Hail Stones and Oil Consumption

I got my PA-18 hailed on last spring and have a commitment from my insurance company to recover it. It's really not that bad, but I don't want to let the insurance company off the hook without reimbursement. It has Stits and buterate dope on it now. My question is, what should I recover it with? For longevity and durability. We use it pretty hard and I want something tough enough to take a beating, but still looks good enough for good resale value. I will probably have it done by a professional. so my skills aren't an issue.

Next question is, how much oil consumption is too much? Are there any remedies short of a top overhaul for an engine that's blowing-by oil. The 0-320 A2B engine has 1016 hrs. on it.

Thanks,
murph

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paint and oil

Murph, I have to agree with TJ. Polytone is probably the best way to go for abuse/patching. 'Thane will crack eventually and is a pain to patch.

Oil, I hadn't heard of the MMO trick in the crank before but it might be worth a try. (I still like the AvBlend stuff). How much are you running normally? 6 Qts? Any more than that and it may blow-by on you. (mine used to spit out everything above 6.5) Another thing is the rings may have lined up over the years on one or more cylinders. Jerry Englebrecht back here just put on an air/oil seperater on his newly rebuilt Cub. (Check out the picture posts) There's one going on a new Husky amphib in the next week or so and one going on a 206 amphib that just had a top overhaul and is still blowing oil to beat-the-band. Might be an idea.

Brad

Hail stones and Oil consumption

Murph I'll add my two cents worth. If you've read my previous posts you know that I like Randolph, but I'll admit it might not be the system to use down in Texas because of the climate. I would say that you should talk to the mechanic or shop that you plan to have the work done and see what they are comfortable using. You'll have an easier time if they use a polyurathane system and you want them to use a dope system versus the other way around. It gets down to what you want the aircraft to look like when you are done. If you don't mind a satin type finish that is easy to repair then use Poly-tone. If you want a wet look or at least some shine then you could use Randolph dope and still have some repairability. Poly systems will get you the shine but repairability is a bitch. Just make sure you understand fully the can of worms you open when you cut the fabric off because a simple cover job can turn ugly if there are other problems with the aircraft.

On your oil consumption question: are the hours you quote total time on the first run? hours on chrome major? what work has been done in the past on the top end? and what are you using per hour? If it is first run steel then I would try the MMO trick and run it hard for 25 hours or so. Use Areoshell 100W when you do and see if it helps.

Matt

Fabric Covering

How bout SuperFlite.........dacproofer system....have used it for years..and have several friends that have used it for years........and have had good luck with it. We also use pigmented dpoe for the coloring. I have a friend that has a PA-11 its been outside for 30 years with this process..and granted is somewhat faded, but as far as the fabirc..........it's still in good condition. I had a J-3 that I had covered using this process and it took a 1st at Arlington in Washingto for craftsmanship a couple years back.....and that was a few years after I had covered her. I've never used Stitts.....but the AI where I work won't allow it in the shop....he hates the stuff......and another friend doesn't like it..because he claims it cracks to easy. Like I've said.I've never had any personal use with it......so I don't know. Good luck on whatever you end up using. Happy flying "Brian"

Thanks to all those that responded to my questions.

I have been running Phillips XC 20W50 oil. I had a new oil/air separator installed just before the comsumption appeared to increase, but it appears to still have excessive blow-by. I have tried putting a small amount of MMO in the crenkcase, but maybe not enough. I probably should try the AvBlend. And maybe I need to get off the multigrade oil and go to AeroShell 50. Maybe I need to run another compression test as well to see if we can find rings lined up.

I'm still as confused as ever about the fabric.. I knew you guys would know what to do.

Thanks again,
murph

I'll try to give you a little basic info. The primary fabric used in today's recovering systems is polyester fabric. The system names are ceconite, polyfiber etc. The coatings are what cause the most debate. The most traditional is nitrate and buterate dopes. these are made with cellulose and are marketed under Randolf, classic aero, superflight etc. The most well known alternative is the polyfiber/stits system. The primary solid in this system is vinyl just like the dash of your pickup truck. A third product are the all polyurathane systems, such as air tech. Urethane is the main solid in this system. All of these systems are solvent based. There are a couple of water based systems but I'm not familiar with them. There are the yins and yangs of each. As in a lot of things pertaining to aviation there are strong preferences for each of these systems. We could fill volumnes on this. Polyfiber, superflight and air tech have web sites and would be a good place to start your research. The biggest debate is what to put on as a top coat. There is one part buterate dope and polytone which is also one part. The two part catalysed(sp) polyurethane is avialable for the three main systems. The key is to stay with one system from start to finish and that it is applied according to the manufacturer's specs. If someone suggests to mix this and match that ask them where they got their chemistry degree. I hope this helps. The others are welcome to critic this. Good luck, ps. there is another grand debate over powder coating or epoxy.pak

