I am spraying water-based poly which needs about 2 hours between coats
(according to the can).

I am wondering how thoroughly I need to clean the gun between coats --
balancing efficiency vs. the need to keep the gun clear of any hardened
poly (especially since water-based dries fast).

Would it be sufficient to spray water through the gun after each coat (I
bought an extra 20oz paint cup that I can fill with water) and then just
wipe off any obvious excess poly from the gun itself and the nozzle?

Or do I need to do more of a full cleaning/dissassembly of the gun
between coats? If so what would you recommend?

Also, my rationale for buying an extra cup is that I could keep the
excess poly in the cup between coats rather than repeatedly refilling
the cup and then pouring it back with each coat...
Is this OK, or is it recommended to fully empty and clean the cup
between coats...

On Nov 20, 10:13*pm, blueman wrote:
I am spraying water-based poly which needs about 2 hours between coats
(according to the can).

I am wondering how thoroughly I need to clean the gun between coats --
balancing efficiency vs. the need to keep the gun clear of any hardened
poly (especially since water-based dries fast).

Would it be sufficient to spray water through the gun after each coat (I
bought an extra 20oz paint cup that I can fill with water) and then just
wipe off any obvious excess poly from the gun itself and the nozzle?

Or do I need to do more of a full cleaning/dissassembly of the gun
between coats? *If so what would you recommend?

Also, my rationale for buying an extra cup is that I could keep the
excess poly in the cup between coats rather than repeatedly refilling
the cup and then pouring it back with each coat...
Is this OK, or is it recommended to fully empty and clean the cup
between coats...

Personally, I would clean it. I have tried just about every way
possible to get around it, but two hours is too long to have the gun/
material exposed. Cleaning the fluid passages and rinsing with water
will get you only so far with a gun.

A couple of other notes - labor is expensive, material isn't. If I am
going to shoot a project, or cabinets, or anything else, I never save
any material for more than a few minutes in the cup. Some of the
lightening fast lacquers and conversion finishes I will keep in the
gun, and put the whole gun/cup assembly in a 5 gallon bucket with a
sealing lid since I know I will be spraying again in 15 minutes.

And if you are shooting a finish that you need to wait (to me, more
than 30 minutes) to recoat, only load what you need in the gun, and
pour out the remaining finish into your proper waste barrel and clean
the gun after you make a pass. Don't ever "wipe" the nozzle, air
horn, or any other part. On better guns the airstream around the
fluid discharge area will have holes that are literally few
thousandths in diameter, and the smallest bit of debris wiped across
them can easily clog them. That will affect your spray pattern and
finish, and can be incredibly hard to clean if material sets up inside
that air stream hole.

Depending on the material, you may not have to clean the cup. Remove
the gun, fill your cup to a bit more than half, then seal with one of
these:

http://www.turbineproducts.com/servlet/Detail?no=11

Those are the best, but I have also used poly lids that fit nut cans
(free) and some other odds and ends of poly lids that sealed tightly.
If you really want to save some time, put a cup liner in your cup
before using, and just charge your second cup with water and a bit of
detergent to use as cleaner.

The only way to a really good finish from a gun is to keep it as
spotless as possible. That means keeping it as clean as possible. So
as little fun as it is, I would clean between each coating if I had to
wait two hours.

Robert

blueman wrote:
I am spraying water-based poly which needs about 2 hours between coats
(according to the can).

Is this what the can specified for spray application? That would surprise
me. I don't spray poly, but in general terms, spraying is different than
bushing. When spraying, you only wait for the finish to flash before
applying the next coat, so the time between coats is more like 10 minutes.


I am wondering how thoroughly I need to clean the gun between coats --
balancing efficiency vs. the need to keep the gun clear of any
hardened poly (especially since water-based dries fast).

If I had to wait 2 hours between coats, I'd be dumping the material and
cleaning the gun.


Would it be sufficient to spray water through the gun after each coat
(I bought an extra 20oz paint cup that I can fill with water) and
then just wipe off any obvious excess poly from the gun itself and
the nozzle?

Nope. There is no substitute for a thorough cleaning with your bush kit -
regardless of what you're spraying.


Or do I need to do more of a full cleaning/dissassembly of the gun
between coats? If so what would you recommend?

Complete cleaning - run your brushes through everything, blow whatever
solvent is appropriate (in this case water) through the gun a couple of
times.


Also, my rationale for buying an extra cup is that I could keep the
excess poly in the cup between coats rather than repeatedly refilling
the cup and then pouring it back with each coat...
Is this OK, or is it recommended to fully empty and clean the cup
between coats...

