Silver Soldering studs?

[Bo’sunParticipant @bosun58570]

Good morning,

I’ve been Silver Soldering some 5 BA bronze studs into a copper boiler, but despite careful placement of the solder, it runs up the stud thread.  A little careful filing and re-threading solves the problem, but I’m concerned the re-threading force may weaken the solder joint.

For the future, is there a way to stop the Silver Solder running up the thread?

[roy entwistleParticipant @royentwistle24699]

Tippex on thread

[Michael GilliganParticipant @michaelgilligan61133]

Tippex [original version]

MichaelG.

.

Roy beat me to it.

[Bo’sunParticipant @bosun58570]

Thank you Michael, what do you mean by “original version”?  Is it likely to still be available, and how would I recognise it?

What a surprise, the new “eco friendly” version doesn’t work as well as the old.

[Michael GilliganParticipant @michaelgilligan61133]

If I recall correctly, the original version is in an all white bottle, and is thinned with something of which Nanny disapproves.

I will check later.

MichaelG.

.

Edit: __ Here’s a proper ‘grown-up’ paper about the safety implications

https://www.inchem.org/documents/ukpids/ukpids/ukpid29.htm

[Engine BuilderParticipant @enginebuilder]

I have always used Tipex but latley have used acrylic paint with equal good results.

[bernard towersParticipant @bernardtowers37738]

Original is white bottle with red writing and eco friendly is white bottle with (yes you guessed) green writing. Original can be thinned with cellulose thinners to make it easier to apply and get finer lines.

[JasonBModerator @jasonb]

Solvent based is what you want.

 

Also be careful not to burn the crests off the threads, that is why boiler bushes are not fully threaded until after soldering, studs are more at risk due to their smaller mass.

You should have some plain shank on the stud anyway unless it is to holed some very thin parts rather than using Allthread. So risk of solder getting onto the thread is far less.

[Bo’sunParticipant @bosun58570]

Thanks Jason,

The studs are fully threaded, made from 1/8″ plain rod.  I like the idea of some plain shank.  That would have been a better way to go, had I realised the solder would creep up the thread.  Well, as they say, every day’s a school day.

[HopperParticipant @hopper]

Milk of magnesia was the traditional masking agent for silver soldering.

Some nanny states (The Police State formerly known as Australia) have banned its sale but apparently compounding chemists will make it up for you. No idea of UK availability these days.

[Bo’sunParticipant @bosun58570]

Hi Hopper, it would appear it’s escaped (for now) the interests of the UK nannies.

[john fletcher 1Participant @johnfletcher1]

The original Tipex contained Carbon Tetrachloride, same as used by dry cleaners and do you remember “Thawpit”,same chemical, used to remove spots of oil and fat on clothes. Kids used to sniff Tipex and apparently it damaged their brain. john

[Harry WilkesParticipant @harrywilkes58467]

Carbon Tetrachloride wasn’t that the stuff in the old brass fire extinguishes ? Remember pulling them off the wall to ‘degrease’ the odd job.

H

[john fletcher 1]

On john fletcher 1 Said:

The original Tipex contained Carbon Tetrachloride, same as used by dry cleaners …

Not quite, John … at least according to the paper I linked earlier

At a personal hazard level, however, the differences are possibly  trivial …

MichaelG.

.

1.9 Physico-chemical properties

Chemical structure
1,1,1-trichloroethane
Molecular Weight = 133.42
CH3CCL3

Physical state
Liquid (non-viscous)

Colour
Colourless

Odour
Sweetish odour similar to that of chloroform or carbon
tetrachloride. The odour of 1,1,1-trichloroethane is considered
distinctive or powerful enough to provide satisfactory warning of
exposure, however, it is usually noticeable at about 100ppm which
is below the level required to cause acute toxic effects (Clayton
and Clayton, 1981).

.

[Martin KyteParticipant @martinkyte99762]

Carbon Tetrachloride is carcinogenic.

regards Martin

[Bill PhinnParticipant @billphinn90025]

Bo’sun, in addition to painting on whatever flow-retarding gloop you decide to put on the threads, make sure you apply plenty of torch heat to the boiler body around the stud (preferably from the inside), not just the stud itself.

[Nigel Graham 2Participant @nigelgraham2]

Tipp-Ex (Rapid) to quote the label correctly, is in a white bottle with blue and red ornamentation, white and black print, three warning diamonds and doom-laden tiny print…. The label does not specify the solvent beyond “hydrocarbons”, a description so broad it covers us as well as Tipp-Ex, but it won’t be carbon tetrachloride.

… and is indeed still available.

I bought a bottle only yesterday, its first use being to correct a mistake in a questionnaire.

I survived.

Once opened, materials like this are best re-closed securely and kept at the back of the ‘fridge to minimise solvent loss.

[Bo’sunParticipant @bosun58570]

Thanks for the tips and advice.  A colleague has just mentioned that Graphite (soft B grade pencil) will also resist Silver Solder.