Murph, As for fabric covering, if you aren't doing it yourself? Find a rag and tube mechanic (that is usually an older fella that learned the trade around the 50's. Find out what he likes to cover with, (GO LOOK AT HIS WORK! THAT IS A COUPLE YEARS OLD AT LEAST) see for yourself, talk to the guys he has covered for? If he doesn't have any he's done lately, he problably isn't he guy for you. The next is decide how you are going to use the plane. There is not much question in my mind I won't put "paint" on a cub. They are a fun airplane to fly and if you fly (work)them into the areas they were intended you will scratch, dent, ding and tear them now and again. A good "Dope and fabric' job can be repaired anywhere, and done right you can't much tell. The only cubs I see covered and painted with Poly Uerothane--how ever you spell it are usually owned by "urban cub pilots". They like to look at them, have others admire there shine. They clean easier, but are a pain in the A$# to repair and make look good, especially after a couple of years.

Dope and fabric work is time consuming and you will be out of action for quite a while, especially if the mechanic can't stay on it till it's done.

Do your home work in your area, the reputation of a good covering man usually preceeds them.

PS: some of the best work I have ever seen is done by "Women".

Up here in WA/ OR, Tom Murphy has a reputation as doing great work? Also Bill and His Wife at Pearson Airpark does nice work.

Also there may be an EAA group in your area that has a referal or two?

Are you still confused? I am confusing myself?

Tim

Fabric

Your current system (Stitts with Buyterate dope) is an illegal system for what it's worth. The STC for Stits (now called Poly Fiber) calls for their fabric only and their coatings only, no exceptions, period. The only option with Polyfiber / Stitts is the top coat. Polytone or Aerothane, both made by Polyfiber. Polytone being a vinyl product and Aerothane being polyurthane. When polyurathane cracks, get out the knife and start all over. Nothing will lay it back down. It's shineyer then dope or polytone and dosn't fade as fast. Ceconite is usually used with Nitrate and Buyterate dope. A system that I like is Ceconite 101 fabric glued on with Polyfiber Polytak cement, Superflight Dacproofer as the first coat, tapes applied with clear nitrate, then Superfilght Sprayfill, then Randolfe colored Buyterate dope. Dupont Imeron (with flex additive and 40% less hardener) for striping and metal cowlings etc.. It's the metal and striping that set the plane off anyway. The dope is easy to patch and the Imeron has the wet look and won't fade. Crash

Say Crash? We used to use Stitts fabric and "Poly tack", slightly finer weave then Ceconite 101, then as you described nitrate/ butrate/ etc. It was just a few years ago that Stitts came out with the notification that there STC was void unless "all components" were exactly as stated in their "system manual". I haven't heard where the FAA has put out any requirement for the (likely) 100's of GA tube planes that are "technically illegal" have you? Most cubs I have seen have been signed back into service using 337" and pointing to the STC or just listing the "components used".

How about a couple of you IA's letting us know how that effects the Airworthiness of our planes?? I don't know two many that can tell the Stits fabric from Ceconite, unless you can still read the writing from the inside?

Tim

Stits

Tim

I don't know of an IA in his right mind that would sign off a cover job on a certified aircraft after the Stits STC/Manual change unless it's with all Stits products. As far as is your aircraft legal it would depend on when the cover job was done and the Fed. that might look at it. In any event it's the IA's rear that's out on the limb if he signed it off and it doen't comply with the STC.

Si

Hail stones and Oil consumption

Tim as far as aircraft being airwothy with Stits fabric and build up (sliver) with some other top coat (dope,Imron ...etc.) as long as the work was done prior to the manual change it would be legal. The reason is most of the STC's only covered the process up through silver so you could put any top coat on you wanted. As far as identifing fabric the only way to be sure is to read the markings on it.

Matt

Thanks guys, That confirms what I researched. My 12 is covered with Ceconite 101 with Randolf Dope products! I personally like that combination. SI you are right that the challenge comes when a mechanic makes repairs, it will "now" take a little more scrutiny to determine what was the previous proccess that he is repairing.

As for "total recover" It should make common sense to use the required and recommended components to comply with an STC, or to "prior" to begining, get FAA field approval for the work proposed.

Murph, Don't be fooled by "looks" there is a lot more to properly coveriing, structure prep, tension, chafing protection, stitching, seam location, taping, fill, UV protection, sanding, finish coating.

