts. I've been using qualalac
and it is cracking. I mean lots of cracks. When I first noticed it I
thought it was the wood but the cracks are in the finish. Moisture
content in the wood is not an issue as the pieces that this is
happening to are quite dry at about 6%. I'm mixing the lacquer with
lacquer thinner 50% as per the directions. I'm using a small hvlp
sprayer.
I used to use nitrocellulose and never had a problem. I can't find it
anymore or I would still be using it.
Has anyone had this problem with qualalack or know what is causing
this?
TIA, Bob

http://outofcontrol-woodturning.com

On 11 May 2007 15:19:40 -0700, wrote:

I'm having a problem that is driving me nuts. I've been using qualalac
and it is cracking. I mean lots of cracks. When I first noticed it I
thought it was the wood but the cracks are in the finish. Moisture
content in the wood is not an issue as the pieces that this is
happening to are quite dry at about 6%. I'm mixing the lacquer with
lacquer thinner 50% as per the directions. I'm using a small hvlp
sprayer.
I used to use nitrocellulose and never had a problem. I can't find it
anymore or I would still be using it.
Has anyone had this problem with qualalack or know what is causing
this?
TIA, Bob

I've never used qualalac (in fact, I'm not even sure if that is the
name of the laquer you're using or the wood!,) but I have used plenty
of laquer, and experienced the same problem from time to time.

There are three main things that have caused a problem with laquer for
me in the past, and one, all, or none of them may apply in your case.

The first two are related- excessive sunlight and/or heat when curing.
I had a project not only crack, but even develop bubbles after
laquering because I left it in front of a window on a hot, sunny day.
Sometimes it's tempting to rush it, but laquer doesn't like being
hurried (and it's really not that slow to cure in any case.) If
you're setting it near a window, try putting it in the shade to dry.

The third is something I doubt you're doing, but here it is. Layered
finishes- in my case, this happened when trying to exactly match an
old, semi-transparent stain for a really picky customer who *wanted*
the trim I was making for them to look old and (IMO) crappy. The only
way to match the color was to do the same thing the original finisher
did- to paint the stain on thick, and let it dry without wiping it off
so it would deaden the grain pattern. When I sprayed the laquer
over, it was able to slightly dissolve the stain that had cured on the
surface, and ended up cracking pretty badly. The solution ended up
being to paint the stain on, then follow that with a coat of shellac
to act as a barrier between the stain and the laquer, and then laquer
it. It looked like junk to me, but the customer was happy.

If there is something in the wood that is attacking the finish, you
may want to try the shellac trick to seal it before the final topcoat.
I used a 1/2 pound cut, and wiped it on with a clean rag. It will dry
within minutes, and you can proceed to the final finish. If you're
doing a really complex layered finish, I'd do this between each layer-
the reason for the shellac is that it is alcohol based, and does not
dissolve (or does not dissolve much) when it is covered by most
commerically availible finishes.

Though of course, I'm still fairly convinced that finishing is more
voodoo than science- the above is just what worked for me when I had
the same problems with laquer cracking.

On May 11, 8:58Â*pm, Nova wrote:
wrote:
I'm having a problem that is driving me nuts. I've been using qualalac
and it is cracking. I mean lots of cracks. When I first noticed it I
thought it was the wood but the cracks are in the finish. Moisture
content in the wood is not an issue as the pieces that this is
happening to are quite dry at about 6%. I'm mixing the lacquer with
lacquer thinner 50% as per the directions. I'm using a small hvlp
sprayer.
I used to use nitrocellulose and never had a problem. I can't find it
anymore or I would still be using it.
Has anyone had this problem with qualalack or know what is causing
this?
TIA, Bob

http://outofcontrol-woodturning.com

Â*From Behlen's product catalog:

"Qualalacq„¢ Thinner are recommended to be used in conjunction with this
product."

http://www.hbehlen.com/Behlen_Catalog2006.pdf

--
Jack Novak
Buffalo, NY - USA


Hi Jack, Yes I read that but I have a hard time believing that thier
thinner is any different than any other lacquer thinner. I suppose
there could be a difference. Certainly is a price difference. Problem
is I've been using qualalack for about 6 months and the problem just
started in the past couple weeks. I was looking at the spray gun this
evening and I'm wondering if the air adjustment got turned. The air
adjustment is very easy to turn and maybe it has gotten turned a
little at a time.

On May 11, 5:19 pm, wrote:

SNIP

I'm mixing the lacquer with
lacquer thinner 50% as per the directions. I'm using a small hvlp sprayer.
I used to use nitrocellulose and never had a problem.
I can't find it anymore or I would still be using it.
Has anyone had this problem with qualalack or know what is causing
this?
TIA, Bob

Hi, Bob. First, really nice work on that website. I think that
spalted maple bowl with the square edges is really pretty. Well
designed, too.

The following may be more than you are interested in, but it might
help others too. Me, I like to have as much info as possible, so here
goes.

I'll try to hit the high points of your post with some ideas
So that you won't think I'm just getting started in finishing, look at
rec.woodworking under this same name, and you can see that I have
written extensively on finishing (especially lacquers and
urethanes), as well as on Woodweb. As a remodeler, I spray about 50+
gallons of lacquer on a heavy year (you read that right), and a little
less than half on a lighter one. Along with industrial enamels and
urethane coatings, I have had to break down and study, learn, practice
and "trial and error" my way to finishing that I like.

I started finishing for myself many years ago when the people I had
subbed the cabinet finishing to didn't do a good job and couldn't find
their way to work except on Friday.