Not if you have to wait 2 hours between coats. Perhaps if you can seal off
your cup really well, it might work - sorta like the poly in the can, right?

I still have a hard time believing you have to wait until it's fully dry to
apply a second coat. Try some scrap and shoot a coat, wait for it to flash,
and shoot another coat, wait for that to flash, shoot another, etc. until
you have the buildup you want.

--

-Mike-

On Nov 21, 6:39*am, "Mike Marlow"
wrote:
blueman wrote:
I am spraying water-based poly which needs about 2 hours between coats
(according to the can).

Is this what the can specified for spray application? *That would surprise
me. *I don't spray poly, but in general terms, spraying is different than
bushing. *When spraying, you only wait for the finish to flash before
applying the next coat, so the time between coats is more like 10 minutes..

SNIP

I still have a hard time believing you have to wait until it's fully dry to
apply a second coat. Try some scrap and shoot a coat, wait for it to flash,
and shoot another coat, wait for that to flash, shoot another, etc. until
you have the buildup you want.

Hey Mike! Hope things are going well for you and yours these days,
and that you're getting ready for a nice T-day.

I think blueman may have made a typo about the 2 hour recoat, but
since he didn't mention the manufacturer, who knows?

I can tell you that there are certain waterborne products that require
an hour (or a bit more!) before recoating. I found this in the
Sherwin Williams line of WB finishes

http://www.sherwin-williams.com/docu...n/035777464236

and a couple of others. Still, you know me. I will quit spraying
solvent when they no longer make it, and have only used this stuff
because SW was running a promo on it and they gave me a gallon.
Strangely (please don't tell anyone said this...) it shoot quite
well! You can see that they recommend 1 hour until a second coat, and
the rep here told me best when you can't leave a good thumbprint after
the 60 minute mark.

SW also makes a super high performance coating that requires min 2
hours dry, and no more than 5, or you wait 21 days (until completely
cured) to sand, then recoat.

If I had to wait 2 hours between coats, I'd be dumping the material and
cleaning the gun.

Amen, brother. I tried for years to cheat every way I could to save
time and the dreaded cleaning ritual, but there just isn't any way
around it, is there?

Complete cleaning - run your brushes through everything, blow whatever
solvent is appropriate (in this case water) through the gun a couple of
times.

Yup.

Not if you have to wait 2 hours between coats. *Perhaps if you can seal off
your cup really well, it might work - sorta like the poly in the can, right?

Mike, if you aren't using a really high VOC witch's brew, the lower
VOC stuff like poly really will last with the fake cup top on it in
the link I posted. And seriously, you can get good mileage if you
take the cup off the gun and seal with a poly lid of some sort. They
sold those at HF for a while, but then quit. I should have bought a
case.

I will say this, I have heard some static about leaving tinted or
colored water based finishes in a gun cup for more than an hour or
so. Better minds than mind seem to think there is a chemical reaction
to the aluminum from all the ammonia and formaldehyde compounds in the
finish, and then the added possible reaction of using an alcohol based
tint like Behlen's for a one shot color.

I can't attest to that personally, but I can say that when i sprayed a
lot of dye from my gun (without sealer) I had some kind of chemical
reaction. I thinned the Behlens Sola Lux about 75% so I could mist
over the surface and touch up as much as I wanted (with some
patience). Since the thinned material had so little substance, I
didn't think there would be a problem leaving it in the gun. Overall,
it was in there about 2+ hours. At the bottom of the cup there was a
thin coating of goo that went up the sides of the cup.

It came out easily, and although I noticed it, I didn't pay attention
because my finish wasn't affected.

But the next time I did that, I had the same problem. Hmmm.... so,
after that, I went to HF and bought a teflon lined cup, and problems
solved. So it had to have something to do with the aluminum.... no
other metal parts were fouled. Now, a PVC line does the trick.

Robert

wrote:


Hey Mike! Hope things are going well for you and yours these days,
and that you're getting ready for a nice T-day.

Yup - all is well here. Great, in fact. We're looking forward to
Thanksgiving. All of the kids except one will be over in the afternoon, for
desert and all that stuff. The one that won't be there has to work on
Thanksgiving. But - she lives here now that she's back from Dallas, so
we'll see her later at night.


and a couple of others. Still, you know me. I will quit spraying
solvent when they no longer make it, and have only used this stuff
because SW was running a promo on it and they gave me a gallon.
Strangely (please don't tell anyone said this...) it shoot quite
well! You can see that they recommend 1 hour until a second coat, and
the rep here told me best when you can't leave a good thumbprint after
the 60 minute mark.

Ugh!


