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Recommendations for Viscosity cup for HVLP spraying
I am admittedly a newbie to HVLP...
I have read that a viscosity cup is useful (if not necessary) in order to select the right nozzle size and to know how much to thin the liquid being sprayed. Googling I saw Ford and Zahn viscosity cups of various sizes... which left me confused about what type of cup I would want for "run of the mill" HVLP spraying where I might want to spray anything from shellac to lacquer to poly (oil or water) to latex paint... Could someone point me in the direction of what cup (or cups) I might want to get for such purpose? Also any recommendations for specific cups or brands? Thanks! |
Recommendations for Viscosity cup for HVLP spraying
On Nov 22, 1:21*am, blueman wrote:
I am admittedly a newbie to HVLP... I have read that a viscosity cup is useful (if not necessary) in order to select the right nozzle size and to know how much to thin the liquid being sprayed. Googling I saw Ford and Zahn viscosity cups of various sizes... which left me confused about what type of cup I would want for "run of the mill" HVLP spraying where I might want to spray anything from shellac to lacquer to poly (oil or water) to latex paint... Could someone point me in the direction of what cup (or cups) I might want to get for such purpose? Also any recommendations for specific cups or brands? Thanks! First, spraying shellac from an HVLP rig is suicide. You can get the finish out of the gun, but keeping it clean during a shoot and cleaning it afterward is a huge, time consuming waste. I would look at a a CAS gun or an old high pressure rig to do that. Second, there is a lot of information on this group starting years ago about HVLP spraying, gun set up, etc. You can easily search this group from he http://groups.google.com/group/rec.woodworking/topics I have had several Ford cups, and have never used any of them. Why? Because every gun shoots differently the way you set up your spray rig will change that even more. Ford cups are made to provide guidelines for spraying, not parameters set in stone. The only exception to that would be folks that shoot high end finishes in a controlled environment such as upper end car finishers, airplane finishers, chemical coating specialists, etc. where all other aspects of the application environment is controlled. The Ford cup and its brothers are simply one more thing to learn. The Ford cup only measures viscosity, nothing else. Not one other thing. So even if you have the material set up right, it won't help you with how that works with your tip (say a 1.3mm vs. a 1.5mm), your turbine (if a true HVLP) and how that output works with your gun. It is a guideline because in HVLP you throw droplets of material thinned for application, as opposed to material that was marginally thinned and "atomized" when shot out of a high pressure rig. The Ford cup is an artifact from a different type of material application. Your best bet (to me, always) is to buy the finishes you want to learn to shoot and experiment with your gun and thinning mixtures. Spent $50 on finish and thinner and mix up some sample batches of finish to shoot. Record time of day, temp, humidity, and of course, your mixture. If you have multiple tips, write that down along with the gun settings. If you are using a CAS gun, then write down the compressor psi settings at the compressor and at the gun. On my old Fuji gun it didn't have anything on the fluid knob except the knurling, so I took a three cornered file an put a notch in the knob at twelve o'clock for reference. That way I knew exactly what to record. After you spray enough, you will pick up the characteristics of the gun and the materials you shoot and will be able to use the equipment without too much fuss. So practice, practice, practice. Most of the time you can get good results right off the bat with today's finishes. But repeatable, great results are from learning the craft, no different from learning woodworking or brick laying. You have to invest the time and money. Robert |
Recommendations for Viscosity cup for HVLP spraying
On 11/22/2011 1:33 PM, wrote:
First, spraying shellac from an HVLP rig is suicide. Dead man walking here ... :) -- www.eWoodShop.com Last update: 4/15/2010 KarlCaillouet@ (the obvious) http://gplus.to/eWoodShop |
Recommendations for Viscosity cup for HVLP spraying
On Nov 22, 1:54*pm, Swingman wrote:
Dead man walking here ... *:) Still LMAO... That is either the bitter irony of experience, or a warning of an upcoming attempt... Or... could it be... success??? Robert |
Recommendations for Viscosity cup for HVLP spraying
On Nov 22, 3:45*pm, Swingman wrote:
