chrisb
Part of the e-furniture
Posts: 345
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Post by chrisb on Oct 29, 2023 6:59:36 GMT
What sort of strength citric acid solution is recommended for picking a copper boiler for a clean up?
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Post by flyingfox on Oct 29, 2023 7:13:57 GMT
Hi Chris, I use a level table spoon per litre for boiler pickling, and that is as strong as you need. high temperatures help the process, and if making a boiler, I add some more Citric Acid towards the end of the boiler build.
Regards
Brian B
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Post by racinjason on Oct 29, 2023 7:52:11 GMT
I mix mine really strong and use it for cleaning all the silver soldered parts, my new boiler came out spotless in few hours from cold it doesn't burn but stings in a cut. cheers Jason.
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kipford
Statesman
Building a Don Young 5" Gauge Aspinall Class 27
Posts: 566
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Post by kipford on Oct 29, 2023 22:52:07 GMT
I use 20g/lt into hot water. Works fine.
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chrisb
Part of the e-furniture
Posts: 345
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Post by chrisb on Oct 30, 2023 4:26:23 GMT
Thanks for the input guys. It’s given me a ball park strength to start with.
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Greg
Involved Member
Posts: 84
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Post by Greg on Nov 1, 2023 10:06:01 GMT
Hi, So I've been building a 3/12" gauge boiler. Just the caulking left. Done with high temp plumbers solder (3% silver). I obviously need to clean it after caulking. My pickle had been sulphuric acid until now, but I was worried about it eating the soft solder, so I thought I'd use citric acid instead, because I thought it'd be gentler. I've never used if before with a boiler, but thought it was week. So I thought I need plenty of poweder. So my mix was 4x100g of citric acid mixed into to 6 litres of water. Used warm water to help get it mixed in. I thought that shouldn't be too weak. Well in a few hours the copper wasn't that much cleaner, but all my solder softr had turned into grey mush So 60+ grams per litre is too strong for soft solder. I don't know if it liked the tin, lead or silver in it. Although I felt it was still slow to clean the copper, so I'm wondering if perhaps I return to using sulphuric acid? Greg
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Post by flyingfox on Nov 1, 2023 12:27:39 GMT
Greetings Greg, that was mighty a strong concentration, and it would have worked a lot better hot. The excess acid actually pacifies the copper and makes it more difficult to clean. regards Brian B
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Greg
Involved Member
Posts: 84
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Post by Greg on Nov 2, 2023 9:59:29 GMT
Yes not good outcome.
So how do people get their new boilers looking so spotless? After removal from the pickle can the copper rubbed with some light abrasive material to finish cleaning it up?
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Post by simplyloco on Nov 2, 2023 10:44:44 GMT
Yes not good outcome. So how do people get their new boilers looking so spotless? After removal from the pickle can the copper rubbed with some light abrasive material to finish cleaning it up? Brillo Pads!
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Greg
Involved Member
Posts: 84
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Post by Greg on Nov 2, 2023 11:30:29 GMT
Yes not good outcome. So how do people get their new boilers looking so spotless? After removal from the pickle can the copper rubbed with some light abrasive material to finish cleaning it up? Brillo Pads! Thanks. That sounds easy. I thought they'd scratch thet copper up a bit much.
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Post by simplyloco on Nov 2, 2023 13:05:57 GMT
Thanks. That sounds easy. I thought they'd scratch that copper up a bit much. It all depends on what sort of finish is required, and whether the boiler will be covered. If you want shiny then there's always Solvol Autosol...! John
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Post by flyingfox on Nov 2, 2023 16:21:07 GMT
I use a green scouring pad. regards Brian B
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jo479
Hi-poster
Simplex, Pricess of Wales, Prairie, N24X, LNWR Jumbo, Jeannie Deans, 7 1/4 Lion
Posts: 189
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Post by jo479 on Nov 2, 2023 18:40:44 GMT
Make sure ALL your soldering is complete before using the Brillo Pad
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Greg
Involved Member
Posts: 84
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Post by Greg on Nov 3, 2023 7:10:07 GMT
Thanks all for the advice.
I have some of the green scouring pads, so I'll go with them until all the leaks are sorted.
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stevep
Elder Statesman
Posts: 1,070
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Post by stevep on Nov 3, 2023 9:42:33 GMT
Scotchbrite is what I use.
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Post by doubletop on Nov 9, 2023 8:16:01 GMT
Mine eventually ends up as a saturated solution with a cake of crystals in the bottom. It starts off in a large plastic container with a lid but more citric acid gets added over time. If I do a small volume mix in hot water for say fittings that all gets chucked in the bigger bin when finished. As it is organic a bit of bleach in the mix to ward off mould growth. Every few years the liquid is drained off and what remains allowed to dry out and the crust in the bottom removed to start again.
Pete
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Post by cupalloys on Nov 9, 2023 8:46:04 GMT
Wow!
In my day, 10gm of salt per litre of water worked remarkably well removing flux residue.
It was cheap and cheerful and when it was spent, it was tipped down the drain and fresh solution made.
Do not attempt to clean the boiler until all the brazing is completed and tested - but why would you?
Oxide removal is the function of the flux not the model maker!
Or have the basic principles of successful silver soldering changed?
If not, get the book from CuP Alloys.
Keith
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chrisb
Part of the e-furniture
Posts: 345
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Post by chrisb on Nov 13, 2023 18:50:44 GMT
Thanks Keith, I am cleaning up an older boiler rather than making a new one.
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