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water based lacquer atomization issues
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Author:  Conor_Searl [ Sat May 26, 2018 6:55 pm ]
Post subject:  water based lacquer atomization issues
Hi I've been using this water based lacquer called Brite-tone and I'm getting horrible atomization. The lacquer comes out kind of globby and dries to a very pronounced orange peel. But no matter what I do, increase pressure, decrease pressure, increase the amount of lacquer flowing or decrease it it doesn't seem to change anything.

I've got a pretty good HVLP spray gun and a small compressor, I spray in my garage. The pressure guage on the compressor reads about 80 PSI, and then I'm running at least 30' of hose. The temperature in the garage is probably about 20/68 degrees. I've thinned the lacquer with about 5% appropriate reducer.

I feel like maybe it's the temperature but I'm stumped. I don't spray often enough to have developed a thorough process yet. But the last time I sprayed was in the winter, I left a heater on with the garage sealed up for the first half of the day before doing any spraying and I didn't have the same problem with atomization, but I know I put too much reducer in and had drips, sags, and runs, for days...

Any thoughts?
Author:  Michaeldc [ Sat May 26, 2018 7:04 pm ]
Post subject:  Re: water based lacquer atomization issues
Conor_Searl wrote:
Hi I've been using this water based lacquer called Brite-tone and I'm getting horrible atomization. The lacquer comes out kind of globby and dries to a very pronounced orange peel. But no matter what I do, increase pressure, decrease pressure, increase the amount of lacquer flowing or decrease it it doesn't seem to change anything.

I've got a pretty good HVLP spray gun and a small compressor, I spray in my garage. The pressure guage on the compressor reads about 80 PSI, and then I'm running at least 30' of hose. The temperature in the garage is probably about 20/68 degrees. I've thinned the lacquer with about 5% appropriate reducer.

I feel like maybe it's the temperature but I'm stumped. I don't spray often enough to have developed a thorough process yet. But the last time I sprayed was in the winter, I left a heater on with the garage sealed up for the first half of the day before doing any spraying and I didn't have the same problem with atomization, but I know I put too much reducer in and had drips, sags, and runs, for days...



Any thoughts?


Are you using the recommended air cap and fluid tip? Is the compressor able to keep up? It seems kinda small. What's the pressure at the gun?
Author:  Conor_Searl [ Sat May 26, 2018 7:24 pm ]
Post subject:  Re: water based lacquer atomization issues
Michaeldc wrote:
Are you using the recommended air cap and fluid tip? Is the compressor able to keep up? It seems kinda small. What's the pressure at the gun?


Fluid tip? I think so, it's 1.3mm.

Air cap? I'm not sure what this is... :oops:

The compressor is smaller, but it seems to keep up, I can get a full pass on a guitar before it kicks in again. It's 7 gallons.

My spray gun came with a guage to attach to the gun, but it never seemed to work and leaked air like crazy. So I'm not sure what the pressure at the gun is.
Author:  StevenWheeler [ Sat May 26, 2018 7:31 pm ]
Post subject:  Re: water based lacquer atomization issues
Michaeldc wrote:
Are you using the recommended air cap and fluid tip?


Right on the mark there Michael. That was giving me some bad orange peel with General Finishes EnduroVar. Felt a bit the fool when I found the answer on the label of the can.

Steve
Author:  Alex Kleon [ Sat May 26, 2018 7:51 pm ]
Post subject:  Re: water based lacquer atomization issues
I sprayed BriteTone with my Fuji 4 stage, and had no problems with atomization. I used to use a HVLP gun and a small compressor for cabinetry with EnduroVar, and IIRC, pressure at the compressor was much lower, around 30psi, and around 8-10psi at the gun.