Anyway - there are a lot of different things that go on with lacquer
and solvents. You are using a nitrocellulose lacquer, so you can use
just about any brand of quality lacquer thinner that is out there on
the market. Crown, Strip Ease, Sunnyvale, etc. are NOT quality
thinners and who knows what they have in them. Not even the
manufacturers know exactly. Many of these low end lacquer thinners
are actually made from recycled materials, and are almost unusable
with some finishes.

Buy a good quality branded lacquer thinner like Sherwyn Williams,
Benjamin Moore, Startex, etc. There are others, and these are paint
store items. cracking lacquer is difficult to do, so you may just
have bad thinner.

Try thinning much less. The instructions on the can are guidelines,
and they are a place to start when you are unfamiliar with the
product. As a high VOC evaporative finish, lacquer will crack if it
dried unevenly. Under certain conditions, say a warm dry area or an
area with constant airflow or movement, the lacquer will begin to
skin over. However, it won't look that way to the eye, and you can't
see it unless you run your finger through it.

The finish cracks as the solvent attempts to outgas through the
partially polymerized finish. The solvent looks for the weak spots in
the "skin" and opens them up, pushing out the gasses through the
cracks. A large amount of thinner (are you sure they said 50%??) will
cause this to happen.

There could be contaminates on your wood. Stearated paper is
notorious for screwing up good finishing. Many buy the cheapest
sandpaper they can find, and overuse it. The lubrication (stearating
compound - commonly known as a variant of soap) will come off the
paper with heat, which of course is generated by sanding. This
lubrication will actually melt into the wood and cause all manner of
problems from patchy cracking to fisheyes.

I see that you do segmented work, and sanding down the different kinds
of oily colored hardwoods as well as the resins in the glues will
cause will generate a lot of heat and a lot of contaminates.

Try this: before finishing, clean the piece well with a rag wetted
(not just damp) with lacquer thinner. Really scrub it. You won't
raise the grain, and it does wonders for cleaning and will pick almost
all the stearate up.

Thin less. 50% is just too much. You did not say if you were using
an HVLP conversion gun (the type used with an air compressor) or a
true HVLP, the type powered with a turbine. But in this instance, I
don't think the problem is in the gun, as gun/pressure/delivery
problems are all about the same. I have both types, and in moderate
weather the thinning protocols for both types of gun are the same.
Start thinning at about 25%, and see how that does.

Put the right amount of sealer on your piece. Normally, the
manufacturers want about 3 to 4 mil minimum on a coat (some more) of
evaporative finish, and it will dry to about 1 mil. It is important
that you find the sweet spot for your finish, and that takes
practice. (To run down how to make your test bed and records to
establish the characteristics of each finish with your individual
equipment, go to the rec. and search there).

Thinner than 3 mil will NOT give you a good finish unless you are up
in the 5th-6th coat of material. For some build finishes a thinner
coat makes a good topper, but we aren't talking about that here. The
rule of thumb is that if you are laying down a thin even coat that is
drying shiny, quickly and evenly as you are finishing, then you are
not putting on enough material.

If you think your piece is contaminated with oils, stearates, or
anything else you might have gotten on it when you handled it, then
uses shellac. You quickly learn in fine finishing though, that
shellac will dissolve or blur those gorgeous spalt lines in many
woods. (THAT was an expensive lesson...) I would only use shellac as
a primer if I knew there were problems with adhesion.

Lacquer is its own best primer. Nothing sticks to lacquer like
itself. Why? Since lacquer is a build finish, properly applied coats
will melt into each other making a monolithic finish. Do not mix any
other coatings in between layers of lacquer for any reason as you
defeat the reason it is used, and that is the ability to build a
thick coating rapidly. If you put anything in between the coats, then
you will have a film finish, or layered. This can easily lead to
witness lines, poor adhesion, etc.

It is easy to have problems with the safest and most forgiving of all
finishes, shellac. For example: Put a coat of shellac on wood for
primer, sand and seal. Put a coat of shellac on top of that. But
wait.. did you thin the shellac to spray it or brush it easier? If
you did, you probably used alcohol from HD, Lowes's or the lumberyard,
and it is only around 96 - 97% pure.

Why is that important? The other three percent is water, and that is
the bugger to get out. This cheap alcohol is distilled from a number
of products, again sometime of unknown origin. However, if you go to
the paint store and buy anhydrous alcohol (99.99% pure) you are good
to go on your thinner/solvent. No water introduced into the shellac.
Sadly, this doesn't show up right away, as water is easily miscible
with alcohol, so you may have to wait for the shellac to cure out
completely before you see the problems.

As far as nitrocellulose lacquer availability, go anywhere they sell
lacquer. If it isn't pre-cat, post cat, or CAB (non yellowing white
with acrylic enhancement) and clearly marked as such, it will be
nitrocellulose. Most of today's lacquers are pretty good quality and
behave well under most conditions, so you should be good with
something off the shelf, nothing from a specialty shop needed.

The common brands are Deft (old reliable), Old Masters (my favorite
off the shelf brand), and there are a few others. Look for something
in the upper teens to lower-mid twenties of solids in the ingredients
when buying.

Good Luck! I hope you let us know how this all turned out.

Robert

wrote:


http://outofcontrol-woodturning.com

From Behlen's product catalog:

"Qualalacq„¢ Thinner are recommended to be used in conjunction with this
product."

http://www.hbehlen.com/Behlen_Catalog2006.pdf

--
Jack Novak
Buffalo, NY - USA



Hi Jack, Yes I read that but I have a hard time believing that thier
thinner is any different than any other lacquer thinner. I suppose
there could be a difference. Certainly is a price difference. Problem
is I've been using qualalack for about 6 months and the problem just
started in the past couple weeks. I was looking at the spray gun this
evening and I'm wondering if the air adjustment got turned. The air
adjustment is very easy to turn and maybe it has gotten turned a
little at a time.


