Javron covering kit

[bamendala]

Hi guys I'm new here. Ordered a javron kit a little over a year ago and am just curious about what route people have taken as far as the covering kit? Jay sells poly fiber and Stewart's with the kit. I've worked a little bit with poly fiber and don't remember having any issues.. but that was over 20 years ago now lol. Wondering if most order the covering kit seperate or with the kit. Also any experience with airtech? They seem to have a good little system too? Also price wise, what do you guys feel the best options are? Seems like sometimes getting parts from the kit supplier is the most cost effective other times not so much. Any info would be much appreciated.
Thanks
Brian

[phdigger123]

Brian, I ordered the covering supplies for my Javron from Stewarts. I was concerned about shelf life and was able to order the material when I needed it. I just finished putting on the fabric yesterday. Now to get the top coats on!

[bamendala]

I never really considered shelf life but that's probably a good call. How did you like the stewart system?

[supercub83a]

I have a javron cub thats nearing completion. It has Oratex on it and Im very pleased with the results. If youre making a show plane then the airtech options look pretty nice. Also I believe it is an acetone based system which would be a lot healthier than mek.

Polyfiber is the gold standard, a very mature system that has proven its longevity. Heavier than oratex and probably heavier than Stewarts.

For me the weight savings and non-toxic nature of oratex were the main selling points. I have weighed covered dacron (ceconite) vs oratex and i, conservatively, estimated I would save 30-40 lbs on my last cub. The oratex is definitely stronger than dacron and I believe I will patch fewer holes on my elevators. Patching it is much easier too. Time will tell how it holds up. If you go the oratex route Im happy to elaborate on the advantages and disadvantages. I will use it again. Oratex is the more expensive option but you will save on labor applying it.




Sent from my iPhone using SuperCub.Org mobile app

[Scott A]

I just picked up part of my kit (everything but the wings) a few weeks ago - Jay mentioned he is transitioning away from Polyfiber to Airtech. He said he using up the Polyfiber stock he has on hand but not replenishing it. I asked if I should get Airtech through him or call Robbie direct. He said to deal with Robbie. For sure easier if everything is just waiting for you there at Javron though.

I do like that I am not locked in to a system yet.

[bamendala]

Supercub83a I would like to know more about oratex. What did it cost you in materials to cover? It might be worth the extra cash just in weight savings alone it sounds like. 30 lbs is alot! Let me know what you like and dislike I'd appreciate it.
Brian

[bamendala]

Scott A thanks for the update with jay... sounds like I'll be doing the same as you and holding off and keeping my options open

[DENNY]

I had Robbie ship everything to Jay for me because getting paint up to Alaska is expensive. I was worried about shelf life, Robbie said as long as I did not open any cans everything would be fine for a while and I take the paint in and have it put on the shaker every 6 mo until I am ready to use it. DENNY

[gntw]

Supercub83a I would like to know more about oratex. What did it cost you in materials to cover? It might be worth the extra cash just in weight savings alone it sounds like. 30 lbs is alot! Let me know what you like and dislike I'd appreciate it.
Brian

if u want to give me your contact I will discuss oratec with u. My son and I have done 6 cubs so far . Doing a north star cub now doing a new javeron kit next winter. Have done most other systems but will only do oratec now .

[bamendala]

Gntw, would love to discuss it with you. I will pm you my info

[bamendala]

Thanks Denny that's a good idea too. Save on some shipping costs. If I go with airtech, which I'm leaning towards right now that's what I'll do ��

[phdigger123]

I never really considered shelf life but that's probably a good call. How did you like the stewart system?

So far I really like the Stewarts System, much better than using Poly Fiber. I will have a more informed opinion after I put on the top coats.

[skywagon8a]

I've done lots of fabric work over the years. This last project I used the Stewarts system for all the favorable reasons for which are given. I was unaware of the shelf life of the top coat materials and was surprised when I found a jug of it very much solidified. So, I attached a paint stirring paddle to a drill press and let it run. Issue solved, the paint became useable again.

[supercub83a]

I am a little over 12K in covering materials for Oratex. It can be done cheaper. This included all of the tools (heat gun, iron, consumables, etc). I also ordered enough to cover an extra elevator for practice before moving on to the actual aircraft. Another thing that increased my cost was ordering two different colors of fabric. This means you end up with a lot of extra fabric and tapes at the end. For example when you cover the wings you can use the scraps to cover the ailerons but my ailerons are a different color so I was unable to utilize the extra pieces. I was also not the most careful at sizing the fabric and had probably a little too much waste causing me to have to order a little extra fabric for the rudder. I would like to have had just a little more margin on my first order so I would suggest ordering some extra fabric upfront and save on the shipping.

