Fortunat1 wrote:
Fred the Red Shirt wrote in
oups.com:


On Aug 8, 7:07 pm, cavelamb himself wrote:

Fred the Red Shirt wrote:


On Aug 8, 5:51 am, cavelamb himself wrote:

Fortunat1 wrote:

cavelamb himself wrote in
arthlink.net:

Fortunat1 wrote:

I have access to a plating facility (aviation, but it's a jet
engine rebuild shop) where I can get my wing fittings plated. My
understanding is that 4130 cad plating is just that, cadmium and
nothing else, but this shop does it's cad plating by a coating
of nickel first and then cad plating.. I'm reluctant to do this
for the obvious reasons until I find out what the story is...
Anyone know?

You might want to research "Hydrogen embrittlement".

Yeah, I was aware of hydrogen embritlement which is why I asked...

I repeat,

You might want to research "Hydrogen embrittlement"

to counteract it...

And I repeat that the link he provided is to a process that is
not plating.

...

All right now.

I'm not trying to be huffy, but clicking on a link is not exactly
my idea of proper research of a critical detail.

Indeed. However OP wrote:

" Actually, I was mistaken about the nickel. This is the actual
process;
http://www.sermatech.com/documents/sts40_sermetel1207.pdf"

Now, if that IS the actual process, then he was mistaken about
the cadmium as well as the nickel. If that is the process the
shop has suggested for his parts, then no information about
cadmium plating will be relevant because they aren't going
to cad plate his parts.

That would be like researching butyrate dope to prepare to paint
your plane with latex house paint.


Nor is accepting any wisdom posted here without further checking...

First off, ask the plating guys about embrittlement.

I disagree. First of all, he needs to understand what the
shop will to do to his parts. Asking the guys about
hydrogen embrittlement makes no sense if they use
sermetel coating. And if they do, they no doubt can
say that hydrogen embrittlement is not a problem, which
could leave OP dangerously confused if he still thinks
that semetel coating is cadmium plating.


If they know what's what, then what's the problem?

The problem would appear to be that _OP_ doesn't
know what the shop does. Quite frankly, it
sounds like a paint shop, not a plating shop.
It may be that they don't do ANY plating at all.


And it thy don't, then don't go there!!!

But maybe they are a very good paint shop, eh?


Right, Sorry for the confusion guys. Here's the whole story with this
question.

Plan A was to paint the parts. We're talking 4130 parts in a wood wing.
Brackets, compression tubes, etc. I had planned to paint them, but my
partner in the project has someone working in a jet engine rebuild shop
that did Cad plating. Just as I posted the first part of the question
about Cad plating, I got a note from my friend telling me that due to
environmental reasons, they've dropped the cad process and are now doing
this sermetal coating instead. I only got this info and the link as I
was ready to walk out the door for a week away from home and only
glanced at it, but I thought I'd throw it in here anyway.
Back to the cad question for a just a minute, then.
I had seen a good few wood wing airplanes with cad plated parts over the
years, but the original info I got was that this shop did it a bit
different, and I suspected the methods used might be OK for the bits
they were plating for engines but maybe not so good for an old
biplane...
In any case, they've dropped the plating in favor of this coating and
i'm thinking since it's similar to powder coating in a lot of ways and
therefore may have the same drawbacks, I'm going to give it a miss and
just use standard epoxy paint instead..




If I may make a suggestion...

I've used, and strongly recommend, Epi-Bond or Randoplate for priming
metal parts.

Epoxy paint, by itself, will not be reliable over the years.

Richard