First experience with HVLP gun - advice?

[devinkato]

Hey all, after being driven to the brink of insanity by rattle cans ruining my cabinets, I have taken a step in the right direction, and got a HVLP setup.

I used it out today, with the following setup/results.
Grizzly gun
1.4mm tip
Rustoleum black satin enamel
Used my buddy's huge air compressor (more than enough flow)

I followed the Rustoleum directions of thinning with up to 15% acetone. I started with ~ 10%. I shut the paint flow off, and adjusted the air flow to ~ medium. I then started slowly introducing the paint flow, and I immediately noticed that there was a lot of spatter. I took this as being indicative of the paint being too thick. I thinned it out more and repeated with the same result. I ended up using probably closer to 20%-25% acetone, instead of the maximum 15% recommended by Rusteolum.

At this point, I was not getting any spatter, but I was getting medium orange peel, no matter how much I adjusted the flow of paint or air.

Any advice? I've done a bit of research, and am thinking this may simply be due to crappy Rustoleum. I have very little experience in knowing what type of paint should be used, as my paint background consists of failed rattle can attempts. What paint do you recommend, and where can I pick it up?

Thanks!

[Pete00t]

Are you using a moisture trap or air drier?

[devinkato]

i did not use either. Any recommendations?

[bobbarkto]

Don't be afraid to thin it. Try using a blend of mineral spirits and acetone. It will flow out a little better.
You'll need to readjust your gun and distance and speed. Might need to up the pressure just a little.
I should add that if the only fault is orange peel you are doing ok. Practice will get you home.

Rustoleum isn't really all that good for spraying. They've spent gobs of money trying to perfect a brushable formulation. Really almpost all oil based enamels are tricky to spray. Even those designed for spraying.

Better materials would be any lacquer, acrylic enamels like Sherwin Williams Pro Classic, Target Coatings water borne finishes, automotive enamels, the list is extensive...
You can color clear water borne varnish/lacquer with artists acrylics. Get any color you want and it will spray nicely. Top coat with clear for better depth and gloss. I like Varathane brand for an off the shelf product. Target coatings if I want something better.

Do you want a solvent based or water borne? What colors? What gloss level?

[Pete00t]

you can go to the local big box store Lowe's or Home Depot. Moisture traps are sized per compressor. Usually there are only two sizes there anyways. There is also an in-line trap/dryer. Most likely right beside the glass moisture traps in store. They're disposable little plastic things. Might set you back $10. Still they are well worth it. Especially in a humid climate. Plus they well help other contaminates from getting in your spray.

[devinkato]

Do you want a solvent based or water borne? What colors? What gloss level?

I'm not looking for anything piano finish. I'm fine with satin black or basic colors as long as the application is even and smooth. I can worry about trying to get to a high gloss finish after I get some more experience. From what I understand, satin + clear coat will end up with a pretty nice gloss - 70% of the way to piano finish.

As for solvent based, or water borne - I have no idea. I do know I want enamel (since lacquer doesn't last as long?), but I haven't done my research - yet - as to solvent vs water. Any pointers?

[PassingInterest]

The gun is not atomizing properly.

Not enough air flow will cause this, as will the wrong tip size for the liquid.
Also, a poorly designed gun will not atomize as well as a better made gun.
But, you can still get the best performance possible for the gun that you have if you set things up properly.

You need a regulator/gauge on the gun. You don't know how much air is at the gun otherwise. If you set the pressure at the tank to meet the gun's specs, you might be surprised by how little air is at the gun once you put a gauge on the gun. With a gauge on the gun, you will find that you need to set the tank a little high. Dial it in using the gauge/regulator on the gun. Also, filter the air at the gun to keep contaminants out of the finish. The regulator/gauge should be on the gun and the filter comes next, then the air hose. That way, if there is any pressure loss through the filter, it can still be adjusted for at the gun.

After these adjustments...

I normally begin by setting the gun's air adjustment wide open and leave it there unless I change the spray pattern at the gun. Since I most often use the widest fan-spray pattern, I leave the air wide open on the gun.

To get the correct fluid flow quickly, I open the fluid flow up pretty far and do a sweep across some cardboard and tweak the fluid flow up or down based on what I see on the cardboard.

Keep cardboard handy for checking any adjustments to your gun--you don't have to sand finish problems on the cardboard.

If you adjust the spray pattern from a wide fan spray to a conical pattern to touch up an area for instance, you will need to adjust the air flow down a bit at the gun.

