# Pickle Solutions for Silver Soldering



## steamer (May 14, 2009)

I was torn as to where to put this so I did a new thread.

In another thread there is an ongoing discussion regarding pickling parts to be silver soldered

This process usually involves submerging the part in question into a water/acid solution to chemically clean the part ready for silver soldering and is important to a good silver solder job.

Old school doctorine usually requires sulphuric and or hydrocloric solutions. These are very effective but not enviromentally friendly and can be very dangerous to the user and those around them.

I've done a LOT of soldering and I usually use Hydrochloric,....but 

I have twin 6 year olds. I am blessed, but I don't like using these acids around them, and they are much too curious for their own good.....So I would love an alternative!

Sandy C, a estemed member of this forum and a model boiler expert recommends using Citric Acid. This is apparently popular in Europe because of it's low impact and is safe.  I had not heard of that!

I being a "Yank" did a bit of research and found the following links, that those of you on this side of the pond may find useful.

http://www.amazon.com/dp/B0017WFX6G/?tag=skimlinks_replacement-20


http://www.mcmaster.com/#3190k624/=1uuy2f


http://www.chemicalforums.com/index.php?topic=27127.0


http://www.amazon.com/dp/B0014UCJ8Q/?tag=skimlinks_replacement-20


Have others in the US tried this solution? I ask because apparently there may be some difference between compounds on this side of the pond as compared to the European side.

Dave


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## kvom (May 14, 2009)

John "Bogstandard" recommends this in his silver soldering tutorial that was part of the paddleducks engine thread.


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## steamer (May 14, 2009)

Thanks KVOM

Have you used it?

Dave


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## kvom (May 14, 2009)

No, but I plan to as soon as I get to where I need to. The only silver soldering I've done has been AC tube.


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## steamer (May 14, 2009)

Thankyou kvom, Interesting.

I am going to buy a 5 lb bag of Citric Acid from McMaster...

But like I said, I would like to talk to someone on this side who has used Citric acid purchased "over here"

Dave


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## J. Tranter (May 14, 2009)

I have used it and it worked a dream. I bought a pound of it from a home brew store.
It's supposed to be a saturated solution of citric acid and distilled water. 

John T.


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## aussie bruce (May 15, 2009)

Over here in Australia i use the little tubs / packets from the supermarket of citric acid they are in the baking section.

I think a small tub of approx 100 or 150 grams in a 9 litre bucket works best.

I made the switch over on my last boiler and i am not going back to the harsh acids i too have small children. 

It is not as quick so you need to leave the parts in the bucket for 15 Min's minimum though and it works best if the bucket is full of warm water.

its cheap enough to make a bucket use it for a week and then tip it on the garden when finished.

Have a go you will not be disappointed mate 

Bruce


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## steamer (May 15, 2009)

Bruce and John,

Thank you for your comments!

What brand did you buy?.....I'm curious

I'll check the baking section next time I buy groceries

Thanks!


Dave


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## joe d (May 15, 2009)

Steamer

I got some in the drugstore here in Montreal, it was a couple of bucks for 125 grams. (No-name house brand). It was in with the dietary supplements.

Joe


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## cobra428 (May 15, 2009)

Hi Guys,
Did anybody think about vinegar? I use to build HO Loco's from kits. Zmac and brass parts. They recommended to pickle in vinegar over night before painting. The vinegar cleaned things up pretty good.
Tony


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## SandyC (May 15, 2009)

Hi Guys,

For hobby use in a domestic environment, especially where there are young children, the use of the higher (more severe) Acids (Sulphuric, Hydrochloric etc) is courting disaster and the much safer alternative of Citric Acid is the way to go.

Mix strength is not that critical, a weaker mix just takes longer to do the job, and even in a fully saturated mix it will be considerably slower than the higher acids, but for hobby purposes a few hours soak is no big deal, and no harm will be done to young inquisitive hands should they get in to it (The same cannot be said for the other types) and should they manage to get some in thier mouth, it will taste very bitter (Lemon Juice), which should readily put them off from further tasting. (Again, the same cannot be said for the higher Acids)

Disposal,after the job is done, also presents no problems as the solution can be safely poured on to your garden (acid loving plants will love it) or even flushed away down the sink, being totally organic it will do absolutely no harm to the environment.

The one problem most people have, when using Citric Acid, is that being totally organic it readily promotes fungal/bacterial growth on its surface if stored for more than a couple of weeks after being mixed in water.

This can readily be overcome by the addition af 1 cap full of ordinary Household Bleach per 5 litres of mix, but if this is done then it will become more of a problem where young children are about.
BLEACH, even very diluted as it would be, is not something they should get in thier mouth.

It would still be safe to put hands into though.

As a professional model boiler maker for many years, where time was much more of a cost issue, then I naturally used the higher acids and had in place the necessary disposal contracts (you can't just dump this sort of stuff down the public drains). Items were pickled for no longer than 2-3 hours then rinsed off in clean water. They could not be left in soak for much longer than this without the acid starting to attack the actual metal surface.

Now that I have retired I only use Citric Acid in my workshop and often leave jobs in the pickle for several days with absolutely no harm done to the metal.... it is very clean though.
This can be of great help when you may need to solder a boiler up over several days of free time.... just remove the required parts from the pickle and the remaining parts can be just left in the pickle until required for later assembly.
If all the parts were cleaned and then left on the bench, until required, then (especially with copper) IN AIR OXIDATION can/will set in and the parts will require cleaning all over again before they can be assembled.

To sum up, if you have got children around then take the sensible approach... it only takes a few seconds with higher acids to do irreversable damage to them.... and you would never be able to forgive yourself.    


