youngdylan

Yeah, I did kinda kick myself for not getting a 35KVA. I'm still finding my way round uses for the machine but one thing I like is being able to heat on the fly with a flick of a switch. Some times I want to feed large irregular pieces of work through the coils so the largeer coil I have on it, the more "wiggly wiggly curly wurly" bits I can get through the coil. The looser the fit between the coil and the work, the lower the coupling efficiency. To my way of thinking the more Amps you can pass through the coil, the more Amps will be induced into the work and so maybe overcome some of the poor coupling. Just a gut reaction, no science or real observation there. I think the energy used is related to the amps induced in the work, not what are flowing through the coil (it's probably around 90 deg out of phase with the voltage under no load). Poor coupling efficiency refers to the efficiency of converting the electomagnetic field of the coil into a shortcircuit current in the workpiece, not the effeciency of energy use .... I think. It does get complicated because the machine relies on the inductance of the coil to do all it's self tuning gubbins re frequency, and coil geometry affects this. The amount of amps also seems to depend on what is in the coil. Sometimes on full power and a big chunk of steel in it it starts quite low, say around 300A and this automatically increases up to say a 1000A when the steel goes none magnetic. The numner of turns on the coils used is also an issue. It would be good to have a longer coil but I haven't had time to play around and find what the limits are. It does seem you can use more turns with non magnetic metals. I'm not sure if a more powerful machine can overcome any limits on using longer coils/ more turns. These machines are wonderfully simple to use (the frequency is automatically adjusted) but the physics behind them isn't. I guess it would be possible to use some science to work out varius aspects of the performance with differnt coil geometry, metals, power etc but it probably comes down to sucking and seeing. One thing is that a more powerful machine probably wont speed up the time to heat large section of metal. Above about say 40 or 50mm diameter on mine, the outer surface will spark and burn before the core gets hot. You need to use lower power with very big sections and allow time for the heat to sink in. Re cooling, yeah a bigger machine needs more cooling. That said on my 25KVA I'm only using a little Tweco TIG cooler. This really isn't good for more than a few minutes before the water gets too hot and the machine shuts down. However I also use my slack tub as a heat excahnger using the pump in the TIG cooler more for circulation. This was suggested by Mike B, more info on this page It does allow for pretty much continuous heating as I use it. That said, the 25KVA is only rated at an 80% duty cycle, the 35KVA has a 100%. Now if I add a thermostat and microprocessor control to my slack tub I can have it hooked up to the interenet so it can have a chat with my toaster back home and when it dies it will go to silicon heaven. (Any early Red Dwarf fans out there?) It is actually sods law that now I've got the heater, my next bit of work is a few months of more or less cut and weld so the only use the machine will see is me playing around with coil geometry. It does look like I may have a large bronze railing job in a few months so the machine will be great for that .. hey ho, it sure will be great being able to directly see the colour of the bronze. Re bigger machines how often do we buy a machine and almost immeadiatley kick ourselfs for not getting a bigger one. I'm genreally of the attitude to stretch myself and get the biggest (for most machines) you can afford and have space for; they usually become idespensible

Thanks for that Danger. How are you doing the curved sections? Are you making it as a raked flat panel and then curving the whole panel. I've had some sucess with this on a much less complicated spiral balustrade. Or are you pre curving the individual elements before assembling the panel. I did briefly think about doing this but couldn't get my head round the idea.

I seem to recall K types suffer from one of the elements going none magnetic around the curie point which is somewhere around the 600 mark and this affects the output voltage. This might be related to what you're seeing. I'm sure type N don't have this issue

nice work there Danger and I Iike the crisp joinery. Looking forwards to seeing how it progresses. Do you have any photos of making and fitting the top/bottom rails to the stairs?

I use 2 off 1" layers of fibre board. It's a 3 off 3/4" burner forge and the unsupported area is about 9" by 24". The board is rated at 2300 deg. It 's stood up pretty well over a few years. The inner layer has a few cracks in it running through the holes for the burners but it's still holding together. The top layer is just fine. I don't do much if any forge welding but I do run it very hot at times.

making ladies do what?

gut reaction is a 3/16 plate will warp like crazy over a period of time

I'd stick with Grant, backup and help is second to none. His company is Off Center Products. A bit of Googling should help you get in contact outside of pm'ing Seperate head will probably have a degree of loss of power associated with coupling leads the leads. If you do occassionally need to "take the coil to the work" Grant can supply you with a "flying lead" from the box to the coil

Somebody want to tell me how on earth to do that. I'm a gas man myself but did rig up a coke forge. I experiemented with a sideblast with a tuyere made from solid 75mm with a 1" hole bored through. Only lasted a week or so. Made a water cooled side blast; lasted years, still going strong now but I much prefer using oxy-propane torch/gas forge/ induction heater to solid fuel.

I do sometimes wonder about the selection panels. A few years ago I was short listed for a commission to design and make some work in Welsh hospital. I spent a lot of time making a macquette and designs. When I went along to the selection interview I found out one of the other two candidates was a Welsh female blacksmith who lived in the area ........... I wasn't a total waste of time because I got the work for the railings in this thread on the back of the macquette, but I've never bothered submitting an application for "selected" commissions since.....

Looks like he's still selling them from that batch. http://cgi.ebay.co.uk/BLACKSMITHS-ANVIL-NEW-/180549188260?pt=LH_DefaultDomain_3

google say it's a mind control forum. ?????????????????????????????? http://www.mcforum.n...d048619681e;www

What do all the "up and down very fast" machines do to your hands/arms? Are antivibration gloves any use. I got some nasty tinglings down one arm for a week or so after doing a few hours worth of small (1/4 I think) stainless rivets cold with a 7X aircraft fitters rivet gun and holding 2kg chunk of steel as a bucking bar. Worn the gloves ever since.