I got a little confused and was thinking of Qualasole padding lacquer.
Qualalacq is a sanding sealer. I don't think it's designed to be used
as a final finish.

--
Jack Novak
Buffalo, NY - USA

"Nova" wrote in message
news:gFi1i.469$w51.429@trndny09...



Qualalacq is a sanding sealer. I don't think it's designed to be used
as a final finish.

Look again.

CW wrote:

"Nova" wrote in message
news:gFi1i.469$w51.429@trndny09...


Qualalacq is a sanding sealer. I don't think it's designed to be used
as a final finish.


Look again.




Oops, too many Quala...'s.

--
Jack Novak
Buffalo, NY - USA

On May 12, 2:03 am, "
wrote:
On May 11, 5:19 pm, wrote:

SNIP

I'm mixing the lacquer with
lacquer thinner 50% as per the directions. I'm using a small hvlp sprayer.
I used to use nitrocellulose and never had a problem.
I can't find it anymore or I would still be using it.
Has anyone had this problem with qualalack or know what is causing
this?
TIA, Bob

Hi, Bob. First, really nice work on that website. I think that
spalted maple bowl with the square edges is really pretty. Well
designed, too.

The following may be more than you are interested in, but it might
help others too. Me, I like to have as much info as possible, so here
goes.

I'll try to hit the high points of your post with some ideas
So that you won't think I'm just getting started in finishing, look at
rec.woodworking under this same name, and you can see that I have
written extensively on finishing (especially lacquers and
urethanes), as well as on Woodweb. As a remodeler, I spray about 50+
gallons of lacquer on a heavy year (you read that right), and a little
less than half on a lighter one. Along with industrial enamels and
urethane coatings, I have had to break down and study, learn, practice
and "trial and error" my way to finishing that I like.

I started finishing for myself many years ago when the people I had
subbed the cabinet finishing to didn't do a good job and couldn't find
their way to work except on Friday.

Anyway - there are a lot of different things that go on with lacquer
and solvents. You are using a nitrocellulose lacquer, so you can use
just about any brand of quality lacquer thinner that is out there on
the market. Crown, Strip Ease, Sunnyvale, etc. are NOT quality
thinners and who knows what they have in them. Not even the
manufacturers know exactly. Many of these low end lacquer thinners
are actually made from recycled materials, and are almost unusable
with some finishes.

Buy a good quality branded lacquer thinner like Sherwyn Williams,
Benjamin Moore, Startex, etc. There are others, and these are paint
store items. cracking lacquer is difficult to do, so you may just
have bad thinner.

Try thinning much less. The instructions on the can are guidelines,
and they are a place to start when you are unfamiliar with the
product. As a high VOC evaporative finish, lacquer will crack if it
dried unevenly. Under certain conditions, say a warm dry area or an
area with constant airflow or movement, the lacquer will begin to
skin over. However, it won't look that way to the eye, and you can't
see it unless you run your finger through it.

The finish cracks as the solvent attempts to outgas through the
partially polymerized finish. The solvent looks for the weak spots in
the "skin" and opens them up, pushing out the gasses through the
cracks. A large amount of thinner (are you sure they said 50%??) will
cause this to happen.

There could be contaminates on your wood. Stearated paper is
notorious for screwing up good finishing. Many buy the cheapest
sandpaper they can find, and overuse it. The lubrication (stearating
compound - commonly known as a variant of soap) will come off the
paper with heat, which of course is generated by sanding. This
lubrication will actually melt into the wood and cause all manner of
problems from patchy cracking to fisheyes.

I see that you do segmented work, and sanding down the different kinds
of oily colored hardwoods as well as the resins in the glues will
cause will generate a lot of heat and a lot of contaminates.

Try this: before finishing, clean the piece well with a rag wetted
(not just damp) with lacquer thinner. Really scrub it. You won't
raise the grain, and it does wonders for cleaning and will pick almost
all the stearate up.

Thin less. 50% is just too much. You did not say if you were using
an HVLP conversion gun (the type used with an air compressor) or a
true HVLP, the type powered with a turbine. But in this instance, I
don't think the problem is in the gun, as gun/pressure/delivery
problems are all about the same. I have both types, and in moderate
weather the thinning protocols for both types of gun are the same.
Start thinning at about 25%, and see how that does.

Put the right amount of sealer on your piece. Normally, the
manufacturers want about 3 to 4 mil minimum on a coat (some more) of
evaporative finish, and it will dry to about 1 mil. It is important
that you find the sweet spot for your finish, and that takes
practice. (To run down how to make your test bed and records to
establish the characteristics of each finish with your individual
equipment, go to the rec. and search there).

Thinner than 3 mil will NOT give you a good finish unless you are up
in the 5th-6th coat of material. For some build finishes a thinner
coat makes a good topper, but we aren't talking about that here. The
rule of thumb is that if you are laying down a thin even coat that is
drying shiny, quickly and evenly as you are finishing, then you are
not putting on enough material.

If you think your piece is contaminated with oils, stearates, or
anything else you might have gotten on it when you handled it, then
uses shellac. You quickly learn in fine finishing though, that
shellac will dissolve or blur those gorgeous spalt lines in many
woods. (THAT was an expensive lesson...) I would only use shellac as
a primer if I knew there were problems with adhesion.

Lacquer is its own best primer. Nothing sticks to lacquer like
itself. Why? Since lacquer is a build finish, properly applied coats
will melt into each other making a monolithic finish. Do not mix any
other coatings in between layers of lacquer for any reason as you
defeat the reason it is used, and that is the ability to build a
thick coating rapidly. If you put anything in between the coats, then
you will have a film finish, or layered. This can easily lead to
witness lines, poor adhesion, etc.

