Its probably just easier to ignore it but sooner or later, youll have to slide under your airplane and confront the greasy mess on the belly. This is an exercise limited to lying on your back and swinging your arms wildly about your head, hopefully not in vain. Plan on getting wet and dirty.
Having the right cleaning material helps. In fact, picking an effective degreaser makes or breaks the entire job. Some wont touch months of solidified goo while others will take it right off, along with most of the paint, not to mention the top surface of the underlying aluminum.
There are literally dozens if not hundreds of cleaning and degreasing products on the market. We didnt try them all by a long shot but merely poked through the available selection in search of a couple that work. If you have your own works-like-a-charm method or technique, drop us a line. We know lots of shops and owners have their favorites. Otherwise, heres what we learned:
Rags and Stuff
There are two types of degreasers; those that say you need to rinse off with water and those you dont. To be on safe side, we think you should rinse off anything you put on that tender belly, but especially any material thats caustic. It may be a pain in the neck, but youll have a cleaner airplane and youll minimize the chances of corrosion.
Besides, once you go through the trouble of getting out the hose, finding an outside tap and arguing with the line person about what the hell you think youre doing, you might as well give the airplane a complete bath.
The right equipment is a must, starting with eye and hand protection. (If you believe in that sort of thing.) I dont so I didnt wear gloves when using these solvents. Men dont wear gloves. I changed my mind the next day. My hands stung and my skin was cracked and bleeding. I still consider myself a man but now Im a man who wears gloves. I recommend the heavy-duty chemical-resistant gloves most auto parts stores sell. Theyre easy to find and cheap. In a pinch, a better grade of kitchen gloves will do.
While youre at it, find a pair of goggles or a face shield. Some of this chemical junk is caustic and when youre under the airplane squirting it around, most of it will stay on the belly, the rest will fall in your eyes, your clothes and your hair. Did I mention a hat?
Paper towels or cloth? Paper is okay, although even a small airplane will require a lot of it. Bring a couple of rolls. A better choice is old terrycloth towels from home or painters terrycloth tack rags sold in the local Home Depot. Theyre cheap and reusable and do a better job than paper towels. To pry loose really sticky blobs of stuff, invest in a 79-cent scrub sponge.
The Scotch Brite Heavy Duty Scrub Sponge is an essential accessory for this project, regardless of which degreasing solution you choose. Be careful with the green spun plastic side of the sponge, however, because it will scratch and dull the paint if used carelessly. Use it sparingly and only on the stubborn deposits.
Try to beg, borrow or steal a creeper from your local FBO. You cant really do this job well without getting cozy with the belly and without a creeper, you cant do that without getting soaked. It may be an aircraft owner right of passage, but I find no pleasure in being both wet and greasy. One or the other I dont mind, but not both.
Where to Get It
I found the degreasers in four locations: The supermarket, the auto parts store, the FBO and a small company in North Carolina. The grocery-store degreasers all performed as anticipated, which is to say marginally acceptable. These include Easy-Off, Lysol Direct, Pro Formula 409 and Greased Lightning.
Each of these have some variation on the warning, Do not use this product on aluminum. On painted surfaces test in an inconspicuous area. I tested all the products straight out of the bottle on a clean aluminum baking sheet and the only product to etch the aluminum after 10 to 15 minutes was the Lysol Direct.
None of the products mentioned harmed the paint but my paint is old and because the sheen has long since faded, it was difficult to tell if any subtle damage was being done. At least none of the chalky paint came off on the rags I was using. No one at the airport would let me near any of their nicely painted airplanes so my bottom-line conclusion is this: If youve got an old beater paint job, who cares? But on nice new paint? Forget it.
The fastest performers in the grocery category were Lysol Direct Multi-Purpose Cleaner and Easy-Off Self-Scrubbing Kitchen Cleaner. The Lysol product shot the less stubborn grease off the belly on contact. The tougher spots required an extra dose or two of the product and the tough grease deposits (six to 12 months old, shame on me) came off with a swipe or two of the business side of the Scrub Sponge.
Greased Lightning and Pro Formula 409 were not as quick or thorough in removing the top layer of grease. Both products needed to be reapplied to get the surface free from the loose dirt and grease and had a tough time with the old deposits, despite the Scotch-Brite. Remember, these products werent meant to be used on aluminum. But how else can you get your belly degreased and have it 99.9 percent free from E. Coli, Salmonella, Staph and Strep?