Oratex is a completely different material than the traditional Dacron systems and you can't use the same methods to apply it. It definitely requires a different skill set.

What I like:
Weight savings. My last cub was fairly light for a cub, the paint was not thick and having weighed pieces of that fabric I think Better Aircraft Fabrics claims of 20 to 30 lbs of savings over traditional systems is conservative. I would've saved something closer to 35lbs. I don't think you can find a single other mod to save that much weight.

No painting and no fumes. I didn't want to build a paint booth and the thought of shortening my life by huffing MEK all day for months was not appealing.

Tough. It is much more resistant to punctures than Dacron. It can also be used for things like a lighter weight seat back/spring or in place of interior panels (although I've got Randys carbon panels because Im rough on interiors)

No future ringworm and super easy to patch. My order also included their patch kit. It is preglued fabric that you cut to size and stick on the hole. When you get a chance you iron it to make it tight and more permanent. It doesn't get easier than that.

What I dislike:
The glue on the finishing tapes is a little wimpy. They do make an adhesion promotor for it and if you are careful you could tape and glue with the primary system glue (which is an outstanding glue). I also went with the straight edge tapes, I believe they go on easier with this system. That said if one lifts you just heat it and stick it back down. I'm pretty sure finishing tapes are more cosmetic than structural with Oratex.

Finish. You just can't get the finished/smooth look of traditional systems. I suppose you could paint it but I think you would lose out on the weight savings and one of the biggest advantages if you did. I think it looks great when applied correctly but a wet sanded nice polyfiber or similar finish is another level.

Reshrink. As oratex heats it gets stretchy. It seems to have about the same amount of shrink as dacron, but the problem is it gets stretchy as it gets warm so I don't think it can pull as hard when you shrink it. Most oratex planes (that i've seen) that operate in the cold get wrinkles in the fabric. This isn't a big deal, you just have to hit it again with some heat to remove the wrinkles. After you do that once the wrinkles will be gone for good and reheating oratex isn't a problem.

No biased tapes and dealing with curves. They way oratex achieves rounding a curved surface (like elevators, rudder and stabilizers) is by heating and stretching and also shrinking. I was able to do my entire plane without any problems except where my nav light mounts are located and I was able to hide my little fabric puckers there using a method Lars described to me. I am very glad that I did a practice piece with curved surfaces first or I may not have done so well.

Ribstitching thread. You can't use waxed rib stitching thread. It takes a little time to figure out how to get their thread to pull tight and then you must glue each knot. The whole system is faster but you will spend more time ribstitching.

Priming metal surfaces. I used polyfiber epoxy primer on the wings for longevity. But you will need to prime metal surfaces where the glue contacts anyways to get the design strength. I don't believe that traditional systems require this??

Overall I'm happy. You will save a lot of time, health points, and you will get a stronger product that is much lighter. Most of my gripes are very minor, I do wish the glue on the finishing tapes was a little stronger being my main complaint. It is also a little pricey but what is your time worth?!

[bamendala]

Supercub83a.... man thank you for the super in depth review! You're going to make this decision way harder now! Lol! But that just goes with the territory and everything else involved in aviation. Seriously tho thanks again for all the info I really appreciate it.
Brian

[ak49flyer]

Those of you weighing covering system options: I’d strongly suggest you make your decision not only based on installation process/pros/cons, but also on longevity(unless that’s not important to you). Find a plane (or better, 2 or 3) covered 10-20 years ago in the process you’re considering, and used/parked in the conditions you expect, and pick accordingly. Installation is a big job, and expensive enough, you want to make sure you’re happy with what you end up with in the long run…

[Sikorsky]

I used Stewart’s through silver, a light coat of PPG Aerospace primer and PPG Aerospace top coat. This was my first covering job and it turned out fairly decent. I’d do it this way again although if I were painting yellow I’d consider a different top coat brand than PPG.