Use a paint filter in the gun and use a paper cone paint filter when you pour your material into the gun. This will help to avoid spattering and even clogging of the gun.

Get a viscosity cup and test the material you intend to spray. I think you will find that your tip set is too small for the material you are trying to spray. Over-thinning beyond the manufacturer's recommendations is a bad idea. A proper tip size is better than over-thinning. A viscosity cup will help you to determine the proper tip size.

What you are spraying probably needs a 1.8-2.0mm tip set. But, a viscosity cup will eliminate the guesswork.

[Pete00t]

Don't be afraid to thin it. Try using a blend of mineral spirits and acetone. It will flow out a little better.
You'll need to readjust your gun and distance and speed. Might need to up the pressure just a little.
I should add that if the only fault is orange peel you are doing ok. Practice will get you home.

Rustoleum isn't really all that good for spraying. They've spent gobs of money trying to perfect a brushable formulation. Really almpost all oil based enamels are tricky to spray. Even those designed for spraying.

Better materials would be any lacquer, acrylic enamels like Sherwin Williams Pro Classic, Target Coatings water borne finishes, automotive enamels, the list is extensive...
You can color clear water borne varnish/lacquer with artists acrylics. Get any color you want and it will spray nicely. Top coat with clear for better depth and gloss. I like Varathane brand for an off the shelf product. Target coatings if I want something better.

Do you want a solvent based or water borne? What colors? What gloss level?

I agree with everyone's tips. Until Bob mentioned paint types it slipped my mind. If you you are moving too fast, especially with water borne. You will definitely get orange peel. There;s a thing line of error with runs or orange peel depending on the speed you move across the piece.

[bobbarkto]

Any of hte finishes I mentioned before will work fine.

Lacquer is pretty durable, even the old nitro stuff.
Modern acrylic and catalyzed lacquers are good enough for kitchens so they should be fine for a speaker enclosure. Pre-mixed colors can be limited. Custom are always an option.
The nicest things about lacquers are they were designed for spraying, can be reduced heavily to flow through almost any gun and dry very quickly so you can usually apply several coats in a day.

If you don't mind mail order Target Coatings makes some very good products designed for spraying. They have a coating to meet any need, in any color. all are water borne.

Behr and Sherwin Wiliams make acrylic enamels that can be sprayed and will dry to around a 70+ gloss level. No need to topcoat, but can be.
They do not rub out well. For more gloss and depth you will have to top coat with a higher gloss clear.
You'll have to test to see which clear coat will work. Some are incompatible.
For spraying you'll have to add water and Floetrol for Latex paint (a flow enhancing additive, available at the big box stores).
For primer use plain old Zinsser Bin Primer, thin with denatured alcohol (or use the Behr or SW brand primer if you like an all water borne solution, but they cost more and don't perform as well on mdf (BIN is a gem on mdf)).

There is little difference in solvent vs water borne. Great coatings can be had in both formulations. I think the safety and convenience issues weigh more than anything.

I'm not looking for anything piano finish. I'm fine with satin black or basic colors as long as the application is even and smooth. I can worry about trying to get to a high gloss finish after I get some more experience. From what I understand, satin + clear coat will end up with a pretty nice gloss - 70% of the way to piano finish.

As for solvent based, or water borne - I have no idea. I do know I want enamel (since lacquer doesn't last as long?), but I haven't done my research - yet - as to solvent vs water. Any pointers?

[devinkato]

Thanks all for the valuable advice.

I've been doing some more research and am leaning towards an acrylic enamel for the following reasons - let me know if I'm totally wrong.

- Acrylic enamel will dry to a decent shine whereas lacquer will have to be rubbed to get shine (but it is superior after that point)
- Acrylic enamel can have a "hardener" added to it during the mixing/reducing process that will provide even further shine and protection.
- Acrylic enamel can accept a clearcoat (as long as it's compatible) for further shine.
- Acrylic enamel is relatively easy to spray, and should work through my HVLP 1.4 tip without issue and with correct reduction.

The main place that keeps on popping up in my searches is TCP Global. Are they any good? Their website gives me a headache - here's a link to their mid level paints - http://www.tcpglobal.com/restorationshop/rspcolors.aspx

Other than the paint, hardener, and reducer, is there anything else I need?

Are there any glaring cons to using acrylic enamel that I should know? Most places only boast the pros of product, and it's hard to find the cons.

Thanks!

[bobbarkto]

From your descriptions and links you were looking at automtive acrylic enamels. They're good.

