Prepared by Jim Snowdon Originator Bob Lumley

1. Bob Lumley, Aug 13, 2017
Cant recall having this before. After soldering I always wash items in warm water and leave to dry. However on inspection the following day the soldered areas have a white powder covering. Cleaning the stuff can be a tiresome experience.
I've been using the Safety flux as produced by Building O Gauge on line for some time now so don't understand why this is happening.
Regards
Bob

2. Allen Morgan, Aug 13, 2017
Hi Bob
If it is only happening with they flux it could be something to do with it's makeup. I think if it was something you are doing it would happen with any flux or general wash, i.e. lime scale from the water. Might be worth contacting the supplier.
Regards
Allen Morgan

3. Bob Alderman, Aug 13, 2017
Only warm water, nothing else? Some of the cleaners like Cif can leave residues in the corners where the solder is.
Are you in a hard or soft water area? If soft you may have had a pH imbalance turning the water slightly more acidic and the results you see may be an oxide on the solder.
Bob

4. Stephen Freeman, Aug 13, 2017
If you don't wash it off, I find you will get said deposit. If still there after washing, probably something in the water. Try some water from melting some ice that has formed in your freezer (they all do it despite claims to the contrary).
Stephen

5. Terry Ratheram, Aug 13, 2017
I`ve always found a spray with Viakal , a quick rub with an old toothbrush, and then a wash in warm water works best.
Terry

6. Stephen Freeman, Aug 13, 2017
Terry
That’s what I do, not sure if water needs to be warm though.
Stephen

7. Dave Round, Aug 13, 2017
.. funnily enough I have just spent most of the day cleaning up my Collett tender before washing and leaving out to dry. This is something I have noticed in recent times and a good scrape back, also with the use of a Fibre brush, releases a white powder. After which it does not appear to reoccur. I am using Green label flux with a Loctite 140 degree lead solder. The water around here has got terribly hard.
Dave

8. Bob Lumley, Aug 13, 2017
Thanks Gents for the replies all much appreciated. I should have added that I always spray recent soldered areas with Viakal then soak in warm water for few minutes then allow to dry. Returning today to the chassis it had white deposits in various place which had to be removed using a fibre brush. I have been building models for years and cant recall having this problem before The green deposits yes but not white
I’m just wondering what effect these white deposits have once a model is covered in paint
Regards
Bob

8. Jeff Moore, Aug 13, 2017
StephenFreeman said(Post #6):
That’s what I do, not sure if water needs to be warm though.
IMHO, the warm water will dry out a bit quicker than cold, partly because to will have raised the temp slightly of theitem you've just cleaned.
Jeff

9. Dave Round, Aug 14, 2017
.. one other possibility is a change to the make up of the solder and of course the flux itself . With all the new EEC regulations outlawing a lot of chemicals, anything can happen. Take modern weedkillers, they are a waste of space, as they do not do what it says on the tin! … My lawn weeds, are laughing at me !!!!!

10. Bob Lumley, Aug 14, 2017
Yes thank you for that I am using a new roll of solder cant recall the source. I will hunt around in the store / spares drawer to see if I have any other solder available to try out Another factor is that I have noticed after washing and drying that white deposits have appeared around soldered joints which were done at least six/eight months ago and would have been washed then. This is a build I keep putting to one side while I get on with something else
Perhaps as someone has previously raised…… it may be the house water
Regards
Bob

11. Jim Snowdon, Aug 14, 2017
Bob,
It may seem like a daft question, but why are you washing your work in what amounts to a dilute flux solution? The active ingredients of Viakal, which is marketed as a limescale remover, are formic acid and citric acid, both of which will attach the lead in the solder, and quite probably the tin as well. Citric acid has already been discussed elsewhere on this forum as a viable soldering flux, and some people have confirmed that it works quite well. I won't profess to be a chemist, but a quick check reveals that both lead formate and lead citrate, the two obvious reaction products, are white. If the object is to neutralise any residual acid flux, I would suggest that you might be better off washing your work in a dilute alkaline solution, such as washing soda.
Jim

