Anyone have experience using a HVLP sprayer unit for fabric work through color? Painting a/c sheetmetal with Poly-Tone? I am looking at recovering some J-5 tail feathers through paint and in reading the Poly-Fiber book they talk about using a HVLP compressor set up.
One of the other things I was also concerned with was the exposure to the toxics with the P-F system and have been looking into a dedicated breathing air supply and see that Aircraft Spruce has HVLP units with an second compressor for a dedicated breathing supply.
Any thoughts?

Thanks,
Dave

Hi Dave,

A separate breathing supply would have been really nice to have.

I found the Polytone system easy to use, but the chemicals smell awful to work with, even with a mask. They're not as dangerous as a two-pot paint system, but still pretty nasty to breath for extended periods, even with a charcoal filter.

I used a 2.5hp compressor with a standard middle-of-the-range spray gun. It was perfectly adequate. I can see that HVLP would almost certainly be better, and save lots of over-spray. For a whole aircraft or two, I bet it would pay for itself in paint savings... Maybe not if you already had the basic set-up, and you're only doing a few small jobs, like tailwings.


Painting sheet metal with Polytone:
You definitely do need to follow the manual's advice on using the EP primer underneath and spraying Polytone into the tacky primer. It peels off in sheets if you put straight Polytone on metal.

Don't let the primer tack up too much, else the layers wont join very well. If you can leave a fingerprint in the paint without getting sticky fingers, you waited too long. Better to let it dry, and spray a little more EP primer, than to have your paint flaking off in 6 months time.

There is no need to go thick with the EP primer, a little goes a long way. Runs are hard to fix, but being a little light on the EP primer really doesn't cause a problem. You don't even need 100% coverage - any subtle "orange peel" pattern in the primer soon blends out with the Polytone, and provided there the surface is 90% covered with micro-droplets of primer, the finish will still adhere as well as EP primer can. That depends a lot on your prep of the base metal.

DO NOT forget to scratch up the metal really good, with a red Scotchbrite, before applying the EP primer. Otherwise, the primer can flake off when flying in the rain or hosing the plane down. This goes double for smooth composite finished parts, such as fairings.

Note that even when mixed and thinned perfectly, the EP primer runs much more easily than Polytone, especially on vertical surfaces and smooth surfaces. Just a fraction of a second too much spray will start the EP primer beading up into drips, on a vertical. But - if the surface is flat and horizontal, you really have to drown it to get the paint to run. Polytone is much more forgiving in all situations, especially when you are spraying it onto the silver. Just don't get sloppy

If you are painting red or yellow finish colour, you need to remember to use a while primer and white Polytone base layer. This gives the bright, even finish you expect. Using other colours means the primer tones show through even 4-5 coats of yellow / red - and you end up repainting the dull looking surface
White is very easy to paint and get a good finish.

Jonathan

Dave-

I have a Citation Axis HVLP system that also provides breathing air. Its a well built unit and you can buy direct at axispro.net. Customer service is excellent.

A couple of things, and you may know this stuff already:

Unless you have a dedicated air compressor large enough and with lots of filters to keep the water and oil out the HVLP stand alone unit is pretty nice. Not cheap. Upgrade to the 4 stage pump. The Apollo 7500T HVLP gun that comes with it is a very good gun. Can run it gravity or pressurized. Get the adapter to use the 3M PPS liners. You'll want the large liner set and a small liner set. The medium is unnecessary IMO. Way, way less mess to clean up. They can sell you the PPS adapter then buy the liners and cup assembly off Amazon.

It is a little different to use than standard high pressure rig. The paint comes out in larger dots than you might be used to but do not despair as these paints flow well. Its hard to waste expensive paint practicing, but its worth it to experiment a little before you start spraying color on something important. Mine came with a 1.3 needle. Its about right for Superflite which is glorified PPG Delfleet. I dont know anything about Polytone system but their techs can lead you in the right direction I imagine.