Alex
Author:  Clay S. [ Sat May 26, 2018 9:52 pm ]
Post subject:  Re: water based lacquer atomization issues
A couple of thing s you can try -

1. Buy a cheap Harbor Freight regulator ($5) to put just before the spray gun.

2. Warm the finish material in front of or on a space heater and spray it "hot".

If you are using a compressor with an HVLP gun, it would be a "conversion gun" which often uses more air than a regular spray gun. You could buy a cheap HF jamb gun ($15) and see if you have better luck with that.
Author:  Freeman [ Sat May 26, 2018 10:14 pm ]
Post subject:  Re: water based lacquer atomization issues
I have had good luck reducing "waterborn" lacquer with a small amount of denatured alcohol. However I've only used KTM-9 and that stuff StewMac used to sell so I can't say here. I also have found that when I wash my gun out with water if I put some DA in the cup and shoot a bit it takes the water out (water is soluble in alcohol) and if I leave a little DA in the cup and lightly mist the work before the next coat I've never had a witness line (KTM again). Seemed to give the old lacquer surface a slight tack that the fresh coat melted to immediately.
Author:  B. Howard [ Sun May 27, 2018 6:09 am ]
Post subject:  Re: water based lacquer atomization issues
What is the pressure at the tip? At the gun?? When actually flowing, not static? That is where it counts as far as pressure.

5% reduction sounds like a reasonable start and 1.3 tip sounds good too.

Are we sure it is poor atomization? lots of other things can cause orange peel/lack of flow..... Here is a copy of a chart I did for problem solving spray finish issues if you don't already have it...https://howardguitars.blogspot.com/2015 ... rt_18.html
Author:  B. Howard [ Sun May 27, 2018 6:12 am ]
Post subject:  Re: water based lacquer atomization issues
Also I have this on gun set up. Pic#4 shows my regulator at the gun and the pressure drop at the end of a 30 foot 1/2" hose. Thgis why you need to measure the pressure here. https://howardguitars.blogspot.com/2015 ... brian.html
Author:  Clay S. [ Sun May 27, 2018 9:23 am ]
Post subject:  Re: water based lacquer atomization issues
Hi Brian,
I like your chart. A lot of well organized information to remind us of - all - the possible causes that we might not think about.
Author:  Conor_Searl [ Sun May 27, 2018 10:31 am ]
Post subject:  Re: water based lacquer atomization issues
B. Howard wrote:
What is the pressure at the tip? At the gun?? When actually flowing, not static? That is where it counts as far as pressure.

5% reduction sounds like a reasonable start and 1.3 tip sounds good too.

Are we sure it is poor atomization? lots of other things can cause orange peel/lack of flow..... Here is a copy of a chart I did for problem solving spray finish issues if you don't already have it...https://howardguitars.blogspot.com/2015 ... rt_18.html


My gut is that I'm not getting enough pressure, the compressor is cranked all the way up and reads 80 psi, but I know over 30' of hose that number reduces.

Looking at your chart I'm pretty sure it's poor atomization, when I look at the spray from the side through light it looks like the gun is spitting, and the size of the droplets is very inconsistent. Holding the gun about 6" away from the surface I'm spraying is the only way to get any kind of wet coat down and I have to move painfully slow, and it ends up way too wet. If I pull the trigger and let one blast hit the surface it looks like small to medium drops of water.

I'm looking forward to reading your spray gun set up article. Everything I seem to find online about spray gun technique comes from the car world, and is full of terms I don't really understand.
Author:  Mike_P [ Sun May 27, 2018 11:11 am ]
Post subject:  Re: water based lacquer atomization issues
30' of hose...of what diameter?

note that Brian is using a 1/2" hose (I've always wondered just how much things are affected by the 1/4" couplers, but that's another argument)...be aware that as you go smaller in internal diameter of the hose accumulated friction really has an impact on what is happening at your gun.

as a note I use 3/8" hoses ideally no longer than 25' as measured from my oil and water traps (and those are already 20' from my compressor)

have you also thoroughly cleaned your gun? it is also possible that you have some other issue going on internally in regards to the seals and such.

skipping all the automotive terms what I've found the most important to pay attention to is the CFM requirements of the gun as it is set up (needle and air cap) and how that relates to the viscosity of the material being sprayed. and of course this directly correlates to just what your compressor can put out.

I guess my system is rather old school (30 year old Campbell Hausfeld twin tank wheel barrow compressor and a 10 year old Binks Mach1-SL gun), but that aside I have my gun set up with a cap that perfectly utilizes the capability of the compressor...e.g. when spraying and the compressor kicks in (you know, I've never noticed the supposed issues that "occur" when that happens, things just keep on going with no ill effects) I can keep on spraying forever (erm, at least until the gun is empty or the compressor burns up).
Author:  Ken Lewis [ Sun May 27, 2018 1:09 pm ]
Post subject:  Re: water based lacquer atomization issues
"My gut is that I'm not getting enough pressure, the compressor is cranked all the way up and reads 80 psi, but I know over 30' of hose that number reduces."