Although some owners use them, I recommend steering clear of both Formula 409 and Greased Lightning. I tried the baking sheet test with the latter before I used it on my Cessna and it etched the aluminum in about three minutes. Yikes. No way. If you insist on using these products, rinse thoroughly with water two or three times and work at night, when curious bystanders cant read the labels.
According to the manufacturers, Simple Green, Fantastic and Lestoil are safe on painted surfaces and aluminum, although Id still test the target surface in an inconspicuous area. Surprisingly, Lestoil preformed better than expected, although its hardly the easiest to apply. Lestoil is a petroleum-based degreaser which is applied full strength right out of the bottle. You need to pour it on a cloth or sponge, smear it over the surface to be degreased and wait about 10 minutes.
Lestoil must be washed off with plenty of water and wiped off with a rough cloth or sponge and the entire surface rinsed clean. The result is worth the effort; 90 percent of the grease washed off right away and the deposits needed little coaxing from the sponge. Lestoil is the only product tested which cant be sprayed onto the surface.
Fantastick isnt. Even after spraying the greasy area twice, there was still a noticeable film left on the surface and the stubborn little grease nodules werent effected. But, your belly wont mold or mildew so thats always a plus.
The only environmentally friendly product in the grocery category is Simple Green. Its also the safest, easiest to use and ultimately the best performer in the category. Doesnt smell bad, either, if you consider the odor of perfumed pine sap to your liking. Its easy to apply; it has a special foaming spray tip which causes the product to adhere to the underbelly in a way thats useful for busting loose those solidified quarts of ashless oil you dumped into the engine last month.
Use it straight out of the bottle. It wont harm the paint, etch or corrode the aluminum and you can leave it on as long as you want; just dont let it dry out. The instructions advise to wet the surface first. They dont say with what, so I wetted one area with water and another with a light coating of Simple Green, then re-coated both surfaces with Simple Green using the foam applicator.
I left the Simple Green on for about 20 minutes while I cleaned the windshield. The double-coated Simple Green area was much cleaner after the first wipe and the tough deposits came off with light scrubbing.
Simple Green doesnt leave any residue and you dont have to rinse it off, although I did as a matter of habit. In the grocery store category, this one is the clear winner.
From the Auto Store
Since the average car gets way greasier than the average bathroom, automotive degreasers can be the chemical equivalent of nuclear weapons. When using any of the automotive type products, use some type of respirator.
Most of these degreasers are either petroleum-distillate based or contain some form of sodium hydroxide and have noxious fumes which can cause organ failure or (according to the labels) death. A clean belly is a must, but trust me, its not worth dying for.
There are two types of products found in the automotive store: Those that work not-so-well and those that work great and will destroy the airplanes finish. The destructive products in the engine degreaser category include GUNK Super Spray, GUNK Engine Brite, STP Grease-Eater and most other engine-specific degreasers. GUNK Super Spray indicates on the label that it will remove built-up dirt, grease, oils, gums, waxes and varnishes from metal surfaces. I tried it in the ubiquitous inconspicuous area and as far as Im concerned, the instructions should have read: Spray this stuff on your airplane and call the paint shop. It not only destroyed the finish, but blistered the paint in about 30 seconds. However, the tough deposits did come right off with the paint.
GUNK Engine Brite didnt blister the paint, but did live up to its promise (on the label) to streak the paint considerably. Still, it didnt remove any of the heavy deposits. STP Grease-Eater was a little gentler on the painted surfaces. The label states: Avoid prolonged contact with aluminum or any painted surface. My test lasted five minutes and didnt seem to harm the finish. Most of the grease came off, but the solution had difficulty penetrating the tough deposits.
Blaster Aqueous Degreaser suggests that you rinse the area thoroughly to avoid spotting when used on aluminum, magnesium and painted surfaces. I followed their advice and my finish wasnt affected. But neither was the grease. I wouldnt get near the expensive magnesium tail feathers on a Bonanza or Baron with this stuff.
Castrol Super Clean states on its label that its Three Times Stronger on Grease than Simple Green. My tests suggest that it was about 50 percent more effective than Simple Green but isnt as environmentally safe.