I have the full mask breathing apparatus. It seals nice and tight. Get lots of the lens protectors because of the overspray. Don't be tempted into the half mask as the isocyanates enter your body through your eyes as easily as your lungs. Don't be tempted to wipe the lens with reducer. I learned this the hard way and had to order a new lens. It really sucks to have to use the full mask because it is hard to see out of. Also, the unit must be placed where it gets fresh air all the time or it will pump contaminated air right into your facemask.

Hope that helps.

gbflyer wrote: I dont know anything about Polytone system but their techs can lead you in the right direction I imagine.

The Polyfiber people were as quiet as a mouse when I tried to contact them with questions / troubles with their coating systems.

As a result, and because it's nasty stuff, I recommend people work with a less MEK-centric system like Stewart Systems water-borne etc.

Battson,

I have had the exact opposite experience with the Poly Fiber people, They always answered my questions, even on a Sunday. Sorry your experience wasn't the same as mine.

I have been a professional painter for most of my adult life, Too long. I have watched the spray guns change over the years. . When HVLP was first introduced, the finish obtained from them was less than perfect. Atomization was inadiquite, causing excessive orange peal. The new, high end HVLP guns spray just like the good old guns. Infact, I don't believe they save any paint like they are supposed to. I use the same amount of paint to spray a car now as I did in the 1980's, the paint just costs 10 times more and isn't as good. I personally think the whole thing was a scam to make us people who paint for a living, buy new guns. I was perfectly happy with my old Sata Jet non HVLP spray gun. When I was forced to change to HVLP, by law, I struggled with the new technoligy. For several years we were forced to use junk HVLP guns that just made our job harder. The latest version of HVLP from Sata sprays just like my old Satajet, Just as much overspray, just as much paint useage, but costs 4 times as much.

After this long rant, the advice I have for anyone wanting to paint their own project is to use whatever spray system works for them. If you have an old Binks #7 that works for you, go for it. In my state of PA if I get caught with a non HVLP gun in my commercial paintshop I will be fined. If I was painting my own project in the garage at my house, I can use any gun I want to. In PA HVLP rules only applie to commercial operations. Your state laws may vary. Good luck with your project.

Dave: I have a fresh air breathing system I bought new when I last built in 2007. It's been sitting in the paint booth unused since then. It has the half mask which I preferred as I was concerned about my glasses steaming up, (back when I wore glasses!) I would imagine a full face could be used, just a matter of replacing one with the other. If I build again, I am going with Oratex..... so I will sell this CHEAP (and throw a few bucks toward the site for blurbing it here), PM me if interested and I'll send complete info/pictures etc.

Polyfiber systems is all I've used, on 5 planes, I've had real good luck with it and am familiar enough with it that I resist these newer systems that have come along, you'll get the hang of it in no time. Just take the time to set up a proper area to do the painting in, you don't need the hassle of fighting an improper setup plus all the usual work.

Battson wrote:H
I found the Polytone system easy to use, but the chemicals smell awful to work with, even with a mask. They're not as dangerous as a two-pot paint system, but still pretty nasty to breath for extended periods, even with a charcoal filter.

I had no issues with a charcoal filter and poly... I did have to change filters often, but they seemed to do well until they broke through.

I used my Binks #95 because that is what I had to spray with. So, no help on the HVLP thing.

I have a Graco HVLP that I bought in the '90's. I use it only for air now and not for paint. I use harbor freight HVLP guns but I can't call myself a painter. Reading Cliff's remarks about paint guns has me rethinking my paint guns. I have an old Model 7 Binks in nice shape, was given to me and I've never used it. As far as polytone on metal, I went with sort of matching enamel as I've had poor luck in adhesion of the polytone to metal. I'm sure it was my prep work or lack of the same. Battson has some spot on polytone advice.

Maybe I should qualify my comments a little further:

I know Polyfiber has a huge following and is the popular choice. But a friend of mine used the Stewarts System at the same time I was doing mine with Polyfiber... and I strongly encourage you to do your own research... but in my opinion the Poly is inferior in almost every way.