It is easy to have problems with the safest and most forgiving of all
finishes, shellac. For example: Put a coat of shellac on wood for
primer, sand and seal. Put a coat of shellac on top of that. But
wait.. did you thin the shellac to spray it or brush it easier? If
you did, you probably used alcohol from HD, Lowes's or the lumberyard,
and it is only around 96 - 97% pure.

Why is that important? The other three percent is water, and that is
the bugger to get out. This cheap alcohol is distilled from a number
of products, again sometime of unknown origin. However, if you go to
the paint store and buy anhydrous alcohol (99.99% pure) you are good
to go on your thinner/solvent. No water introduced into the shellac.
Sadly, this doesn't show up right away, as water is easily miscible
with alcohol, so you may have to wait for the shellac to cure out
completely before you see the problems.

As far as nitrocellulose lacquer availability, go anywhere they sell
lacquer. If it isn't pre-cat, post cat, or CAB (non yellowing white
with acrylic enhancement) and clearly marked as such, it will be
nitrocellulose. Most of today's lacquers are pretty good quality and
behave well under most conditions, so you should be good with
something off the shelf, nothing from a specialty shop needed.

The common brands are Deft (old reliable), Old Masters (my favorite
off the shelf brand), and there are a few others. Look for something
in the upper teens to lower-mid twenties of solids in the ingredients
when buying.

Good Luck! I hope you let us know how this all turned out.

Robert

Thanks Robert, A lot of good info in your post. The directions on the
can do in fact state a 1:1 mixture. Thinking that might be the problem
I cut back to 3/4:1 with the same result. I would guess the thinner
I'm using is ok as I've used the same thinner with success in the
past. With both qualalack and parks nitrocellulose.
The can suggests a 35-50# setting. Being an inexpensive sprayer I has
no idea what it is putting out.
My question to you is could the air mixture in an hvlp system have
anything to do with a poor (cracking) finish?
While I've used the sprayer for a few years my experience is limited.
Up until now its been point and pull the trigger.
My guess would be to turn down the air while still maintaining an even
flow.
Thanks, Bob

On May 12, 12:20 pm, wrote:

Thanks Robert, A lot of good info in your post. The directions on the can do in fact state a 1:1 mixture. Thinking that might be the problem I cut back to 3/4:1 with the same result. I would guess the thinner
I'm using is ok as I've used the same thinner with success in the past. With both qualalack and parks nitrocellulose.
The can suggests a 35-50# setting. Being an inexpensive sprayer I has
no idea what it is putting out.
My question to you is could the air mixture in an hvlp system have
anything to do with a poor (cracking) finish?
While I've used the sprayer for a few years my experience is limited.
Up until now its been point and pull the trigger.
My guess would be to turn down the air while still maintaining an even flow.
Thanks, Bob

And thanks for responding, Bob. Sometimes you never know if anyone
even bothered to follow the thread they started.

I am setting aside application technique in this as I am figuring if
you have been getting acceptable results with your setup for years,
you have put the time into that aspect of finishing to get it where
you want it.

Turning down the air flow will only make the material droplets bigger,
and give less of a consistent pattern.

New products have to be fine tuned to your equipment with you use
HVLP, and it is much more critical than the old high pressure days.

Here's the easy way to set the gun up with a new finish.
Take a sheet of plywood (anything smooth) outside and lean it up where
you can see the finish in strong light. Turn on the turbine unit or
compressor and set them at a pressure you have had good results with
in the past.

Put some thinned material in the gun and close the fluid control valve
completely. Walk over to the plywood and slowly open the fluid valve
with gun in the proper spraying position. You should see tiny
droplets, no mist. At about 8" from the surface, if you see more than
just a very small amount of bounce back, turn down the pressure to the
gun.

When it covers to a wet consistent surface easily, leave the fluid
nozzle alone. Leave the pressure alone. Check your surface after
your material has dried. On the area that you like the finish, add a
second coat. If it looks good and stays good when dried, you are
finished. I have three HVLP guns that do different things - each has
a little nick in it on the fluid control for the different products I
spray.

Anything is possible, but in this instance, the gun or the air
delivery is not a likely suspect. Unacceptable delivery symptoms
usually attributed to HVLP equipment can be

1) sputter - not enough air to the gun, fluid nozzle opened too high,
product not thinned properly

2) uneven coating thickness - inconsistent delivery of air to the
gun. This can be caused by dirty or blocked air filter, or air flow
set too low

3) A splotch or splatter occasionally on the finish - not enough air
to the equipment to properly disperse the particles (remember, HVLP
doesn't atomize like high pressure)

4) #1, #2 and #3 above can also be caused by a dirty aircap assembly.
Many times when people clean their HVLP systems they don't clean the
holes in the horns, which are a precisely determined set of venturi
that determine direction, pattern and dispersal of fluid droplets. I
clean mine with a wooden toothpick, and the tiny holes with one
bristle from a stainless steel brush

5) Fisheyes, craters and voids - while these are usually associated
with poor surface prep, they can be attributed in some cases to gun
cleaning. Many people use the same gun for both water based and
solvent based products. Water, ammonia, and all kinds of things can
be in the gun from using a water based product. This is classic cross
contamination

Just about everything else happens outside of the gun, leaving only
fluid materials and project preparation.

Cracking or crazing is not usually an application issue. To help bear
this out, if you have been using this piece of equipment for years, I
have to think you have been using it correctly or you would certainly
have run into this before, no matter the manufacturer of sealer.

These annoying problems can be the bane of finishing. They take the
fun out of it. When I am committed (by contract!) to do the
finishing, and something like this cracking pops up, this is how I
keep my head in the game: I ask myself - how much would I pay to get
myself OUT of this mess and finish this project? $20? $30? $50?

