Bounceback w/HVLP??

Art - sounds like you have the air flow up too high. And it also
sounds like your finish is indeed drying too fast.

Contrary to what many believe, you can waste just as much finish in
overspray and drift as you can with an HVLP system. I have a Fuji 4
stage, and during the summer months I rarely thin anything more than
about 10%, and some things like oil based primer, not at all. I know
Barry has a Fuji system too, and he doesn't thin much at all, if any.
Try your product unthinned; you can always thin later if it is too
thick. Remember, your viscosity cup is a guide, not a rule.

The second thing I would do would be to turn the airflow almost down
to nothing and open it back up until you could apply the proper
thickness coat without leaving an orange peel finish when dried. A
good rule of thumb with HVLP is that you don't have more than 4-5
inches of bounce back when spraying. Keep the gun about 8" from the
surface, and practice your spraying motion without anything in the gun
to make sure you are staying uniform in this 8" distance.

Next - check your aircap. To shoot latex you should have something
like a 1.7 mm fluid nozzle with the proper aircap. If you ahve that,
you won't need to thin near as much.

Robert

On Aug 6, 2:37 pm, Art Greenberg <[email protected]> wrote:

> Thanks. I'm shooting an oil based primer (Benjamin >Moore "Fresh Start"), with the Fuji Super 4 turbine, XT >gun and the #4 nozzle and air cap (stock setup with the >XT gun).

So far, so good. Great gun/system, great product.

> I thinned by adding 4oz. of mineral spirits to 14oz. of >primer. Is that 28% the way you compute it?

This gets into a sticky commentary by "shooters". By total volume?
By starting volume? WTF, over?

The manufacturers even differ on this way of communication. I am not
sure which way the current wind is prevailing, but 4 oz on 14 is a
deep winter blend for primer.

When you over-thin, you are spraying too much solvent for the product
to perform as designed. It dries too quickly and sprays so thin it
over atomizes. Sound familiar?

>Then 10% would be 1.4 oz. of mineral spirits. I started >at 2oz., and IIRC that resulted in about double the
> 20-25 seconds the manual suggests.

Make a half batch at that speed, and try it. I the summer time, I
would try to spray first, then if it is coming out too thick, then
thin the amount I had by 10%, which is roughly where you are in the
second formula. During the summer, I spray either Zinsser or Kilz oil
base, and don't thin either one. Make SURE you are getting enough
material on the surface as too thin a coat will ensure that your
surface dries too quickly making it rough.

Primer is strange stuff; it doesn't spray like a coating as it usually
has some high metal solid content and some other polymers to seal that
make it different from paints and sealers.

You will find that every new product you shoot will present you with
these challenges. I suggest you keep a notebook of notes and
conditions so you can go back to them when setting your gun up. Keep
buying quality finishes and stick with them as they will give you the
most consistent performance.

> I did try reducing the airflow, all the way to the lowest >setting of the air flow control valve (the plastic ball valve >that came with the sprayer). Is there a better way to do >that? The Super 4 turbine doesn't have a speed control.

That is the best way. Make sure you have it mounted on the connection
just under the gun. Don't worry about "speed controls". It is a
turbine, not a blender. Turn it on, control the air flow at the gun.
I think SpeedAire just needed something else to sell.

> I probably was too close to the surface, too. More like 5-> 6 inches.

Wayyy to close. Actual spraying is a matter of technique. Your arm
should look like one of those robots that paints car hoods. Exactly
the same distance from the surface with exactly the same speed when
spraying. I wasn't kidding when I said to practice that motion. Cut
yourself a stick 8" long, and just before starting to shoot, put the
stick in front of the nozzle so you can see the 8" and keep it in your
mind while spraying. Sounds silly, but it works.

I only close that up when I have a difficult finish to apply or ugly
conditions, but in any case these guns are not made to shoot any
closer than about 6" as they won't develop the atomized pattern from
the gun.

Since you don't get that satisfying hiss from high pressure spraying,
it is hard to tell if you are doing what you need to do while
spraying. Try running a couple of quarts of water through your gun.
Spray on a fully sealed surface (or if the wife isn't around, the
patio door!) to check out your pattern. You should be little more
than misting your product onto your surface.