Shellac's about all I spray, and always with an HVLP rig. ! ! ! ! ! Maybe time for my lesson, señor. I tried spraying shellac out of my Fuji four stage, and about halfway through a large kitchen of cabinets I had large icicle looking things coming out from around the fluid passage, just around the super fine air holes. I had been spraying for about 20 minutes straight and shot about quart and a half of material. I got splatter. I got ****ed off. I stopped, cleaned the gun, and it did the same thing. I had it on low pressure, and was spraying straight sanding sealer, so I the viscosity wasn't a problem. Someway, between me and my setup the shellac fired off too fast. I can't seem to get the mix right for my HVLP, and actually, not even close. It is exasperating, since I can easily spray BIN which is no more than a pigmented shellac. A call to the manufacturer of BIN was no help; they told me they had "proprietary conditioners" in the BIN mix that allowed me to spray it so easily. What makes that more maddening is that Zinsser makes both the shellac and BIN and they still couldn't help me. Oddly, I can easily shoot shellac out of a CAS gun, including when mixed down to sanding sealer cut, so I don't worry about it. But out of a true HVLP, it's voodoo to me. Until a year ago with an el cheapo ($150) Campbell-Hausfeld rig; now with an Earlex 5000 SprayStation ... still mid-level or below. I usw two cups: one filled with the shellac cut I'm spraying; the other filled with alcohol for gun storage between coats. Between coats I simply switch cups, slosh the alcohol around good and spray some through the gun. When I'm ready for the next coat, I simply switch out the cups. Now that sounds really simple. Suspiciously simple. Any offerings to those Cajun folks in your heritage... maybe a chant or two you aren't sharing? =^0 If you would indulge me, how big are your spray projects? Are you spraying out enough material all at once to dump the gun? How big is your cup? What size air cap are you using, and what cut do you shoot? IIRC, the Earlex is a two stage unit, no? Are you controlling the air flow or are you wide out? Inquiring minds... I hate unsolved puzzles. TIA - Robert |
Recommendations for Viscosity cup for HVLP spraying
Reading your info, you appear to have a lot of experience.
What I don't understand is what am I doing wrong if I shoot with shellac successfully with an hvlp gun. I don't have a problem cleaning. Just throw alcohol thru, open the valves to throw a lot of alcohol thru and your done. I don't use brushes to clean, I just run it through. When I reload it melts any light coating that might be there. So what am I doing wrong? On 11/22/2011 2:33 PM, wrote: On Nov 22, 1:21 am, wrote: I am admittedly a newbie to HVLP... I have read that a viscosity cup is useful (if not necessary) in order to select the right nozzle size and to know how much to thin the liquid being sprayed. Googling I saw Ford and Zahn viscosity cups of various sizes... which left me confused about what type of cup I would want for "run of the mill" HVLP spraying where I might want to spray anything from shellac to lacquer to poly (oil or water) to latex paint... Could someone point me in the direction of what cup (or cups) I might want to get for such purpose? Also any recommendations for specific cups or brands? Thanks! First, spraying shellac from an HVLP rig is suicide. You can get the finish out of the gun, but keeping it clean during a shoot and cleaning it afterward is a huge, time consuming waste. I would look at a a CAS gun or an old high pressure rig to do that. Second, there is a lot of information on this group starting years ago about HVLP spraying, gun set up, etc. You can easily search this group from he http://groups.google.com/group/rec.woodworking/topics I have had several Ford cups, and have never used any of them. Why? Because every gun shoots differently the way you set up your spray rig will change that even more. Ford cups are made to provide guidelines for spraying, not parameters set in stone. The only exception to that would be folks that shoot high end finishes in a controlled environment such as upper end car finishers, airplane finishers, chemical coating specialists, etc. where all other aspects of the application environment is controlled. The Ford cup and its brothers are simply one more thing to learn. The Ford cup only measures viscosity, nothing else. Not one other thing. So even if you have the material set up right, it won't help you with how that works with your tip (say a 1.3mm vs. a 1.5mm), your turbine (if a true HVLP) and how that output works with your gun. It is a guideline because in HVLP you throw droplets of material thinned for application, as opposed to material that was marginally thinned and "atomized" when shot out of a high pressure rig. The Ford cup is an artifact from a different type of material application. Your best bet (to me, always) is to buy the finishes you want to learn to shoot and experiment