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Orange Peel with HVLP Sprayer

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Forum topic by Sunnygirl posted 914 days ago 6966 views 0 times favorited 14 replies Add to Favorites Watch
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Sunnygirl

31 posts in 989 days


914 days ago

I bought a used Titan Capspray 105. It had little use and I got a really good buy on it. I cleaned it really, really well and installed a new check valve and can seal. I’m new to spraying, but have read a lot about it. On my first try with waterborne polyurethane I’m getting orange peel. I’m using a #3 projector set. I’ve tried adjusting the amount of fluid and also the air. When I backed these off it reduced the problem significantly, but never could get it to go away completely. Any ideas on what to try?


14 replies so far

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Bill White

3356 posts in 2566 days


#1 posted 914 days ago

My first thought was air, but you’ve answered that. Is the viscosity of the finish corret?
Bill

-- bill@magraphics.us

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PurpLev

8476 posts in 2254 days


#2 posted 914 days ago

have you tried spraying closer/further away from work piece?

-- ㊍ When in doubt - There is no doubt - Go the safer route.

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Earlextech

917 posts in 1296 days


#3 posted 914 days ago

You should be using a 1.5 mm needle setup with that finish and also be spraying from about 4” – 6” from the project. If you can, always spray projects as they lay down, that way gravity works with you instead of against you. As for the orange peel – orange peel is the result of the finish drying faster than the time it needs to flow out to a nice flat film. You need to spray a “wet” coat, a wet coat being “no dry spots that you think will flow together” and at the other end “no puddles or runs”. This takes practice. I’ve used waterborne for over 25 years. I suggest that you add a little Floetrol which will break the surface tension and allow the material to flow easier.

-- Sam Hamory - The project is never finished until its "finished"!

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BobM001

388 posts in 936 days


#4 posted 914 days ago

One of the other things I do is collect/restore liquid fueled gas pressure appliances, Coleman lanterns for lack of a better description. I paint with rattle cans. For every 5 paint jobs I did 4 would get orange peel requiring a strip, start over. Then an old auto painter told me “practice on a pane of glass”. “If you can paint on glass with no orange peel or runs, you can paint anything”. So I tried it. What I found is that I was crowding the work piece. I backed up about 3-4 inches and that gave the spray pattern a chance to develop. Smaller droplets contacting the surface. The result was a finish that looked wet and stayed that way. No runs, no drips, no orange peel. The other thing with at least paint is what they call “flash time”. That has to do with the reducer that is in the paint. Some are faster/slower than others. I found that most spray paints in aerosol cans it’s 10 minutes. If you wait to long between coats there is a chance for orange peel forming when you second coat. That happens I assume when droplets penetrate the surface layer when it has “skinned over” and begin to flash off under that layer. Maybe contact the finish manufacturer and ask them what they feel the flash time is for their product. Make sure that no silicone or even petroleum products were on the wood before finishing. Hope this helps.

Bob

-- OK, who's the wise guy that shrunk the plywood?

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Sunnygirl

31 posts in 989 days


#5 posted 914 days ago

All good advice. I was spraying about 6 inches from the surface because that’s what I’d read, but will try other distances. It seemed to start setting up very quickly, within just a couple of minutes or so. The projector I’m using is a 1.3, and the next step up is 1.8 (it’s a Maxum II gun). Which one would work better for waterborne poly?

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Earlextech

917 posts in 1296 days


#6 posted 914 days ago

1.3

-- Sam Hamory - The project is never finished until its "finished"!