I think your gut may be misleading you. :D High Volume Low Pressure usually implies low pressure at the tip. Most HVLP guns that I've
used usually worked best when set around 30 psi. (Some older style conversion guns required higher working pressure, I haven't
used these)Using a mini regulator and filter at the gun you can forget about the hose length etc. pressure
is tweaked just a little to get a proper flow. That said I've always found spraying waterborne with this kind of setup to be problematic.
Viscosity for good flowout seems to be always too near the threshold of runs and sags. gaah I always have good results tho when using a Fuji turbine system. I think I'm saying what Alex said. A completely airless system is even nicer for the water based stuff.
At present I use nitro with a jamb gun to spray my guitars, enough left to do two instruments. When that's gone I'm gonna switch to General EV and the Fuji setup. My point again though, is that spraying waterborne with an air system isn't easy and requires a fair bit of
experimentation. IMO
Ken
Author:  Clay S. [ Sun May 27, 2018 7:39 pm ]
Post subject:  Re: water based lacquer atomization issues
O.P. wrote:
"I've been using this water based lacquer called Brite-tone and I'm getting horrible atomization. The lacquer comes out kind of globby and dries to a very pronounced orange peel."

One reason HVLP and waterbourne finishes give you a better transfer rate is they generally don't have as fine an atomization as solvent based materials in high pressure guns. Less in the air, more on the work.
Author:  Conor_Searl [ Sun May 27, 2018 9:24 pm ]
Post subject:  Re: water based lacquer atomization issues
Talking with some cabinet makers I'm friends with they've talked about how water based lacquer can be a lot more finnicky to work with than other products, but since I don't really have a dedicated spray booth, and lots of kids around I like the lack of fumes. I can even brush this stuff on in the house and the fumes are barely noticeable. Even though the learning curve seems to be steeper with this stuff I like that it is more friendly to the environment, and it seems like I might as well learn on this stuff since the regulations around other finishes keep getting steeper.

Here's a couple pictures of what I ended up with.

If nothing else my sanding skills are increasing... :D
Author:  johnparchem [ Sun May 27, 2018 9:56 pm ]
Post subject:  Re: water based lacquer atomization issues
I spray Em6000 a bunch and it both atomizes nicly and levels with a 3-5 mill wet coat. However I need to pull my gun apart and clean it between each spray session even though I am spraying every hour. Otherwise I get the sort of spitting I see on you guitar. I believe the with water based lacquer it is not dissolved in the water like lacquer is dissolved in the solvent rather there are some relatively large bits of lacquer suspended that bond to each other when the water goes away. You will really quickly get a build up of gunk in bunches of places that make the gun not work very well if you let the gun sit.

I run a little water through the gun. A little alcohol through and then I pull the gun apart and make sure everything is clean, like the little air holes on the gun or even a small blob on the tip.

I do have a gauge right on the gun so I know the pressure at the gun while I am spraying.
Author:  Conor_Searl [ Sun May 27, 2018 11:42 pm ]
Post subject:  Re: water based lacquer atomization issues
johnparchem wrote:
I spray Em6000 a bunch and it both atomizes nicly and levels with a 3-5 mill wet coat. However I need to pull my gun apart and clean it between each spray session even though I am spraying every hour. Otherwise I get the sort of spitting I see on you guitar. I believe the with water based lacquer it is not dissolved in the water like lacquer is dissolved in the solvent rather there are some relatively large bits of lacquer suspended that bond to each other when the water goes away. You will really quickly get a build up of gunk in bunches of places that make the gun not work very well if you let the gun sit.

I run a little water through the gun. A little alcohol through and then I pull the gun apart and make sure everything is clean, like the little air holes on the gun or even a small blob on the tip.

I do have a gauge right on the gun so I know the pressure at the gun while I am spraying.


You know what this may be it. I do try and thoroughly clean the gun at the end of the day, but some days I'm more thorough than others, and I do let it sit throughout the day while I wait for a coat to tack up.