> You've suggested a number of things I should try:
>
> - Increase distance to surface.

Yes.

>
> - Thin less, maybe even not at all.

Yes. Experiment. Take notes. Find a product you like and learn
everything about it. This may take a bit of time and money, but WELL
worth it. Make small batches to experiment with and you won't invest
as much as you think.

> - Keep air flow low. Lower than the ball valve will go?

Close the fluid knob completely. Open it up about 3 full turns and
start there. Close the air valve completely. Open it a tiny bit at a
time until you can see the coating atomizing properly. In my Fuji,
this is only about 1/3 open! These units move a lot of air and have
plenty of power. You may need to move it a little more open depending
on the finishes, but try it from there.

> - Try adding some retarder.

NO retarder. First, you cannot retard primer. Second, why would you
retard a finish that takes 20 minutes to skim over?

Spray the correct amount on the surface to begin with and you will be
surprised at how slow it will dry. You should shoot for about 3 mil
in application with the primer, and about 4-5 mil wet thickness with
latex. It will dry fine.

> Seems there could be a bunch of combinations of >these. I'll try all of these together first, as it is clear I >was too close and I need to slow down drying anyway.

You are on your way Art! Some practice and careful notes
(repeatibility is everything!) and you will be spraying everything in
sight!

Good luck!

Robert

On Aug 6, 12:55 pm, Art Greenberg <[email protected]> wrote:
> I finally tried using my new Fuji HVLP sprayer

I think a 28% mix would be 5x of thinner to 13x of material for 18x of
thinned material.

roughly 9 oz of thinner and 23oz of material per Qt.



he paint control until
> I was getting what looked like the right amount of paint on the wood, and
> painted the inside of one cavity. The result looks OK. It feels a little
> rough, though, as if I had used a water based finish and raised the grain.
>
> From what I have read, the rough finish might be due to the paint drying
> too quickly, so I'll try adding a little Penetrol to the primer and see
> if that helps.
>
> What surprised me was the amount of paint mist that came back at me out of
> the shelving unit. I wound up with dried paint droplets on my glasses, on
> my respirator, on my arm, in my hair, and on the gun. There seemed to be a
> paint fog in the air. Was I doing something wrong to cause that? I tried
> backing off the air control (and adjusting the paint control accordingly),
> but that didn't seem to reduce the amount of bounce back.
>
> Can anyone offer any words of advice or wisdom?
>
> TIA!
>
> --
> Art Greenberg
> artg at eclipse dot net

On Aug 7, 3:52 pm, Art Greenberg <[email protected]> wrote:

> Robert, thanks so much for all of your suggestions. I hope to get back
> to this this weekend. I'll let you know how I make out.
>

Good luck! I hope it works out and you post some results. I will be
out of pocket this weekend, but will certainly check back when I am
available.

Robert

On Aug 7, 11:55 am, "Swingman" <[email protected]> wrote:
> After reading/perusing this post last night, and halfway through spraying a
> sideboard, I tried your not thinning the Zinsser Bullseye on a test piece
> this morning and no matter how much futzing I did with the material/air flow
>I still could not get a satisfactory coverage/pattern with this POS gun/rig.

This may be a double post as I was called away and was unsure if I
pushed "send or not".

As with everything I scribble electronically on this group, this is
my opinion/observation. So we are sure we are both on the same page,
please remember in context that the OP stated that he was painting,
not clear coating.

I think the actual problem may be as noted, the equipment. I
intentionally bought the Fuj as it has the highest air delivery of any
unit I could find. Their gun was not my favorite, but hey... you
can't have everything. And since I have learned to use it, the gun
works great.

I would guess that the CHPOS probably is a two stage (or maybe a one!)
that doesn't move enough air to deliver the thicker materials. But
since you are or have been getting good finishes with your clear
coats, it means that you know what your gun can do and are
thinning properly.

However, if it is shooting clearcoat properly and not an heavy solids
coating, that could mean two different things.

As far as shooting the shellac the first could be that with your lower
powered machine (has Festool come out with an HVLP yet?) it may
not be able to pressurize the cup and have enough air left over
to atomize (we all know that is the incorrect term, but to stay on
subject, we all understand the concept) the coating or paint and
push it to the target.