Thankfully, for this kind of thing is a $20 science lesson. I change
brands of lacquer ($10 for a quart of off the shelf stuff) and $8 for
a gallon of good thinner.

In your particular case my best guess is the thinner is the culprit.
Behlen's makes a good quality product line, although I am not
personally familiar with qualalac.

Please understand that all lacquer thinners are not completely
compatible with all lacquers. The Crowns, Sunnyvales, etc. are made
from recycled mixtures and may have products in them that react
differently with certain lacquer formulas. Those thinners will fine
with some, not with others. That is the specific reason I use the
above mentioned brands to clean the equipment (hence the term "gun
wash" you have probably heard) but not to mix the products. Sometimes
it just comes down to compatibility.

Since HVLP does not atomize, it is necessary to use products that can
accept thinning well, and aren't too touchy about it. You should know
(and probably do) that ALL manufacturers recommend their own thinners,
retarders, flow controllers, etc., to be used with their product.
This is without exception. But no finishers I know ever do unless it
is economically feasible.

Since you have the Behlen's now, I would try thinning with a really
good quality thinner. If that didn't work, for my own satisfaction I
would change lacquers and try it first with the old thinner, and then
with the new. Unless the lacquer you have is old, a bad batch, or has
been improperly stored (not necessarily by you) or shipped, the answer
should be in there somewhere.

It will be easy enough for you to find out.

Once again, let us know how this pans out. If it were me, I would
spend the dough and get through this as quickly as possible.

Robert

On May 12, 3:25 pm, "
wrote:
On May 12, 12:20 pm, wrote:

Thanks Robert, A lot of good info in your post. The directions on the can do in fact state a 1:1 mixture. Thinking that might be the problem I cut back to 3/4:1 with the same result. I would guess the thinner
I'm using is ok as I've used the same thinner with success in the past. With both qualalack and parks nitrocellulose.
The can suggests a 35-50# setting. Being an inexpensive sprayer I has
no idea what it is putting out.
My question to you is could the air mixture in an hvlp system have
anything to do with a poor (cracking) finish?
While I've used the sprayer for a few years my experience is limited.
Up until now its been point and pull the trigger.
My guess would be to turn down the air while still maintaining an even flow.
Thanks, Bob

And thanks for responding, Bob. Sometimes you never know if anyone
even bothered to follow the thread they started.

I am setting aside application technique in this as I am figuring if
you have been getting acceptable results with your setup for years,
you have put the time into that aspect of finishing to get it where
you want it.

Turning down the air flow will only make the material droplets bigger,
and give less of a consistent pattern.

New products have to be fine tuned to your equipment with you use
HVLP, and it is much more critical than the old high pressure days.

Here's the easy way to set the gun up with a new finish.
Take a sheet of plywood (anything smooth) outside and lean it up where
you can see the finish in strong light. Turn on the turbine unit or
compressor and set them at a pressure you have had good results with
in the past.

Put some thinned material in the gun and close the fluid control valve
completely. Walk over to the plywood and slowly open the fluid valve
with gun in the proper spraying position. You should see tiny
droplets, no mist. At about 8" from the surface, if you see more than
just a very small amount of bounce back, turn down the pressure to the
gun.

When it covers to a wet consistent surface easily, leave the fluid
nozzle alone. Leave the pressure alone. Check your surface after
your material has dried. On the area that you like the finish, add a
second coat. If it looks good and stays good when dried, you are
finished. I have three HVLP guns that do different things - each has
a little nick in it on the fluid control for the different products I
spray.

Anything is possible, but in this instance, the gun or the air
delivery is not a likely suspect. Unacceptable delivery symptoms
usually attributed to HVLP equipment can be

1) sputter - not enough air to the gun, fluid nozzle opened too high,
product not thinned properly

2) uneven coating thickness - inconsistent delivery of air to the
gun. This can be caused by dirty or blocked air filter, or air flow
set too low

3) A splotch or splatter occasionally on the finish - not enough air
to the equipment to properly disperse the particles (remember, HVLP
doesn't atomize like high pressure)

4) #1, #2 and #3 above can also be caused by a dirty aircap assembly.
Many times when people clean their HVLP systems they don't clean the
holes in the horns, which are a precisely determined set of venturi
that determine direction, pattern and dispersal of fluid droplets. I
clean mine with a wooden toothpick, and the tiny holes with one
bristle from a stainless steel brush

5) Fisheyes, craters and voids - while these are usually associated
with poor surface prep, they can be attributed in some cases to gun
cleaning. Many people use the same gun for both water based and
solvent based products. Water, ammonia, and all kinds of things can
be in the gun from using a water based product. This is classic cross
contamination

Just about everything else happens outside of the gun, leaving only
fluid materials and project preparation.

Cracking or crazing is not usually an application issue. To help bear
this out, if you have been using this piece of equipment for years, I
have to think you have been using it correctly or you would certainly
have run into this before, no matter the manufacturer of sealer.

These annoying problems can be the bane of finishing. They take the
fun out of it. When I am committed (by contract!) to do the
finishing, and something like this cracking pops up, this is how I
keep my head in the game: I ask myself - how much would I pay to get
myself OUT of this mess and finish this project? $20? $30? $50?

Thankfully, for this kind of thing is a $20 science lesson. I change
brands of lacquer ($10 for a quart of off the shelf stuff) and $8 for
a gallon of good thinner.

In your particular case my best guess is the thinner is the culprit.
Behlen's makes a good quality product line, although I am not
personally familiar with qualalac.