All the best Dr Sarver

I learn somethimng new everyday......but as an ex teacher (and SO glad to be so) I can testify that the parodies are so more relevant in this day and age.......in particular "those that can't teach, teach teachers". There's a lot of ex teachers scared of the chalkface and doing little more than paying the mortgage by quoting dogma in those teacher trainer colleges.

Maybe's John N will spot this thread and give you more info, but they've got some working scale models of drop and other hammers over at Massey

John, about a year or so I was desperate to get my hands on one and it didn't look like I'd be able to get one over here because of CE and stuff. I did some quick and superficial looking around at "industrial" heaters over here. We were talking £10,000's here so it was a non starter for me. These are nowhere near that. Okay so it's made in China (as are probably just about any). That doesn't worry me one iota, as long as the quality control is there. The way I look at it is, these tools are a million miles away from the cheap power tools that flood the DIY market. Up till now it's only been industrial or serious professionals that have used induction heating. These sort of people don't usually buy tools that fail. Grant Sarver is "The Man" for this stuff on t'other side of the pond, he's had no reliability issues with the ones he's sold. As far as I know he's been selling them for about 5 yearss (maybe more) Politically it would be nice to buy domestic but if "we" can't/won't produce one small/cheap enough ................ My same thoughts apply to the small Anyang power hammers PS it's John that may be selling them over here (Grant does so over there). I've just paid my money as a more than willing "Guinea pig"

John B John N's is the 240V single phase and rated at 15KVA, mine is the 3 phase 415 version rated at 25KVA but I'm running from a large (32A) red 3 phase socket with a 32A breaker behind it at the distribution board. Hasn't tripped it yet in a few hours use. Mine does need a good water cooler to use it. I'm posting more of my thoughts over here. Maybe it best to pm John re potential cost .... I've an idea but it's not my place to say!!! What I can say is that it's real good value for professional users and opens up allsorts of possiblities for the hobbyist. As Grant say it great for the garage bladesmith with "neighbour" problems, this tool and a hydraulic press

Absolutely awesome. My personal preference is for the face as shown in the fourth photo. Awesome

Latest videoshows the machine with thinner stuff and being pulled through. Boy is this a quick way to heat steel. Someone asked about insulating the coil with fibre glass. Nope, it's just bare copper with none of the coils touching. The work shouldn't really touch or short out the coils. The occassional brush seems no problem (see about 0.07 but if you do a big short the machine will just shut itself down. Quick swith off and on and everything is hunky dory. I'm going to experiment with a sleeve of say 1 or 2 mm ceramic paper between the work and the coil. By my way of thinking this should 1. cut down on the heat that is radiatied from the work into the coils (and taken away by the cooling water), the work should heat up quicker and the water cooler has less cooling to do 2. You can use a coil that "hugs" the work more closely without worrying about shorting as you pull the work back and forth. This allows a better coupling of energy between the work piece and machine .... faster heating (as if it wasn't fast enough) I'm going to play around (when I get time) with forge welding DIRECTLY inside the coil as per the good Dr. Sarver

OK so whilst making a temporary shelter with the cardboard box it came in, I thought this might work as a practical solution. I'll make a similar box out of steel so it's only open to ingress at the front. About 4 inches of clearance at the back where the fan is and 1-2 inches around the sides/top/bottom. I'll then pack the gap between the heater and the box at the front where the air is drawn in with a suitable high flow filter material. I'll pull the power supply lead and water cooling pipes round the front as in the photo. I can then slide the unit in and out for easy maintenance/ regular blowing out etc, all I have to do is remove the packing at the front My way of thinking is the heavy lifting of the cooling is done by the external water cooler unit (and the water pipes go ALL round the electronic gubbins inside the box). The air for the fan is drawn round past the top/ sides to get to the fan at the back so it might be more of a cooling action than just directly in through the fan. I'll also run a bead of silcone around the edges/joins of the panels of the machine itself I don't need to go overboard with some sub micron filter,, it's the particles of metal I'm most worried about. Any that do get past what ever filter material I use at the front will have to travel about 2 foot AND get drawn UP to get at the fan. Chances are they'll just drop down before they do. All this, combined with regular blowing out might keep the dreaded dust of death at bay. I've only had the machine 2 days and already I can see it being utterly indespensable.

Finally got the induction heater I've been wanting for over a year. Many thanks to Grant and John N. I also finally got to grips with Youtube. It's a 25KVA machine, a lot of the ones on youtube are 15KVA. The extra power means it can put a LOT of heat into a bar VERY quickly. The top figure on the display is the elapsed time. The lower is the current in the coil, this starts around 600A and then gets up to over 1000A.....thats a LOT of Amps....even more are flowing around as eddy currents in the bar .... so it gets hot .... very very quickly The bar is 40mm diameter. Note how the heater heats the outer layer of the bar and this heat is transferred by conduction into the centre, rather like an eletrical gas torch. Note the spark at around 1.20 When I find time to play I'll post some videos showing it being used to make things.

Ah HA ... I did wonder if they might be snakeskin ;)

None that I'm aware of, thats for the induction heater, the Lincoln TIG and the Thermadyne plasma cutter. The more I think about it the more I realise I've been skating on thin ice. I just had the TIG and plasma cutter under the bench thinking "that'll do". Also thinking about it, I did have a laptop that I take to the workshop go down (secondhand "IBM thinkpad" so we're supposedly talking quality here) and two cordless battery chargers (DeWalt and Makita) When get a bigger workshop, a grinding room is a must