Sikorsky

[rotto789]

I am also considering a Fabric and or paint system for my recently delivered Javron kit. My last Super Cub build (Smith Cub) I used Poly fiber and had a very good result with it, albeit heavier than I would have liked it to be. Given the new products available, and without the MEK solvent base, I am opting for a different route this time. After much discussion with friends who have used Oratex and the Airtech coatings system, I am leaning toward the Airtech system. After talking with Jay about the weight savings, which in his opinion, the weight savings is not that great between the two, Jay recommended Airtech for a better finish result while using the medium weight fabric which would result in very little weight penalty over oratex as long as you don't go crazy with the paint layers. Basically, Airtech uses a two step process after the fabric is applied as I understand it. The spray on primer acts as the fabric weave filler and UV protector, all that is needed before top coat is some light sanding to achieve the proper surface for top coating. Oratex on the other hand, is a dull finish, and some colors are translucent which allow you to see the structure under it, this is undesirable to me. Well oratex maybe a good fit for those who don't have good painting equipment and skills, I have done enough automotive and aircraft paint work that the prep and spray painting part doesn't really bother me that much, plus I already have all the equipment necessary to complete the Airtech system. obviously, there is something to be said for the speed and ease of application with oratex, but is that enough to sell me on my next project? the weight savings is a plus if it is really as much as some people say it is? Maybe, Maybe not. Is price point a consideration? maybe for some, maybe not for others. I definitely want a product that will last a long time and still look good. This is the last build I will be doing and I want it to be perfection. I ain't getting any younger. Opinions are like, well, you know!

[Mauleguy]

There is a thread somewhere here on my experience with Oratex. I did not like it. Tapes came loose in flight even after I went around with compressed air trying to lift edges to find any loose ones.... Once dirt gets under loose edges and it will you can not just hit it with heat because it will not stick to dust/dirt. I saw my airplane a few years after I sold it and it spent some life on the ramp in Alaska not in a hanger and it did not look as good as I would have expected. I would never use it again YMMV

[1934A]

Anyone have an estimated cost fir the Airtech process from start to finish?

[Bill Rusk]

My opinion only......

Oratex is simply not attractive and rapidly gets worse with age. The tapes have a sharp edge (like putting a piece of duct tape there) and that collects dirt and grit. With a painted tape the edge develops a fillet that softens the edge and it does not collect dirt and oil nearly as bad. That fillet also helps keep it down and sealed.

I believe Oratex will seriously reduce the resale value of the airplane. At least it would for me personally. We all hope to never sell our Cubs but life happens. So you spend more to put Oratex on then lose 30K in resale value. But.....each person must find what works for them. Collect all the data you can then make the decision that works best for you.

I will offer that we plan to do the interior of the 4S cub in Oratex, but NOT the exterior.

Bill

[Bill Rusk]

I like and use the Airtec system. It is acetone based rather than MEK based. The MSDS for MEK is 17 pages. The MSDS for Acetone is one page.

However, I do things different than the Airtec recommended procedure. I use 1.5 coats of primer (that is three passes, or one crosscut + one more pass). Sand non glued areas aggressively but only scotch bright the glued areas. Color is just one cross coat. Put the first pass on medium. Don't get runs, but a little more that just a mist pass. Don't forget to trim the edges. Wait for that to get tacky. Finger clear means you can touch the paint and it is tacky but no paint gets on your finger. Then the second half of the crosscoat goes on pretty heavy. That first half tack coat creates a sticky surface that allows you to put the second pass on pretty heavy without getting runs, and enough to avoid orange peel and nice flow out.
This is where it is hard to answer the cost estimate. Between the first pass tack coat and the final pass (about 20 minutes) I throw out any paint and clean the gun and completely start fresh for that second topcoat. I have had the paint start to kick off in the gun and it makes a mess. It also does not flow as well (orange peel) because it has percolated and started to cook off while waiting for the first pass to tack up. So.....unfortunately I throw out some paint. Yes, I have tried refrigeration, reducers, and about every other trick I can, and none seem to give the finish that starting fresh for the second pass does. All this is just another idea to throw out there and let folks collect data to find a system that works for them.

Hope this helps

Bill

[KJC]

So I wonder about the compatibility of using Stewart’s glue which everyone seems to like and Airtec top coats which are very nice? Experimental only obviously.

[bamendala]

Thanks for the input maulguy that is something I definitely don't want to deal with down the road. Even if their is a miniscule chance of it happening I don't like the fact that it can happen. Sounds like I'll be sticking to one of the tried and true methods. Now I just gotta figure out which one! Lol

[Bill Rusk]

KJC

I have used Stewart’s glue underneath the Airtech primer and paint, and it works beautifully.