Please understand that all lacquer thinners are not completely
compatible with all lacquers. The Crowns, Sunnyvales, etc. are made
from recycled mixtures and may have products in them that react
differently with certain lacquer formulas. Those thinners will fine
with some, not with others. That is the specific reason I use the
above mentioned brands to clean the equipment (hence the term "gun
wash" you have probably heard) but not to mix the products. Sometimes
it just comes down to compatibility.

Since HVLP does not atomize, it is necessary to use products that can
accept thinning well, and aren't too touchy about it. You should know
(and probably do) that ALL manufacturers recommend their own thinners,
retarders, flow controllers, etc., to be used with their product.
This is without exception. But no finishers I know ever do unless it
is economically feasible.

Since you have the Behlen's now, I would try thinning with a really
good quality thinner. If that didn't work, for my own satisfaction I
would change lacquers and try it first with the old thinner, and then
with the new. Unless the lacquer you have is old, a bad batch, or has
been improperly stored (not necessarily by you) or shipped, the answer
should be in there somewhere.

It will be easy enough for you to find out.

Once again, let us know how this pans out. If it were me, I would
spend the dough and get through this as quickly as possible.

Robert

Thanks Robert, Your input is very much appreciated. I think I'll try
different thinner as you recommend. I didn't really think the air was
the problem but I will go through the setup as you recomended just for
peace of mind.
In a way its kind of good that this happened. It got me back on usenet
again.
I used to come to rec craft woodturning daily for years and read every
post. I'm talking way back when google was deja news. Heck I even
remember Arch. Thanks, Bob

On 12 May 2007 12:25:12 -0700, "
wrote:

Snip

Since you have the Behlen's now, I would try thinning with a really
good quality thinner. If that didn't work, for my own satisfaction I
would change lacquers and try it first with the old thinner, and then
with the new. Unless the lacquer you have is old, a bad batch, or has
been improperly stored (not necessarily by you) or shipped, the answer
should be in there somewhere.

It will be easy enough for you to find out.

Once again, let us know how this pans out. If it were me, I would
spend the dough and get through this as quickly as possible.


Great couple of posts Robert- that filled in a couple of gaps I had,
and is an excellent reminder of the process (I don't spray laquer from
my cup gun very often- because I'm usually too lazy to want to clean
it afterwards, and just use a rattlecan instead.)

From Behlen's product catalog:

"QualalacqT Thinner are recommended to be used in conjunction with this
product."

http://www.hbehlen.com/Behlen_Catalog2006.pdf

--
Jack Novak
Buffalo, NY - USA


Hi Jack, Yes I read that but I have a hard time believing that thier
thinner is any different than any other lacquer thinner. I suppose
there could be a difference. Certainly is a price difference. Problem
is I've been using qualalack for about 6 months and the problem just
started in the past couple weeks. I was looking at the spray gun this
evening and I'm wondering if the air adjustment got turned. The air
adjustment is very easy to turn and maybe it has gotten turned a
little at a time.



I don't know this specific product - I do know that with the automotive
lacquers I use (on cars), the thinner is VERY different from the stuff I get
at home depot, though both are called lacquer thinner. I have used the
cheap thinner with DEFT that I get in gallon cans with no problem though



--
Posted via a free Usenet account from http://www.teranews.com

On Sat, 12 May 2007 20:34:28 -0700, "William Noble"
wrote:


From Behlen's product catalog:

"QualalacqT Thinner are recommended to be used in conjunction with this
product."

http://www.hbehlen.com/Behlen_Catalog2006.pdf

--
Jack Novak
Buffalo, NY - USA


Hi Jack, Yes I read that but I have a hard time believing that thier
thinner is any different than any other lacquer thinner. I suppose
there could be a difference. Certainly is a price difference. Problem
is I've been using qualalack for about 6 months and the problem just
started in the past couple weeks. I was looking at the spray gun this
evening and I'm wondering if the air adjustment got turned. The air
adjustment is very easy to turn and maybe it has gotten turned a
little at a time.

Without being familiar with the product, is there a chance that it
just got old? I know I've got a can of shellac down in the shop that
just will not cure anymore, no matter how long I let it dry. It just
got old, and is no longer good.

I don't know this specific product - I do know that with the automotive
lacquers I use (on cars), the thinner is VERY different from the stuff I get
at home depot, though both are called lacquer thinner. I have used the
cheap thinner with DEFT that I get in gallon cans with no problem though

On May 12, 8:15 pm, Prometheus wrote:

Great couple of posts Robert- that filled in a couple of gaps I had,
and is an excellent reminder of the process (I don't spray laquer from
my cup gun very often- because I'm usually too lazy to want to clean
it afterwards, and just use a rattlecan instead.)

Thanks. I don't mind helping when someone is trying. And finishing
can be very, very frustrating. I have worked on problems for hours
(sometimes a couple of days) to get things ironed out. And in the
end, there have been times when all is said and done I am not really
sure why it worked out.

And as for that rattlecan.... what a lifesaver. I use them wherever I
can! Touchups (hey - if you apply Deft from a quart can, it comes in
a spray can for touchups, too!), small projects, lathe stuff
(especially Christmas ornaments), etc.

I really like the "no cleanup" part of spray cans and the consistency
of the finish. At 35% or less material delivery ($$$ !!) from a spray
can, I don't go wild with the stuff but I wouldn't be without it
either.

Robert

you don't need to clean a spray gun after using laquer if you just dedicate
a spare gun to clear laquer only - if it gets plugged up, just spray a
litthe thnner through it and continue - I've used the same gun for about 6
years, always keep laquer in it, only had to clean it once in that time



"Prometheus" wrote in message
...
On 12 May 2007 12:25:12 -0700, "
wrote:

Snip

Since you have the Behlen's now, I would try thinning with a really
good quality thinner. If that didn't work, for my own satisfaction I
would change lacquers and try it first with the old thinner, and then
with the new. Unless the lacquer you have is old, a bad batch, or has
been improperly stored (not necessarily by you) or shipped, the answer
should be in there somewhere.

