3 Stg Turbine HVLP w/ water based Urethane Enamel _ Satin Sheen

[andrew whicker]

Hi,

I'm painting w/ a Fuji 3 stage HVLP gun (first time user) on MDF. I bought some Satin Urethane Enamel (water based). I'm spraying it on MDF.

I have a 1.3, 1.5 and 1.8 tip. The 1.5 hasn't arrived yet. Yesterday I tried the first coat w/ 1.8 and thinned the paint to take about 30 seconds on the viscosity cup (about 4:1).

The paint went on pretty heavy (reminded me of airless) and when I sprayed vertically it had a few runs. Obviously, my technique is going to take some practice (speed, distance, fan size, etc). However, if I have "too thick" issues, should I be watering down the paint, reducing tip size or something else? The manual notes that w/ water based the needle should be all the way out to avoid confusion. According to the manual, it sounds like I'm not thinned out enough? I'm not sure when tip size comes into effect.

I'll be practicing more today.

Also, the satin sheen seemed to be matte when it dried. Is this generally a 1st coat on MDF issue or can I thin the paint "too much" and cause sheen issues?

[John TenEyck]

Who's Urethane Enamel? It might helpful to know. Are you using a Ford #4 viscosity cup or another type? 30 seconds on a #4 Ford cup would go well with a 1.3 mm N/N set, or even smaller, definitely not a 1.8 mm. That's what you might use for a viscosity near 100 seconds.

Hard to believe your manual says to have the needle all the way out for WB products. I'm not sure what that even means. Does it mean closed or wide open? In any case, the needle is adjustable for a reason, to adjust the flow for the best atomization possible with the chosen nozzle size. If the atomization is not good, speed, distance, fan size, aren't going to fix it.

If you thinned it 4 paint to 1 water, that's far too much, as the viscosity numbers show, assuming you used a Ford cup. If you have to thin more than 10%, at the most, then you need to use a larger N/N set. But in your case, again assuming you used a Ford cup, you want to thin it a lot less.

If the Urethane Enamel you are using is SW's Emerald Urethane Enamel Trim paint, I can tell you that it sprays great with my pressure assisted gun (which yours is, too) with a 1.3 mm N/N set and thinned 10%. If that's the paint you are using, those settings would be a good place to start. The objective is to get the best atomization possible with the chosen N/N set using the least amount of thinner. If that atomization isn't good enough for the finish quality needed, then you have to go to a smaller N/N set and thin it more.

John

[andrew whicker]

This is extremely helpful. Thank you so much

[andrew whicker]

And yes, it is SW' Emerald product you mentioned.

I re-read the manual and it states a special method for LATEX paints because apparently these weren't meant to be HVLP sprayed. That's fine. I don't want to be a house painter anytime soon.

I do have a #4 cup that came w/ the package. (Fuji Minimite 3 w/ T gun). I did a little more practice last night and am getting better. I also came across this article and now I think I may actually understand how to go about getting the atomization right, between your response and the article!

whew. Looking forward to trying again today. The 1.3 tip and thicker paint helped a lot!


Article: https://www.woodworkingnetwork.com/b...un-atomization

Manual: https://fujispraysystems.com/wp-cont...08-Digital.pdf

[Jim Becker]

Dialing in the gun for a particular finish is nearly at the "heart of the art", for sure! It's honestly one reason I have not been too adventuresome with trying a bunch of products. But one I have sprayed successfully is the Emerald Urethane trim enamel on that "scrap vanity" project awhile back. I'm using a different system than you, but it's still the same kind of challenge with setup.

[andrew whicker]

Does it always look a little orange peel when wet and you have to rely on the flattening of the paint?

[John TenEyck]

Does it always look a little orange peel when wet and you have to rely on the flattening of the paint?

That often is the case with some products, Andrew, but I can't remember if Emerald Urethane behaved that way for me or not. What I do remember is that it flowed out to a dead flat finish within a few minutes.

The air from a turbine gun gets warm, and that sometimes causes the atomized finish particles to set up too quickly, which can leave you with orange peel. You can try moving your gun closer to see if that helps. Another option is to add some of GF's or BM's Extender, which will increase the time it has to flow out. Another approach is to thin it more and go to a smaller N/N set, based on what the viscosity value is. Here's a screenshot from an article on Homestead Finishing's website about spraying paint. I use this chart as a starting point to determine which N/N set to use after I measure the viscosity. Your gun is pressure feed, so use that column, same as I use with my pressure assisted HVLP gun.

Keep at it. You'll get there soon.

John

[Dennis Jarchow]

if you don't have one already, get a wet film measuring gauge. Better paint stores have them, or you can order off amazon. https://www.amazon.com/82-479-Film-G...s%2C102&sr=8-6

Then practice on scrap laying down the wet film thickness the paint mfg. recommends. Looks like emerald is 4 mils per coat wet. Getting it on too thick can cause orange peel, or runs as you experienced. Too thin and it might not flow out well or feel rough.

[andrew whicker]

Thanks much. I thought about this and never followed up. I'll see if Sherwin Williams has one.