Hi all
You may have seen our latest update on the Stirling flight deck and that we’re now looking to mount both of the Pilot’s seats. The P2 one isn’t a problem as it’s a repro, however the P1 is original and is made of mag alloy tubing. Since the attached photo was taken, the seat has been bead blasted to remove the paint and external corrosion and looks ok apart from some areas which we’ll have to do splice repairs on.
However, bead blasting has it’s limitations and we’ve been unable to remove corrosion from within the tubes itself. Have any of you educated Forumites got any advice on chemical treatments that can stabilise the corrosion? It’s my intention to fill the tubes with something akin to Waxoyl or lanloin once it’s been treated but we need to get to that stage.
John
By: TonyT - 8th May 2012 at 20:58
Ok link
By: ZRX61 - 8th May 2012 at 20:53
If you haven’t the Manual I put up PM me and I will sort out a link for you.
Yes please 🙂
By: 12jaguar - 8th May 2012 at 20:18
Well, tonight I removed as much of the corrosion deposits as I dare. I have a hard copy of AP119 somewhere and I’ll dig it out.
thanks for the good advice, I’ll let you know how we get on
cheers
John
By: Snoopy7422 - 8th May 2012 at 19:35
Nasty Stuff.
I’ve had to deal with mag-alloy corrosion on Elektron castings. For anything airworthy, it’s usually fatal when it gets a real grip. I suggest you get it warm and dry and remove as much of the loose material as possible. I say ‘possible’, because on Elektron castings, the corrosion can get right inside the grain of the metal. Cavities; I’d try and clean out as much as possible mechanically first. Get it really warm and dry and then use some sort of oil for the inside. It seems to work fine to inhibit further reaction.
I really wouldn’t contemplate filling tubes with resin. If you do. It will just sit on the surface, and do nothing to stop the corrosion. Added to that, as more corrosion occurs, it may well cause fragile old tubes to blow-outwards. Not really what you were aiming for….!:)
By: TonyT - 8th May 2012 at 19:17
True, but it is a very brave man that tries it on something irreplaceable to see if yours is the safe stuff.
By: ZRX61 - 8th May 2012 at 18:14
WHATEVER YOU DO… DO NOT LET MAG ALLOY COME INTO CONTACT WITH PAINTSTRIPPER…….. it WILL dissolve in front of your eyes…
Not ALL paint strippers dissolve mag….
By: TonyT - 8th May 2012 at 17:59
Yep selenium acid, have it at work… Have you downloaded the RAF painting manual I put online, it as a whole section on treating various corrosion, including Magnesium…… WHATEVER YOU DO… DO NOT LET MAG ALLOY COME INTO CONTACT WITH PAINTSTRIPPER…….. it WILL dissolve in front of your eyes…
If you haven’t the Manual I put up PM me and I will sort out a link for you.
By: mjr - 8th May 2012 at 15:08
Selenious acid. Official chemical for mag alloy corrosion…..I doubt you will get hold of any though, as its fatal if injested.
By: 12jaguar - 8th May 2012 at 11:44
Thanks for the info John
I think that anything that prevents further oxidisation of the internal material is the way forward, just finding the best means for doing it
John
By: John Green - 8th May 2012 at 11:33
12Jaguar
I’d be thinking about filling the tubes with either a polyester or epoxy flocoat. I do not know of any possible chemical contradiction or adverse re-action.
Either of these mixtures would prevent further internal corrosion and would also add strength to the frame.
John Green
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May 8, 2012 at 11:09 am