The world's most popular metal finishing site, and striving to be the internet's friendliest cornertopic 43831 Treating old Beechcraft 'V-Tail' Bonanza magnesium Flaps bare metal before painting2007Hi, I'm Thom an aircraft mechanic. A Beech Bonanza owner asked me to strip & paint his wings from a very early model 'V-Tail'. It turns out his Flaps & Ailerons are magnesium. There's a fair amount of surface corrosion on the skins and I've sanded the parts with 320 and 400 grit aluminum-oxide but now I need to pickle the skin before I spray the Epoxy Primer & Polyurethane Topcoat. Mfg's Manual calls for a mixture of Chromium Trioxide & plaster of Paris solution in water applied to the skin, a kit called Dow19 however I can't find it anywhere and I have to treat these surfaces pronto!Can anyone out there tell me where I might secure this Chromium Trioxide or Chromic Acid (technical-grade) or DOW19 kit?Does anyone else know of another corrosion inhibiting process that would allow me to paint over it once it's applied? Thom Barlow A&P IAFAA Certified Aircraft Mechanic - Wesley-Chapel, Florida, USA2007First, be aware of the many EPA and OSHA restrictions on the traditional hexavalent chromium processes for magnesium.See letters # andfor magnesium pretreatment info.
Also, SanChem has a a chrome-free conversion coating for magnesium, SafeGard 3400Mg. Ken Vlach- Goleta, California.
The problem Magnesium corrodes rapidly when exposed to the atmosphere, and the need to reskin ruddervators is fairly common. However, there are no approved repairs to even very light damage or corrosion to magnesium ruddervators except for complete control surface reskin. May 10, 2019 The problem According to society officials, the grade of magnesium used for ruddervator (pitch/yaw) flight control skinning in Beech Model 35 (V-tail) Bonanzas is very costly and difficult to source. Magnesium corrodes rapidly when exposed to the atmosphere, and the need to reskin ruddervators is fairly common.
There are really only two ways to remove rust; chemically, and manually. Chemically is going to involve CLR, or some stronger grade that is applied and then removed, or you immerse the thing into saltwater and lemon juice or something to remove the rust. Manually is going to be just as it sounds, sandblasting(which is not cheap, and runs a high risk of damage), or taking sandpaper to it or some similar method that will basically involve scouring it down to the metal again. There is no real shortcut. My advice would be to do it by hand.
It will take a long time, and it will suck, but you will end up with a better finished product with less change of damage. I know it is not the answer you are looking for, but there is just no miracle solution, it is time to apply some elbow grease.John. I use vinegar and let it soak in a bucket or a wet old rag enclosed in plastic for 12 hrs. Then wire brush (come in many sizes)For big jobs I use diluted Muriatic acid (Walmart or Hardware store)For quick jobs I use a wire brush attachment/drill bit on a drill.drill sizes range from large hand helds to small drexels.There is no magic solution-it is labor.Then to prevent more rust you must use an oil base paint of which the only kind is rustoleum-clear or a multitude of color choices, spray or paint on.If it is a tool or item for outdoors-wood or metal; I coat with boiled linseed oil to preserve it.
Does all the rust have to be removed? With old wood furniture, I know that the experts look for unvarnished areas, to confirm age. (I’m told that in colonial times, the woodworkers didn’t waste varnish on parts that wouldn’t be seen) Could the same thinking be applied here?
Rust is, in small amounts, a protective coating; and shouldn’t hurt anything. Granted, in areas where the metal will show, you’ll want to clean it up and paint it. But if the rust won’t show, and won’t interfere with the use of the item, why not leave it be? It’s not a health hazard, and will actually help date the item in the future.
It will take you forever and a day to remove all the rust manually. The bacteria that makes rust loves about 55 degrees and moist air. If you are keeping the bed somewhere dry and warm, it should slow down the rust process. Now if it were me, I would see if there were a way to cover the box spring so it didn’t show.
I haven’t seen it, so I don’t know if you can take it out to make a cover, or fix lengths of a waterproof canvas or flannel rubber sheeting to cover the rusty springs to help keep a clean mattress from getting rust on it. It probably depends if you planned on selling it or keeping it, to determine how much work you want to put into it.
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