It doesnt contain petroleum distillates, but it does have sodium hydroxide and 2-Butoxyethanol, which arent environmentally friendly. Castrol passed the painted-surface and baking-sheet test with flying colors. Its effective on the loose grease and handled the tough spots with light scrubbing.
3M Foaming Engine Degreaser claims to be safe for under-the-hood rubber and plastic parts. I took this to mean that its safe on painted surfaces and I was rewarded for my optimism. It didnt harm the finish-it actually left it a little shinier-and it did a decent job on the grease, even the tough spots, with a few swipes of the Scrub Sponge. In the auto store category, 3M Foaming Engine Degreaser is the only product Id consider. Again, dont forget to rinse the surface thoroughly.
ZepTeen and TR-1000
The only solvent my FBO-and lots of others-recommends is ZepTeen. Its safe on aluminum as well as painted surfaces. The ZepTeen label indicates that you can mix the product 1:1 with mineral spirits.
The field chemist at Zep Manufacturing told me that most people use it full strength, which I found eliminated the heavy grease and the associated deposits within 60 seconds of the application.
Rinsing off the ZepTeen was the only scrubbing necessary. I was so impressed with the power of ZepTeen that I tried it on the 15-year-old grease deposits accumulated on the engine of my 1980 Chevy pick-up. Wads of grease, some a quarter-inch deep, melted off. Be careful with this product on old and chipping paint, however, because it will remove loosened paint and streak the old finish.
Now, the only problem with Zep: The company doesnt sell its products to the general public. The field chemist informed me that the industrial line of Zep chemicals is only available through their distribution network, which sells directly to transportation companies. Zep Manufacturing does market a home version of their solvents through Home Depot, but I was informed that these are similar to the home cleaning products and not as strong or effective as their industrial counterparts.
The official word from Zep Manufacturing is that ZepTeen is not recommended or certified for use on aircraft. They are about to approve a similar (but not as effective) product called High Foam Transportation Degreaser for use on aircraft.
My FBO has been using ZepTeen on aircraft for years without incident so Id say concerns about using it on aluminum are probably unjustified. Still, you should rinse the surface, just to be sure, and dont let it near your Plexiglas. As for obtaining it, I dont see any reason why your FBO cant order it through a distributor.
But wait. Theres a better product yet. Reader Roger McCall of Raleigh, North Carolina did his own tests on belly degreasers. McCall sent me 8 ounces of some pretty amazing stuff; TR-1000. TR-1000 is made by Tomar Industries in Raleigh. According to Tom Scoggins, owner and founder of Tomar, TR-1000 is biodegradable and environmentally safe.
I discovered that its 95 percent as effective as Zep Teen and can be used to clean anything on your aircraft, including the windows. Use it full strength to spot treat the really bad grease deposits, dilute it 1:1 with water for normal degreasing and about 8:1 for giving the airplane a complete washing.
The penetrating capabilities of this product work as well on hardened globs of grease as on rock hard bugs on the leading edge of the wing. TR-1000 is Ph-balanced for use on aluminum and will leave Plexiglas sparkling clean.
Tomar currently sells TR-1000 in gallon containers for $8.95 plus shipping and handling. Quart size bottles with spray nozzles will be available by press time. Theyll sell for $6.95, plus shipping and handling. You can contact Tomar Industries at 919-828-0859.
If you want to clean up your belly without doing damage to the paint or aluminum, plan ahead and get the right materials. Stay away from the engine degreasing category. They work well on your grease but are very caustic, potentially hazardous to your health and the environment. The noted exceptions to this are Castrol Super Clean and 3M Foaming Engine Degreaser.
These are acceptable but not ideal. If you need to degrease that belly now and dont want to wait until you can find ZepTeen or TR-1000, Simple Green is the best choice. Its safe, effective and available in grocery and hardware stores.
But before you tackle the job again, order some TR-1000. Its the overall best choice and worth the trouble to obtain . Follow all the safety precautions listed here and on the individual products and not only will you have a better looking belly, but youll be around to enjoy it.
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by Joseph Brignolo
Joe Brignolo is a writer, film editor and multi-media guru. He bases his Cessna 172 at Danbury, Connecticut.