12. David Littlewood, Aug 14, 2017
It's possible, but both tin and lead are fairly unreactive and those acids are rather weak ones. Maybe worth some experimentation.
David

13. Bob Alderman, Aug 14, 2017
I first started using Viakal quite some years ago on the recommendation of Malcolm Mitchell. It has never been a bother to me. I've used it neat and sometime a prolonged immersion in a dilute solution - two table spoonsful to around 10 litres of hot/warm water. All the solder has done with either method is blacken. No signs of any salts appearing. However I always give the model a very thorough rinse in hot water and, when appropriate, dry it on a radiator.
I missed asking my metallurgist friend her opinion last night. I'll try her again later.
Bob

14. David (DLOS) Smith, Aug 14, 2017
Bob Lumley said (Post #10): -
it may be the house water
Seems unlikely but you could easily use rainwater to confirm or not.
David

15. Jim Snowdon, Aug 14, 2017
I've only ever used Viakal (or its Lidl equivalent) to clean brass after annealing, which it does rather well. It does pose the question as to whether Malcolm was really using it as a means of both washing the model and keeping the brass clean at the same time - my recollection of seeing bits of his work was that it was always very clean.
It will be interesting to hear what Bob's friend has to say, and in the mean time (or at least as soon as I get back to 7mm scale from 1/8th) I'll just carry on without having to wash my brasswork at all. It rather depends on what you use for flux, and that's been the subject of other topic threads.
Jim

16. Bob Lumley, Aug 14, 2017
Again my sincere thanks for the very informative replies. Washing soda as Jim has suggested could be the way to go.
Regards
Bob

17. Terry Ratheram, Aug 14, 2017
Jim Snowdon said (Post #15):-
It will be interesting to hear what Bob's friend has to say, and in the mean time (or at least as soon as I get back to 7mm scale from 1/8th) I'll just carry on without having to wash my brasswork at all. It rather depends on what you use for flux, and that's been the subject of other topic threads. I was always told to wash after soldering in order to remove any residual flux. Also Viakal is useful in cleaning any parts which will be subject to further soldering as handled parts can pick up grease. I remember as well the use of Calgon being recommended for removing white deposits, or stopping them in the first place.
Terry

18. Bob Alderman, Aug 14, 2017
Someone I know swears by sugar soap as a cleaner. He has been known to put a model in the dishwasher too!
Bob

19. Jim Snowdon, Aug 14, 2017
Terry,
If working with the old-fashioned fluxes, typically phosphoric acid or Killed Spirits (Bakers), I would agree with you, as whilst effective enough, these are nasty corrosive products. There really are much better fluxes available, but not from our traditional model railway suppliers, whom I suspect will go on selling the stuff so long as modellers persist in sticking with what they knew decades ago. Until fairly recently, I was using a flux from the electronics industry, Fry’s Flowcoat 362, which is alcohol based and leaves no corrosive residues following soldering. As that is no longer available, I have found an alternative in the form of T208C flux from Solder Connection, in Chepstow, that has the same useful properties. The down side is that they are used to supplying in industrial quantities, and nothing less than a litre.
Jim

20. Jim Snowdon, Aug 14, 2017 Bob Alderman said (Post #18):-
Someone I know swears by sugar soap as a cleaner. He has been known to put a model in the dishwasher too!