Bill

[Scott A]

I know there are other threads on Stewarts - Doug Stewart of the Stewart brothers taught me to fly RC airplanes as a kid. I really good guy and the only one from the RC club that showed up at my dads funeral and even spoke. So I feel I should give it a good look. But the auto-fuel issue doesn't seem to be fully resolved or maybe not really resolvable. However if topcoat with Airtech primer and paint that should (?) fix that issue? Not super familiar with the problem I just see it come up now and then still. Figured I would research better as I approach cover. I know Marty on here said it was fixed (I think) but that 'California has weird auto-fuel that was still causing issues' which still gives me pause as can never really know where or what fuel I will use. Covering parts at the kitchen table would be nice.

KJC

I have used Stewart’s glue underneath the Airtech primer and paint, and it works beautifully.

Bill

[Scott A]

Take with a grain of salt as this is just what Jay mentioned offhand - he said when switches over to selling Airtech with the kits about the same as the Polyfiber which he still lists at $5200 or so. Also his price list is old so there is that. He told me prices where supposed to go up on the kits after Oshkosh last summer but he hadn't updated the web yet - well, it is still not updated ... good time to buy a kit before he fixes it

Anyone have an estimated cost fir the Airtech process from start to finish?

[supercub83a]

I will report back if my oratex covering doesn't hold up to the test of time. I'm definitely not the person that thinks what they have is the best simply because that's what I own and I would be highly dissatisfied if the plane doesn't hold up for a few decades.

To address a few of the oratex concerns mentioned above: I also thought the translucent nature of some of the lighter colored oratex fabrics was very unattractive, but that has been addressed. They are all available with a backing that adds no appreciable weight that prevents that translucence.

The finishing tapes seem to be a common issue. Its hard to know if there was application error (I have seen some use waxed rib stitching thread), but something prone to human error (because we all err) is a good candidate for design improvement.

As for weight savings, maybe take my results with a grain of salt because it is one sample set, but the fabric I weighed was ceconite medium weight fabric that had a light to average amount of product on it and the weight difference was stark. Has anyone weighed a finished piece of airtech? I just weighed a piece of oratex and it came out to .11 g per sq/in.

Has anyone had the airtech system out in the arctic to see how durable it is in the cold? I have not been impressed with the stewarts systems cold weather and top coat performance. If airtech withstands the test of time (and the arctic) and I wanted a shiny plane I would be very interested.

I will try to find some other fabric samples from other planes and systems and get some weights to post here. I've also been meaning to test some fabrics and glues with an engine hoist and scale. I have some superseam, stewarts glue and the oratex glue around the hangar. If I ever get time I'll be sure to post.

[Mauleguy]

It has been awhile since I used oratex, maybe it is improved. Since then I have covered one airplane in polyfiber with aerothane and one airplane with Superflite. I like both processes but have decided that Superflite is the least steps and good results. So going forward I am using Superflite.

I would not use oratex if it was free if that tells you anything about how I feel about the product. Like others have said it is a time consuming process that makes or breaks the value of airplane in my opinion.

[Sikorsky]

One thing I should have mentioned about the Stewart products: wait until you are about ready to start before you buy. The shelf life doesn’t seem to be that of the old school chemical based stuff.

That said, the glue is great!

Zach

[JTA]

I finished restoring a 1963 super cub in 2020. When it came time for fabric, I talked with a lot of people in the Fairbanks area about what type fabric system they would recommend and I also looked at a bunch of cubs/fabric planes as well. Didn't take long to make the decision to use Poly Fiber. I have no experience with any other system. I have a lot of time into reading the Poly Fiber book. I followed it to a T and it turned out really nice. As a side note, out of the planes I looked at that at a distance (and up close) really stood out as looking very nice where either Aerothane or Airtec. I'm working on another cub and I'll use Poly Fiber again only because i know what I'm going to get. I do like the idea of Stewarts or Oratex and I do believe they will be the ones to use in the near future....anyone try to buy MEK lately? Non airplane people are surprised when i tell them that the fabric was the easy part. Yea, months and months of reconditioning/fabricating/assembly was the "hard" part.