Solution: Whether it is clear or Stain Block for painting(white)
Bullseye, thin it with the proper thinner. With the thinner
solution, give it more air flow and spray.

> Since I did the drawers and doors yesterday the old way, I went ahead and
> did my usual 40 alcohol/60 shellac-out-of-the-can mix and got something I
> could live with. The humidity the past few days has been high. I had to
> leave the sideboard case outside to acclimate a few hours this morning
> before I dared spray it.

This high humidity and fast rising temps kill alcohol based
finishes. For me, no matter what I do in this weather any finishes
except paint are dicey. I can usually get some nice blush on
lacquer with no problems at all with 87% humidity.

Spraying outside in the elements or in an unfinished
(unairconditioned) house or in a garage is so different from spraying
in nice shop. Now with the temps and humidity so high, I am glad
I am doing mostly repairs and no finishing.

BUT... as they say, the show must go on. If I were in your shoes, I
would drag out that shellac and really give it a dose of thinner.
Here's my thinking - you know you can build the finish on these since
the shellac will simply dissolve into itself. So I would take it from
another direction to test it out. Think about it for a second; you
know you are on the right track when thinner is better. Since you are
essentially shooting resin with a solvent, who cares how much you
thin?

I would cut the shellac by about 50% due to heat and humidity and then
try it at 60 - 40 alcohol to shellac. The shellac will stick... it
just depends on what you are trying to do with it. If it is a
sanding sealer coat on a nice wood, you don't need it thick. Since
the shellac will dry quickly, you can see what it will do on a test
piece. I would thin the hell out of it then spray about a 3 mil coat
on it and see how it does. That just may do the trick. If you like
the results, it is certainly easy enough to build the coats. To me,
it's worth a pint of material to try it out.

In a push job in similar weather, I was having so much trouble getting
the shellac out of the gun I was ready to put it on with a heavy nap
roller and be done with it. The dried coating texture would have been
the same.

In a moment of really pissed off inspiration I thinned the Bullseye to
a 70/30 alcohol to shellac (I also had the wrong aircap for the
gun and couldn't get it to behave with the one I had with me) and it
worked fine. I sprayed a pattern that was fairly thick, but since it
was mostly solvent it dried thin (1/2 mil maybe?) and then in about
thirty minutes (just able to leave a fingerprint in the finish)
sprayed another coat spraying the opposite pattern. It worked
great.

You can get away with thinning the daylights out of any resin finish
(OK, to a point) since there are no solids to fall out of solution.
You can thin them so much that they don't perform properly, but I
wouldn't worry about that with shellac.

> I do get some rough surfaces, but mainly on plywood drawer bottoms and
> places that don't show, because that's where I start ( to make sure things
> are going OK), but nothing that couldn't be easily dealt with using the old
> brown paper rub rub down trick.

I dont' know if some of the stuff we get has green veneer or
outgassing fish guts glue made with diesel, or what. But I never had
that problem until a few years ago. I went for a few years thinking I
wasn't doing the prep right, but now I think it is something to do
with the wood.

Something is different, and if that is the roughness you are getting
when you spray, I am getting the same.

So another voice is heard...

> I guess I just need to get a better outfit ... long as I'm cleaning, might
> as well be cleaning a good gun instead of this Chinese special.

Will you be getting a new 4WD Japanese carrying case for it?

I am tighter than a top on a banjo, and I don't like buying new tools
anymore. Just as an unsolicited opinion, I would probably goof with
that setup a little more. If it worked for you in the past, it
should work fine now. No, it won't have the power to spray some of
the finishes as easily, but unless you are using finishes
specially designed for HVLP you will be mixing up new formulas
anyway with a new unit. As with any of this stuff, there is a lot to
be said about being comfortable with a certain piece of equipment.

On the other hand, it sounds like you have sure gotten you money's
worth out of it and more. It may be time... some of these new units
are just nothing short of great.