NOTE... the above comments regarding exposure/ingestion apply equaly where you may have pet animals around.

Play Safe.

Best regards.

SandyC ;D ;D


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## ScottM (May 15, 2009)

SandyC

Bleach can be used to Purify water for drinking.


http://www.ohsep.louisiana.gov/factsheets/LocatingSafeDrinkingWate.htm

  * Chemical sterilization. In some situations, boiling may not be an option. The alternative is to treat the water chemically. Plain household chlorine bleach may be used. Be sure the label states that hypochlorite is the only active ingredient. Bleach containing soap or fragrances is not acceptable. With an eye dropper, add 8 drops of bleach per gallon of water (16 if the water is cloudy), stir and let stand. After 30 minutes the water should taste and smell of chlorine. At this time it can be used. If the taste and smell (and appearance in the case of cloudy water) has not changed, add another dose and let stand. If after one half hour the water does not have a chlorine smell, do not use it.

- Scott


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## SandyC (May 15, 2009)

Hi Scott,

Yes you are quite correct, the only reason I suggested caution was the fact that a great many of the readily available 'Household' bleaches do in fact contain other additives, such as those you mentioned, in which case these could/would possibly present problems.

The use of pure Hypochlorite would be perfectly safe as you have stated.

Thank you for clarifying my oversight.

My apologies if this has confused any of you.

Best regards.

SandyC


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## ScottM (May 15, 2009)

Yea it's the additive that get you in the end :-}

What I'd be worried about is whatever dissolves into solution from the part you are pickling.
I did not know until recently that there was an alloy of steel with lead in it, probably not the thing to use in a toy.

no matter what you use for a shop project it should probably be kept away from the kiddies,
almost everything is bad in some way if used wrong as i remember you can die from too much oxygen,
or too little(I'm sure about the little part).


- Scott


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## steamboatmodel (May 15, 2009)

I have used both Citric Acid and vinegar for pickle solutions, both much safer that the stronger acids. if you add a couple of drops of bleach and keep the storage container closed you will not run into fungal/bacterial growth. I also used to add a couple of drops of Bitrex to it to discourage young hands and pets, I don't think any of my kids tried tasting it, but my dog and one raccoon did.
Regards,
Gerald.


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## firebird (May 15, 2009)

Hi

I'm in the Uk. I used citric acid on my boiler project and got on with it very well. I bought it from the home brew department of a local store. I believe they use it for sterilising bottles. As Sandy C has stated leaving parts in this type of pickle does no harm, I have left parts in soak for over a week, ready for the next time I went to the workshop. My pickle bath is a large plastic tub with a lid. I think its a large cake container (the tuppaware type, do you have tuppaware in the states?) Keeping the lid on tight I have had no problems with fungi.

Cheers

Rich


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## kvom (May 15, 2009)

> (the tuppaware type, do you have tuppaware in the states?)



*Tupperware* was invented by Mr. Tupper here in the good old USA :


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## Maryak (May 15, 2009)

kvom  said:
			
		

> *Tupperware* was invented by Mr. Tupper here in the good old USA :



And provided some very neat tool stowage items along the way. ;D

Best Regards
Bob


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## firebird (May 15, 2009)

Hi

Do you think Mr. Tupper was a model engineer at heart??? He has certainly provided me many storage solutions.

cheers

Rich


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## steamer (May 15, 2009)

Hello All,

Thank you for your support and input.  I will try the Market variety and report back.

Dave


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## Loose nut (May 18, 2009)

SandyC  said:
			
		

> Hi Guys,
> 
> For hobby use in a domestic environment, especially where there are young children, the use of the higher (more severe) Acids (Sulfuric, Hydrochloric etc) is courting disaster and the much safer alternative of Citric Acid is the way to go.



Vinegar may be safer but dilute Sulfuric acid (battery acid 37% diluted 7 or 8 to one) will do in ten minutes what will take over night with vinegar.

If you have kids and pets around you better keep the shop locked anyway because there is a lot of other things that can bite them there besides acid. Don't forget your goggels and don't put hot items into the acid bath, the steam that comes out is diluted acid not just water.


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## steamer (May 27, 2009)

Hi Loosenut,

I agree with you about efficiency of the sulphuric, but with my shop so small, any acid fumes and I have rust everywhere....I just bring it outside if I can.

I am intrigued by the citric acid, as it supposedly won't evaporate off and cause the rusting.

My Kids whom I adore know better than to even go into the shop without me. That is drilled into them CONSTANTLY!... When they are there they wear their goggles........but at 6 they haven't got their heads wrapped around the concept of that watery looking stuff can burn them.....I may need to give them a demonstration....but I would rather just do something else if it works well enough.

So far I am having a tough time finding a regular supply that doesn't come in a 5 lb bag or need to be mail ordered......I'll let you know when I do.

Dave


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## Ora Banda (May 27, 2009)

Built with the help of citric acid... food for thought (excuse the pun)


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## rickharris (May 27, 2009)

steamer  said:
			
		

> ...
> 
> So far I am having a tough time finding a regular supply that doesn't come in a 5 lb bag or need to be mail ordered......I'll let you know when I do.
> 
> Dave



Here in the UK you can buy citric acid as Kettle de-scaler in small sachets in any supermarket.

You can also get safety pickle from jewellery making suppliers - it's about £8 for a Kg


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## PTsideshow (May 27, 2009)

Here you go Sodium Bisulfate or PH reducer for swimming pools....http://www.homemodelenginemachinist.com/index.php?topic=4099.msg42783#msg42783
 ;D
glen


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