What are you guys using to check the viscosity of latex paint, poly, etc when spraying with a HVLP? It’s a shot in the dark right now with me.
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Do you own a Zahn Viscosity cup? If so, a drip every few seconds oughtta be right, but it depends on the guns cap and needle size, and the CFM/Pressure you are running.
" I press my lips against her name"
I don't own a viscosity cup Zahn or any, never used one. I am going to have to spray tomorrow so I'll have to use the "stir stick drip" or "pattern" method mentioned. I'll look into the cup.
If you use flotrol does that reduce the need for water to thin the latex? I made a viscosity cup out of a ladle - at least I can get some consistency. We drilled a 1/8 in hole in it and timed it down to a certain level. By the way, do any of you guys hook up a little hose to the cap over the paint? Mine has the fitting there - I don't have any supply fitting available. Is it good or a problem?
First..most Latex PAINT is not meant to be thinned. Esp w/ water. Flo-Trol in small amounts is OK, depends on the paint manu. (I did this for a living once). And Latex is broad term.
Second, your HVLP is ??????????????
There is a Zahn Cup and Ford cup...both resemble a funnel, with an aperature for the desired finish, auto industry and Emeron type heavy bodied laquers, want a Ford cup ( but this is not written in stone...conventional sprayers like Binks, can be adjusted, or regulated by either standard)..your call
4 OZ of finish, with an aperature of SAY and 1/8" will give you two things...specific gravity of the fluid, and flow rate...which will translate to atomization ability..
I suggest reading a book by Michael Dresdner ( who was a contributing author to FWW, for many Yrs) and is titled "Just Finishing"....
He is also one of the foremost inventors of WB ( water based) finishes..as was I under his tuteldge. Sorry I don't know what LATEX you are referring to, but MOST hate HVLP, or vice versa.
You do know that your guns guts must be stainless steel, right?
You do know that HVLP adds hot air to the mix right?
You do know that a clean gun is most important, right?
You do know that an air comp. supplied air ( conversion) needs an oil seperater?
Get back to me if ya need more help.......
That little hose is a problem..I need to know what kinda gun ya got, sounds like a siphon feed, mishooked to a HVLP, the hose as you call it, should run from the cup cover to the handle.Inmate # 40735 At Taunton Federal Penitentiary.
Do you remember the seconds for a #2 Zahn or #4 Ford cup for spray viscosity?
Water soluable and such products were just being developed when I left the product development lab back in 76. I worked in genral industrial, coil coating, and appliance labs, but my speciality became insturmental color matching.
For some reason 15-20 seconds,#2 Zahn sticks in my mind for spray products. That is reduced viscosity, not ship vicosity.
You stimulated some pretty old brain cells with the Zahn, Ford nomenclature :-)
Dave
Old cells is right..I was thinking it was a #4 Zahn..
yup..30 seconds seems to stick in my head, for the Hydrocote Water based Poly we were working on, but to this day, I do the stir stick test,,,pull the stick, and wait from steady stream to change to drop lets, and go from there.Inmate # 40735 At Taunton Federal Penitentiary.
Zahn and Ford cups come in a whole bunch of flavors. I member #4 Ford from the general industrial lab where we did spray, dip and flow coatings. The #2 Zahn was maybe a coil coating thing, where we did drawdowns on panels.
I'll do a search and see what I can find.
http://www.finishsystems.com
Dave
Edited 3/22/2007 10:38 am ET by DaveRicheson
Ok, I need to schedule several sessions. I don't have a pic handy right now of this gun I bought on Ebay. The plastic cup is above the sprayer. There is a little hose fitting on the cup lid but no place to install air to it. I have it hooked to a normal compressor with a water filter. I have a regulator on the gun handle and run at about 35. Yesterday I thinned the primer with water and sprayed the doors on a spinner, then two coats of finish thinned with water and flotrol added. I have pics of the spinners using 4 in cement screws - first time on that, working good.
Ok, I found a gun like mine:
From what I can see, it looks like a SATA conversion gun.
Go to http://www.homesteadfinishing.com and check their catalouge and you might find it.
You have a gravity feed cup gun..I am sorry, but I have zero exp. with that. I like siphon/suction feed and the lower center of weight..
Is your gun a bleeder? I mean does air play out continuosly? and material flow on trigger actuation?
I think you need to just keep on exp. with what ya got..but 35 air, ain't my idea of LP. You want to get to about <10 PSI and +30 CFM...if the air ain't getting warm, you have too much pressuer.
Wait, I an still in Turbine mode..nix that.Inmate # 40735 At Taunton Federal Penitentiary.
Ok thanks for the slant on more/less air. I tend to be in the "more is better" mode. It worked pretty good today. I will be spraying another coat on 6 doors tomorrow, and I'll try the lower pressure.
I think ya want an air cap that measures .035, the one installed with the gun may have been the .022, which is fine for general lac. But heavy bodied paint needs the larger size oriface to atomize properly..thats why you are bumping up the pressure too much.Inmate # 40735 At Taunton Federal Penitentiary.
Sphere,
Hey, it went 10 times better today. I think I found something. Take the little screen filter out. Pattern was great, etc - it never coughed all day once. I had already strained the paint anyway - can't believe how much better it worked. In the instructions it mentions about 5 optional orifices.
Good deal, I knew you could outsmart it.Inmate # 40735 At Taunton Federal Penitentiary.
I always use a vicosity cup w/my Fuji for the first canister full. Then I just pour in the same amt of thinner for every batch and adjust accordingly after.
I did a bus load of fences last fall...a gazillion spindles and rails and posts..I found it better to make it a hair thinner and do more coats if necessary.My first coats were all oil primer. That went on a lot easier than the latex top coats..I did change the atomizer for each cuz you have/should to really. Depends what kind of job youre doing..if its cabs/funature than its more critcal than fences.
I didn't find that Flotrol thins..I found it just conditions. Thinner and water thins.
http://WWW.CLIFFORDRENOVATIONS.COM
I forgot to answer the question on the bleeder. It's two stage. It doesn't do anything with no trigger action. Half trigger it blows air.
Sounds like a pressure feed to the cup. Hard to use a siphon gun with thick stuff. Look at your manual and see if you have a fitting on the gun handle. You need a anti siphon valve on that line too...
I tried using a cup but wound up just basing it on the coat on a test piece.
Same here..LOL
Or just watch the stir stick drips.Inmate # 40735 At Taunton Federal Penitentiary.
Depends on if yo're using a pressurre cup or pot, or just straight siphon in a conversion gun. Pot at 10-20 PSI, compressor at 70 PSI, gun at 32 PSI with a 2.5mm tip is what I use on my two Asturos.
I don't know anything about the fan-type HVLP units, but when spraying laytex or acrylic, I usually thin about 10-15%, mix well, then watch the stream as it comes out of the strainer funnel. Kind of an eye thing. Temp can make a big difference in the thicker material. I try not to spray below 55 degrees.
http://www.furniturefinishwizard.com/viscosityandwetmils.htm
That's a great link!