It will be easy enough for you to find out.

Once again, let us know how this pans out. If it were me, I would
spend the dough and get through this as quickly as possible.


Great couple of posts Robert- that filled in a couple of gaps I had,
and is an excellent reminder of the process (I don't spray laquer from
my cup gun very often- because I'm usually too lazy to want to clean
it afterwards, and just use a rattlecan instead.)



--
Posted via a free Usenet account from http://www.teranews.com

On May 13, 11:39 am, "William Noble" wrote:
you don't need to clean a spray gun after using laquer if you just dedicate
a spare gun to clear laquer only - if it gets plugged up, just spray a
litthe thnner through it and continue - I've used the same gun for about 6
years, always keep laquer in it, only had to clean it once in that time

I have heard of this, but never tried it. I know for me, I don't want
(or have the dough!) a $300+ gun dedicated to one finish. My work
requires that I spray too many types of finish, so I am used to
cleaning them, sometimes a few times a day . But I DO keep a
different gun for water borne and solvent coatings.

And even though I shoot a lot of lacquer, my formulas for retarding
and thinning are different (similar) for every type of weather. I
don't want to pick up a gun and load it if I has anything other than
the mix I am spraying for the day. For me it is easier to start with
a completely clean slate than a pretty clean one.

When I have a full day of spraying, one trick I learned (really
frowned on by the product reps) is to put about 1/2" of the
appropriate thinner in the bottom of a 5 gallon bucket and snap the
lid on between coats. It keeps the area around the aircaps ready to
go and prevents any drying of the coating.

Robert

On Sun, 13 May 2007 09:39:57 -0700, "William Noble"
wrote:

you don't need to clean a spray gun after using laquer if you just dedicate
a spare gun to clear laquer only - if it gets plugged up, just spray a
litthe thnner through it and continue - I've used the same gun for about 6
years, always keep laquer in it, only had to clean it once in that time

What do you do, just dump out the cup and run laquer thinner through
it when you're finished, or actually store the laquer in the cup?

Sometimes, that would probably work out great for me, but if I didn't
need to laquer anything for six months or something, I wouldn't think
storing it in the gun would be a very good idea!

Maybe I'll get it out and give that a try- worst thing that could
happen would be a nasty clog, and a couple days soaking in thinner
would *hopefully* take care of that. If it works, it would save me a
bit of money in finishing products, if not, it'd just be a PITA to
clean once.

On 13 May 2007 10:56:39 -0700, "
wrote:

On May 13, 11:39 am, "William Noble" wrote:
you don't need to clean a spray gun after using laquer if you just dedicate
a spare gun to clear laquer only - if it gets plugged up, just spray a
litthe thnner through it and continue - I've used the same gun for about 6
years, always keep laquer in it, only had to clean it once in that time

I have heard of this, but never tried it. I know for me, I don't want
(or have the dough!) a $300+ gun dedicated to one finish. My work
requires that I spray too many types of finish, so I am used to
cleaning them, sometimes a few times a day . But I DO keep a
different gun for water borne and solvent coatings.

Might work for me, though- laquer is the only thing I spray from the
gun (most other things can be brushed on successfully), and it's not a
super high-end piece of equipment in any case. At $80, it's not junk-
but it's definately not in the same league as some heated true HVLP
rig.

Like a lot of guys in woodworking (or metal working for that matter),
finishing is sort of a chore for me. I make a point to always do my
level best at it, and research it before doing something new, but it's
really not something I *want* to spend a day doing!

And even though I shoot a lot of lacquer, my formulas for retarding
and thinning are different (similar) for every type of weather. I
don't want to pick up a gun and load it if I has anything other than
the mix I am spraying for the day. For me it is easier to start with
a completely clean slate than a pretty clean one.

And that is one of the main differences between a hobbyist and a pro-
if you're shooting laquer everyday, you're bound to have preferences
like that. For me, I just get it close and tweak things until it
looks good enough. That's the beauty of no longer doing this stuff
for a living- the one or two things I'm coating are never really that
big of a rush, because there usually is a week or two between side
jobs. That, and I almost never have a full shop full of trim to
spray- though I will next week (I'm milling some custom ash trim for a
guy at work), which is why your run down was greatly appreciated!

When I have a full day of spraying, one trick I learned (really
frowned on by the product reps) is to put about 1/2" of the
appropriate thinner in the bottom of a 5 gallon bucket and snap the
lid on between coats. It keeps the area around the aircaps ready to
go and prevents any drying of the coating.

Not sure what you mean- are you putting the thinner in the bottom of
the bucket, then setting the open can of finish in there as well
before snapping on the cap so the fumes keep the finish from skimming
over, or putting the gun in there?

If it's the latter, I use a similar trick, but I like yours better. I
always just splashed a little thinner inside of a plastic grocery bag,
then stuck the gun in that and wrapped it up tight before lunch,
between coats, etc.

On May 13, 4:30 pm, Prometheus wrote:

Might work for me, though- laquer is the only thing I spray from the gun (most other things can be brushed on successfully),

The lacquer that I spray now is actually spray only. It was not
designed or intended to be brushed or padded. This stuff was a real
step up for me, and at $42 a gallon it was hard to part with the dough
to practice with this stuff.

It is designed for HVLP as atomizing the finish (like the good old
high pressure days) will cause dusting of dried particles in the
finish.

and it's not a super high-end piece
of equipment in any case. At $80, it's not junk-
but it's definately not in the same league as some heated true HVLP rig.

