Gun Choice for Spraying Toner Over Sealer
To avoid mottling, use equipment that is recommended for spraying toners. April 30, 2006
Question
I was spraying a toner made with seal coat reduced about 50% with alcohol and dye, about 1 1/2 gallons of material to 5 ozs. dye. I sprayed it with my Kremlin and a 06 tip - that is the smallest I have. It seemed like no matter how much I adjusted the pressures, I couldn't get rid of the spottiness. I sometimes have this same problem when I'm shooting Valspar spray stain, which I believe is made with micronized pigments. There is very little settling in the can. I was once told by a Kremlin dealer that dyes should really only be sprayed through a compressed or turbine type gun, not an AA. Any suggestions would be appreciated.
Also, what type of gun would you recommend for onsite spraying of stains and toners? For me, portability is most important. I have a pancake type Porter Cable compressor. I believe it's 1.5 hp with a 6 gallon tank. I might get a slightly bigger compressor if necessary, but nothing too big.
Forum Responses
(Finishing Forum)
From contributor G:
I can't comment on using an AAA for spray stain because I never tried it. I use a separate pressure pot and HVLP gun for those and the AAAs are for the clears. As for onsite spraying - I have run a pressure pot off a pancake compressor before, you just can't do a lot at a time.
From contributor M:
Just a thought - can you try reducing it some more, and then making more passes to get your color?
From Paul Snyder, forum technical advisor:
Are you spraying the toner over a sealed and smoothed surface? That works well for me using the pump. Spottiness sounds like the toner or stain is being absorbed unevenly by the wood. What exactly does spottiness look like?
For on-site work, I use an Asturo ECO connected to a pressure pot. It runs off a small compressor (needs around 5 CFM) and atomizes very nicely. The key is selecting a spray gun that only needs a small amount of air to match the output of your compressor.
From the original questioner:
I did reduce it some more, but still seem to have the same problem. Surface is definitely sealed. Actually, this particular toning is being done over a painted surface to simulate wood. I switched over to my turbine HVLP and had no spottiness. As for the spottiness, it looks like little darker spots, not specks, randomly spread out through the spray pass pattern.
From contributor W:
Is it possible you're not getting atomization with the Kremlin? What settings are you using? I've seen what I think you are talking about because of lower air settings.
From contributor P:
I was using 200-300 fluid and about 8-12 air.
From contributor R:
It sounds to me like you are a little high on the fluid. When I get spots, it is because I am laying it on too heavy.
From contributor S:
Your Kremlin is not a good choice. The rep was correct. Devilbiss designed a gun for just this application (VTX). This gun will eliminate the mottling you are getting. If you have to use the Kremlin, go with the 04 series, reduce fluid pressure and elevate air pressure to cap.
From contributor P:
That's the word I was looking for - mottling. I think you're right about the pressures and tip. Do you think the 03 would be better than the 04 for this? Any other gun recommendations? I believe the vtx gun is quite pricey. I was hoping, since I'm spraying such thin materials, that a lower priced gun would do a good job as well.
From contributor D:
I use a Kremlin M22 LVLP, connected to a pressure pot, to spray dyes, stains and toners. Works great.
From contributor S:
I thought the 4 tip was the smallest insert they made. Go with the 3 tip.
From contributor J:
Are you using your Kremlin onsite with the pancake compressor? If so, does it provide enough air and do you like using it onsite? All of my work is onsite as well. For the toners, I always get great results with a turbine, but I'm still using an electric diaphragm pump for clears.
From the original questioner:
The M22 or M21 is the gun the Kremlin dealer recommended. I think there are guns with lower cfm requirements, though.
What pressure settings would you recommend? I don't think I can come down much lower on the fluid pressure. I have a 20-15 pump which is a 20:1. Even the 10-14 pump, which is a 10:1, has a fluid operating pressure range of 300 psi and up.
Spraying finish with the Kremlin and pancake compressor onsite is not a problem. The compressor is working hard, though. I would like to get a 2 or 3 hp compressor. When you're cleaning the pump, sometimes you have to wait for the compressor to catch up. It is unbelievable how little overspray and how much material you save with this pump. I have a turbine unit as well and that is what I ended up using to finish toning. I do have to get a remote pot for it so that I can spray small cabinet interiors. The turbine is so much slower, though. If I could get the Kremlin dialed in I would only use it alone, but I'm not sure that it will do everything that I need it to do. So I'll probably end up getting some sort of gun and pressure pot unit.
From contributor S:
I just assumed you had a 10/14 since many seem to have this model. I happen to have the less popular Craico Falcon with the new G-45 gun (positive flow) material feeds on up and down stroke 10-1. Try 10 lbs - that should give 200 lbs fluid pressure (if she'll stroke).
From contributor J:
Thanks for the info. I'm also considering a low cfm Asturo or Accuspray setup. It's probably best to own or at least try out a few different setups.
From Paul Snyder, forum technical advisor:
Mottling of the color happens when you spray the toner too wet. Try backing off the surface a little and moving faster (as well as dialing in a pressure/flow you're comfortable with). You want to lay down just enough material to develop a continuous wet edge, but no more. You can spray toner too heavily with any gun, the pump just makes it easier since it has such a high output.
I use the pump to spray toner sometimes, but a lot of the time I use a Binks 2001 connected to a pot. I have the toner in the pot, clear in the pump, and spray glaze in a touch-up gun. That way I can glaze, tone, and topcoat in rapid succession.
On another point, what topcoats are you spraying? Just curious why you're using shellac for your toner.
P.S. I had a Kremlin M-21 gun and didn't like it (my opinion).
Click here for full size image
From the original questioner:
I'm using Fuhr Precat # 375 as my topcoat. I didn't want to use the 375 for toning because I needed such a dark color and didn't want to have to wait for the coating to dry to apply the successive coats of toner. With the Seal Coat you can layer quite quickly. Not as fast as lacquer, but close. Do you spray the glaze on and wipe off or do you let it dry and rub it off? Just curious what to do for a water based system.
From contributor S:
I'll stick to my guns. A.A. is not a good choice for spraying dyes, toners, spray stains with good results, however shading lacquers spray well. The reason is the material output is too great and difficult to set low. Feathering is impossible and it's also hard to achieve a small enough particulate (spray droplets too large) landing on the surface to minimize mottling. Over atomizing helps. Kremlin, Craigo, Binks - you name one, they don't market them for toning and spray staining. They are a great tool for clears, primers, pigmented coatings.
From contributor D:
I agree that the AAA Kremlin would not be the best overall choice for spraying "spray only" stains or toners, however I believe the Kremlin AAA with MVX is used quite often, in a production setting, to spray dyes. They advertise it for this purpose. In reference to the Kremlin M21 & M22, there are several different models of the M22 (the new model). The M22 LVLP uses considerably less air than the old M21 or the regular M22. The M22 LVLP does a fine job with "spray only" stains and dyes, however I am not sure if you could run it off of a portable compressor.
The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).
Comment from contributor E:
I find with a spray stain ngr stain the best result is a HVLP. As far as toners or shaders I have found my Binks pressure pot with the mach 1 HVLP gun works great. You can mix a huge bath all at once and adjust the fluid and air pressure anywhere you want it - right down to an airbrush effect if necessary.