with your gun and thinning mixtures. Spent $50 on finish and thinner and mix up some sample batches of finish to shoot. Record time of day, temp, humidity, and of course, your mixture. If you have multiple tips, write that down along with the gun settings. If you are using a CAS gun, then write down the compressor psi settings at the compressor and at the gun. On my old Fuji gun it didn't have anything on the fluid knob except the knurling, so I took a three cornered file an put a notch in the knob at twelve o'clock for reference. That way I knew exactly what to record. After you spray enough, you will pick up the characteristics of the gun and the materials you shoot and will be able to use the equipment without too much fuss. So practice, practice, practice. Most of the time you can get good results right off the bat with today's finishes. But repeatable, great results are from learning the craft, no different from learning woodworking or brick laying. You have to invest the time and money. Robert |
Recommendations for Viscosity cup for HVLP spraying
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Recommendations for Viscosity cup for HVLP spraying
On Nov 23, 1:01*pm, tiredofspam nospam.nospam.com wrote:
Reading your info, you appear to have a lot of experience. What I don't understand is what am I doing wrong if I shoot with shellac successfully with an hvlp *gun. I don't have a problem cleaning. Just throw alcohol thru, open the valves to throw a lot of alcohol thru and your done. I don't use brushes to clean, I just run it through. When I reload it melts any light coating that might be there. So what am I doing wrong? Obviously, if it all works for you, nothing. End results of finishing are subjective, and if you are happy with your results and method of application, don't change anything. FOR ME, shellac didn't get it done. I am not sure if I spray too long (literally spraying out a quart cup before stopping), or of when spraying cabinets the blowback didn't contribute to my unsuccessful attempts. Maybe it was all of that. I did that when I thought priming was necessary. Now I spot prime only, and use the finish material as a primer and top coat as recommended by better finishers than me. No problems since. That doesn't mean I am not still puzzled and annoyed by my lack of ability to solve the problem. To me, I should be able to spray a solid 30 minutes and blow out a couple of quarts before I have to worry about any material's behavior. I have seen Karl's work ( da Swinger ) up close and personal, and his quality of work and and scope of projects are just about as good as it gets. He is the shellac master, no doubt. His projects (and Leon's too, by the way) tell their own story of their mastery of wood craft and finishing. Karl has long been a fan of bug spit, way back to O'Deen's days here. But, me and shellac don't see eye to eye anyway. I tend to think in commercial terms, and that means hard finishes that don't need any kind of maintenance. Shellac isn't abrasion resistant, is provides no color protection, it isn't cleanable except with a damp rag, it isn't heat resistant, and provides little water resistance. While many tout its ability for easy repair if damaged, it won't be so easy if you are using a tinted shellac, shellac that is naturally colored (orange, amber, etc.) or shellac over stain. Shellac will bond with the stain in most cases, and pull up the color with the finish. Good luck matching that! Of course, clear shellac is a snap to repair unless it is on some old antique which you shouldn't be refinishing anyway. Seriously, there aren't many hard fast rules to finishing. I have said it before and will repeat it, most folks learn finishing by folklore. They will try something traded in idle conversation with someone at Woodcraft on a Saturday sale before they will sit down and research out the process for themselves. So if your processes and materials are working and you like your end result, don't change. You have reached the goal! Robert |
Recommendations for Viscosity cup for HVLP spraying
On 11/23/2011 12:25 AM, wrote:
Now that sounds really simple. Suspiciously simple. Any offerings to those Cajun folks in your heritage... maybe a chant or two you aren't sharing? =^0 If you would indulge me, how big are your spray projects? Are you spraying out enough material all at once to dump the gun? How big is your cup? What size air cap are you using, and what cut do you shoot? IIRC, the Earlex is a two stage unit, no? Are you controlling the air flow or are you wide out? Inquiring minds... I hate unsolved puzzles. Came in late, worked hard ... give me until sometime Friday and I'll address this. Going to lick a wet dog now ... -- www.eWoodShop.com Last update: 4/15/2010 KarlCaillouet@ (the obvious) http://gplus.to/eWoodShop |
Recommendations for Viscosity cup for HVLP spraying