Robert

On Mon, 06 Aug 2007 11:51:43 -0700, [email protected] wrote:
> Art - sounds like you have the air flow up too high. And it also
> sounds like your finish is indeed drying too fast.
>
> Contrary to what many believe, you can waste just as much finish in
> overspray and drift as you can with an HVLP system. I have a Fuji 4
> stage, and during the summer months I rarely thin anything more than
> about 10%, and some things like oil based primer, not at all. I know
> Barry has a Fuji system too, and he doesn't thin much at all, if any.
> Try your product unthinned; you can always thin later if it is too
> thick. Remember, your viscosity cup is a guide, not a rule.
>
> The second thing I would do would be to turn the airflow almost down
> to nothing and open it back up until you could apply the proper
> thickness coat without leaving an orange peel finish when dried. A
> good rule of thumb with HVLP is that you don't have more than 4-5
> inches of bounce back when spraying. Keep the gun about 8" from the
> surface, and practice your spraying motion without anything in the gun
> to make sure you are staying uniform in this 8" distance.
>
> Next - check your aircap. To shoot latex you should have something
> like a 1.7 mm fluid nozzle with the proper aircap. If you ahve that,
> you won't need to thin near as much.
>
> Robert

Robert,

Thanks. I'm shooting an oil based primer (Benjamin Moore "Fresh Start"),
with the Fuji Super 4 turbine, XT gun and the #4 nozzle and air cap
(stock setup with the XT gun).

I thinned by adding 4oz. of mineral spirits to 14oz. of primer. Is that
28% the way you compute it? Then 10% would be 1.4 oz. of mineral
spirits. I started at 2oz., and IIRC that resulted in about double the
20-25 seconds the manual suggests.

I did try reducing the airflow, all the way to the lowest setting of the
air flow control valve (the plastic ball valve that came with the
sprayer). Is there a better way to do that? The Super 4 turbine doesn't
have a speed control.

I probably was too close to the surface, too. More like 5-6 inches.

You've suggested a number of things I should try:

- Increase distance to surface.

- Thin less, maybe even not at all.

- Keep air flow low. Lower than the ball valve will go?

- Try adding some retarder.

Seems there could be a bunch of combinations of these. I'll try all of
these together first, as it is clear I was too close and I need to slow
down drying anyway.

--
Art Greenberg
artg at eclipse dot net

On Mon, 06 Aug 2007 13:16:54 -0400, B A R R Y wrote:
> Art Greenberg wrote:
> >
> > Can anyone offer any words of advice or wisdom?
>
>
> How far was the tip of the gun from the work?

5-6 inches.

> I usually use my Fuji 6 inches or so off the surface. I'll normally
> get some finish in the air, but not what I'd call lots of bounce,
> once the air flow control (the one on the hose) is turned down.

Its impossible to compare our experience without some objective measure.
But I'd say I was getting a lot of finish in the air, much more than I
expected.

My only prior experience with HVLP was at WW shows, where I sprayed an
unknown paint (probably latex) onto a paper pad on an easel. And I did
not see _any_ bounceback there. I'm sure the floor in front of the easel
would show the paint color if there was as much as I've experienced
here.

--
Art Greenberg
artg at eclipse dot net

On Mon, 06 Aug 2007 13:46:26 -0400, <<<__ Bob __>>> wrote:
> Paint BEFORE installing the backs .. what you're experiencing is
> pretty typical for the method you're using .. .. gotta think a little
> differently about your projects when yuo're spraying

Thanks, Bob. Too late for this project!

Seems this doesn't reduce the bounceback, but instead lets it flow
"through" the work?

--
Art Greenberg
artg at eclipse dot net

On Tue, 07 Aug 2007 07:10:52 -0400, B A R R Y wrote:
> The materials Robert mentioned that I spray without thinning time at
> more like 18 seconds on the included vis cup. With that stuff, I use
> a #4 setup with a gravity cup or #3 with the pressurized siphon or
> remote pot.

I'm using the pressurized 1 quart cup, with the #4.

> I'd try thinning further, or a #5 setup. The #4 is still pretty
> small.

I'd have to order the #5. I can try thinning more - I have a small
quantity of the already-thinned primer, and I can add more mineral
spirits to it.

> I'm actually familiar with Fresh Start and Enamel Underbody,
> but I've only applied it with a brush or roller. Both are quite
> thick from the can, but the Fresh Start version I'm familiar with is
> water based. Are you thinking of "Enamel Underbody" primer?

