Soldering cast iron with silver solder.

I did not think it was possible to solder cast iron but this solder from Micro-Mark claims to be able to do that. It looks like it cannot be posted outside the US. Has anybody tried this product or something similar ?

**LINK**

Edited By Brian John on 13/06/2016 01:57:53

That's a low temp (430*F) 95% tin, 5% silver, solder. It works perfectly on most everything including stainless steel. But not aluminum. I've never tried it on cast iron. I suspect that it would work well on really clean cast iron. I have silver brazed cast iron with EZFlo. The iron must be absolutely clean. No old, greasy, machine parts. New iron. You should be able to find 95/5 under another name somewhere. It's important to use the acid flux recommended.

Pete

Edited By Peter Krogh on 13/06/2016 02:00:50

Edited By Peter Krogh on 13/06/2016 02:03:15

I've soldered cast iron with Easyflow. Heat first to bring the carbon to the surface, wirebrush and then solder.

Last time the subject came up I posted this pic of Mike Sawyers Bently engine block which shows what can be done.

Even I've done it, just make sure you have fresh, clean surfaces.

Neil

Yep-----well covered in the brazing books.

The important thing is to heat the cast iron well above the normal brazing temperature to burn off the graphite and then let it cool. Then wire brush vigorously and apply flux. This brings the surface to more like low carbon steel. Done this lots of times to repair broken castings etc.

I bought the silver solder and flux kit from Jaycar today but I had no luck with it. The solder just rolled itself into a ball.

I have reread John's post and he said to heat the cast iron well above brazing temperature to burn off the graphite. I did not do that ; I only got it hot then let it cool. I did not read his instructions properly. I will have to do this again but I will need the big burner to preheat the cast iron. That means doing it outside if the rain ever stops.

What sort of pickle should be used for cast iron after soldering ?

NOTE : I do not like wetting cast iron with anything. I remember the last time I washed a piece of cast iron with soapy water prior to painting and it went rusty in about 10 minutes. I was told to do this by PM Research when I inquired about painting cast iron. Now I never wash it with water ; I clean it with meths prior to painting it with a meths based etch primer.

The fact that the solder just stayed as a ball/globule shows it is not hot enough, heat the item, and apply the solder and it should wet and run in straight away. This is a common fault when soldering, not getting it hot enough, the metal should be seen to glow and then offer the solder to the joint. But of course add flux on the solder rod.

Clive

Edited By Clive Hartland on 14/06/2016 11:31:38

The few times I soldered cast iron I sandblasted the workpiece to clean it. Niko.

Brian,

Forgive me for this digression, but your thread seems the most likely place for people to find this information, if they need it in the future.

Tidying-up my small-but-costly collection of Silver Solders, I found a stowaway ... A small coil of Thesscal "A", purchased years ago from K. R. Whiston [UK readers of a certain age will remember his 'Cat'].

Importantly, the little leaflet was also there, albeit barely legible.

What follows is a transcript:

Thesscal "A" Hard Aluminium Solder

Approved for use in aircraft
Melting Range 420--450 degrees C

All parts to be soldered must be mechanically clean.
For, Aluminium and its alloys, copper and brass, do not pre-flux the parts, but when making joints to steel a thin layer of paste flux on the steel surface will prevent oxidisation.
Prepared parts held in position should be brought up to temperature EVENLY with a suitable torch. Heat the solder and dip in flux, apply flux on the end of solder to joint area (not directly in flame). When flux flows temperature will be about 400 degrees C. A little more heat and Thesscal "A" will flow and complete the joint. Allow contact with the joint to melt the solder rather than heat from the flame. After prolonged exposure to a torch flame the flux will tend to dry up and this prevents the solder "Taking".
When joining Aluminium to Stainless Steel it is necessary to apply a thin layer of Silver Solder to the Stainless Steel first, Aluminium Solder adheres to this successfully.

Thesscal "A" joints should NOT be Anodised.

K. R. WHISTON, NEW MILLS, Stockport

.

Unfortunately, I must have already used-up the small packet of flux already.

MichaelG.

Edited By Michael Gilligan on 14/06/2016 18:42:55

Is it still possible to buy aluminium solder/flux ?

For info.

I have just found this review of Thesscal "A" by Flight, in 1955

MichaelG.

MichaelG, a bit OT, but very interesting, that sort of thing could be very handy if you stuff up or get a dud aluminium casting, I vaguely remember something like that, I think it was in the form of a bar, not unlike plumbers solder sticks. Ian S C

K.R.Whiston New Mills, Stockport. What a marvellous company that was. Whatever happened to them?
BobH

.

Regrettably, the place is now a Plumbers Merchant

We moved to the area in 1988, and Ken Whiston retired shortly thereafter

... I don't think it was cause & effect but you never can tell.

MichaelG.

been there, done that

This stuff seems to be a more modern version. I did little experimantation, reported here

Cheers,

Rod

Rod,

Check your pc; clicked on the link above... my AV came up with ' antivirus prevented a harmful file downloading'... ?

George.

Hi George,

AVG hasn't thrown up any problems on my machine. I'm don't understand why you would think that links to external websites via this website would be an issue with my PC . It seems more likely that your PC is unhappy with something on the target website. I don't get any warnings accessing the links from my Android tablet either.

Cheers,

Rod

Silver soldering of cast iron is sraightforward once the surfaces are clean and free of carbon/graphite. Silver solder will not wet onto carbon. The best jigs are carbon.

Get rid of the surface carbon by using the oxidizing part of the flame. That's the bit outside the blue zone of your flame. Heat to red and hold for a couple om minutes.

Allow to cool naturally in air and then clean with a stiff wire brush. Apply a long life flux eg HT5. Reheat. When the flux melts and flows apply the alloy.

Soldering aluminium is also straightforward. Any soft solder can be used, but,as above,. success depends on getting the surfaces lean. Proprietary fluxes are readily available. Your alloy selection will be based on price (?), colour match (?) melting range (?)

For more info see "Best Brazing Practice" and "FAQ" here. **LINK**

Keith

I found Alutite quite easy to use and it doesn't require a flux, just gentle stirring & scratching with a steel wire.

60/40 solder will take on aluminium, apply oil over the area to be soldered and again use a steel wire or even a screwdriver to scratch the area.

Neil

Would SIF BRONZE be as good or stronger than using silver solder, and would the same techniques apply - Ie heat up and scratch off the carbon before brazing?
BobH