Will lacquer thinner work to clean the gun? I don't have any alcohol at home, but I do have lacquer thinner.
Author:  B. Howard [ Mon May 28, 2018 5:59 am ]
Post subject:  Re: water based lacquer atomization issues
Yes WB finishes are trickier to spray, especially in the land of cabinets where no buffing is done and an off the gun finish is mandatory. That is a big difference between the rest of the wood finishing world and us, they do not cut and buff.

I do agree that the spray pattern looks a lot like a dirty gun but it could still be other things.... We have a darker color here so something that may apply is surface temp. If you have lots of lighting, especially halogen lamps or out in the noon sun that could be raising the surface temp and drying the coating before it has a chance to flow. Atomization is only half of the equation, the other is how much the coating flows before it freezes. In traditional lacquer work this is where different evap rates of solvents comes in and can apply here. You mentioned using the "proper" reducer, What was that?
Author:  Conor_Searl [ Mon May 28, 2018 11:28 am ]
Post subject:  Re: water based lacquer atomization issues
B. Howard wrote:
I do agree that the spray pattern looks a lot like a dirty gun but it could still be other things.... We have a darker color here so something that may apply is surface temp. If you have lots of lighting, especially halogen lamps or out in the noon sun that could be raising the surface temp and drying the coating before it has a chance to flow. Atomization is only half of the equation, the other is how much the coating flows before it freezes. In traditional lacquer work this is where different evap rates of solvents comes in and can apply here. You mentioned using the "proper" reducer, What was that?


I sprayed in my garage, the lighting is okay but it's not super bright. There is one overhead light on the garage door opener, and then one flourescent light on the back wall over the work bench, plus I left the garage door open to let in other light and let any fumes escape. It wasn't a particularly warm day, so I don't think surface temperature would come into play causing the lacquer to set up too quickly.

The reducer I used was specific Brite-tone reducer I bought at the same time and from the same place I bought the Brite-tone lacquer. The can recommends anywhere between redcution of 1% - 10%.

After reading some of the other posts here, I realize I really need a regulator/pressure guage at my gun to ensure that I have enough pressure, and also that my cleaning regimen is probably too lax. I'll try these things this weekend and see if I get different results.

Thanks everyone.
Author:  Alex Kleon [ Mon May 28, 2018 12:27 pm ]
Post subject:  Re: water based lacquer atomization issues
Something that I would suggest is to always filter your finish into a clean glass container - just enough for the spay session at hand - and never pour what's left in the gun back into the original can. This will help avoid contamination.

Alex
Author:  StevenWheeler [ Mon May 28, 2018 5:16 pm ]
Post subject:  Re: water based lacquer atomization issues
Wow Conor, that is a rough finish. Curious as to what you used to color the wood.

Steve
Author:  Conor_Searl [ Mon May 28, 2018 5:41 pm ]
Post subject:  Re: water based lacquer atomization issues
StevenWheeler wrote:
Wow Conor, that is a rough finish. Curious as to what you used to color the wood.

Steve


Yes, not what I was hoping for...

To color the wood I mixed some blue dye (made by color fx) and water. Wiped it on and sanded it back a bit. I was going for a faded denim kind of look...

I'm happy with the color, but not so much with my orange peel-y clear coat.
Author:  Freeman [ Mon May 28, 2018 6:06 pm ]
Post subject:  Re: water based lacquer atomization issues
Conor, you are doing something very wrong.

First, make you gun scrupulously clean and clean it every time you use it. I've heard of people leaving finish in during the day between coats. I don't. With waterborn finish (KTM-9) I empty the gun, take it all apart and wash it in warm soapy water, put it together, fill the cup half full of DA and shoot some thru the nozzle. I leave the alcohol in the cup, when I'm ready for the next coat I shoot some of it out making sure the pattern is good and the gun is working correctly. I often mist a coat of alcohol on the guitar, that seems to help with eliminating witness lines. Mist the guitar, dump the DA in a container and pour the KTM in the cup.

As I said before, I reduce the finish with DA, and it is often more than 10% - maybe up to a quarter. I have a regulator at the compressor, I think its set for 40 psi, then a water filter, my hose (maybe 15 or so feet) a regulator and gauge at the gun. I haven't shoot KTM in a while so I'm not going to quote a pressure (30 comes to mind but I could be very wrong) - I just adjusted it until the pattern looks good.

