Any Recent Progress in Induction Heating ?

This LINK shows all forum threads containing the word induction

Some interesting bits and pieces there.

This LINK goes to a recent Tutorial I saw regarding making an induction heater.

I get the impression that although people have been interested in using these things for heating up bits of metal in the workshop the technique is limited to melting stuff and heating bearings.

It has never been regarded as useful for soldering and brazing, Is that still the case ? Has anybody recently used these gadgets to solder or braze or are gas torches still the main tool.

Bill

"It has never been regarded as useful for soldering and brazing" -

On the contrary, I would say..It is used extensively in industry, from soft soldering to silver soldering and brazing on all manner of items. Specially formed induction coils hug the workpiece which is preloaded with flux and the filler material, and heated/soldered/brazed in one go. A lot to be seem on the internet on that process.

The main issue is what material the workpiece consists of. Materials such as copper, aluminium, steel, stainless steel, HSS, etc, can all be done this was - Tungsten carbide inserts are brazed onto toll holders this was. However, the induction heater operating frequency and power varies hugely for the different materials, with plain magnetic steels being the easiest to heat, copper and aluminium the most difficult ( LOTS of power needed) and stainless somewhere in-between...

Joe

I shall be watching this thread with interest and appropriate caution [*] ... having just 'decommissioned' two of these: **LINK**

https://www.appliancesdirect.co.uk/p/bhi100/baumatic-bhi100-1-zone-induction-hob-hob

MichaelG.

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[*] the pacemaker clinic suggested I should keep at least 600mm away from an active Inuction hob; but that is very broad advice ... If anyone has quantitatve information I would appreciate sight of it.

I'd be really excited if someone comes up with a reliable, cheap soluition. I tried and failed. Very fragile - read down the tutorial and it hints that if your power supply isn't right then it self destructs. i've destroyed one big one and two small ones being slightly careless with the sequences of start-up. Banggood now do one twice the power if you can arrange a suitable DC supply.

Or you can buy a proper one for blacksmith forging for about £5K (all protection circits and stuff to auto adjust according to load 'built in' ) - I have limited experience forging a knife and it left me with the conclusion that you will need to adjust what you think you know as my knife was riddled with stress fractures probably from forging too cold.

Edited By jaCK Hobson on 27/03/2019 07:55:34

Used in a lot of workshops for shrink fit tool holding but probably not hobby ones.

Am I right in thinking the Weller soldering iron (gun shape) uses induction in which case I and many others have been using induction as a means of soldering for years.

Edited By JasonB on 27/03/2019 08:12:54

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'fraid not, Jason

The Weller gun is just a low voltage transformer, and the tip is part of the 'secondary' ...

MichaelG.

I think I've seen a little induction loop heater used for general soldering in a silversmith's craft workshop - or did I just make that up?

Thanks for the answers, didnt realise it was used like that in industry, will have a look for a few videos on google.

Looking doubtful that us common shed dwellers will ever be using induction to solder up our boiler ends in the near future .....

Kitchens! My electric cooker is fitted with an Induction hob. For heating saucepans I rate it slightly inferior to gas, though cleaner, and rather more effective than a conventional element. There's always a booby trap - not all cookware is suitable for induction heating.

I'm far too cowardly to experiment heating workshop metals on it. The easy-clean surface plate looks easy to damage and expensive to replace.

Swotting up on industrial induction heating I get the strong impression that the process does an excellent job, especially for inside-out heating, but demands careful setting-up. The power and frequency of the machine has to be tuned to the metals, job size and desired heating effect. More suited to repetitive processing than semi-skilled one-offs in a small workshop.

Dave

I recently saw on the tube induction heating of tyres for locomotive wheels where a loose coil was wrapped round the tyre which was fed with hundreds of amps, the tyre went blue and fitted nicely!

Alan

The main problem with large induction heaters is keeping pace makers away from them and avoiding operatives wearing jewellery! I expect there are severe regulations for the safety provision regarding induction hobs, let alone letting joe public loose on anything which could latch to something other than the target material!

Some time ago at a company that I worked at had a large demagnetising coil in the workshop, I was using a bowers three point internal micrometer which had become covered in small steel filings because it had obviously become magnetised, the swarf and filings were clustered like whiskers. I had a brainwave, pass it through the demagnetiser and all the filings and swarf would be gone, that was the plan, it was the first time that I had used this demagnetiser, it was fairly substantial because our product used lots of magnets in their construction, well I passed the micrometer into the coil, holding it quite securely and switched the coil on, I wasn’t prepared for the immediate rapid rise in the temperature of the instrument that I was holding, I nearly dropped it but managed to hold on to it. I learnt a hard but important lesson that induction coils can generate a large amount of heat very quickly, my mind must have been in neutral that day but I learned from the experience.

Dave W

Induction coils are the go-to method for annealing ballscrews before machining:

youtube link

I remember one at university that was used in a general lab rather than the workshop/foundry because it was clean and no combustion gasses. In this case it was melting rare earths for dropping onto the rim of a two ft dia spinning disc cooled by liquid N2 for making superconducting wire.

In my last employment, for an aerospace company we had about half a dozen induction heaters made by inductelec ltd, they replaced the old radynes that dated from the seventies. We had to use them for silver soldering stainless steel elbows and ferrules together to form the ends of aircraft ignition leads. We wound close fitting rings of easyflo no2 up to fit on the elbow, fluxed it all with easyflo stainless grade flux and heated it in a close fitting coil for about 15 seconds and that was it, job done, lovely penetration all through the joint, another job they were used for was melting the glass preforms used in the tips of aircraft igniters, this process took around three minutes in a jig which applied pressure to the components so that they were forced down into the semi molten glass. I used the induction heater and their silver solder to make up pipework for my loco and it made a great job of soldering on nipples but I would hesitate to use it on a boiler, the heat is far too intense and localised, but great for fitting bearings etc