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Removing Galvanised Finish from metal parts

Posted: Wed Apr 26, 2017 12:14 pm
by Tim Page
Hi all, I got some galvanised shackles for my Comet this week, but found them to be far too shiney.

I did a quick google search and found a relatively safe method to strip away the Galvanised finish.

Simply drop them into a sturdy plastic container of Harpic toilet cleaner with bleach and leave for a few hours or overnight.
Rinse off with water and then dry.

This process seems to start almost imediatley and works well.

Just be mindfull that Bleach is pretty nasty stuff so wear protection.

Cheers
Tim

Re: Removing Galvanised Finish from metal parts

Posted: Wed Apr 26, 2017 12:44 pm
by paul&robinmargle
Soak in vinegar and leave in the rain to rust is a safer option, although takes longer.

Robin

Re: Removing Galvanised Finish from metal parts

Posted: Wed Apr 26, 2017 1:52 pm
by Stephen White
Why would you want it to rust? Serviceable tow ropes are never rusty. Of course, modellers are always able to make their own choices about their models but the emphasis on rusting is misplaced if you want a realistic model. Stephen

Re: Removing Galvanised Finish from metal parts

Posted: Wed Apr 26, 2017 1:59 pm
by Tim Page
I will post a picture of before and after.

I am not wanting any rusty parts, just less shiney.

Tim

Re: Removing Galvanised Finish from metal parts

Posted: Wed Apr 26, 2017 3:24 pm
by Phil Woollard
I know the problem well with shiny shackles, even when painted they will chip with the slightest knock, and believe me they will get knocked, and then the shiny coating shows through and looks pants.
Easy way to remove the coating (sometimes it's chromium based and others are zinc) no matter place in a log, coal or your garden bomb fire and burn the coating away,the hotter the better, then a wire brushing and you have a lovely surface ready for painting or not if you want the oily rag metal look. I have had some makes that are highly polished, then you have to use emery paper strips in the vice to remove.
It's tempting to use a blow torch, this will work but the zinc fumes cause flu like syptoms (not good) cheers Phil :D

Re: Removing Galvanised Finish from metal parts

Posted: Thu Apr 27, 2017 12:41 am
by Gerhard Michel
Hi Phil,

all this ' fiery methods' can be a little problem when you furthermore need the toughness of the shackles for tightening the model while it is transported (emergency braking). I prefer 'cold' methods like a little sandblasting.

Re: Removing Galvanised Finish from metal parts

Posted: Thu Apr 27, 2017 5:55 am
by Phil Woollard
Sandblasting nice, I like burning things :D I like burning things a lot ! :D

Re: Removing Galvanised Finish from metal parts

Posted: Sat Apr 29, 2017 3:39 am
by Michael Cecil
I use Muriatic Acid to remove zinc coatings. Available from hardware stores. Just dip the object in until it stops fizzing, then rinse off in clean water and dry. It is then ready for undercoat.

A small bolt takes only a couple of minutes to stop fizzing. I usually decant a small amount into a plastic tub with a tight lid. The acid can be used repeatedly until the process slows down, in which case it is time to discard and put in some fresh acid. Between uses, make sure the lid is on and tight.

Mike

Re: Removing Galvanised Finish from metal parts

Posted: Sat Apr 29, 2017 7:46 am
by Phil Woollard
One fact to consider with your choice of shackle, the crews hated the threaded pin! If the pin was bent out of true ( even a small misalignment ) the threads would bind up and require a large wrench or even the gas axe to remove, not ideal if you were recovering a vehicle under fire.
I must confess for ease of use I use the threaded type, but for close up photos or video I prefer the non threaded look cheers Phil.

Re: Removing Galvanised Finish from metal parts

Posted: Thu May 04, 2017 12:49 am
by John Fitzsimons
I soaked in vinegar. Just took the shine off.