Amen, brother. I tried for years to cheat every way I could to save
time and the dreaded cleaning ritual, but there just isn't any way
around it, is there?


I know - I hate cleaning - especially if I have to clean mid-job. But - I
don't know any way around it. I've certainly had to fight my way through
more than one gun that didn't get cleaned well when the time was right, and
I hate that even more than cleaning mid-job. There's just no shortcut.

SNIP

But the next time I did that, I had the same problem. Hmmm.... so,
after that, I went to HF and bought a teflon lined cup, and problems
solved. So it had to have something to do with the aluminum.... no
other metal parts were fouled. Now, a PVC line does the trick.


I have some teflon lined cups, but they're all for my older syphon guns.
They are the ticket. I haven't looked at what HF has for gravity cups in a
long time. Might be worth seeing what they might have for my Devillibis.

--

-Mike-

On Nov 21, 7:30*pm, "Mike Marlow"
wrote:
wrote:

Hey Mike! *Hope things are going well for you and yours these days,
and that you're getting ready for a nice T-day.

Yup - all is well here. *Great, in fact. *We're looking forward to
Thanksgiving. *All of the kids except one will be over in the afternoon, for
desert and all that stuff. *The one that won't be there has to work on
Thanksgiving. *But - she lives here now that she's back from Dallas, so
we'll see her later at night.



and a couple of others. *Still, you know me. *I will quit spraying
solvent when they no longer make it, and have only used this stuff
because SW was running a promo on it and they gave me a gallon.
Strangely (please don't tell anyone said this...) it shoot quite
well! *You can see that they recommend 1 hour until a second coat, and
the rep here told me best when you can't leave a good thumbprint after
the 60 minute mark.

Ugh!



Amen, brother. *I tried for years to cheat every way I could to save
time and the dreaded cleaning ritual, but there just isn't any way
around it, is there?

I know - I hate cleaning - especially if I have to clean mid-job. *But - I
don't know any way around it. *I've certainly had to fight my way through
more than one gun that didn't get cleaned well when the time was right, and
I hate that even more than cleaning mid-job. *There's just no shortcut.

SNIP

But the next time I did that, I had the same problem. *Hmmm.... so,
after that, I went to HF and bought a teflon lined cup, and problems
solved. *So it had to have something to do with the aluminum.... no
other metal parts were fouled. *Now, a PVC line does the trick.

I have some teflon lined cups, but they're all for my older syphon guns.
They are the ticket. *I haven't looked at what HF has for gravity cups in a
long time. *Might be worth seeing what they might have for my Devillibis.

--

-Mike-


I'm a pot guy. With a liner. I snuffle the head in a wet rag.... goes
all day like that.

Also, If it is a whole kitchen, I build in an additional pair of cheap
guns, disposable-like...G

I try to stay away from kitchens now.

"Mike Marlow" writes:

blueman wrote:
I am spraying water-based poly which needs about 2 hours between coats
(according to the can).

Is this what the can specified for spray application? That would surprise
me. I don't spray poly, but in general terms, spraying is different than
bushing. When spraying, you only wait for the finish to flash before
applying the next coat, so the time between coats is more like 10 minutes.


I didn't realize the time was that much faster... I was using the time
for brushing (which is the only time I saw listed on the can)

How do you define/detect "flash"?

I am wondering how thoroughly I need to clean the gun between coats --
balancing efficiency vs. the need to keep the gun clear of any
hardened poly (especially since water-based dries fast).

If I had to wait 2 hours between coats, I'd be dumping the material and
cleaning the gun.

Makes sense

On Nov 21, 6:30 pm, "Mike Marlow"
wrote:

Yup - all is well here. Great, in fact. We're looking forward to
Thanksgiving. All of the kids except one will be over in the afternoon, for
desert and all that stuff. The one that won't be there has to work on
Thanksgiving. But - she lives here now that she's back from Dallas, so
we'll see her later at night.

Good for you!

What... no big production meal? In a way, that can be better. Gives
folks that don't cook much a much lower stress day and more of an
opportunity to sit and chat. That's really my favorite part these
days.

You know, Thanksgiving is one of the few holidays I really enjoy. I
always see my family (for better or worse!) but I also get to see my
extended family on Kathy's side (which is always good) and usually end
the evening up with good friends I don't see much of anymore. A
little bourbon.... a little relaxing blues on the victrola.... good
stuff.

Sadly, me and the boys vow every year to get together more often, then
don't. Honestly, I know I sound like an old man, but where DOES the
time go?