[ak49flyer]

To add to/address a couple of above points: I’ve maintained several oratex planes and every single one exhibited the tape lifting issues previously mentioned, combined with the dust/dirt/general ugliness factor. All covered by different people- maybe the all made the same “installation error”…? A great way to make your cub look like an ultralight, in my opinion. Stewart’s glue: I absolutely love using it, but it can and will soften/detach when exposed to auto fuel, regardless of topcoat. I don’t use the system anymore, for that and other reasons, but I do use it in certain very limited areas, especially d-window channels.

[cubdriver2]

To add to/address a couple of above points: I’ve maintained several oratex planes and every single one exhibited the tape lifting issues previously mentioned, combined with the dust/dirt/general ugliness factor. All covered by different people- maybe the all made the same “installation error”…? A great way to make your cub look like an ultralight, in my opinion. Stewart’s glue: I absolutely love using it, but it can and will soften/detach when exposed to auto fuel, regardless of topcoat. I don’t use the system anymore, for that and other reasons, but I do use it in certain very limited areas, especially d-window channels.

Ethanol or efree mogas?

Glenn

[Skywalker]

Is Oratex claiming long term uv resistance in the translucent colors? How would a "backing that adds no appreciable weight" protect the fabric? There's nothing magic about the Oratex fabric, except that it's precoated.

[supercub83a]

Oratex does claim long term uv resistance in the translucent colors, the backing was to address complaints about the aesthetics of the lighter colors. At least thats my understanding.


Sent from my iPhone using SuperCub.Org

[ak49flyer]

Ethanol or efree mogas?

Glenn

All my experience has been with AK auto gas, which has no ethanol.

[Bill Rusk]

Folks

In all fairness I received a response from a friend that does not post often but lurks. He said his Javron Cub covered in Oratex looks a good today as it did when it was completed 6 years ago.


It has been hangared and it has not spent time tied down outside in Alaska.



You can see the translucence and tapes a little here.


Understanding fabric

The problem with fabric and painting is the magnitude of failures. If you screw up a rivet the cost to fix it is a few minutes and a few cents. If you mess up a part you are fabricating, the cost might be measured in 10 or 20 dollars of materials and a couple of hours. If you have a fabric and painting failure the cost can hit a couple of grand and two weeks of labor very quickly (I am thinking a paint failure on a wing panel). A failure is a BIG BIG deal. In both time and money, not to mention frustration.

Stits has been around a long time and it is almost unheard of to have a system failure (paint coming off in sheets, bubbles, major sags, serious ringworm, pinholes etc). It is long lasting, they have an excellent manual, etc. In short it is a proven and good system. It takes more time as there are several coats, and it uses MEK which is pretty nasty stuff from a health perspective.

Stewarts has now been around for 15 plus years. They had some teething problems in the early years and there were a LOT of epic failures over the years. Some of the failures were no doubt operator induced as it did require different techniques, but there were enough failures that you really could not always say it was operator induced. The number of failures has gotten pretty small in the last few years. Stewarts changed paint formulas etc and things seem to be much better. But..... and I will emphasize...... But.... it is still a urethane topcoat with all the safety hazards as any other urethane. There is the misperception that because it is water based it is somehow as safe to breath as latex house paint. It is certainly better than most other systems from a personal health perspective but the topcoat should still be sprayed with a full fresh-air respirator system. It is not the ultra safe system folks are often led to believe.

AirTech has been around for many years. It was originally designed for crop dusters, because the chemicals were trashing the conventional covering systems. It is a urethane system. There are only two steps. Primer and paint. It is acetone based which is better than MEK. Not hazard free but better. It is hard and has an excellent gloss. It is a high solids paint and it is easy to get it on heavy if you are not careful. Paint failures are rare. A lot of award winning airplanes are using AirTech these days.

Superflight is another system that has been around a number of years.To the best of my knowledge paint failures are rare. It too, like AirTech, is a two step process. Primer and paint. I have sprayed a little of the topcoat and I like the way it flows out. I do not have a lot of experience with Superflight but I don't think I have ever heard of problems or failures. It does not seem to have quite the popularity of other systems but it seems good.

Oratex we have been discussing.

These are just some things I have heard, and learned from experience over the years. Steve Pierce has much more experience than most. Perhaps he will chime in.

I will be the first to admit I don't know it all, and I value other opinions and experience.

Hope this helps

Bill

[bamendala]

So all you painters out there... what is the the most user friendly process for painting. I'm not a painter. I've painted many houses during my construction days and painted my murphy rebel with a Wagner hvlp and rustoleum paint (which is still holding up after 20+ years even with auto fuel spills. Lol. Which is why it surprises me the Stewart's system can't hold up to auto fuel? ) what's the hardest system for me to screw up is really what I'm asking?