tiredofspam wrote:
Reading your info, you appear to have a lot of experience. What I don't understand is what am I doing wrong if I shoot with shellac successfully with an hvlp gun. I don't have a problem cleaning. Just throw alcohol thru, open the valves to throw a lot of alcohol thru and your done. I don't use brushes to clean, I just run it through. When I reload it melts any light coating that might be there. So what am I doing wrong? Apparently - nothing. Some materials like shellac may well clean well - in some guns, just by shooting the respective solvent through them. Other materials will come back to bite you in the ass with that technique. Catalytic finishes won't be as nice to your gun, if you ever take up shooting those. Back in the day when lacquer was king, a lot of guys used to just shoot lacquer thinner through their gun to clean it, and all was well - for a while. Like your experience, if there was anything left in the gun, the next time you used it, the residue would blow out as the new material burned into it. Sorta... Stuff built up over time and eventually the gun started misbehaving. So, ya stripped it down, soaked it in thinner or carb cleaner for a couple of days, and went at it with brushes and picks. Royal PITA. Maybe you won't hit this point with shellac (I don't shoot it, so I don't really know how it behaves), and maybe your gun will tolerate more build up than another gun will. If so - good for you! If however, you begin to see your gun behaving erratically, or in an unfamiliar way, the first place you might want to consider looking is at build up. -- -Mike- |
Recommendations for Viscosity cup for HVLP spraying
On 11/23/2011 12:25 AM, wrote:
If you would indulge me, how big are your spray projects? Are you spraying out enough material all at once to dump the gun? How big is your cup? Not all that big ... this is about as big as they get: https://picasaweb.google.com/1113554...TexasTansu2005 Mostly furniture sized projects ... I leave the kitchens, and most of the client's who want a lacquer finish, to the pro's ... but I do spray all my personal projects. What size air cap are you using, and what cut do you shoot? I generally shoot shellac with 2.0mm air cap and a 1 1/2 -2# cut, but don't get real fussy measuring. I do get fussy about the humidity and which alcohol I'm using when it's high (99% isopropyl), otherwise I just use denatured from the Borg. IIRC, the Earlex is a two stage unit, no? Are you controlling the air flow or are you wide out? Just turn her on let'r rip. Inquiring minds... I hate unsolved puzzles. When it comes to spray finishing I operate on the "ignorance is bliss" principle (the less I know the less I have to fuss with settings and the less I'm befuddled) ... I turn it on, adjust for the pattern I want, adjust the material flow and distance (on a piece of scrap) to my suiting, and wave away (using my politically correct, well practiced waving method, which apparently also has the pope's blessing because it comes out good ... AAMOF, I no longer feel I need to say a rosary before pulling the trigger!) Dood!, I'm a simple man ... no complications please! -- www.eWoodShop.com Last update: 4/15/2010 KarlCaillouet@ (the obvious) http://gplus.to/eWoodShop |
Recommendations for Viscosity cup for HVLP spraying
On Thu, 24 Nov 2011 10:52:02 -0600, Swingman wrote:
On 11/23/2011 12:25 AM, wrote: If you would indulge me, how big are your spray projects? Are you spraying out enough material all at once to dump the gun? How big is your cup? Not all that big ... this is about as big as they get: https://picasaweb.google.com/1113554...TexasTansu2005 Oh, the BeigeSu project. Mostly furniture sized projects ... I leave the kitchens, and most of the client's who want a lacquer finish, to the pro's ... but I do spray all my personal projects. Smart man. IIRC, the Earlex is a two stage unit, no? Are you controlling the air flow or are you wide out? Just turn her on let'r rip. VERY cool. Inquiring minds... I hate unsolved puzzles. When it comes to spray finishing I operate on the "ignorance is bliss" principle (the less I know the less I have to fuss with settings and the less I'm befuddled) ... I turn it on, adjust for the pattern I want, adjust the material flow and distance (on a piece of scrap) to my suiting, and wave away (using my politically correct, well practiced waving method, which apparently also has the pope's blessing because it comes out good ... AAMOF, I no longer feel I need to say a rosary before pulling the trigger!) Dood!, I'm a simple man ... no complications please! KISS has a very large following here, too. -- Happiness is not a station you arrive at, but a manner of traveling. -- Margaret Lee Runbeck |
Recommendations for Viscosity cup for HVLP spraying
I do agree if it works you have reached your result.