No, this is definitely Fresh Start. The can says "Fresh Start Alkyd
All-Purpose Primer, White, 024 00". It is not as thick as their better
latex paints, but it is pretty thick.

> My favorite primers for spraying are BIN pigmented shellac and auto
> body primers. Either are dreams to spray, and can be overcoated by
> virtually anything. I've also used clear Zinnser Seal Coat as a
> paint primer, with excellent results.

Thanks for the suggestions, something to try. Shellac might be good to
experiment with, since cleanup is easier than with the oil based
products, and it won't raise grain.

My first use of the sprayer, soon after I received it, was an experiment
with unthinned oil-based Killz. It seemed to work OK on a test target
(scrap plywood). Unfortunately, I left it in the gun while I stopped for
dinner. By the time I got back to it a few hours later, it had dried in
the gun. And since I could not get the nozzle loose (man, the factory
put that thing on TIGHT), I had a very difficult time cleaning the gun.
I ended up pulling the packing seals (and destroyed them in the process)
and going into the gun block from the back to clean it. What a mess ...
it took me 4 hours to clean it all up. I wasn't able to use the sprayer
again until I got new packing seals.

> You can also ask your local Ben Moore dealer if they have specific
> information for spraying. I poked around the BM site, looking for a
> data sheet. The only spraying BM mentions on paper for either "Fresh
> Start" or "Enamel Underbody" is airless, but they may be able to get
> local knowledge from the BM rep for HVLP.

I really should ask.

The data sheet for this primer says it can be sprayed, and it also says
"do not thin".

> If you saw latex sprayed at a show, chances are they had either a #5 or
> #6 setup (or another brand's equivelent) installed.

Could be. I don't really know what it was that was being sprayed, but it
was probably latex.

Thanks for your help!

--
Art Greenberg
artg at eclipse dot net

On Tue, 07 Aug 2007 11:26:23 GMT, B A R R Y wrote:
> NEVER try finishing methods for the first time on the actual work.
> That's not to stick your nose in it, but we all need a reminder at
> times.

Yes, I know. <hangs head in shame>

I never even considered leaving the back off this piece, though. At the
time I built it, SWMBO was going to brush & roll on the finish. I bought
the sprayer when she came up from her first pass very frustrated with
the results.

I actually did play a bit with the sprayer prior to attacking this
piece, on a scrap of plywood. But that was with a different material
(oil based Killz) and I wasn't very critical of the results. I think my
confidence was falsely raised by that one session.

> Make some 12"x12" panels of MDF or cabinet grade ply, and a small
> notebook. Properly prepare the panel for finishing by sanding,
> scraping, filling, etc... as you would with your best piece.
> Practice with the gun, noting EVERY variable, including material
> brands, gun options and settings, and time, temperature and
> humidity, in the notebook. Change one variable at a time until you
> get the hang of it. Keep the notebook handy with the finishing
> equipment for next time.

But this requires patience! 8-)

> If you're not comfortable next time, spray a practice panel with the
> best known settings and get comfortable. In time, you'll
> automatically save decent cutoffs from your projects, and finish sand
> and scrape them with this step in mind.
>
> Every time I've messed something up finishing, I was improvising on
> the actual work. After a few headbanging sessions, I realized that I
> didn't have to hit my head on the bench. Every time I fell like
> experimenting, I look at the ruined door that I saved and hung up as
> a reminder. <G>

I don't have the room in my shop for that kind of reminder!

> BTW, 5x7 spiral notebooks are also great next to the sharpening
> equipment, router jigs, or with any tool that's infrequently used or
> has detailed setup information. I fly with checklists all the time,
> so I figured notes and checklists would be as handy in the shop.
> They are!

Good advice.

> Please let us know how it all works out!

I will! This is very much a background task, though, so it might be a
few weeks before I have much to report.

Thanks for your help.

--
Art Greenberg
artg at eclipse dot net

On Tue, 07 Aug 2007 08:09:28 -0700, Hoosierpopi wrote:
> I think a 28% mix would be 5x of thinner to 13x of material for 18x of
> thinned material.
>
> roughly 9 oz of thinner and 23oz of material per Qt.

