Orange Peel

[Dennis Johnson]

For the past 10 years or so, I have been using a Wagner Finecoat HVLP sprayer with very good success. Most of the approx. 15-20 gallons I have sprayed has been Hydrocote (water based) lacquer and polyurethane.

I recently decided to move up and bought the Turbinaire 1235 because I will be doing a lot more finishing now that I am retired and it will handle high viscosities. Problem is, I don't know how to use it. Have tried varying the parameters and nothing I do gets away from orange peel.

Some facts that might help. The diameter of the Wagner tip is 0.09in (per my vernier caliper) which is a smidge under 2.5mm. The viscosity of the Hydrocote poly that I'm spraying is 25sec. Room temperature where I'm spraying is 70 F moderate low humidity (shop is in heated basement).

I have tried using the 1.0 and 1.5 mm tips ( per the viscosity charts) on my Turbinaire and varying air and flow with no success.

As I'm writing this, it seems that the answer is that I should buy a

2.5mm tip for my Turbinaire and I just might be successful. But this seems to go against what I've read about correcting orange peel and doesn't make sense to me in the viscosity charts.

I would really appreciate critique from any of you experienced sprayers.

[Mike Marlow]

Hi Dennis. At least your problem is pretty easy to deal with. Orange peel only happens from one cause - paint too dry. You need wetter coats. A bigger tip may help that but only if it atomizes the material better. Your best advice there is to go by the manufacturer's charts. More than likely you can decrease the orange peel by either spraying slower to achieve a wetter coat, or by holding your gun closer. How far is your gun from the object you're painting now? 6" - 12" max is what you should be holding. I generally prefer closer to 6" myself. Watch your spray as it goes on. Look at it from a slight angle as you're spraying and imagine yourself pulling a sheet of clear plastic wrap over the material. A nice even smooth covering. Make sure you get a slight overlap on each pass so as not to have dry lines with each pass.

Most sprays will handle a medium wet coat just fine. Practice on some scrap and first try to achieve a wet coat. That's a coat that is so heavy that it's *almost* ready to sag, but still does not. Once you achieve that, try for a dry coat. That's a coat that just barely shoots an even coverage. You don't want lots of space between the paint specs. Once you achieve that you've identified the two extremes. You should be able to judge something in between those two extremes. That would be a medium wet coat. Keep the medium wet as your standard spray technique. As you develop skill you'll move on to the point where your final beauty coat is a nice wet full flow coat, but that's down the road.

Set your gun up per the manufacturer's directions. Spend the time shooting it at scraps from the proper distance and observe the adjustments to the air volume and the pattern adjustments. There's no substitute for learning your gun.

[nailshooter41]

Mike, while you are here....

Can't orange peel also be caused by water/moisture in the spray system?

I know this is highly unlikely in a closed system like one of the turbine powered HVLPs, but on a pressure gun isn't water often a culprit of fisheyes?

Robert

[JGS]

Hi Dennis,

I have found that I spray WB materials at an air setting of 4-5. This may help as too much air can cause premature drying as you make the overlapping pass. Cheers, JG

Dennis Johns> For the past 10 years or so, I have been using a Wagner Finecoat HVLP

[Mike Marlow]

Hey Bob - no water won't cause orange peel. It will cause bubbles and fisheye (oil will cause fish eye also), but orange peel is a result of dry layers. You start with a bumpy layer caused by insufficient paint droplets on the surface and as you build those up and start to generate a layer that begins to lay down, it lays down on the highs and lows. It will never lay down flat because of those droplets at the base of the film. It will flow some which is what gives the orange peel effect, but it will always present a bridging of the droplets, thus the orange peel.

[Mike Marlow]

overlapping

A good indicator of this will be dusting on each pass. A right awful pain in the butt.

If the paint does not look wet and does not look like a sheet, then you've got a problem. Too much air and/or not enough material coming out of the gun will give more of a dusting problem though than a real orange peel problem. Some times it's a matter of semantics and people may use one word to mean another. Classic orange peel is too dry a coat - too much space between the paint droplets on the surface of the project. What you describe above can make for a rough finish instead of a nice smooth one, but as long as the paint is laid on heavy enough it can be sanded and buffed to a decent finish. Orange peel can be sanded and buffed, but very often will result in visible orange peel under the surface (especially with clears). The surface can be made to be smooth, but you can still see the orange peel through the finish.

[Swingman]

I only spray shellac, but orange peel happens with shellac most often when the mist starts to dry before, or as it hits, the surface.

IME, and on those dry days, you can usually minimize orange peel with shellac by spraying closer, and thinning it a bit more.

