Spraying problems

[John Reeves]

Help please.

I am still trying to spray high gloss water base black paint over primer using a HVLP. Paint has been cut 25% with Lestroll. Paint glow is up all the way and are is up all the way.

I am getting a lot of splattering creating an uneven surface and some bubbles.

 

[wayne]

What kind of air system do you have, give us some details, size hose,length of hose, type compressor,probibly don't have sufficent air supply for the hvlp gun would be my first guess. Hvlp systems need 3/8 minimum hose with the fittings sized for hvlp there is a differance.The key factor is volume of air at the gun not amount of pressure.

 

[dozer]

Well I would have to say you need a bigger needle for the gun. it is pigment strands that are caused by lack of volume flow. Flowtrol won't help all that much as far as thinning the pint down due to it being black pint the pigment is really heavy. Try 3oz of warm water to every 12oz of paint if it is still to thick add 1/2 oz of water at a time until you get the flow of the paint thin enough to eliminate the pigment splatter you are getting.

Send me a pm if you have anymore questions I will be glad to help you out.

 

[Alan in Little Washington]

Is that water based Latex you are shooting? While HVLP guns are supposed to handle stuff that thick, I don't know of many people who successfully do that. What size fluid tip and aircap are you using? I would continue with Flowtrol and try a little warm water as Dozer says. Actually if you warm the who mix that can help. Also, HVLP needs a lot of air- large air hose (min 3/8" id) with good flow to the gun. I use a short hose from the regulator. Also it doesn't do any good to have 3/8" hose if you have a lot of 1/4" fittings everywhere and a filter/regulator that can't provide the volume you need.

All that being said, I have a cabinet maker friend who does a lot of white cabinets. He doesn't use his HVLP, but instead uses an airless sprayer for shooting acrylic latex. He uses a standard Graco, the kind you would use for painting a house, and gets super finishes that rival what you can get with an HVLP applied lacquer finish.

 

[John Reeves]

My air supply is a 1/4" hose from a 30 gal Craftsman compressor. The regulator is get to 90psi the compressor pumps the tank up to 140psi.

The nozzle is 1.4mm. The manufacturer calls for a 1.5mm nozzle as written on the paint can.

I have a 2.0 mm nozzle that I can use. Just came today. I am planning to wait a day or two before I put more paint on.

 

[wayne]

You need a 3/8 hose and fittings on the gun, hose and regulator intended for hvlp usage before you worry about the rest. After you get your air supply setup properly then work on proper settings at the gun IE=material and spray pattern if you use the larger nozzle you need run the fluid needle adjustment in most of the way and while spraying on a practice panel adjust it out to where you feel confortible with the pattern and flow of paint. Don't try to get coverage with 1 or 2 heavy coats, build your coverage up with mutible light coats while letting the previous coats flash off sufficent before applying next coat. If its drying slowly and you have a couple Halogen lights rig them up over the table so the heat they put off can dry the paint. Halogen lights put off a lot of heat and make good heat lamps for drying waterbourne paints, just don't get them to close, you want to help the paint flash off not cook it.:lol: Hope this helps. I'm sure others will offer good advice also

wayne

 

[dave_the_woodworker]

What is the viscosity of the paint? It needs to be matched to the needle/nose that you are using in the gun. Without knowing what it is you're just shooting in the dark when you add Flowtrol and/or water. From your description, I would guess that the viscosity of your paint is too high (paint is too thick for the gun setup). Viscosity cups are just a few bucks and usually come with spray equipment. You should be able to pick one up at any good paint store.

 

[ToeNailer]

John....I have a very similar gun and used the Behr recently. I used a 1.7mm nozel/pin set up. I think the 2.0 should work.
I also stopped using the small 'auxillary' screens and just siphoned my mix w/ a strainer.

Good luck.


Jim

 

[John Reeves]

Today I cut the paint by 25%, 8 oz of paint included 2 oz of water. I turned up the air and started from no paint, valve closed. I opened the paint until I got a decent coverage with good atomization. I got pretty good results. The water reduces the glossy finish but all in all it is smooth.

After a day or so, I will smooth with 0000 wool and try another coat of paint.

Thanks all.