Just like with all tools, it is almost always the user more than the
equipment when you see a failure. I have a Taiwanese touch up gun
that I bought from HF about 7-8 years ago that I love. It is a
knockoff of a Binks touch up gun, and it works just as well. It is a
high pressure gun, but can be powered by a 3hp roll around compressor
pretty easily. I put an in line dryer on it and take it to the site
to spray industrial urethane on metal doors, burglar bars, custom
metal work, etc. It uses a lot more material, but it eats that
urethane up.

My other favorite gun (besides my HVLP stuff) is a knockoff of a SATA
auto painting gun. It is an HVLP conversion gun (not turbine
powered), but puts a great deal of the material on target. This gun
has shot everything I shoot, from metal primers to finishing
lacquers. If I go to a job that just has one or two things to shoot,
I put this gun in the truck with the inline drier, and use a jobsite
compressor.

Like a lot of guys in woodworking (or metal working ?for that matter), finishing is sort of a chore for me. I make a point to always do my level best at it, and research it before doing something new, but it's
really not something I *want* to spend a day doing!

I don't like a steady diet of it either. I did a lot of finishing and
refinishing for a while, but that has slowed down. I really like to
finish here and there, using some of the specialized coatings to make
more money.

I have a kick ass super hard enamel (again - no brushing or padding
and the colors have to be mixed at the batching plant) that dries in
15 minutes. Recoat in 20. Third coat in 30. Dried for use in one
hour. Cured hard in two. Great for handrails at a commercial
building , coating metal table frames, chairs, etc. I can start in a
morning and have them up by opening for lunch.

And that is one of the main differences between a hobbyist and a pro- if you're shooting laquer everyday, you're bound to have preferences
like that. For me, I just get it close and tweak things until it looks good enough. That's the beauty of no longer doing this stuff for a living- the one or two things I'm coating are never really that
big of a rush, because there usually is a week or two between side
jobs. That, and I almost never have a full shop full of trim to spray- though I will next week (I'm milling some custom ash trim for a
guy at work), which is why your run down was greatly appreciated!

I am glad to hear I helped. I spent so damn much time learning some
of this stuff I just don't see why someone else should.

Actually I think one of the big differences in the "pro v. hobby" guy
is the need for speed. I have seen some non professionals that turn
out a pretty damn good product. It takes them longer, but they get
there.

For me, the term is "off the gun". My last coat, my finish coat, has
to be the money coat. No fisheyes, fruit rind, craters, spots,
blemishes, blush, crazing, witness lines, holidays... nada.

But some days, not matter what you do, the finishing sucks. Those
days are few and far between for me, but when something goes wrong
sometime it just keeps acting up all day. The next day, you follow
the same procedures, and it works perfect. Drives ya nuts.

Not sure what you mean- are you putting the thinner in the bottom of the bucket, then setting the open can of finish in there as well before snapping on the cap
so the fumes keep the finish from skimming
over, or putting the gun in there?

I put the thinner in the bottom of the bucket. and put the gun in
there with it still attached to the canister. I just disconnect it
from the air and put it in. I have a 2 1/2 gallon bucket that I keep
the gun in most of the time, and I actually use that, too. If the gun
has an aluminum canister, don't leave it in too long as some of them
will pit from the thinner. A couple of mine sure did.

Just put the thinner in the pail, put the gun in, snap on the and
that's it.

As for the finish, I never leave it open. I am not so much worried
about the drying of the top as the attraction of bugs, and any blowing
debris.

No matter what I am spraying, I measure out anything that is going
into the coating on the side into paper cups I buy at the dollar
store. At the last minute, I pour out the finish into the canister
after a quick stir. Then I close the can, and put in the additives
into the coatings and mix it in the canister.

I usually mix a quart at at time, but usually no more than 1/2 gallon
at once. This give me a chance to fine tune the application if I need
to. But the key here is to have those adds on the side ready to go
and keep that material open for a little time possible and the can
sealed tight when not in use.

When I get to the lower third of a can and know I won't be back to it
for a couple of weeks or so, I will put a very thin layer of
compatible thinner on the top and leave it without mixing. I don't
know that it actually does, but it seems to help.

Robert

I just leave the laquer in the cup - the gun I use for this is an older
Binks (sold by sears) that I used for automotive work until I bought a
gravity feed gun - ive left laquer in the gun for many months with no
problem
"Prometheus" wrote in message
...
On Sun, 13 May 2007 09:39:57 -0700, "William Noble"
wrote:

you don't need to clean a spray gun after using laquer if you just
dedicate
a spare gun to clear laquer only - if it gets plugged up, just spray a
litthe thnner through it and continue - I've used the same gun for about 6
years, always keep laquer in it, only had to clean it once in that time

What do you do, just dump out the cup and run laquer thinner through
it when you're finished, or actually store the laquer in the cup?

Sometimes, that would probably work out great for me, but if I didn't
need to laquer anything for six months or something, I wouldn't think
storing it in the gun would be a very good idea!

Maybe I'll get it out and give that a try- worst thing that could
happen would be a nasty clog, and a couple days soaking in thinner
would *hopefully* take care of that. If it works, it would save me a
bit of money in finishing products, if not, it'd just be a PITA to
clean once.



--
Posted via a free Usenet account from http://www.teranews.com

All this talk of thinner and equipment, and I was wondering if the
real culprit may be simpler. If the change of seasons has brought more
humid air, the coats of finish may not be completely drying before you
apply the next. Perhaps you need to experiment with your application
timing for different seasons? Since I don't use lacquer very often I
don't know for sure, but my experience with varnish and paints has
shown me that I really need to let the first coat dry hard or I get a
mess that will wrinkle or crack.