Some things I liked about Stewarts:
It cleans up with water, not highly poisonous MEK.
If you make a mistake, you just pour on the water and try again.
Uses the same popular / available fabrics as Poly.
Finish turns out amazing because you can fix mistakes so, so easy.
Contains no chemicals known to the state of Kalifornia to cause cancer.
My buddy wasn't spending hundreds on charcoal filters and still getting headaches anyway.
And the list goes on.......

But rather than argument about it online, best to do your own research.
That's just my 2c

Dogsbody wrote:Anyone have experience using a HVLP sprayer unit for fabric work through color? Painting a/c sheetmetal with Poly-Tone? I am looking at recovering some J-5 tail feathers through paint and in reading the Poly-Fiber book they talk about using a HVLP compressor set up.
One of the other things I was also concerned with was the exposure to the toxics with the P-F system and have been looking into a dedicated breathing air supply and see that Aircraft Spruce has HVLP units with an second compressor for a dedicated breathing supply.
Any thoughts?

Thanks,
Dave

Hey Dave, if you're doing any fabric covering work, I'd love to come by and check it out. I'm trying to gain some experience prior to tackling my own.

Thanks all for the info. Even though I've painted before but I don't consider myself a painter. I realize my current compressor set up is inadequate for larger projects like wings, it would work for tailfeathers.
I am still weighing the pros and cons of just going with a larger compressor.

Thanks,
Dave

I'm using the hobby air...think that's what it's called...bought it from ACS. Any painting other than water born...fresh air is a must have. I made the mistake of mixing primer without the fresh air supply...stunk up the shop something fierce. Then used some nasty solvents to clean the HVLP gun...That night had a hell of a low back ache....not from muscle tension. The pain felt like urinary tract infection that got into the kidneys. I peed in a cup...clean catch. Then did a urine dip. Came back positive for protein, glucose and ketones.. Cleared up the next day....breathing the stuff is bad!

M Moyle,
My wife's young cousin took a job painting truck caps at a manufacturer in Ohio, right out of highschool. He loved the job, but shortly after getting the hang of spray painting , he started having head aches, vommiting and other horrible sickness after the company switched there paint brand. He used a fresh air system and was a saftey related type person. He ended up having an allergic reaction to the resins in the new clear coat.
Be very careful. It can be lethal if you have an allergy. You probably already know this but I am going to say it any way, Use this stuff in a well ventilated area. Certain shop heat sources will make the fumes more hostile to your body. I once was stripping a few parts with chemical stripper in a hangar with a keroseen heater running far off in the corner. After a short time I encountered a smell followed by eye watering and loss of breath. I threw open the hangar doors, unplugged the heater and ran out into the fridged winter air. I had used the same stripper dozens of times with no effects to my breathing but not around a heater like that.
Be safe and good luck with your project.

Cliff,
Thanks....the project is time consuming...mostly enjoyable...cept sandblasting. In the past...I would ignore back aches... That macho thing...I'm tough....phbbt! That day I hadn't man handled a 92 series head onto an engine...or lifted a 55 gallon drum of fuel... Wanted to know...first time I ever connected the dots with a urine test strip...
Mark

What many fail to understand, and a few don't want to, is that the isocyanates are absorbed through all the soft tissue in your body.....eyes, ears, throat, groin...etc. Just providing fresh breathing air is a great step ahead, but equally important is the protection of the rest of your body as well. Trust me...been there, done that and have the health problems to prove it. Another thing that many don't understand is that the most dangerous time of all for that paint is when you're mixing it. That stuff is "looking" for a place to go, and since we're mostly made up of moisture, that's where it goes. I can't count how many times I've seen people totally unprotected, mixing paint....many times it was me....not smart! Bottom line is that this is nothing to mess with...sit down and READ the can to see what's in there!
As far as an HVLP unit for dealing with Polyfiber, it's a great way to go! I've done many with my Croix turbine, and many with my HVLP compressor powered guns... there really isn't any discernible difference in the finish when done properly. If you have any doubts, get ahold of the tech reps at Polyfiber and they'll help you.
John

John,

I agree 100% with your post above and will add this, it's not worth risking your health to save a buck when it comes to saftey equipment around hazardous materials. I want to live long enough to fly my projects for many years.

Cliff