Dick,
I have used the Birchwood brass black on the Class A Climax locos I've
built. I have blackend the gunmetal truck castings and wheels, the
Roundhouse boiler cladding and the brass smokbox and stacks I've made.
I've found the best results are obtained by immersing the parts in the
fluid and vigorously brushing with a old toothbrush or acid brush. I've
noticed that the slightest oxidization or patina on the parts causes the
process to be inhibited or not take at all. Even though you degreased
the cylinders there could still be enough worked in steam oil etc. in
the pores of the brass to give trouble.
Now, obviously, you don't want to remove you Ruby cylinders. So I would
first thoroughly clean and degrease them (again!). Use a strong
degreaser such as brake cleaner. Then use a brass or steel brush on them
to remove any oxide. I guess you could also use some wet-or-dry paper.
Then degrease again.
Use a faily stiff toothbrush to apply the blackening fluid and keep
scrubbing the with it. You should find that it starts to take in small
areas that you can then work on and get to grow. You will have to mask
or cover the rest of the engine as it will tend to splash as you scrub
the cylinders with the solution. Now you can see why I do it before I
assemble everything!
Blackening the brass cladding on the Roundhouse boiler required a lot of
cleaning of the brass first. I'm not sure if they apply a varnish or
polish, but the blacking fluid just ran off without touching it the
first time I tried it. Sanding with a fine grit paper and then
degreasing was required before it would key to the metal and start to
blacken it. Even then it took several coat, wash, clean, re-coat cycles
before I got the effect I wanted.
It gives a very nice finish when done, but does require some attention
to surface preparation first.
Cheers
Keith
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Keith Manison Phone (876)702-0337
7 Mulberry Close Fax (876)702-0661
Jacks Hill P.A. Email [EMAIL PROTECTED]
Kingston 6, Jamaica W.I.