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pintodeluxe

3283 posts in 1419 days


#7 posted 914 days ago

Increase air pressure from the compressor, or thin the finish.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

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boatworkstoday

20 posts in 916 days


#8 posted 913 days ago

My experience is that orange peel comes because of 1 of 2 things (or even a combination of them both).. As what was mentioned above, if the material is flashing off before it can flow out, you need some reducer (slow thinner). If you’re working with thin material, then it’s probably a matter of dialing in the gun. Increase the air pressure and back off on the flow; open up the spray pattern (fan size) and you should be good. Even if you have to back the fluid to the point that you don’t get a full wet coat on 1 pass that’s typically ok. Make another pass (or two) until everything is wetted out (making sure you don’t get a dry edge…) When the material is laid down, it needs to be able to flow out and blend.. Spraying takes practice (both with the gun and the material you’re working with). Stick with it, you’ll find the right combo :-)

-- Andy Miller, Boatworkstoday.com; Twitter:@BoatworksToday

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Jim Finn

1643 posts in 1527 days


#9 posted 913 days ago

would tempature of the spray or the air make a difference?

-- In God We Trust

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404 - Not Found

2544 posts in 1575 days


#10 posted 913 days ago

WHOA!!! Stall the digger on the Floetrol idea!!!
Floetrol is not compatible with ALL waterborne finishes. It will work with acrylic based finishes but will congeal into a yogurt like mass with other finishes. If you are going to try Floetrol, mix it in a jar first to test compatibility.

Quick checklist from my own experience -

Is the finish you are using suitable for spray application? Does it have to be thinned for spray application?

Do you have a ‘Sec’ cup for checking consistency?

How wide a fan are you spraying? 4-5” wide from 6-8” inches away works for me,

Are you overlapping properly – aim to overlap 1/3 – 1/2 with each pass

Are you moving the gun quickly enough? Look at some videos on youtube and some of those guys move it around like a Conductor’s Baton.

Don’t turn the air down too much – more air = finer atomisation.

the most common causes I’ve found are too much fluid and finish not thinned enough.

Hope that helps.

One more thing to remember is you won’t be a master finisher on the first attempt. But you will get there with enough practice.

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Craftsman on the lake

2369 posts in 2043 days


#11 posted 913 days ago

I’ve been using a $39 HVLP gun for the past few weeks. It’s something from Lowes. I have a gauge on the gun and keep it at 40psi. I adjust the gun so that the medium is like a mist. Something that might make rainbows if it were water. It doesn’t work like other types of high pressure guns. You don’t spray like it was a coat of paint on a car. It mists out and subsequent coats fill in as each one is applied. So,yes the coats do dry fairly quickly. You do have to have a compressor that can keep up with the high volume of air needed.

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful.

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JAAune

759 posts in 922 days


#12 posted 913 days ago

Something else to consider is that water-based finishes do not work anything like the old solvent-based products. My first attempt at spraying water-based came after years of experience with pre-cat lacquers. Naturally, I applied my knowledge of spraying to the water-based finish. What surprised me was just how bad all my test samples looked and none of the tricks I’d learned in the past prevented the orange peel I was getting.

The whole problem I had was nothing more than spraying too heavy of a coat. With the pre-cat I’d shoot a nice, smooth layer of lacquer on the project and would end up with a nice finish. All three water-based products I used were the opposite. If I applied a smooth, level coat I’d end up with orange peel when it dried. If I applied a thin film of finish that looked mottled and uneven it would level itself out and dry flat and smooth.

Thinning the finish with water helped as well but once I figured out the technique I’ve not had any problems spraying the stuff right out of the can. Water-based finishes are complex formulations so it is important not to thin it too much. Usually the can will give the maximum amount recommended for thinning. Too much water will upset the balance of chemicals that are used to disperse the resins.

If I really have to thin I prefer using heat over water. Warm finish flows better than cold. Sticking the can inside a container of steaming hot water for several minutes improves the flow a great deal. I know someone that uses a coffee cup warmer to warm his finish before spraying.

-- See my work at http://remmertstudios.com and http://altaredesign.com

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Earlextech

917 posts in 1296 days


#13 posted 913 days ago

Excellent suggestion JAAune, warming the finish is a tried and true method. Sometimes just warming the thinner will make the difference.

-- Sam Hamory - The project is never finished until its "finished"!

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Sunnygirl

31 posts in 989 days


#14 posted 911 days ago

All incredibly valuable information. Thanks so much. This week has been a whirlwind, but plan to start spraying again on Saturday. Hopefully can avoid the orangepeel.

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