Makes sense. This is exactly how breathing gas mixes are denoted in
scuba. One refers to the fraction of one gas relative to the entire
mixture.

Therefore, a 10% thinned mix would be 1x of thinner to 9x of material,
and the mix I created - 4x thinner to 14x material - would be called a
22% mix.

--
Art Greenberg
artg at eclipse dot net

On Tue, 07 Aug 2007 15:08:13 -0400, Renata wrote:
> But, _too little air_ may be your problem. Or, it may just be that
> you're spraying within a deep area and having the mist "blow back" as
> a result (as others have said).

Too little air seems counterintuitive. But the manual for the sprayer
says to start with the air valve open all the way, which reinforces your
thought.

> Anyway, the advice was: open the air ALL the way, open the material
> valve only a bit (for hydrocote). I looked up (on Hood Finishing's
> site) the proper amount to open the material valve and their
> recommendation is 1.5 turns for the initial coat, 2 for subsequent
> coats. Works Great!.

Again, this is exactly the approach called for in the Fuji sprayer
manual. And it is the approach I followed. After seeing the extreme
bounceback, I tried backing off the air.

Robert suggested that I was way too close to the surface I was shooting.
This might turn out to be the primary cause.

> What I noticed after I started to practice his advice was that the
> room was no longer filled with a misty fog after I sprayed as it had
> been before. Which is what prompted me to post this after I read your
> situation.
>
> My 2 cents or so.
>
> Renata

Thanks, I do appreciate your input, as well as all of the other comments
I've received.

My fingers are crossed! I sure don't want to have to set up a bazillion
CFM fan in a spray booth to do this work ...

--
Art Greenberg
artg at eclipse dot net

On Tue, 7 Aug 2007 02:05:32 -0400, Upscale wrote:
>
> "Art Greenberg" <[email protected]> wrote in message >
> > What surprised me was the amount of paint mist that came back at me out of
> > the shelving unit. I wound up with dried paint droplets on my glasses, on
> > my respirator, on my arm, in my hair, and on the gun. There seemed to be a
>
> > Can anyone offer any words of advice or wisdom?
>
> As Bob mentioned, he said that he felt sprayback in your case was typical
> when not spraying before the backs of the shelving were installed. You can
> easily test out that suggestion by spraying some wood in the open air and
> not partially enclosed like a shelving unit and seeing if there still is
> sprayback.

Agreed, an easy experiment.

Thanks.

I've gotten plenty of input on this, and I'm anxious to experiment now.
All I need is the time ....

--
Art Greenberg
artg at eclipse dot net

On Mon, 06 Aug 2007 13:26:51 -0700, [email protected] wrote:
> On Aug 6, 2:37 pm, Art Greenberg <[email protected]> wrote:
>
> When you over-thin, you are spraying too much solvent for the product
> to perform as designed. It dries too quickly and sprays so thin it
> over atomizes. Sound familiar?

Uh ... yes!

Robert, thanks so much for all of your suggestions. I hope to get back
to this this weekend. I'll let you know how I make out.


--
Art Greenberg
artg at eclipse dot net

<[email protected]> wrote in message

> second formula. During the summer, I spray either Zinsser or Kilz oil
> base, and don't thin either one. Make SURE you are getting enough
> material on the surface as too thin a coat will ensure that your
> surface dries too quickly making it rough.

After reading/perusing this post last night, and halfway through spraying a
sideboard, I tried your not thinning the Zinsser Bullseye on a test piece
this morning and no matter how much futzing I did with the material/air flow
I still could not get a satisfactory coverage/pattern with this POS gun/rig.

Since I did the drawers and doors yesterday the old way, I went ahead and
did my usual 40 alcohol/60 shellac-out-of-the-can mix and got something I
could live with. The humidity the past few days has been high. I had to
leave the sideboard case outside to acclimate a few hours this morning
before I dared spray it.

I do get some rough surfaces, but mainly on plywood drawer bottoms and
places that don't show, because that's where I start ( to make sure things
are going OK), but nothing that couldn't be easily dealt with using the old
brown paper rub rub down trick.

I guess I just need to get a better outfit ... long as I'm cleaning, might
as well be cleaning a good gun instead of this Chinese special.

