Howdy folks!
I know, I know, this thread is NOT about airplanes.. but I know the concentration of folks with right knowledge here is great, so I decided to try my luck..
But hey! It involves spraying, and wood - so not too bad, huh?
Anyway.
I am trying to spray clear on a bunch of windows (66, to be exact...).
Being a total noob in spraying (this is my first try at it), it seems that I have picked up probably one of the hardest possible jobs to be my first.
Finishing these windows is beating me
I am using General Finishes Enduro-Var; water-based poly, spraying with Fuji T70 gun driven off of MiniMite 4 (4-stage turbine), 50 ft air hose, full open air, 1.3 mm needle / cup, in a room with ~50% RH and 70F temp. All that is in the range of manufacturer's recommendations.
The way EV (EnduroVar) behaves, slowing down the "depositing" process, initially you get a bunch of droplets, and as you keep adding it eventually you get the wet film. That's right about 3 mil wet (I measured). The problem is, going just a bit wetter makes it flow real good to the bottom of vertical surfaces (which with these windows is pretty much the only thing I get!). I do get real runs sometimes; but more often, I just get a lot of it kinda "flowing" to the bottom under gravity...
If I go just a bit drier, it doesn't flow completely, leaving kind of mini pinhole craters in the film.
What Im trying to say I guess is that it's extra sensitive to the amount you lay on...
I do not thin. I tried; that makes things worse (those "pinhole craters" I described). Manufacturer tells you thinning is not necessary.
If I thin, it seems that it flows WAY worse; these pinholes are much more numerous... until you get it on too thick.
I am pretty decent at spraying flat stuff at this point. I overlay strokes ~50% and have my fan set up so that two passes at the speed I wanna go at will give me just that right film thickness.
See the picture of a window, and a closeup of all the millwork. (You can see a bunch of coats of my practice spraying it ).It's a damaged one that we replaced and I kept as a practice piece.
As you can see, it's pretty complex and the worst possible situation, probably. It's all blind inside corners! It's about 3 inches "deep", those mullions are 1" wide and maybe 3/8 thick; the corner strips are 1/2" squared.
What I can't figure out is what's the best sequence and settings to avoid material accumulation in corners, runs, and dry spots. I am trying to come up with a reliable, repeatable sequence; partly because getting these windows lit up in such a way that I can see reflection in sprayed on material at ALL times is virtually impossible (they are installed!), so I have to go kinda "blind", and vertical. The fact that there's a very small margin between "too much", "too little", and "just right" ain't helping.
My main problem is that if I want to reliably cover it, I virtually always get too much in areas marked with the red circles on the picture. The one marked (3) is one of the worst offenders.
First approach I tried is corner mouldings (2) first at 45 (to hit the face 2.1)), then sides (4), then inside mullions (1) at 45, each side.
I tried reversing that too - mullions (1), then corners (2), then sides (4).
I get those accumulations in circled areas fairly reliably.
Another approach I tried is to turn my fan to smallest (~1" circle) and close up the fluid, so that I get a very slow flow. Almost airbrush-y.
First, I build up mullions shooting at 45" from each side (marked (1) on the picture). This typically deposits enough on the top of them, if not, I add a bit. I start and stop where they intersect, not to flood that corner.
Then, I build up the spots where they intersect (just on the top, since corners have already been hit).
Then, I focus on the corner moulding (marked (2)), building it up. I shoot it at 45 degrees "into" the corner, at 90 degrees to the "flat" face (marked (2.1)). Going super slow allows me to make sure I don't flood moulding / mullion intersections, especially the bottom one (marked (3)).
So far so good -- but this is where I get stuck. I can't hit the sides of the window (marked (4)) without flooding the corner mouldings (2), corners (5), or mullion/corner moulding T-intersection (3), (6).
Reversing this sequence and doing sides (4) first doesn't help much -- I get a ton of overspray on corner mouldings (2) which is virtually impossible to hit all in time before it flashes enough to create problems (I am going to get some retarder tomorrow to see if that helps this problem).
Any advice or help will be much much much appreciated!
