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Customer feedback wanted!

Posted: Tuesday, November 29, 2016 11:58 AM Quote
Hey guys,  If anybody out there has experience with turbine systems spraying our products, we would really appreciate your feedback.  Please tell us what model you are using and what tips and techniques have worked best for you.  Or, alternately if you have tried a turbine system and just could not get it to work well for you, please let us know that as well with the model that you used.  We get frequent questions about the turbine systems, but we have very limited experience with them.

Thanks lots!
Andy Humphrey
Andy Humphrey A&P
Stewart Systems Tech Support
Posted: Saturday, December 10, 2016 4:52 PM Quote
I'm glad you've asked, Andy.  We have spoken many times on the phone concerning my application of EkoPoxy primer and EkoCrylic topcoat on our aircraft.

I'll try to be brief here - please contact me for additional details.

For reference, I initially spoke with Dan, before the company ownership change, and he advised that I should be fine to spray with a turbine system, and advised I would need a 4-stage turbine and a 1.4mm fluid tip.  In accordance with this advice, I purchased a Fuji Mini-Mite 4-stage turbine, two 25' lengths of hose, and their best HVLP gun, the "T" model.  Why did I do this?  Because the area where I was working is supplied with a single 20-amp, 115V electrical service.  There is no way I could run the size of compressor recommended by Stewart Systems to go along with the recommended Finish Line HVLP gun.  With Dan's assurance, I went ahead and spent $1500 on the Fuji equipment.  What a mistake!

After initially getting a bad batch of EkoPoxy, very willingly replaced by Stewart after a brief chat with Dan, I moved ahead with applying the EkoPoxy primer.  It was difficult to apply but I eventually got the hang of it.  The turbine system worked well, produced zero overspray, produced a very usable spray pattern, and generally seemed like it had been a good choice.

Fast forward a year and it was time to spray EkoCrylic.  I had ordered a gallon of each of Insignia White and Pontiac Red, and a quart of black to use as trim paint.  Despite assurances to the contrary, these three paints are of very different consistency.  The black is like water, the white is like a cream-based soup, and the red is somewhere in between.  Yes, I know, it's not supposed to be like this, but I can assure you it is.  I was so surprised by the consistency of the black paint that I double and triple-checked the label on the can to make sure it actually was EkoCrylic, simply because it was so runny as compared to the white EkoCrylic.

Application of the EkoCrylic started with the Insignia White.  I ran several test panels, following the printed instructions meticulously, save for one minor deviation.  I couldn't source Isopropyl Alcohol readily so used Methyl Hydrate instead as a wiping agent.  I later sourced some IPA and found it to be not nearly as easy to use as the Methyl, and there was no discernible difference in final finish quality.  The methyl was much easier to use for wiping and could be used on a much wetter wiping cloth, thereby doing a much better job of picking up sanding dust.  More on the sanding dust later...

Once I thought I had the hang of painting with the Insignia White on test panels, I started on airplane parts.  In summary, I rapidly discovered that there was NO margin between too dry (orange peel) and too wet (runs) with this paint and turbine/gun setup.  I varied every variable available to me and always ended up with the same result.  Rather than risk runs, I opted to go for the orange peel look.  Horrible, ugly frustrating orange peel everywhere.

Not being content with the final look, I sanded it all off.  Yes, hand-sanded it all off.  That was something on the order of 80 hours of sanding, making LOTS of dust.  Now you know why having a wiping system that picked up all the dust was so important.

The second application of Insignia White was just as bad as the first, but I learned how to sand it off more efficiently, so taking it off the second time only cost me about 30 hours of labor.

Was the third time the charm? Heck no!  It was just as ugly the third time, but this time I decided to just keep adding more layers of paint, knowing my only viable option was to "cut and buff" the orange peel off.  Yeah, that means a LOT of labor, but the paint does come up nicely when wet-sanded with 600, then 1000 grit paper, buffed with 2000 grit buffing compound, and finished off with 3000 grit polishing compound.  As-sprayed, the EkoCrylic produces a beautiful gloss.  The cut-and-buff result is almost as good as the as-sprayed finish, and I likely could spend a bit more time with the polisher in order to get a better gloss.