This year we will be going to see my folks in the retirement home like
we did last year. It will be pleasant, and will probably be the last
T-day we will have together. Mom still misses the T-day dinners we
used to make together, and that was something we both used to look
forward to every year. My sisters are both second generation women's
lib, so it was illegal for them to learn to cook back then. So Mom
and me had the kitchen to ourselves, and we had a blast. She
remembers it like it was yesterday and she makes herself laugh and
giggle just thinking about it.

Amen, brother. I tried for years to cheat every way I could to save
time and the dreaded cleaning ritual, but there just isn't any way
around it, is there?

I know - I hate cleaning - especially if I have to clean mid-job. But - I
don't know any way around it. I've certainly had to fight my way through
more than one gun that didn't get cleaned well when the time was right, and
I hate that even more than cleaning mid-job. There's just no shortcut.

Cleaning mid job is the worst; almost. Screwing up the second coat
because you were too lazy to clean the gun, *that* is the worst. I
have done it more than once, and even ruined a gun once. It said
"recoat after two hours" (the old Defthane solvent poly) so I put the
gun in a five gallon bucket, put a puddle of mineral spirits in the
bottom, and sealed the bucket. Went to check on other work, and came
back to spray the second coat. The gun was hopelessly gummed up and I
never got it clean after that. I panicked, and bought another gun and
finished the job.

Lesson completely learned.

As a sidebar, check the newer Defthane out:

http://www.deftfinishes.com/trade/si...talog_page.pdf

I have it on good authority it is an excellent finish, but come on...
not made for any type of production. If the time between brush coats
is FOUR hours, you know that it is probably close to that between
coats when spraying. I say that because you spray it unthinned.

I have some teflon lined cups, but they're all for my older syphon guns.
They are the ticket. I haven't looked at what HF has for gravity cups in a
long time. Might be worth seeing what they might have for my Devillibis.

I got my teflon lined gravity cup on a fluke. Dial down this page and
check out the disposable cups. At $1.25 each, it is hard to beat the
disposables.

http://www.harborfreight.com/catalog...word=paint+cup

I still remember Mike, that you were the one that encouraged me to get
a cheap gun to shoot poly to try it out. I had never considered
buying anything to rely on at HF, and the idea of a sub $200 gun just
seemed like I would be buying junk. I wouldn't shoot poly at all.
But you were persuasive... and the gun you pointed me to was something
like $14.95 (siphon high pressure) and I decided to take a chance.

I liked the gun, and it shot poly and enamel like a champ for a couple
of years. Then the blue plastic gun housing cracked. Damnit! I
still have the cup, though!

That was several years ago, and I remember I wouldn't spray poly and
didn't like to use it at all. For anything. But I had many a client
that wanted poly on their cabinets, exterior doors, bathroom doors,
and other things. They had seen it on Norm's show, seen it in
woodworking magazines, and just about everywhere else where someone
was talking finishing. I had to do it, and for some reason I just
wouldn't. I didn't understand that the differences in finishes these
days is just so miniscule in performance and in actual ingredients.

I don't know how long ago that was, but you made me money by getting
my mind right on spraying poly.

*blush* I'll always remember you fondly for that.

And HF, too. I buy my inline filters there and even bought my in line
water separator/filter/gauge system there. Works great. Great place
to buy the nitrile gloves, too.

Anyway, I digress. If I don't see you here before bird day, you and
your family have a happy one.

Robert

blueman wrote:

I didn't realize the time was that much faster... I was using the time
for brushing (which is the only time I saw listed on the can)

How do you define/detect "flash"?

You will see the coat you shot begin to appear to dry - it goes from that
shiney wet look to a duller look. You don't have to wait for it to dry
completely, since the spray coat is not nearly as heavy as a brush coat
would have been. When it flashes, you can shoot on another coat. You can
test by touching a taped off area - if you have it taped off, or by touching
a bottom area that will never be seen. If it's tacky, you can shoot on
another coat.


--

-Mike-

wrote:


What... no big production meal? In a way, that can be better. Gives
folks that don't cook much a much lower stress day and more of an
opportunity to sit and chat. That's really my favorite part these
days.


Nope - no big production dinner. Our daughter from Philly won't be getting
in until 1:30 (taking a bus up), and the other two kids are doing dinner
with other parents this year. So - rather than all the effort to make a big
spread for 3 people, we're just going to join my wife's sister and family
for dinner, then come home for desert with the kids.


Sadly, me and the boys vow every year to get together more often, then
don't. Honestly, I know I sound like an old man, but where DOES the
time go?


No freakin' kidding! We were just talking the other day about how fast time
flys now.

