Assembly and blackening of Slater's 3 link couplings

Dog Star

Western Thunderer
As Slater's Plastikard has had several "versions" of the hook over the years then the starting point is to say that I am using the cast brass hook which is supplied as two hooks per sprue in the 7mm wagon kits for PO wagons. In addition to the cast brass hook the kits include six individual steel links to form the coupling chain.

My current procedure is:-

1/ fettle a hook casting to shape, adjust the size of the rectangular portion to fit the slot in the headstock and then open out the holes in the casting to take the link and a split pin (which retains the spring against the rear face of the headstock);

2/add a link to that hook a solder the ends of the link to disguise the butt join. Remove excess solder with emery cloth;

3/ add a second link through the first link and solder the ends of the second link. Remove excess solder as above;

4/ add a third link through the second link and solder the ends of the third link. Remove excess solder as above.

So now I have an assembled 3-link coupling - the assembly is degreased using IPA, then dipped in Carrs Acidip, then rinsed in water and finally dried.

Given that the 3-link coupling is comprised of a brass casting and steel links... how do WTers think that the assembly ought to be blackened?

thank you and regards, Graham
 

Rob R

Western Thunderer
Graham,
I'm not too well versed in the art of blackening but taking a logical approach:-
Does the best substance for blackening the steel have a detrimental effect on blackened brass?
If not, blacken the brass hook at the end of stage 1 with the appropriate stuff then proceed to stages 2 onwards, blackening the loops at the end.
Some steel blackening stuff we had at work many years ago left brass a nice rusty brown colour. Can't remember which brand though.

Rob
 

lankytank

Western Thunderer
Graham

I simply clean with IPA or cellulose thinners, sommat to get the muck/grease off.

Then dunk the whole job in neat Birchwood Casey Brass Black or Gun Blue - which ever comes to hand first, they both seem to work equally well & I'm no chemist - (I know others like to thin theirs down) gripped in the teeth of 'reverse' tweezers so I can keep an eye on progress, when the fizzing has calmed a bit, out they come and dropped into a jar of rinse water. Out of the rinse onto kitchen towel to drain, then a bit of a rub with more kitchen towel, any bald patches indicate that the above is repeated. Once satisfied, steel items get a rub over with an oily rag (yes, literally a bit of oil soaked bog roll).

Always bear in mind there are a couple of methods to remove the fur from a feline......... Not saying mine is the right/only way.

HTH
 

simond

Western Thunderer
To simplify the chemistry, I recall that Bill at Premier had steel hooks for sale. Obviously his links are also steel.

They’re stamped, but not coined, so they’re pretty 2-dimensional, but a bit of filing sorts that out.

hth
Simon
 

Dog Star

Western Thunderer
To simplify the chemistry, I recall that Bill at Premier had steel hooks for sale. Obviously his links are also steel. They’re stamped, but not coined, so they’re pretty 2-dimensional, but a bit of filing sorts that out.
Thank you Simon; if I was starting from fresh and not building Slater's kits then using steel hooks is a good shout. At the last count there are circa 25 PO kits to be built and so changing to steel hooks represents a significant outlay... plus the need, possibly, to re-work the corresponding slot in every headstock.

regards, Graham
 

Overseer

Western Thunderer
Definitely blacken the hook and chain separately before assembly. I use a cheap smallish coarse brush to apply the Brass Black, scrubbing it on seems to give a more even finish, then wash off after a minute or two. The chain is treated the same way with the steel blackening or heated and dunked in oil.
 

simond

Western Thunderer
I like the look of oil quenched parts, but it doesn’t sit well with soldering the links closed, unfortunately.

it’s ideal on the steel hooks, though!

tant pis
Simon
 

Dog Star

Western Thunderer
Definitely blacken the hook and chain separately before assembly.
Blackening the hook before adding links is the way that I shall go for future assembly of 3-links. I can assemble two links with the join of each link soldered up, blacken the two links and then use a third link to attach the links to the hook.

Fraser (@Overseer) , how do you deal with the link which is attached to the hook? (given that I wish to solder each link closed and that shall take place before blackening the link)

regards, Graham
 

Overseer

Western Thunderer
Blackening the hook before adding links is the way that I shall go for future assembly of 3-links. I can assemble two links with the join of each link soldered up, blacken the two links and then use a third link to attach the links to the hook.

Fraser (@Overseer) , how do you deal with the link which is attached to the hook? (given that I wish to solder each link closed and that shall take place before blackening the link)

regards, Graham
Graham, I don't worry too much about the joint as coupling chains are a functional item I like to be able to remove. I do sometimes file the lip off the cut ends so when lined up the joint is less obvious and a spot of black paint fills any visual gap.
 
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