Hello all, Currently building an anemometer, and have various brass/stainless bits fabricated by silver soldering made in the last week, I want to paint it this weekend but have a frequent problem-how to ensure all the easy-flo flux has been removed. My usual method is to leave bits outside for a week or so & then wash well, always seems to work ok. but want a quicker method sometimes. I usually resort to trying any random selection of household chemicals, vineager,bleach,dishwasher powder etc, with varying results. Anybody got a good method ? Incidentaly the electrics of this anemometer comprise a push bike "computer" which cost £4.99 from Halfords and seems to work fine, calibration will take a few runs with the thing on the car roof, but so far it works very well. Mark
Removing ss flux
Feb 19, 2005
13 Replies
How about soaking in warm water for a while, if you're lucky it'll rub off fairly easily after that.
HTH Tim Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service
I use a 'pickle' solution - which is basically a 50/50 mix of Nitric acid and water, though a much safer ( but slower ) solution is a pickle comprised of 2 parts Sulphuric acid, 7 parts water and 1 part Nitric acid.
More often than not though I find it's easier to rapidly cool the job ( a water spray is ideal ) and tackle the flux residue before it fully hardens.
I don't know how effective Hydrochloric acid would be - but it's widely available under the guise of drain cleaner.
Regards,
Nice idea for the electronics, and I was contemplating building an anemometer too. But the local paper reported some gentleman in these parts had one, which recorded 140mph and _then_ blew away...
anyone know of a bike computer that'll record 150mph?
- Brian
... and they say that on a cold, clear night you can still sometimes hear the echoes of the 'Doh!!'
Regards,
Disclaimer: My soldering experience is pretty much limited to electronics, so the fluxes used may differ.
Have you tried sticking the parts in a dishwasher? It works for cleaning flux from PCBs. Just don't tell SWMBO ;-)
When cleaning flux by hand I use isopropyl alcohol, but that's mainly because I always have some about.
Tim
I do usually use the dishwasher for final cleaning any way ! But be warned, dont put to many oily parts in a dishwasher- the mineral oil destroys the pump and door seals ! Killed our last washer that way ! Electrical solder flux ( multicore) is a resin that disolves in alchohol, and that is soft solder anyway. Silver ( hard ) solder flux is different ( borax based ). The basic "raw" flux powder dissolves easily in water, but when heated forms a glass. It will dissolve in water if left to soak for a long time-days. Web search yesterday indicated citric acid as a possibility, and this has worked fine. "Traditionally" sulphuric or muriatic acid is used, but I have a small workshop and the presence of sulphuric tends to rust anything in a 50 yard radius!! As as warning to any on-line buyers -I note that my web search showed a couple of commercial (american) sites listing silver solder as a form of soft solder, 98% tin 2% lead. Mark
In message , Mark G writes
I have certainly found concentrated citric acid solution to be a perfectly satisfactory for pickle for cleaning components prior to silver soldering.
Some threads of slime can grow in 'Old' pickling fluid (presumably the products of reaction between the citric acid and some of the contaminants on the pickled components) but that is not really a problem. It is immediately flushed off by clean water.
I bought citric acid crystals from a local retailer of home-brewing products. But before he would sell me reasonable quantities I had to reassure him that I was not into wholesale production of "illegal substances"!
That rings a vague bell! I saw some very cheap "silver solder" recently (B&Q?) what ever it was it was, and where ever it was, it was certainly of US provenance.
I've used citric acid, made up from the powder used by home winemakers for sterilising. It was a lot easier to get hold of than acid - but not as quick.
It seems to be harder to obtain these days, home brewing is a lot less common and at least one chemist told me he couldn't sell it because it was being used as a cheap "filler" with drugs!
Dave Burrage
Johnson Mattey recommendations :-
Avoid overheating or unnecesarily prolonged heating
Use plenty of flux
The glassy residue of overheated flux or flux saturated with metal oxides is much more difficult to remove.
Hot water is sufficient to remove Easiflo if treated as recommended
For more obstinate cases:-
Easiflo Easiflo paste Easiflo stainless steel grade Easiflo Aluminium bronze grade Tenacity No 2 Tenacity No 6 Tenacity 5
Warm 10% caustic soda solution followed by brushing in warm water.
Tenacity 4A
Warm 10% Sulphuric acid followed by brushing in warm water.
(Tenacity 4A is a differently compounded fluoride flux for brazing temperatures over 750deg C)
*************For general crud removal a dish washer tablet in a pan of boiling water is pretty effective.
Jim
In article , Brian Drummond writes
Yep, there's at least one that'll go up to 199. Let me know if you need the name, and I'll have a rummage.
Oh and , let me know if you need it calibrating up to 175...
"Well, officer, it's a scientific experiment..."
Worth pointing out that the EU lead directive means it's more and more common to find soft solder with a composition of something like
95.5:4.0:0.5 Sn:Ag:Cu. This is usually described as "lead free solder" but it seems quite prevalent to call it "silver solder" as well which is not exactly wrong but quite possibly not what is expected either !Emptor caveat as they say...
hee! Different kind of bike, methinks! that or *someone* went overboard with the bragging rights... If the name turns up I'd be curious, but I was thinking of using the wheel/sensor from a dead mouse, and a frequency counter.
- Brian
In article , Brian Drummond writes
It's a Sigmasport
formatting link
Reads up to 300KPH.
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