I think you missed one of the amazing things about Shellac. It pops the wood. Better than most other forms of finish. BTW I also french polish, so I am not limited to spraying it. I love it for its ease of use, no VOCs. I wish I had the HVLP when I used to spray Imron. I still have my scott airpac style respirator. On 11/23/2011 2:56 PM, wrote: On Nov 23, 1:01 pm, tiredofspamnospam.nospam.com wrote: Reading your info, you appear to have a lot of experience. What I don't understand is what am I doing wrong if I shoot with shellac successfully with an hvlp gun. I don't have a problem cleaning. Just throw alcohol thru, open the valves to throw a lot of alcohol thru and your done. I don't use brushes to clean, I just run it through. When I reload it melts any light coating that might be there. So what am I doing wrong? Obviously, if it all works for you, nothing. End results of finishing are subjective, and if you are happy with your results and method of application, don't change anything. FOR ME, shellac didn't get it done. I am not sure if I spray too long (literally spraying out a quart cup before stopping), or of when spraying cabinets the blowback didn't contribute to my unsuccessful attempts. Maybe it was all of that. I did that when I thought priming was necessary. Now I spot prime only, and use the finish material as a primer and top coat as recommended by better finishers than me. No problems since. That doesn't mean I am not still puzzled and annoyed by my lack of ability to solve the problem. To me, I should be able to spray a solid 30 minutes and blow out a couple of quarts before I have to worry about any material's behavior. I have seen Karl's work ( da Swinger ) up close and personal, and his quality of work and and scope of projects are just about as good as it gets. He is the shellac master, no doubt. His projects (and Leon's too, by the way) tell their own story of their mastery of wood craft and finishing. Karl has long been a fan of bug spit, way back to O'Deen's days here. But, me and shellac don't see eye to eye anyway. I tend to think in commercial terms, and that means hard finishes that don't need any kind of maintenance. Shellac isn't abrasion resistant, is provides no color protection, it isn't cleanable except with a damp rag, it isn't heat resistant, and provides little water resistance. While many tout its ability for easy repair if damaged, it won't be so easy if you are using a tinted shellac, shellac that is naturally colored (orange, amber, etc.) or shellac over stain. Shellac will bond with the stain in most cases, and pull up the color with the finish. Good luck matching that! Of course, clear shellac is a snap to repair unless it is on some old antique which you shouldn't be refinishing anyway. Seriously, there aren't many hard fast rules to finishing. I have said it before and will repeat it, most folks learn finishing by folklore. They will try something traded in idle conversation with someone at Woodcraft on a Saturday sale before they will sit down and research out the process for themselves. So if your processes and materials are working and you like your end result, don't change. You have reached the goal! Robert |
Recommendations for Viscosity cup for HVLP spraying
On Nov 24, 10:52*am, Swingman wrote:
* *What size air cap are you using, and what cut do you shoot? I generally shoot shellac with 2.0mm air cap and a 1 1/2 -2# cut, but don't get real fussy measuring. I don't know if you are still following this Karl, but I have been away on bidness that couldn't wait. So.... a 2mm aircap, eh? The one specified for latex, and heavy paints? I would never have tried that. Literally, never. Sometimes I do great thinking out of the box, and as in this example, I just don't. I do get fussy about the humidity and which alcohol I'm using when it's high (99% isopropyl), otherwise I just use denatured from the Borg. * *IIRC, the Earlex is a two stage unit, no? *Are you controlling the air flow or are you wide out? Just turn her on let'r rip. Sometimes, that's the best way. When it comes to spray finishing I operate on the "ignorance is bliss" principle (the less I know the less I have to fuss with settings and the less I'm befuddled) ... I always like the process to be as simple as possible. That's why I try new finishes. The easier the application and more dependable the outcome is for me determines if I will learn to use it. I turn it on, adjust for the pattern I want, adjust the material flow and distance (on a piece of scrap) to my suiting, and wave away (using my politically correct, well practiced waving method, which apparently also has the pope's blessing because it comes out good ... AAMOF, I no longer feel I need to say a rosary before pulling the trigger!) Indeed... I have seen the work. Excellent work, excellent finish on it. I bow to the shellac master. :^) Thanks for the follow up. Robert |
Recommendations for Viscosity cup for HVLP spraying
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Recommendations for Viscosity cup for HVLP spraying
On Dec 1, 2:02*pm, "Mike Marlow" wrote:
Correction - shellacChicken Coop master Yep - sprayin' bug spit isn't the only thing he is good at! What a coop... !! Robert |
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