--
www.e-woodshop.net
Last update: 6/1/07
KarlC@ (the obvious)

"Art Greenberg" <[email protected]> wrote in message >
> What surprised me was the amount of paint mist that came back at me out of
> the shelving unit. I wound up with dried paint droplets on my glasses, on
> my respirator, on my arm, in my hair, and on the gun. There seemed to be a

> Can anyone offer any words of advice or wisdom?

As Bob mentioned, he said that he felt sprayback in your case was typical
when not spraying before the backs of the shelving were installed. You can
easily test out that suggestion by spraying some wood in the open air and
not partially enclosed like a shelving unit and seeing if there still is
sprayback.

"Swingman" <[email protected]> wrote in message
>
> I guess I just need to get a better outfit ... long as I'm cleaning, might
> as well be cleaning a good gun instead of this Chinese special.

What make is that Chinese special?

Art Greenberg wrote:
>
> Its impossible to compare our experience without some objective measure.
> But I'd say I was getting a lot of finish in the air, much more than I
> expected.

The materials Robert mentioned that I spray without thinning time at
more like 18 seconds on the included vis cup. With that stuff, I use a
#4 setup with a gravity cup or #3 with the pressurized siphon or remote pot.

I'd try thinning further, or a #5 setup. The #4 is still pretty small.
I'm actually familiar with Fresh Start and Enamel Underbody, but I've
only applied it with a brush or roller. Both are quite thick from the
can, but the Fresh Start version I'm familiar with is water based. Are
you thinking of "Enamel Underbody" primer?

My favorite primers for spraying are BIN pigmented shellac and auto body
primers. Either are dreams to spray, and can be overcoated by virtually
anything. I've also used clear Zinnser Seal Coat as a paint primer,
with excellent results.

You can also ask your local Ben Moore dealer if they have specific
information for spraying. I poked around the BM site, looking for a
data sheet. The only spraying BM mentions on paper for either "Fresh
Start" or "Enamel Underbody" is airless, but they may be able to get
local knowledge from the BM rep for HVLP.

If you saw latex sprayed at a show, chances are they had either a #5 or
#6 setup (or another brand's equivelent) installed.

"Upscale" wrote in message
>
> "Swingman" wrote in message
>>
>> I guess I just need to get a better outfit ... long as I'm cleaning,
>> might
>> as well be cleaning a good gun instead of this Chinese special.
>
> What make is that Chinese special?

Campbell Hausfeld is the brand ... the cup, needle, spring and trigger are
metal, most everything else is plastic. From all appearances, if you could
make a spring out of plastic, this would have one.

But I only paid $149 about four years ago and have sprayed dozens of
projects with it, so, in fairness, it has amortized itself and could be
thrown away at little/no loss.

And I may have to do that soon as the cleaning process appears to have taken
more years off it than actual use.

Then again, my Dad still has, and uses, the DevilBliss rig he bought when I
was six, some 59 years ago!

--
www.e-woodshop.net
Last update: 6/1/07
KarlC@ (the obvious)

.

Paint BEFORE installing the backs .. what you're experiencing is pretty
typical for the method you're using .. .. gotta think a little
differently about your projects when yuo're spraying

>
> Can anyone offer any words of advice or wisdom?
>
> TIA!
>

Art Greenberg wrote:
>
> Can anyone offer any words of advice or wisdom?


How far was the tip of the gun from the work?

I usually use my Fuji 6 inches or so off the surface. I'll normally get
some finish in the air, but not what I'd call lots of bounce, once the
air flow control (the one on the hose) is turned down.

<[email protected]> wrote in message

> Will you be getting a new 4WD Japanese carrying case for it?

Considering the market, truck dealers should take a page from the 50's
bank/gas stations promotions and offer your choice of Festool, Fuji, et al
with each purchase.

Thanks for the comments, Robert.

My best luck so far shooting shellac with this CH rig is roughly 50/50 60/40
shellac - alcohol thinning, but with the table I need to do this morning,
which is not of much import so will stand a little experimentation, I might
kick up the alcohol in the ratio and see what happens.