After spending quite some time on the phone with Andy (who, by the way, was always patient, courteous and respectful, despite my rising level of frustration and rapidly-diminishing supply of patience) it became clear that Stewart Systems has never tested this paint with any turbine application system.  I was not in a mood to play with the turbine system any longer, so I went out and purchased an inexpensive pressure-reduction HVLP spray gun to use as a test.

The new pressure-reduction spray gun produced some interesting results.  I learned that the only way I could get a decent result was to turn the source pressure WAY up, to the point where I was making it into a LVHP gun, with clouds of overspray and mist in the air.  This has led me to conclude that EkoCrylic requires a huge amount of air and atomization pressure to sufficiently break up the paint.  Anything less will result in an unsatisfactory finish.

Fast forward some more and there I was, ready to give up.  Again, a call to Andy caused a light bulb to come on.  He suggested that he had seen folks applying EkoCrylic with a foam roller and achieving results that weren't any more ugly than what I had achieved with the turbine HVLP system.

Rather than even attempt to spray the red EkoCrylic, I simply rolled it on with a foam roller.  Guess what?  The results weren't any worse than with the turbine HVLP!  Sure, there's lots of orange peel, and a few lap marks, but the paint went on quickly, painlessly, and with zero need to mask or take other precautions.  Plus a foam roller costs about 0.1% of what a turbine HVLP system costs, and produces the same results with this paint!

In summary, what I learned is confirmed by Andy's request for feedback.  Stewart Systems has no knowledge or experience in applying EkoPoxy and EkoCrylic via a turbine HVLP spray system.  I advised Andy that they should go down to the local equipment rental shop and rent a turbine system for a weekend to try it out.  Given the target market of homebuilders, many of whom will not have the ability to install a huge 220V air compressor, this kind of R&D would almost be expected.  It's unfortunate that I was bitten by incorrect advice given by a person who no longer has a controlling interest in the company.  It is also unfortunate that, when I initially started asking questions, Stewart Systems didn't fess up and admit that they had never tried a turbine system with this paint.

At this point I'm weighing my options.  Do I spend another three weeks of labor to sand off all the Stewart Systems product and apply the PPG paint that I now know I should have applied in the first place?  Or do I just grin and bear it, and cut and buff the crap out of it.  It's hard to tell which will be the less labor-intensive path to take.  Either way, there is no way that EkoCrylic can effectively be sprayed with a turbine HVLP system.  This information needs to be published by Stewart Systems.  Similarly, Stewart Systems needs to very clearly state the very small range of spray equipment with which they have tested compatibility with each of their paints.

Sorry for what will no doubt be seen as a very bitter post.  The reality is that any reasonable person would struggle to not be maybe just a little bitter after they had spent several thousand dollars on paint and spray equipment, only to have to spend several hundred hours sanding it off because the paint vendor failed to provide meaningful, accurate guidance for the application of that paint.

