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Etched Brass


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Hi all,

A while ago I purchased an etched brass Mallard Models Connoisseur kit of a 70ft Dining car.

I am about to start it and have been looking at the kit.

There are a lot of marks over it which do not äppear" to be tarnishing, but rather possibly residue from the etching process.

Looks to be palm marks from the hand etc.

On one of the bogies it appears one small part has been eaten away by this.

 

Question:

Is there any way I can neutralise this completely.

I was wondering if a soak in some vinegar would do the job?

 

TIA for any suggestions.

 

Khris

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Etching is done with acid so if the corrosion is due to the etching process adding more acid is only going to make it worse so on no account use vinegar.

 

I would give the parts a good scrub with a fibreglass brush and then wash thoroughly.

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Hi all,

A while ago I purchased an etched brass Mallard Models Connoisseur kit of a 70ft Dining car.

I am about to start it and have been looking at the kit.

There are a lot of marks over it which do not äppear" to be tarnishing, but rather possibly residue from the etching process.

Looks to be palm marks from the hand etc.

On one of the bogies it appears one small part has been eaten away by this.

 

Question:

Is there any way I can neutralise this completely.

I was wondering if a soak in some vinegar would do the job?

 

TIA for any suggestions.

 

Khris

 

Khris,

 

Usually etchers "wash" the brass after etching to remove all traces of etchant. A missing part is likely to be just that, something that wasn't correctly tabbed/designed.

 

Handling the brass can leave marks if you have "aggressive" sweat.

 

I would suggest washing the brass with soap in hot water (soap is alkaline and should counteract any acid effects), then clean with a fibreglass brush as Andy suggested and wash again.

 

Jol

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Ah, alas my post has been lost in the cyber regions.

Try no2

That is the vinegar issue sorted.

The part that has disappeared I believe has been eaten rather than not be there.

The metal is black at that area.

I have already tried the fibreglass route but it had no effect on the black areas, apart from dulling them a bit.

I really was more concerned it may still be being eaten by residue.

I suppose when all is said and done, if I washed it again and went on and built the model, by the time I prime it, paint it and use it I will at least get that satisfaction before I croak it...... gota look on the bright side :stinker:

 

Khris

 

Edited correct atrocious spelling!

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Finger prints will tarnish brass - it is the acid in the sweat. But the tarnish should be easy to remove with abrasion. I would avoid using a fibreglass pen over the whole etch and concentrate on using it only at the point you wish remove the parts from the fret and to solder the parts. It might be useful to see this black etched part of the fret. Some rather old etches were not particularly well controlled and air bubbles were allowed to remain on the surface, in addition some of the mixing of the solution was poor and this presented itself as over etched spots. All the chemical should have been neutralised and then washed off at the end of the process. Giving the whole fret a through scrub with something like Cif scouring cream or good old fashioned Vim should certainly make sure - it would also remove the tarnish. But beware brass tarnishes very rapidly when just exposed to air. Simply taking a fresh kit out of its sealed bag and leaving it on the bench for a couple of weeks will see it go from shiny gold to dull brassy. Some frets are supplied with a polish coating (just as if you had used brasso on it) this needs to be removed before soldering by a wipe with a solvent degreaser.

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On old etches you can get places were the copper has oxidised to form a black or brown crust. I have no idea what causes this, but the fact that your etches have hand prints suggest that they have not been well kept. The only solution I have found is to scrape off this crust down to bright metal and hope that you remove whatever caused the problem.

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