Spraying wooden windows with EnduroVar is 100% beating me...

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Forum topic by fidot posted 12-09-2016 02:05 PM 611 views 0 times favorited 7 replies Add to Favorites Watch
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4 posts in 682 days

12-09-2016 02:05 PM

Howdy folks!

Long time reader, first time writer :) Lots of great community wisdom here, I learned a lot over the years!


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!

7 replies so far

View jbay's profile (online now)


2681 posts in 1047 days

#1 posted 12-09-2016 02:36 PM

My typical method would be to spray the 2 sides all the way past the corners, (like there was no corner)
next I would spray the top and bottom just feathering the spray up to the corners, (this way your not hitting the corner twice)
next I would spray the full length of one mullion (both sides) feathering it into the top and bottom,
next I would do one of the cross pieces, feathering it into the side and the mullion, then do the other cross piece feathering into the mullion and side.
Hard to understand but I hope it helps.

View SuperCubber's profile


1037 posts in 2432 days

#2 posted 12-09-2016 03:37 PM

Everytime I spray WB poly, I use very light coats, and as it builds, it creates a nice, smooth finish. Have you tried multiple coats?

-- Joe | Spartanburg, SC | "To give anything less than your best is to sacrafice the gift." - Steve Prefontaine

View fidot's profile


4 posts in 682 days

#3 posted 12-09-2016 07:36 PM

JBay, thanks! I will try this technique. It actually makes 100% sense, you explained it very well.

I would imagine, that when you do sides, you would use a vairly wide fan to hit the whole side and the “inside” corner at the same time?

Will that deposit enough on the “faсing” side of the corner moulding (see picture, circled green) w/o overflooding the side?

SuperCubber: nice to see a fellow pilot here :)

The problem is that it’s a very tiny margin with EnduroVar between a coat that completely flows out (otherwise, I get pinholes), and “too much”... I tried tack and dust coats (didn’t mention that in the previous post); where I would dust, let it tack a bit, and then flow.. If you ever read Stewart Systems fabric spraying manual, kinda like what they tell you to do. On EnduroVar, that resulted in just more orange peel; horrible, actually.

What kind of WB poly do you use?

View jbay's profile (online now)


2681 posts in 1047 days

#4 posted 12-09-2016 07:44 PM

Probably a smaller fan (about 4-5”) to catch the molding on the first lap and 2 more laps for the sides. Might have to back off the material volume a bit.
Honestly 90% of my experience is with lacquer.

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1037 posts in 2432 days

#5 posted 12-09-2016 08:04 PM

Wow, well, I’ve never used EnduroVar. I’ve used GF High Performance and Minwax Polycrylic.

There are a few of us pilots on here!

-- Joe | Spartanburg, SC | "To give anything less than your best is to sacrafice the gift." - Steve Prefontaine

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4 posts in 682 days

#6 posted 12-09-2016 10:24 PM

Yep. A lot of people are saying that High Performance flows better than Enduro :)

So I am just back from Woodcraft, where I dragged one of the sample windows and talked to a couple guys.

One of the guys recommended adding Floetrol to flow it better and thin; 30% (!). I’ll try that.
Another guy recommended trying to get all the small stuff first, including corners, my “airbrush” style. Then, let them dry and hit the sides with the wide fan… I am a bit concerned about overspray ruining the thin stuff; but he seems to think it should blend, if thinned.

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4 posts in 682 days

#7 posted 12-13-2016 04:37 AM

Floetrol didn’t work.

But! I have had a lot of progress! Tonight, I put on a pretty decent coat w/o ANY runs, on that window.

My main problem was having too thick a material. So if I put on mist coats; that wouldn’t flow; and I was left to “wet” coats; that would run.

As I mentioned in the first post, I have tried thinning it with water; and that didnt help. Keyword: water.

I harrassed everyone at local Woodcraft by now who had any experience spraying the same material I did, and finally, I think, Im on the right track.

1. Thin! But not with water, with their “extender”, which is also a flow additive. The guy who said I should try it said he thinks it’s basically glycerin with water. It foams a bit (“forms a nice head” literally were his words). I’m thinning 20% now, bringing me to 10 seconds on Ford #4 (as opposed to 25 straight out the can).

2. Thin thin thin coats. The key word here was, “right after the gun, should look like a 100 grit sandpaper”. It’s almost magic – I expected it to flow right after I spayed it; but apparently, no: it takes a bit of delay for it to start flowing; and then it just flows together. This probably was a super rookie mistake.

When I tried thinner coats before; they would flow together, but not COMPLETELY, leaving essentially this “net” of a finish when dry. But, I didn’t thin then! Now, when those droplets are less viscous, they flow together real good.

3. Reduce fluid flow thru the gun! It will slow me down; but that’s a limitation of my turbine unfortunately. Basically, atomization = (air + fluid), so if I wanted more atomization, and since I can’t crank up air, I have to dial down fluid. Going to 1.0 mm cap / needle (as opposed to 1.3 I tried before) seems to have helped a bit (I tried that in the last session).

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