The hardener is an issue you might want to consider.
They contain iso's (isocyanates) which are quite toxic and known sensitizers.
A fresh air supplied respirator is pretty much essential.
Most dealers will not sell to the general public because of the dangers associated with them.

They can be applied without hardener but will not develop as much gloss nor as much hardness.

Lacquer can lay down to a nice gloss without buffing.

Thanks all for the valuable advice.

I've been doing some more research and am leaning towards an acrylic enamel for the following reasons - let me know if I'm totally wrong.

- Acrylic enamel will dry to a decent shine whereas lacquer will have to be rubbed to get shine (but it is superior after that point)
- Acrylic enamel can have a "hardener" added to it during the mixing/reducing process that will provide even further shine and protection.
- Acrylic enamel can accept a clearcoat (as long as it's compatible) for further shine.
- Acrylic enamel is relatively easy to spray, and should work through my HVLP 1.4 tip without issue and with correct reduction.

The main place that keeps on popping up in my searches is TCP Global. Are they any good? Their website gives me a headache - here's a link to their mid level paints - http://www.tcpglobal.com/restorationshop/rspcolors.aspx

Other than the paint, hardener, and reducer, is there anything else I need?

Are there any glaring cons to using acrylic enamel that I should know? Most places only boast the cons of product, and it's hard to find the cons.

Thanks!

[devinkato]

The hardener is an issue you might want to consider.
They contain iso's (isocyanates) which are quite toxic and known sensitizers.
A fresh air supplied respirator is pretty much essential.
Most dealers will not sell to the general public because of the dangers associated with them.

They can be applied without hardener but will not develop as much gloss nor as much hardness.

You mean I can't just hold my breath? Thanks for pointing that out. That is a pretty big ding against the acrylic enamel.

Lacquer can lay down to a nice gloss without buffing.

If you had to choose between non-hardener'ed acrylic enamel, and lacquer without buffing, which one would you choose? I assume that the ease of application (without hardner), prep, and cleanup will be pretty equal between the 2.

[bobbarkto]

You mean I can't just hold my breath? Thanks for pointing that out. That is a pretty big ding against the acrylic enamel.

Yes, it is imo. There are products that are relatively safe that will do the job.
It's not like you are painting a car that will be out in the elements all day.

If you had to choose between non-hardener'ed acrylic enamel, and lacquer without buffing, which one would you choose? I assume that the ease of application (without hardner), prep, and cleanup will be pretty equal between the 2.

Lacquer, because I use it and know how it will behave.
It works. Pre-cat lacquers are quite tough btw and not overly toxic if used with care. The catalysts (hardeners) are much less troublesome.

But, I use a lot of the water based acrylics too. They are better in some ways and not so in others. They do the job and aren't as hazardous as solvent based. They still merit personal protective measures.
I like Target coatings stuff a lot. Also the Sherwin Williams/Behr/Benjamin Moore acrylic enamels are pretty nice (they are "latex" enamels, water is the reducer/solvent/carrier). Unlike latex house and trim paint they dry hard to a tough gloss finish.

[devinkato]

Lacquer, because I use it and know how it will behave.
It works. Pre-cat lacquers are quite tough btw and not overly toxic if used with care. The catalysts (hardeners) are much less troublesome.

Thank you sir, you've been a huge help throughout my HVLP quest.

Is this what I'm looking for?
http://www.tcpglobal.com/restoration...chsheet_al.pdf

When you mention pre-cat lacquer, I believe you're referring to pre-catalyzed lacquer. Is this AKA "ready-to-spray" lacquer that just needs to get reduced to go through a gun?

[bobbarkto]

Yes, that's generally the stuff, but get a lacquer formulated for wood. They're more flexible and aren't as likely to crack.
Hood, Star Bronze, Sherwin Williams, Campbells, etc. All are good.

Yes, pre-cat has the catalyst added at the factory or dealer. Reduce and spray.
Shelf life isn't too long, ~6 months or so depending on the brand. So use it promptly. Vinyl sealer or straight lacquer primer for undercoats when color coats are used. Self sealing on wood and veneer.

Thank you sir, you've been a huge help throughout my HVLP quest.

Is this what I'm looking for?
http://www.tcpglobal.com/restoration...chsheet_al.pdf

When you mention pre-cat lacquer, I believe you're referring to pre-catalyzed lacquer. Is this AKA "ready-to-spray" lacquer that just needs to get reduced to go through a gun?