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It will come apart ok, but might not be so easy to re assemble.
All hardware will have to be renewed, this could be costly even if still available.
The pipes will come off without a problem and could be spruced up in the workshop, scotchbright on the unions will remove the corrosion- try removing one or two casing bolts to see what condition they are in and what is under the washers, these will clean up, you will be surprised what you will be able to achieve with this.
Don't be tempted to use duck oil or WD40 on this as you will find it impossible to prime and paint afterwards.

If I didn't live so far away I would be happy to have a go at this.

om15 wrote: ↑

Wed Aug 19, 2020 8:51 am

Ah, I see, how much money have you allocated to this?

Method 1, complete disassembly of accessories, fuel pipes, looms and so on, split the casings and send away for cleaning, chemical treatment, priming and application of top coat, re assemble.
Method 2, use a small stiff brush and slowly work around the casing removing loose and flaking material, paint the casing with selenious acid, wash off, prime and apply top coat with a small brush.
Method 3, display as is to demonstrate the effects of corrosion on mag alloy.

A challenging job, good luck with it and keep us updated.

Unfortunately our museum is an all volunteer operation with the available money coming from door sales and our pensions, so not very much.

Method 2 is closest to our intentions. We will find what is the best abrasive and spend a couple of days out in the sun removing what loose material we can. We will not be removing anything we don't have too and will be protecting hoses etc before attacking with the abrasive. Paint to finish the job. Fortunately we have dry storage with no extreme temperatures.

Method 3 would be a disappointment but nonetheless a valid thing to do.

om15 wrote: ↑

Wed Aug 19, 2020 10:08 am

It will come apart ok, but might not be so easy to re assemble.
All hardware will have to be renewed, this could be costly even if still available.
The pipes will come off without a problem and could be spruced up in the workshop, scotchbright on the unions will remove the corrosion- try removing one or two casing bolts to see what condition they are in and what is under the washers, these will clean up, you will be surprised what you will be able to achieve with this.
Don't be tempted to use duck oil or WD40 on this as you will find it impossible to prime and paint afterwards.

If I didn't live so far away I would be happy to have a go at this.

Roger re the WD40 etc. We did a Derwent a few years ago and it was in a bad way though not as bad as this Goblin. It was cleaned and painted and looks OK.

Thanks for your comments and advice, ditto to everyone.

John,
A couple of years ago I visited the flying boat museum at Pembroke Dock, there were a couple of mag alloy bits of Sunderland that had been dredged up from the oggin and displayed as is. I spent some time with the restoration team discussing corrosion treatments, missus om later observed that she didn't realise what a fascinating subject it was and how long that it could be discussed for.

Scotch bright pads that are used in the kitchen might be a good way of cleaning, will not remove too much material, I think that you will get better access with the pipes removed and also will be able to clean up the pipe unions better if removed.
Do we know the original colour?

Good point re pipes etc. The original colour was black.

Don't profess to know much about magnesium alloys, but in the days well before elf and sefty became a force in the land one could buy strips of magnesium from hobby shops. Sticking a piece of said magnesium strip into a small heap of aluminium filings, lighting it and retreating quickly would produce sufficient heat to form a pool of molten aluminum. Useful for welding pieces of aluminium together. (Tip from a 1950's DIY magazine) I know 'cos I remember doing it.

Remember using seleious acid to treat some corrosion on a LTS101 engine gearbox,had rubber gloves on ,somehow one finger of the gloves was torn without my noticing,ended up with an agonizing couple of day's due to acid burns under the fingernail.So John if you use selenious acid treat it with respect and use good PPE.

Thanks bob2s, I don't know what we will be doing once we get the casting 'clean'.

Would pressure-washing be a bad idea?

I am not sure about pressure washing but initially we will be trying abrasive blasting, sand, glass, plastics etc etc.

I am often queried by my better half about why I am keeping this or that and wouldn't it be better in the bin, but seeing this discussion made me remember that at some time I had a small booklet called 'Corrosion in Naval Aircraft' AP(N) 206 published in 1968, so I went digging through some boxes in the garage and there it was - possibly 'come in handy' at long last. These are 1968 vintage treatments so they may or may not be relevant to treatments and substances available today. Here are the pages concerning treatment of different substances, especially magnesium alloy which was also a major problem with helicopters. We lost our beloved and cosseted Wessex 3 and got a poor one in exchange when corrosion was discovered in an awkward to inspect part of the tail as the favourite was taken to RNAY Fleetlands for some deep maintenance. Here are the two relevant pages concerning treatment of mag alloy corrosion:


I hope they are readable!

...........and wouldn't it be better in the bin, ........

And a minute after the bin has been emptied .......... you need it. ( or at least would like it ! ) Murphy Rules.

Sand blasting machine has arrived!
...compare post #14!

Impressive, John - what a difference!

Thanks, that's about four hours work so far on this side and we have just started on the other side. It looks good in some places but even our little sand blaster can blow holes in the bad places. I can see some bog being applied before paint!