alum mating surface corrosion fix?

Was surprised to read of a suitable jb weld fix for aviation engines.

Other welding techniques/materials/methods?

Maybe share this fix rather than keep us wondering?

here's one
"You might repair the damaged gasket surface by bead blasting the area needing repair until all of the corrosion is gone and treating it with magnadyne. Then apply JB Weld to fill the void and bring the JB Weld, after fully cured, down to a finished surface with 320 wet or dry and a flat sanding block or by any other means that will produce a flat surface with the rest of the gasket surface. JB Weld will take the temperature and adhere to the surface IF the surface is clean and roughened as the bead blast will do. Use a small blast nozzle to confine the area blasted."

the other
"I made a repair of acc. case corrosion. I ground out the area with a carbide burr. A couple of burn outs with the torch to eliminate oil. Cleaned with acetone.
I got some ERAZ92A magnesium filler rod. Tig weld, AC, 47 amp, 130 hz., 70% EN., plenty of argon.
It welded very easy, very little if any contaminants came out in the weld puddle. Solid weld, a good result for an amature."

So bead blasting on an aviation engine - presumably aluminum cases ? Wow - what about the beads imbedding in the soft aluminum and finding their way out to bearings , etc. in the future...

Depends on what the surface is for, sealing or structurally critical/integral to engine components. A bit of pitting on a sealing surface should be fine repaired as described with a filled-epoxy (JB-Weld). A metal weld up would also work, but a lot more effort to end up with a similar level of success.

engine is continental e225




looks like the accessory case fix here is magnesium

I have had several E accessory cases welded on during the time I was overhauling them (about 25 or 30+/-). Those accessory cases had very good quality magnesium and welded just great

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in this particular example

Do not forget all the end play of the several gear shafts that are changed when you cut the accessory case to clean up the gasket surfaces. Some of those may require cutting the ends of the shaft gear adapters to regain that end play.

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also

there was one case that had pin holes in the lower left side of the case (probably from an old weld repair) that would seep oil out through the case from the oil gallery that fed the lower left accessory drive shaft gear (checked with air pressure) and after three tries to stop the weeps without success the case was scraped.

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84ok said:

here's one
"You might repair the damaged gasket surface by bead blasting the area needing repair until all of the corrosion is gone and treating it with magnadyne. Then apply JB Weld to fill the void and bring the JB Weld, after fully cured, down to a finished surface with 320 wet or dry and a flat sanding block or by any other means that will produce a flat surface with the rest of the gasket surface. JB Weld will take the temperature and adhere to the surface IF the surface is clean and roughened as the bead blast will do. Use a small blast nozzle to confine the area blasted."

snipped

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Use of sand or glass media is strictly "verboten" for use in aluminum aircraft engines. Most auto manufacturers also forbid it's use on the interior of aluminum engine components, due to the concerns expressed by Richard T. below. Blasting should be restricted to crushed walnut shells, plastic beads or soda blasting. That said, the above method would be safe if the blasting was restricted solely to the area which is later covered in epoxy [JB Weld] as this will seal the abrasive media away from the engine oil.

Richard Tool said:

So bead blasting on an aviation engine - presumably aluminum cases ? Wow - what about the beads embedding in the soft aluminum and finding there way out to bearings , etc. in the future...

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Exactly. Lots of good suggestions on engine building in the link below, including not using sand or glass media.

How the Pros Do It

84ok said:

Was surprised to read of a suitable JB Weld fix for aviation engines.

Other welding techniques/materials/methods?

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Where did you find this suggested repair method? On Continental's web site? A professional aircraft engine overhaul facility? Or simply some private aircraft owner?

Here's another mention of jb weld for alum mating surface prep

Next, if there are any gouges, scrapes, or imperfection in the gasket surface, use JB Weld or Liquid Steel to fill them. Don't use Bondo or any type of body filler. It expands at a different temperature and rate than the metal. Just mix it up and fill only the gouge.

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Is this anything to do specifically with Norton Commamdo's.

Alum mating surface prep, i searched it here first & came up empty.

Applies for covers & for all i know engine/gearbox cases that may otherwise be unusable.

I think jb weld is mostly considered a joke here, is mostly what i've run across.

chaztuna said:

Where did you find this suggested repair method? On Continental's web site? A professional aircraft engine overhaul facility? Or simply some private aircraft owner?

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The bead blast jb weld fix is a quote (from a post by Lew Gage) lifted from an e225 overhaul thread in beechtalk forums,

which is an outgrowth of this organization

where Lew has this cred ..to say the least

E-Series Bonanza expert Lew Gage’s book E-Series Bonanzas:Flying, Owning and Maintaining a Classic is a must-read for all pilots and instructors flying 1947-1956 Bonanzas

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Turns out tho, the part is magnesium (missed that at first) but mated to an alum engine block, so dunno if he would consider it a suitable fix for an alum part,

Tho it did come up in the above honda shadow thread.

Next, if there are any gouges, scrapes, or imperfection in the gasket surface, use JB Weld or Liquid Steel to fill them. Don't use Bondo or any type of body filler. It expands at a different temperature and rate than the metal. Just mix it up and fill only the gouge. Use the gasket scraper to get all the excess removed while it is still wet.

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kommando said:

Is this anything to do specifically with Norton Commamdo's.

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Looks like If i had an engine leak between an engine case & outer cover, that involved "any gouges, scrapes, or imperfection" issue(s) with the engine case side, an easy jb weld fix (or at least attempt) may do the trick vs splitting the cases, for one.