The finish goes on wet and smooth, seems to get a slight bluish cast, then clears as it cures. I do three coats a day usually, sand between coats to 320 or so and mist before the next group of coats. I tried making a paint booth out of cardboard and hanging my guitars but I prefer to put them flat on a stool and walk around. That means I often shoot top and back on alternate days. With an electric I put little blocks of wood in the pickup cavities with double backed tape, I'll shoot the top and head, then very carefully tip it over and set it on the blocks so I can do the back and neck. Here is a page from a LP build thread where I'm doing the basic finish - nothing special but the results are nice

http://www.harmonycentral.com/forum/for ... 33-/page11

http://www.harmonycentral.com/forum/for ... 33-/page13

http://www.harmonycentral.com/forum/for ... 33-/page15

I know nothing of your product but just for laughs try shooting a really wet coat (3 or 4:1 of your reducer or alcohol) with the guitar laying flat
Author:  StevenWheeler [ Mon May 28, 2018 6:52 pm ]
Post subject:  Re: water based lacquer atomization issues
Conor_Searl wrote:
To color the wood I mixed some blue dye (made by color fx) and water.


Just checking, the last time I saw one that bad the customer stained the wood with oil based and shot water based clear over the top. Needless to say, a complete lack of adhesion. I stripped the clear with masking tape and re-sprayed it with nitro.
Keep us posted as you figure this out.

Steve
Author:  Conor_Searl [ Mon May 28, 2018 10:27 pm ]
Post subject:  Re: water based lacquer atomization issues
Freeman wrote:
Conor, you are doing something very wrong.

First, make you gun scrupulously clean and clean it every time you use it. I've heard of people leaving finish in during the day between coats. I don't. With waterborn finish (KTM-9) I empty the gun, take it all apart and wash it in warm soapy water, put it together, fill the cup half full of DA and shoot some thru the nozzle. I leave the alcohol in the cup, when I'm ready for the next coat I shoot some of it out making sure the pattern is good and the gun is working correctly. I often mist a coat of alcohol on the guitar, that seems to help with eliminating witness lines. Mist the guitar, dump the DA in a container and pour the KTM in the cup.

As I said before, I reduce the finish with DA, and it is often more than 10% - maybe up to a quarter. I have a regulator at the compressor, I think its set for 40 psi, then a water filter, my hose (maybe 15 or so feet) a regulator and gauge at the gun. I haven't shoot KTM in a while so I'm not going to quote a pressure (30 comes to mind but I could be very wrong) - I just adjusted it until the pattern looks good.

The finish goes on wet and smooth, seems to get a slight bluish cast, then clears as it cures. I do three coats a day usually, sand between coats to 320 or so and mist before the next group of coats. I tried making a paint booth out of cardboard and hanging my guitars but I prefer to put them flat on a stool and walk around. That means I often shoot top and back on alternate days. With an electric I put little blocks of wood in the pickup cavities with double backed tape, I'll shoot the top and head, then very carefully tip it over and set it on the blocks so I can do the back and neck. Here is a page from a LP build thread where I'm doing the basic finish - nothing special but the results are nice

http://www.harmonycentral.com/forum/for ... 33-/page11

http://www.harmonycentral.com/forum/for ... 33-/page13

http://www.harmonycentral.com/forum/for ... 33-/page15

I know nothing of your product but just for laughs try shooting a really wet coat (3 or 4:1 of your reducer or alcohol) with the guitar laying flat


Yes, after reading many of the responses it seems the way I clean the gun is not thorough enough. I will often spray a coat and hang the gun on the wall while I wait 45 minutes to shoot the next. I'll peel a gummy bit of finish off the tip before spraying again. I never even thought that if the tip was gumming up everything else probably is too. I've probably only sprayed 5 or 6 guitars since I bought this gun and its never been this bad before, but my clogged dirty gun has obviously gotten progressively worse over time.

I have had success in the past, and haven't had any witness line issues with this finish. From what I understand subsequent coats will burn into previous ones much like nitro does. It also doesn't seem to go blue on dark colors like I've heard some other water born finishes will.

I like to lay the guitars flat too Freeman, I tried hanging them but when this finish is working well for me it likes to sag. I like the wood block idea, I've just used longish finishing nails in the pickup cavities. I also never thought about waiting till the next day to do the back, I'll lay the guitar on it's back, spray the front, and then flip it over onto the nails to do the back and sides.
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