Tim

I attended a Polyfiber workshop at Sun N Fun this past spring. It was very interesting. A discussion got going about the "best" finish on their fabric. They strongly recommended the use of Polytone rather than Aerothane, and to go for a finish that still shows some of the fabric weave through the finish. They felt that they supply the best urathane for fabric (aerothane) but that even the best is not nearly as good a the less glossy Polytone.

At one point he said basically why do you guys even want to put a wet look finish on fabric. Good question as it does make it sorta look like one of those spam cans.

Gerald

For grins Polyfiber now owns the Ceconite. If you order fabric it comes off the same roll and gets stamped whatever you order. I annualed Murph's Cub and didn't notice it had Polyfiber fabric with Randolph dope. I know of IAs that have refused to sign of the same and required recover. I would attempt afield approval. My question is with dope. Murph's Cub has pieces of the finish coming off,(where hail stones hit) exposing raw fabric. Granted the cover job is 20 yrs old and the elasticitors have dried out but has anyone had this problem with polyfiber? I have repaired lots of dope finishes that I could peel the finish off with my fingernail or a blow gun. Is there a trick to penetrating the weave with the nitrate where it sticks good?

Steve

The first coating on the bare fabric is very critical. This applies to both dope and polyfiber. The best way is to brush the stuff on rather than spray. Many try to reduce and spray but the results aren't as good as brushing. The reason this is critical is that polyester fabric is very slippery and not much will stick to it, so the fibers of the fabric, must be encapsulated with the first coating. The subsequent coatings will then adhere to the first coating. Many have put dope over polyfiber and the results vary. One of the primary differences between the two is that polyfiber is stabilized and dope continues to shrink through out its life. The potential is bond breakage as the dope shrinks on the stabilized polyfiber. Kind of like painting a baloon then slowly letting out the air. Both are good systems but they each have their own characteristics and must be addressed with these characteristics in mind. It is best to stick with one system and follow the manufacturer's recommended application procedures. I'd say 20 years in the Texas sun ain't too bad for any cover.pak

The first coat of dac proofer, nitrate, or whatever, is the most important. Brushing is the easiest way to insure penetration. I Like to brush the bare fabric in the open panels with straight thinner to prep the weave, don't know if this helps, but it can't hurt. Rememer that the first coat needs to completely soak the weave, it's like painting a t-shirt. The biggest thing I have found to help the first coat penetrate is gravity. Always put the first coat on with the part laying flat, just on the upper surface. Gravity will pull the dope down through the weave, (use a slow thinner), and leave most of it on the inside, where you want it. Let the part completely dry before rotating it to do another surface. This will take some extra time, but the increased penetration is worth it.

I took a couple Clyde Smith's classes where he presented his opinions in great detail about this subject. My own experience is somewhat limited still, so this is from my notes.

First, Clyde tends to favor the Ceconite/Randolf process, with the PolyFiber/Stits process a very close second. And his experience all the other ***thane finishes are a distant third for the repair reasons mentioned above. Don't even think about any of the water based solutions unless you really want to do the job again next year -- they should be listed as hoaxes, not as finishing options. Piper used a water based system during the last few months of production on the PA18s, and the finish cracked and fell off before the planes left the factory.

Butyrate dope won't stick to polyester fabric, that's the main reason that the first coat is nitrate dope. Good penetration seals the weave completely, and provides the nitrate base needed for good butyrate adhesion.

If you really have to have a wet-and-shiny look, it is done by carefully managing the thinning, sanding, and drying times. Somewhere I've got a CubClues issue that details how. If I can find it I'll post it here.

I took a couple Clyde Smith's classes where he presented his opinions in great detail about this subject. My own experience is somewhat limited still, so this is from my notes.

First, Clyde tends to favor the Ceconite/Randolf process, with the PolyFiber/Stits process a very close second. And his experience all the other ***thane finishes are a distant third for the repair reasons mentioned above. Don't even think about any of the water based solutions unless you really want to do the job again next year -- they should be listed as hoaxes, not as finishing options. Piper used a water based system during the last few months of production on the PA18s, and the finish cracked and fell off before the planes left the factory.

Butyrate dope won't stick to polyester fabric, that's the main reason that the first coat is nitrate dope. Good penetration seals the weave completely, and provides the nitrate base needed for good butyrate adhesion.

Rod

P.S. If you really have to have a wet-and-shiny look, it is done by carefully managing the thinning, sanding, and drying times. Somewhere I've got a CubClues issue that details how. If I can find it I'll post it here.