[Engine Builder]

On Engine Builder Said:

I have always used Tipex but latley have used acrylic paint with equal good results.

I think Engine Builder has the answer there.  White acrylic paint consists of water, various organic compounds, and titanium dioxide.  So, a bit like Tippex. With the application of heat the water will boil off, the organic compounds will burn off, leaving the titanium dioxide as a solid layer ( it will melt at about 1,800 C).

Russell

[Harry Wilkes]

On Harry Wilkes Said:

Carbon Tetrachloride wasn’t that the stuff in the old brass fire extinguishes ? Remember pulling them off the wall to ‘degrease’ the odd job.

H

I  believe it was Harry thus CTC Extinguisher on the casing !

Slightly OT but back in the 60’s when we used Carton Tet with Coconut grease dissolved in it as a cutting lube for mild steels and other carbon steels — worked extremely well.

Interesting about the acrylic paint – a very good tip !

John

[Bo’sun]

On Bo’sun Said:

Thanks for the tips and advice.  A colleague has just mentioned that Graphite (soft B grade pencil) will also resist Silver Solder.

If a Graphite pencil is used, best to go softer than B, perhaps 4B.   They’re readily available in Art Shops and on the web,

Almost anything that gets between the metal and the silver solder will do.   It has to be heatproof, a bit sticky, and either harmless on the thread or not too difficult to remove.  Ideally it should be quick drying.

Tipp-ex and other correcting fluids are paints containing a finely powdered inert mineral with a dash of glue, and a solvent.   Rapid drying fluids contain a light organic solvent such as Trike, but these are all somewhat dangerous.   Ordinary Tipp-ex is water-based, which works well enough but takes a lot longer to dry.

The inert material in Tippex is probably Titanium Oxide, chosen because it resists yellowing.  Chalk and many other common paint pigments would do the job, suggesting that any emulsion paint would do, but these come in big cans, not handy little bottles with a brush.

Oil Paint isn’t a good idea because it burns messily.   But I very much like Engine Builders’ Acrylic Paint suggestion,  cheap, non-toxic, and available in convenient sizes.

The number of posts inveighing against the Nanny State and optimistically believing traditional remedies work better than modern rubbish suggests a business opportunity.  My book ‘Duffer’s Receipts for Model Engineers Wishing to Stuff up Nanny by Winning a Darwin Award’ will be a best seller.   It will suggest potions optimised to do a good job at maximum risk to the operator, his family, property, and the environment, plus many risk multipliers.   Smoking, ideally a coarse tobacco with cocaine sprinkled in it, will be compulsory.   Protective Personal Equipment is forbidden unless it happens to be 60 years old and made of Asbestos.  An unshielded home-made x-ray machine will be used to test welds, and there will be a boiler pressure tester based on gunpowder, unless a more powerful explosive is available!   As concentrated Sulphuric Acid is cowardly, my pickle will be a hot mix of Oleum and Fuming Nitric Acid.   Chaps will be able to choose organic solvents to achieve their preferred harm:  they all fry the brain, but Model Engineers may prefer cancer to damaging their reproductive system.  The book will list the benefits of all the most hazardous industrial solvents, but not worry heroes by mentioning any poisonous, explosive, narcotic, carcinogenic or flesh dissolving characteristics.   The ideal workshop isn’t ventilated, will be heated with a coke burner, and all electrical equipment will be connected by crocodile clips to an uninsulated bus dangling from the ceiling.  Model Engineers will be advised that safety earths are more trouble than they are worth, and that circuit breakers should be replaced by fuses, and fuses by paper-clips!    Degreasing will be done by boiling in a saucepan full of Leaded Petrol on a gas ring.   Each workshop session will start with a dose of self-inflicted horse-play, such as rupturing one’s own lower bowel by applying an air-hose per-rectum.     A too small Carbon Tetrachloride fire extinguisher will be available, but that won’t matter, because my book recommends using Carbon Tet stolen from the extinguisher as a degreaser, so it will be empty when needed in an emergency…

Dave

[HopperParticipant @hopper]

SOD , you forgot welding old car petrol tanks by connecting a running car exhuast pipe to the filler neck to displace explosive fumes with hot exhaust gas. And a good start in the morning is always to poke yourself in the eye with a pair of scissors that don’t have the little round ball on the end of the pointed blade.

Followed by a good healthy drink from your motorcycle’s battery, in direct contradiction of modern user manuals telling you specifically not to do so.

[Merddyn’s DadParticipant @merddynsdad]

I’ve always found jewellers rouge to be effective, mixed with a little washing up liquid.

Generally washes off well afterwards, but might need a spell in a ultrasonic cleaner, before you put it in the pickle.

[Engine BuilderParticipant @enginebuilder]

It was white acylic I used. You can get a giant tube for £2 at The Works.

[mark costello 1Participant @markcostello1]

You forgot to leave the car idling outside the door or start up the old generator inside.

[Author]

Posts