Technical question

Yes please – if you can send to [email]hydealfred@sky.com[/email]

It would be much appreciated.

Thanks

I can email you Pics & drawings of how I did ZF578. (Now at Tangmere)

Sandy

I was wondering, have the wings been ‘repaired’ by just skinning over the cut with thin sheet – no structural work done?

Richard

Thank you all –

The above is near to fact – although we have been told there are “RSJ’s” providing support in the wings. I dont think there is any ribbing to attach the ali sheets to at the moment. It is very thin gauge and flex’s very easily.

Safety first..Put the plane up on jacks and trestles before any work..
Here is a good starting point for repairs…
http://www.aviationpros.com/article/10383830/the-art-of-sheet-metal-repair

It does make you think!

I was wondering, have the wings been ‘repaired’ by just skinning over the cut with thin sheet – no structural work done?

Richard

One of the reasons for the warping may not be the heat, but rather that the original repair simply joins the skins together. If possible, I’d also have a look at the feasibility of fitting a much thicker plate across the cut spar webs… By putting the stress back into the spar, where it was supposed to be when the wing was whole, you should end up with a much stronger repair… I appreciate that this may be outside of the realms of possibility…

For it to warp in the sun it must be pretty thin ! I would post some pictures of the strips so we can get an idea of the gauge of skin and what the rivet patterns are like – I take it the strips cover some substancial reinforcement plates in the wings ?

Going off a very hazy tinbasher memory I would go twice the original material thickness.
2024-t3 is the standard for general aircraft repairs.For High stress I would go 7075 T3 but is more expensive..

Post up a picture and we can go from there.

Bruce

If the surface is fundamentally sound, and not breaking up at all, clean it off with a mild detergent, and once dry, apply brown wax boot polish. Buff and repeat. Will look lovely.

Bruce

Thanks for the input so far guys….. what if the surface is not that great 🙁 it appears a few “stress” cracks are appearing and parts of the seat are appearing “chalky”

The finishing oils are long chain hydrocarbons that have residual groups to react on the hydroxyl groups in wood to waterproof and protect. But only a monolayer as you wipe off any unabsorbed 20 mins after application. ( Just be careful to let the oil soaked cloths dry out before putting in the bin as they crosslink with themselves exothermally and can self combust).

Case in point:

http://www.garagejournal.com/forum/showthread.php?t=63523

If the surface is fundamentally sound, and not breaking up at all, clean it off with a mild detergent, and once dry, apply brown wax boot polish. Buff and repeat. Will look lovely.

Bruce

Will ‘ave to try that on the girlfriend, she’s starting to look past her best to 😉

If the surface is fundamentally sound, and not breaking up at all, clean it off with a mild detergent, and once dry, apply brown wax boot polish. Buff and repeat. Will look lovely.

Bruce

Hi Jon,

Your seat is in perfect as-new condition. My suggestion to you is to leave it as it is!

At the moment if its not wood it aint getting a look in 😉 Reminds me I should post a update on progress with VZ193.

No plans to do anything, but always curious as to what advice I can pick up along the way. You just never know when it might come in handy! 🙂

Jon

The seat is made of a phenol/formaldehyde resin. There are lots of pendant hydroxys from the phenol still present on the surface of the resin.

Coating with a polyurethane will react irrevocably with the phenolic residues.

i.e. if you use a PU you probably will not get it off again..

I personally would avoid PU’s as they are aggressive molecules (isocyanates) and not original/appropriate for the time.

I would go with the sanding and a surface treatment. You could try shellac or even a finishing oil followed by wax.

The finishing oils are long chain hydrocarbons that have residual groups to react on the hydroxyl groups in wood to waterproof and protect. But only a monolayer as you wipe off any unabsorbed 20 mins after application. ( Just be careful to let the oil soaked cloths dry out before putting in the bin as they crosslink with themselves exothermally and can self combust).

Alternatively just polish or sand and polish.

No idea, but keen to see what this thread turns up as I have one myself 🙂

Jon

Hi Jon,

Your seat is in perfect as-new condition. My suggestion to you is to leave it as it is!

You can buy it or nick it from Woolworth’s apparently.

Not anymore you can’t! Would a mild T cut give the same result?
Nice seat there Jon, dosen’t look like it needs too much doing to it.

Although I’ve never restored a seat, I’ve done a few radios in my time. The trick for Bakelite / phenolic is use Brasso.

You can buy it or nick it from Woolworth’s apparently.

No idea, but keen to see what this thread turns up as I have one myself 🙂

Jon