This year we will be going to see my folks in the retirement home like
we did last year. It will be pleasant, and will probably be the last
T-day we will have together. Mom still misses the T-day dinners we
used to make together, and that was something we both used to look
forward to every year. My sisters are both second generation women's
lib, so it was illegal for them to learn to cook back then. So Mom
and me had the kitchen to ourselves, and we had a blast. She
remembers it like it was yesterday and she makes herself laugh and
giggle just thinking about it.


That's funny. Our girls all learned to cook but to varying degrees. Amy
(the one from Philly) does best cooking microwave things, but Sarah and
Megan are both good cooks. Megan spent yesterday making all sorts of
different perogies. That's a boat load of work - we usually make perogies
in teams, and at that it's a lot of work, but she did it all alone
yesterday.


Cleaning mid job is the worst; almost. Screwing up the second coat
because you were too lazy to clean the gun, *that* is the worst. I
have done it more than once, and even ruined a gun once. It said
"recoat after two hours" (the old Defthane solvent poly) so I put the
gun in a five gallon bucket, put a puddle of mineral spirits in the
bottom, and sealed the bucket. Went to check on other work, and came
back to spray the second coat. The gun was hopelessly gummed up and I
never got it clean after that. I panicked, and bought another gun and
finished the job.

I ruined an entire paint job on a car once - because the gun had dried stuff
inside and would not spray right, and I tried to take every short cut known
to man to get it to shoot. Foolishly thought I could save it with each coat
of material. Long story short - the whole job sucked and could not be
saved. DA'd the car down, tore the gun apart, and meticulously cleaned, and
cleaned, and cleaned, and picked, and... well - you get the drift. Was
almost ready to give the gun up for lost, but it was too good a gun to give
up on. I spend hours cleaning and picking and soaking and repeating...


I have it on good authority it is an excellent finish, but come on...
not made for any type of production. If the time between brush coats
is FOUR hours, you know that it is probably close to that between
coats when spraying. I say that because you spray it unthinned.

I'd shoot that as a single coat application - lay it on as wet as I possibly
could without sagging. Clean everything up and pretend that the job was
done. Come back at it the next day as if it were a completely different
job.


I got my teflon lined gravity cup on a fluke. Dial down this page and
check out the disposable cups. At $1.25 each, it is hard to beat the
disposables.

http://www.harborfreight.com/catalog...word=paint+cup

I still remember Mike, that you were the one that encouraged me to get
a cheap gun to shoot poly to try it out. I had never considered
buying anything to rely on at HF, and the idea of a sub $200 gun just
seemed like I would be buying junk. I wouldn't shoot poly at all.
But you were persuasive... and the gun you pointed me to was something
like $14.95 (siphon high pressure) and I decided to take a chance.

I liked the gun, and it shot poly and enamel like a champ for a couple
of years. Then the blue plastic gun housing cracked. Damnit! I
still have the cup, though!

That was several years ago, and I remember I wouldn't spray poly and
didn't like to use it at all. For anything. But I had many a client
that wanted poly on their cabinets, exterior doors, bathroom doors,
and other things. They had seen it on Norm's show, seen it in
woodworking magazines, and just about everywhere else where someone
was talking finishing. I had to do it, and for some reason I just
wouldn't. I didn't understand that the differences in finishes these
days is just so miniscule in performance and in actual ingredients.

I don't know how long ago that was, but you made me money by getting
my mind right on spraying poly.

*blush* I'll always remember you fondly for that.

Awe geeze - now you're making me blush... I remember our conversations
about that, and steering you to the HF gun. It's funny because I've sent a
lot of people to HF to buy that, and similar guns and they've had great
success with them. I bought one HF HVLP touch up gun and HATED it. So -
all of my guns are the expensive stuff, or the old-used-to-be-expensive
stuff. Of those, about the only one that really gets any use now is my
Binks Model 7. I just stuck a few bucks into a rebuild kit for it (getting
harder to find these days), because I use it to blow on primer. That thing
will shoot coal tar right out of the ground, without spitting. It's my go
to gun for heavy materials. I primed and shot a trailer frame this summer
with it, using Rustoleum primer and paint right out of the can. Went on
like glass. Just can't beat that gun for the ugly materials.


And HF, too. I buy my inline filters there and even bought my in line
water separator/filter/gauge system there. Works great. Great place
to buy the nitrile gloves, too.

Yup! I keep a stock of water separators in my paint cabinet, boxes of
nitrile gloves, a spare 4 1/2 grinder in the cabinet (for when the one in
use dies - but they're so cheap that I'll never buy a better one again),
cut-off wheels and grinder wheels, etc.


Anyway, I digress. If I don't see you here before bird day, you and
your family have a happy one.


We will for sure - you do the same.

--

-Mike-