To muddy if up even further, I've also had a big differences in the final
results when using 99% Isopropyl versus denatured when the weather/high
humidity is involved (I only shoot outside, and have to wait on the weather
... and the ubiquitous yardmen with a weedeater/leaf blower).

I usually thin with 99% isopropyl when the humidity is this high, and
actually shoot it a bit closer to the surface. I don't analyze why, but it
seems to work.

Like sanding, I dislike finishing, but the importance is all too obvious, so
the piper must be paid in both effort and understanding.

Your (and Mike Marlowe's) analyzing helps ... thanks again!

--
www.e-woodshop.net
Last update: 6/1/07
KarlC@ (the obvious)

On Mon, 06 Aug 2007 11:51:43 -0700, "[email protected]"
<[email protected]> wrote:

>Art - sounds like you have the air flow up too high. And it also
>sounds like your finish is indeed drying too fast.
>
>Contrary to what many believe, you can waste just as much finish in
>overspray and drift as you can with an HVLP system. I have a Fuji 4
>stage, and during the summer months I rarely thin anything more than
>about 10%, and some things like oil based primer, not at all. I know
>Barry has a Fuji system too, and he doesn't thin much at all, if any.
>Try your product unthinned; you can always thin later if it is too
>thick. Remember, your viscosity cup is a guide, not a rule.
>
>The second thing I would do would be to turn the airflow almost down
>to nothing and open it back up until you could apply the proper
>thickness coat without leaving an orange peel finish when dried. A
>good rule of thumb with HVLP is that you don't have more than 4-5
>inches of bounce back when spraying. Keep the gun about 8" from the
>surface, and practice your spraying motion without anything in the gun
>to make sure you are staying uniform in this 8" distance.
>

I am just a beginner at this, and had my own set of difficulties
getting my Apollo HVLP going right, but I got some excellent advice
recently that set me on the right path.

Here's what the guy giving the lectures at the WW Show a few months
ago told me, and it's working great.

But first - It was advice for Hydrocote and whether it would be
equally applicable to paint I don't know.
But, _too little air_ may be your problem. Or, it may just be that
you're spraying within a deep area and having the mist "blow back" as
a result (as others have said).

Anyway, the advice was:
open the air ALL the way, open the material valve only a bit (for
hydrocote). I looked up (on Hood Finishing's site) the proper amount
to open the material valve and their recommendation is 1.5 turns for
the initial coat, 2 for subsequent coats. Works Great!.

He sprayed a board to demo and it was a very fine coat. About 4 coats
are needed. It dried very quickly (5 minutes or so - again he sprayed
lacquer).

What I noticed after I started to practice his advice was that the
room was no longer filled with a misty fog after I sprayed as it had
been before. Which is what prompted me to post this after I read your
situation.

My 2 cents or so.

Renata





>Next - check your aircap. To shoot latex you should have something
>like a 1.7 mm fluid nozzle with the proper aircap. If you ahve that,
>you won't need to thin near as much.
>
>Robert

Art Greenberg wrote:

>
> Thanks, Bob. Too late for this project!

NEVER try finishing methods for the first time on the actual work.
That's not to stick your nose in it, but we all need a reminder at times.

Make some 12"x12" panels of MDF or cabinet grade ply, and a small
notebook. Properly prepare the panel for finishing by sanding,
scraping, filling, etc... as you would with your best piece. Practice
with the gun, noting EVERY variable, including material brands, gun
options and settings, and time, temperature and humidity, in the
notebook. Change one variable at a time until you get the hang of it.
Keep the notebook handy with the finishing equipment for next time.

If you're not comfortable next time, spray a practice panel with the
best known settings and get comfortable. In time, you'll automatically
save decent cutoffs from your projects, and finish sand and scrape them
with this step in mind.

Every time I've messed something up finishing, I was improvising on the
actual work. After a few headbanging sessions, I realized that I didn't
have to hit my head on the bench. Every time I fell like experimenting,
I look at the ruined door that I saved and hung up as a reminder. <G>

BTW, 5x7 spiral notebooks are also great next to the sharpening
equipment, router jigs, or with any tool that's infrequently used or has
detailed setup information. I fly with checklists all the time, so I
figured notes and checklists would be as handy in the shop. They are!

Please let us know how it all works out!