Brian

[Hardtailjohn]

Well.,, I would like to address some of the misconceptions about Stewarts.
Yes, it is a polyurethane topcoat. SO let's talk about polyurethane paint. In order to make a polyurethane...ANY polyurethane paint....crosslink and become the tough, shiny finish that people want, it requires a catalyst. The thing that makes that chemical reaction in the catalyst is a form of cyanide. If you go to the catalyst on any of them and start reading, you'll find the letters CYAN of some form in there somewhere. Now...this is the important part.... cyanide is highly attracted to moisture. That's how it does so much damage to humans...we're about 70% moisture. It attacks you through your soft tissues.(trust me....I have a VERY personal understanding of how it attacks the human body!!) It also follows the path of least resistance. SO... when you're using a solvent borne polyurethane, the cyan isn't "happy" in there and is going to go looking for moisture. In order to ensure that enough cyan is in the mixture to cause the reaction necessary, an abundance is used. More than actually needed. When you are working with a waterborne paint....it's "happy" in there, so no where near as much is needed, and it stays put much better. This is why Stewarts can be shipped Non Haz-Mat, air freight, and why it needs less precaution to use. IF you don't think so, try shipping any of the solvent based or solvent borne paints and catalysts air freight. Trust me, it wasn't just overlooked, it went through a quite thorough evaluation when it was first and subsequently sent out. Yes, as you have read above, Stewarts has some cyan in it's catalyst...just like the rest....but a minute quantity, and the health hazards are much reduced!!! Do you want to rub it all over your body? NO!! Will the average person be exposed enough to generate any health problems? Most likely not. We all have different levels of resistance to different chemicals in our bodies. Personally, I have no resistance to cyan anymore, as it's an accumulative poison (never leaves your system once it's in) and I don't have any more room for any. I'm extremely careful with ANY of the chemicals anymore!!! A little tidbit of info for all you painters out there....the most dangerous time in painting is NOT when you're spraying! It's when you're mixing the catalyst in. At that point, it's a "free radical" and seeking other compatible molecules to combine with, and guess what...there you are!!! How many wear all your protective gear when you're mixing paint? NO two part paint is totally safe, but a little education can make it a lot more safe to work with. I'm not a chemist, not a doctor either, but both have explained the above to me more than once.
As far as car gas.... there have been samples that have messed with Stewart paint...but there have been way more samples that have had absolutely NO affect on it. Unfortunately, with car gas, once the base formula is achieved there's not much control over what else goes in there, and there's some stuff that goes into some car gas that will destroy pretty much anything if left in contact with it for any amount of time. I've seen a well known additive that ate through PTFE bottles in a matter of days, aluminum, and even stainless steel containers, as well as the stainless steel valves we had in the fuel tankers I used to drive. I've also seen other systems have problems with some specific mixes. None are bulletproof.
As far as easy to use, I don't think any of the fabric systems out there are particularly hard to use. I've used pretty much all of them at one time or another, (and a few that aren't around anymore) except Oratex. The biggest difference is that some are way DIFFERENT to use. Just like the difference between landing a ground sniffer or a tail dragger. Not impossible by any means, but if you don't use it according to how it has to be used, it's not going to perform like you expect. Some are less labor than others. I don't think there's a system that I can think of that I haven't seen a failure on. An old friend of mine told me a long time ago, that if I wanted to see the problem with the system I was using, I could look in the mirror and have a 99% chance of seeing it.
John

[ak49flyer]

As far as easy to spray- dope or Poly-tone are dead nuts easy to spray and make look good. Unfortunately, they’re also the least chemical resistant and prone to staining, oxidizing, etc. I haven’t sprayed all of the different fabric specific paints, but I’ve shot Stewart’s, Aerothane, and Ranthane extensively, and lots of other auto-type polyurethane paints. I wouldn’t say there’s a ton of difference between most of them. Some are more finicky than others, but all use the same basic application principles. If you’re a person who can self critique and interpret what you’re seeing, you’ll probably figure any of them out. But if I had to name one, I’d say Ranthane is the “easiest”- goes on a little thicker than aerothane, covers better, and looks great. That said, I think a good Aerothane job is probably more flexible because it goes on thinner and has less solids.