His use of sugar soap isn't as daft as it may seem, as it is mildly alkaline as well as being a degreaser. Putting models in the dishwasher is only taking the logic a step further (and other than in scale, not a lot different from what is done in industry).
Jim

21. Stephen Freeman, Aug 15, 2017
Are you sure that isn't 10 litres Jim?
Stephen

22. Jim Snowdon, Aug 15, 2017
Stephen,
Their website did make reference to 1 litre quantities, but I grant you that they would sooner sell 10 litres. It's the sort of issue that really needs a trader prepared to take the risk, or a body such as the Guild to underwrite the risk, which I recall as not being particularly far removed from the reasoning behind the formation of the Guild in the first place.
Jim

23. Jeff Nicholls, Aug 15, 2017
I use Viakal and I use phosphoric acid flux. Both work for me but maybe I'm headed the same way as the dodo……….
Jeff

24. John Taylor, Aug 15, 2017
I like the idea of sugar soap to clean.
I`ve noticed that the local tap water (Staffordshire) has been particularly hard of late. I also use Viakal and my latest loco construction ( MOK Nickel silver etches)has been afflicted with the white powder developing on the solder stains, about 3- 6 hours after drying. I use Carrs green label flux (and very free flowing solder on a reel from a local car boot)
Hasn`t happened on the previous brass kits………………………..
John

25. Bob Lumley, Aug 15, 2017
Phew !!!! its good to know that I’m not alone regarding this issue.
Bob

26. Jim Snowdon, Aug 15, 2017
The fact that it is only evident where there is solder rather ties it down to a reaction between either the Viakal or the water and the metals in the solder.
I'd suggest, for a start, just washing the work in plain water, which should be more than sufficient to wash away the flux, and see what happens.
Jim

27. Haywood21404, Aug 16, 2017
This may be of interest
http://technotes.alconox.com/detergents/detergent-8/cleaning-solder-flux-residue/

28. Bob Alderman, Aug 16, 2017
That is a very plausible reason. As my tame metallurgist is in the aerospace industry she may well be aware of this report.
However I've yet to speak to her - school holiday time.
Bob

29. Bob Lumley, Aug 17, 2017
I’m grateful for the further replies. I've been unable to get to the modelling table as my better half has done her knee in and has been fitted with leg brace and is on crutches and despite the morphine is still in pain. I'm no stranger to housework or cooking but Supermarket shopping is a new phenomena for me.
I will keep an eye on this thread and yes thank you Jim I will be including washing soda in my shopping list
Bob

30. Ian Rathbone, Aug 17, 2017
I've washed and cleaned hundreds of models using Flash floor cleaner (alkaline) and Viakal or Shiny Sinks (acid). Sometimes there is a white deposit on the solder, sometimes not. The key is to let the model dry thoroughly then brush off the deposit with a stiff brush. The quicker it dries the better - I use a hair dryer in one hand and an empty air brush in the other. Each time the solder is wetted the deposit will come back. I don't know whether it is a tin salt or its powdery allotrope but it is not something to worry about. Once dry and brushed off the model will be OK to paint.
Ian R

31. Pat Buckley, Aug 18, 2017
I can’t say that I have noticed this problem with my soldered joints. I use Bakers fluid applied with the tip of a very small paint brush 60/40 plain solder with a Weller 40w plugged into a dimmer and turned down so it doesn’t get too hot. I always give every thing a quick rinse under the tap with warm water no soap or anything only an occasional scrub with an old toothbrush not every time a rinse under the tap seems to be enough to get all traces of flux and bits of solder off. My friend Len got a jewellery cleaner a while ago and the BR1F tender that I am doing for my 9F build had a session in that the other day and there was a lot less muck than I though there would be but still enough to warrant the use of it.
I looks to me as though the problem must be with the cleaning method rather than the solder -flux reacting with each other I am definitely not a chemist so I could wrong but I have no problem at all with deposits forming.
Pat.

32. Kevin Wilson, Aug 18, 2017
Usually I only wash a loco prior to painting, during construction I keep a pot of plain water and a large artists brush within reach, immediately after a solder joint is done it is washed and cleaned up, seems to work.

33. Dave Round, Aug 19, 2017
.. I soldered on the front valance on my S and D 2-8-0, yesterday and after it had cooled, gave it a scrub with just plain water and a toothbrush.. Later on, when I moved it off the table, there were white deposits, on the newly created joints !!! Dave