I know, I know, this thread is NOT about airplanes.. but I know the concentration of folks with right knowledge here is great, so I decided to try my luck..
But hey! It involves spraying, and wood - so not too bad, huh?
Anyway.
I am trying to spray clear on a bunch of windows (66, to be exact...).
Being a total noob in spraying (this is my first try at it), it seems that I have picked up probably one of the hardest possible jobs to be my first
. Finishing these windows is beating me
I am using General Finishes Enduro-Var; water-based poly, spraying with Fuji T70 gun driven off of MiniMite 4 (4-stage turbine), 50 ft air hose, full open air, 1.3 mm needle / cup, in a room with ~50% RH and 70F temp. All that is in the range of manufacturer's recommendations.
The way EV (EnduroVar) behaves, slowing down the "depositing" process, initially you get a bunch of droplets, and as you keep adding it eventually you get the wet film. That's right about 3 mil wet (I measured). The problem is, going just a bit wetter makes it flow real good to the bottom of vertical surfaces (which with these windows is pretty much the only thing I get!). I do get real runs sometimes; but more often, I just get a lot of it kinda "flowing" to the bottom under gravity...
If I go just a bit drier, it doesn't flow completely, leaving kind of mini pinhole craters in the film.
What Im trying to say I guess is that it's extra sensitive to the amount you lay on...
I do not thin. I tried; that makes things worse (those "pinhole craters" I described). Manufacturer tells you thinning is not necessary.
If I thin, it seems that it flows WAY worse; these pinholes are much more numerous... until you get it on too thick.
I am pretty decent at spraying flat stuff at this point. I overlay strokes ~50% and have my fan set up so that two passes at the speed I wanna go at will give me just that right film thickness.
See the picture of a window, and a closeup of all the millwork. (You can see a bunch of coats of my practice spraying it
).It's a damaged one that we replaced and I kept as a practice piece. As you can see, it's pretty complex and the worst possible situation, probably. It's all blind inside corners! It's about 3 inches "deep", those mullions are 1" wide and maybe 3/8 thick; the corner strips are 1/2" squared.
What I can't figure out is what's the best sequence and settings to avoid material accumulation in corners, runs, and dry spots. I am trying to come up with a reliable, repeatable sequence; partly because getting these windows lit up in such a way that I can see reflection in sprayed on material at ALL times is virtually impossible (they are installed!), so I have to go kinda "blind", and vertical. The fact that there's a very small margin between "too much", "too little", and "just right" ain't helping.
My main problem is that if I want to reliably cover it, I virtually always get too much in areas marked with the red circles on the picture. The one marked (3) is one of the worst offenders.
First approach I tried is corner mouldings (2) first at 45 (to hit the face 2.1)), then sides (4), then inside mullions (1) at 45, each side.
I tried reversing that too - mullions (1), then corners (2), then sides (4).
I get those accumulations in circled areas fairly reliably.
Another approach I tried is to turn my fan to smallest (~1" circle) and close up the fluid, so that I get a very slow flow. Almost airbrush-y.
First, I build up mullions shooting at 45" from each side (marked (1) on the picture). This typically deposits enough on the top of them, if not, I add a bit. I start and stop where they intersect, not to flood that corner.
Then, I build up the spots where they intersect (just on the top, since corners have already been hit).
Then, I focus on the corner moulding (marked (2)), building it up. I shoot it at 45 degrees "into" the corner, at 90 degrees to the "flat" face (marked (2.1)). Going super slow allows me to make sure I don't flood moulding / mullion intersections, especially the bottom one (marked (3)).
So far so good -- but this is where I get stuck. I can't hit the sides of the window (marked (4)) without flooding the corner mouldings (2), corners (5), or mullion/corner moulding T-intersection (3), (6).
Reversing this sequence and doing sides (4) first doesn't help much -- I get a ton of overspray on corner mouldings (2) which is virtually impossible to hit all in time before it flashes enough to create problems (I am going to get some retarder tomorrow to see if that helps this problem).
Any advice or help will be much much much appreciated!