What's maddening is, depending upon the temperature and relative humidity, on one day a higher grade, anhydrous alcohol instead of the BORG's standard "denatured", will minimize orange peel, while on another day it will make it worse.

.... sometimes it's brush time.

[Mike Marlow]

And/or slow down your spray application. Get it on so that you don't have too few paint droplets per square inch.

I've never sprayed shellac, so I'll ask you're experience on this... Does shellac bite into the previous coat and flow together, or is it more like poly and just lay on top? The notion of biting in assumes a second coat applied at the flash, and not after cure. Dealing with dry coats is somewhat dependent upon these characteristics of the material being sprayed. Sometimes the simple identification of a problem does not always result in a simple solution - as evidenced by the multiple approaches already posted to this thread. But then again, this is a woodworking forum...

[nailshooter41]

OK, now that makes sense. With that explanation, I won't forget. I'm not new to spraying, but >I am new< to problems solving with solvent based spraying. Until posting my questions here, all I have been able to get is a shrug of the shoulders and "sometimes that just happens, man."

I can ususally lay down the solvent based coatings correctly, but upon reflection I am remembering that on any job of any size that went really well I had someone else set up the gun/finish.

As for water based spraying (meaning latex paint) I spray away with my airless with wild abandon. The paint brand, type, of use of paint... none of it matters I have been doing that so long. And to me, spraying latex is harder than spraying oil; but I have painted so many houses, trims, doors, walls, etc. and whole buildings it doesn't take much attention.

But as I am now appreciating more and more though, the key to good oil solvent spraying is the setup, not the delivery. Today's latex paints are so forgiving and work so well it is a snap to use them. It seems on the solvent base materials there are a lot more variables to really turn out good work.

As always, thanks.

Robert

[nailshooter41]

Swingman wrote:

[Mike Marlow]

Blasphemy Robert! Urethane shoots so nicely. Come on - take a chance. Life is so short...

[Mike Marlow]

Glad it helped. I'm just such a puddle of useless information and irrelevant facts (ahem... the word "facts" is a loosely defined term in this context) that it feels good sometimes when I stumble upon something that actually works for someone.

That's right. I try to make it a point to encourage guys to really get to know their gun. The best first step is to really read the manufacturer's instructions on the adjustments with the gun and then to practice on some scrap. Experiment with each of the adjustments - which is somewhat time consuming since each adjustment interacts with the others. But... it's the best way to learn about achieving a proper pattern, a proper flow rate, and a proper application rate.

I don't know how effective it really is for other guys when they read it, but the best I've ever been able to come up with is something that was handed down to me and it's the concept of trying to spread a thin layer of plastic wrap with your spray technique. It's amazing how much easier good technique becomes with a well set up gun. Most guys need to really learn the knack of watching the material going on as they're spraying. It just doesn't seem to come naturally. I know it didn't for me. But man... what a difference it makes when you see the coverage happening and you almost instinctively know how to adjust your rate of application based on what you're seeing. It's a break-through moment. That's when you can get to the point that you can shoot it and ship it. No sanding, no buffing, etc. I still end up doing more wet sanding and buffing than I wish I had to, but it's generally because of dust nibs, spiders and/or mosquitoes (who seem ever so attracted to clear coat), or some other issue not really related to technique.

The coolest part about these threads is that there's always something to learn. You shoot latex in your sleep and I'd be a disaster with latex. I just never shoot it. Don't have the guns for it. Swingman shoots shellac like he's some sort of East Indian Beetle and I'd probably screw that up in a heartbeat as well. Never shot the stuff. Don't even know if my guns will shoot it well. But - I picked up an interesting tid-bit from a post by Swingman earlier today, about shooting shellac. May never use the information, but it was cool to discover it.

[nailshooter41]

OK now, Mike. You're gonna get me in trouble.

All I have is my little Binks knockoff which you know about. BTW, as an update on that, I have found it works quite well with 32 oz can attached - no undue strain on the gun frame as you suspected. I went down to HF when we were talking about it in an earlier thread, and lo and behold, there was a teflon lined cup for $5. So I bought the cup, a 1/4 union, and then a 1/4 to 3/8 male/male connector and Frankengun was born. So back to the lab I go with all my parts. I was afraid that the little gun wouldn't have enough siphon power to pull the paint up the larger tube and shoot a consistent finish. Completely unfounded. Worked like a champ and save me a lot of trips to fill the can while finishing up the burglar bars.