Again, I can't stress enough that I believe the Stewart Systems paint is good paint.  It is tough as nails and produces great gloss.  It is also the most difficult paint I have ever worked with, the most demanding of any finish in terms of spray equipment.  Stewart Systems technical support, specifically Andy, is professional and courteous.  It's just a shame the person answering the phone isn't backed up by a much greater depth of knowledge and experience in the different methods of applying the paint.  If you stick with the one application formula that Stewart Systems knows, I'm sure you'll get a great finish.  If you deviate from that one application formula, you're a test pilot.  Caveat emptor.
Posted: Monday, July 17, 2017 12:57 AM Quote
Try running air supply line thru a ice chest to cool supply air... 1,2  tp 1.4 tip, wide fan and move fast
Posted: Saturday, August 12, 2017 4:47 PM Quote
I have a few comments regarding your issues with spraying with a turbine system. I have finally got good results with a turbine set up, but not after a lot of experimentation.
There have been concerns about turbine air being hot, but I measured the 'dry' temperature of the air coming out of the gun I am using and it is about 5 degrees F below the ambient temperature which is not really a surprise. The heat of compression is dissipated by the hose to some degree and when the air expands as it exits the gun the temperature then drops. It will be below the ambient intake temperature upon expansion because of the heat loss in the hose.
The system I am using is the Fuji MiniMite 5 stage Platinum system with an old 25 foot Graco hose and the lightweight Fuji 6' 'whip' hose on the gun end. I spray the primer unthinned with the 1.3 mm tip set and then wet sand it with 3M 300 grit body shop paper to remove any roughness, which is usually fairly minor. I put this on as a final wet coat after a light tack mist coat as SS recommends.
For the final top coat I switched to a 1.0mm spray tip set as recommended by a Fuji tech rep. They also recommended using light coats rather than one heavy coat to avoid an orange peel finish. The use of a remote control for the turbine is also a good idea to prolong turbine life.
I am using Insignia White EkoPoly and following the mixing instructions by WEIGHT on the side of the can using a high quality scale. I use the 4:1:1 ratio of paint:catalyst:water and then spray on a light tack coat, wait 4 minutes then put on a wet coat. I then waited 50 minutes and put on a second wet coat as the first one did not completely cover the smoke grey (fairly dark) primer I used under it.  When I spray the fuselage I will use the white EkoPrime to save this step.
Like most homebuilders I am new to spray painting but am quite pleased with the results I have eventually managed to attain.
I started out using an old Graco turbine from a previous project but at only 5 psi it did a poor job of atomising the topcoat paint, even with the excellent Fuji T70G gravity gun I purchased. It would do a so-so  job with the primer but I had a lot of 'orange peel' with the EkoPoly.
The ambient temperature was 70 F with moderately low humidity in all cases above.
The Fuji tech rep said a four or five stage (9.5psi) turbine with the 1.0 mm tip set would help and the results are very good. Keep the gun 8" or so from the surface for the wet coat and open the fluid knob about 1 turn.
I did a lot of trial and error tries but this seems to work fairly well. My son was impressed with the gear door results, my first 'aircraft' parts. I was hesitant to paint this second aircraft project by myself but am now glad I made the effort.
I would counsel patience and lots of test pieces first. I thank Stewart Systems for producing this product as I did not have the option of using a  normal solvent based system in my basement. There is very little bounce or overspray and fogging in the large ventilated room I am working in.
I use full set of protective gear to minimise paint self exposure.
Fuji Spray tech help and support is very good and this system is a vast improvement over my 20 year old Graco 700 series system.
Posted: Monday, August 14, 2017 12:30 PM Quote
Thanks lots for that helpful information!  Please keep us posted as you complete more with that setup.

Andy
Andy Humphrey A&P
Stewart Systems Tech Support
Posted: Friday, August 18, 2017 8:34 PM Quote
Just a further update on using the Fuji 5 stage turbine HVLP system.
I made a slight error about the sand paper I used on the primer.
It is 3M 400 grit automotive wet/dry paper used wet,
not the 300 as I stated. It may not make much difference.
A couple of further notes about spray technique.
The mist coat should not be glossy.I only open the up the fluid control 1/2 turn for the mist coat.Remember to file a slight mark on the fluid control to help with this. This will likely result in an orange peel finish if this mist coat is too wet. If you notice it is wet looking it might be an idea to use a damp lint free cloth, wipe it down and start over.
I said to open the fluid control about one turn for the wet coat. 1 1/3 turns or up to 1 1/2 might be better for the wet coat, depending on how fast you are moving the spray gun.
The amount of distilled water I add by weight is critical. Since I use a digital precision scale I can control this precisely. I have upped the water to 27:100 by weight to the part A. This helps with the leveling out but is best used only for a horizontal surface as it is prone to runs.
Painting flaps and ailerons now and am still learning, but I am enjoying the results.
Posted: Monday, April 2, 2018 11:55 PM Quote
I see there are some Vans Aircraft Builders that have some recent Turbine System experience with Stewart Systems paint.
Here's a link.
http://www.vansairforce.com/community/showthread.php?t=159127

I am also very interested in using a Turbine system. I know I could probably get a good compressor for an HVPL pressure sprayer for what a decent 4 stage turbine system would cost but then I still have to plumb it, filter and dry the air. Looking at what Devilbiss recomends for high flow disconnects, filter/dryers...etc.. you're probably looking at $1,500 or more for a decent setup. I am probably  6 months away from doing any painting so i'm scouring the internet for RECENT information.

John