Now I had to finish the metal doors on the house. Hmm.... all white. I know white will show every little problem, but I would be shooting the same coating as before, just another color. So I mixed up 16 oz of paint with 1/2 oz of Japan drier, and 1/2 of thinner. And it worked so well I was actually, honestly surprised. I put the big can on it, adjusted the fan out to about 6", and held the gun out about 8", and turned the pressure all the way down to about 42 lbs. Shot a few long runs on a piece of the old well painted wood door to set the flow, and off I went.

The finish is gorgeous, as good as I have seen in a long time. Certainly not as good I have ever seen, but everything lined up right on this one. I did have to recoat one of the doors on one side, though. With the finish juiced with drier and thinner, I couldn't even touch up my starting area (one damn corner) when I was only half way down the door. The touch up just sat on top of the paint. It was sure sticky; but man did it set up. I was able to handle the doors in two hours, and they were dry to the touch in less than four. So as I had hoped, I was able to shoot two coats in the same day and still hang the door that night (late) without fear of the vinyl weatherstrip pulling off the new paint.

What a joy for me to do this. I pull the doors down and screw some handle on them. I sand lightly as needed, then degloss for prep. Spray one door both sides, set it aside. Spray the other door, set it it aside. It isn't even lunch yet. Do the wood repair on on the house as needed. Go to lunch. Come back, spray both doors. Leaving the job at 6:30, I hang the doors and put on the hardware. I have never been able to get more than one coat hard enough to hang the door back the same day as spraying when using latex unless it was the dead of summer when the temps are around 100 here.

Come on... can't you see the feathers on my legs?

But Mike, I'll bite on your post. Do you think the little Binks will shoot urethane successfully? I don't know how to set it up. I buy a couple of cans for small projects and cabinet refinish repairs, but 20 cans for a couple of doors is too much. For flat doors and surfaces, I thin the urethane down about 10% and pad it on. You cannot tell it wasn't sprayed. But one of the doors I am putting up is an old 15 panel wood door, so there is no way to pad it.

And even though I thin the oil paint down pretty far to paint with it, I still don't know how it matches up to urethane as far as viscosity goes.. Thin it? Don't thin it? Will I be able to put the door back on that evening? Like I said, the temptation is awful as she has a studio, detached from the house that is empty that she said I could use.

I am thinking that it will take me about an hour each side to coat the door and inside all fifteen little raised panels and their trim corners, etc. OR I could spray BOTH sides and clean the gun in 30 minutes. I could have finish on both doors and clean the gun in one hour.

But I'm feeling the wind blowing through my feathers...

Robert

[Mike Marlow]

Nah - you're steppin' right out there. I see heat lamps and downpressure booths in your tea leaves.

I know it will. I use my Binks 115 to shoot urethane all the time. Follow paint manufacturer's directions for thinning, retarding, etc. as appropriate and you'll be fine. I shot some gloss black urethane on a steering wheel for a '51 Dodge I did last winter. It was a rubber over steel steering wheel and a lot of the hard rubber had cracked and been broken away, so I had to repair and contour areas around the spokes, etc. Got all of the fillers finished down to what satisfied me, shot a little primer on the whole thing and then laid on the urethane. I shot on really wet coats - just short of sagging. I think I put on about 5 coats. The build up was phenominal and it felt almost like plastic in your hands when it dried. Smooth. Really smooth. Almost as smooth as a 21 year old's... ummmmm... well, you can guess. Almost as good to hold on to as well. But not quite.

You'll be reducing urethanes. The best advice when you're getting started is to pick a brand and stick with the products from that brand. When you get into activators and reducers they are chemically somewhat critical. In reality, you can mix and match products more than the manufacturer's tell you, but you want to know what you're mixing and matching. Disaster can result. So- to be safe, stick with the associated products from one manufacturer and simply follow the directions on the can. Nearly fail-safe. The one thing you'll like is that today's urethanes flash in 20 minutes or so and you'll get better and faster coverage/completion with a nicer, harder finish than you're used to. Lay on a nice coat, wait for it to flash, and lay down another. Cleanliness does become a bigger concern though and that's why I harp on keeping guns as clean as the day they were bought. Not all of mine are - some of mine have primer streaks down the outside of the cups, but all look like new on the inside and around the gun itself. Someday I'll invest a day's worth of effort to clean up those other cups - they just bug me. Some of the stuff I shoot does not simply soften up with a little lacquer thinner though, so the cleanup is an effort after it's been there a while.

That's my boy. Caution be damned.

[Swingman]

Yes it does ... that's one of the reasons, IME, that it is an easy finish to fix.

[Dennis Johnson]

Thanks to you Mike, and the others, we just got a far better explanation than is in any manual.

[Robatoy]

Not enough flow-out..i.e. too dry.

then there is Emma Peel.... *chewing on my knuckles*