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Keep it coming Dee, you've become my new hero!

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Greetings.   Ok, i thought someone out there might want to laugh at my feeble attempts at making a tempering furnace for swords.   I havent finished it as yet, so it might not actually work by t

You don't need 31" of working area. My professionally made forge is 12" long. And even that is too much really for knife making. You only forge a few inches at a time.

You did notice this thread is on electric heat-treating furnace building, right?   JJ is correct, that's way to big for a forge for general smithing. You only need a hot spot around 100-200mm (4 t

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When I used to install new elements in my pottery kilns the first time I would measure exactly how long they needed to be then after that I could pre stretch them painlessly. I was going through alot more elements than you will on this hopefully. My favorite had a very slight lip at the top of the groove that would keep it in after it shrank with the first firing.


I'm really excited to see how yours turns out this is a great idea.

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sorry for the lack of update.


ive finished the actual buildy part of it ... and have set about the wiring ..


and thats where ive hit a snag.


i have a 20amp connection coming into the workshop ... but it had a 15 amp wall plug on it .. so i had to change that out.

ok, no problem there.



next, i wired everything together as per the directions that i was given ...

turned it out .. and..........




it just doesnt kick over the element.


i tried wiring it up a different way ... as per directions that i found around here ..

and still nothing.

ive tested the connections and cant figure on whats the issue im having.


im starting to suspect that my ssr isnt working right.

though it might also be the controller i guess.

im not sure whats going on .. and i need to get ready for work and go tend bar in a little while ... so i have to switch off my brain and stop trying to figure it out for tonight. :(


hopefully tomorrow when i start fresh i can sort it all out and show you the outcome.

until then its kinda pointless showing any more pics etc ... cause, whats the point of showing a furnace build, if it doesnt equate to a furnace?


hmm .. maybe i should change the title heading to:

"large heavy box building 101"


at least i havent electrocuted myself yet.

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Hi Dee,

You're too close to let a little electrical glitch get you down girl. ;) Pic's would be helpful for troubleshooting, but here's a couple of things you can check out. Using a volt meter carefully :excl: confirm that you have power going to the SSR load side and the controller comes on with the power turned on. Make sure that your thermocouple has the correct polarity hooked up to the controller input . Decipher those usually mystic directions of the controller and confirm that it is set to match the type of thermocouple you're using (i.e. Type K...).


Adjust the setpoint value higher than the process value on the controller and using the voltmeter, again carefully, while the power is on confirm that voltage is going to the SSR. Then check that you have the correct polarity wired up to the SSR input, they are normally fed with DC voltage from the controller. It is critical that the polarity is correct at the SSR if it is a DC input, DC input SSR's won't work if wired in reverse. If these don't help you find the problem please let me know what was found, I'll check this thread later today and will help in you in any way I can from over here.


I hope your shift at work went well and you got a good nights sleep to let go of your tension. -_- Believe me when I say I am sure you will work this out. Be cool B)



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Wow, Dee. That looks just like the one I'm building.

I'm not as far along as you though. Smart idea using the pipe with grooves in it to carve the channel in the bricks. I used a modified wood boring tool and my Milling machine, now I have a lot of firebrick powder for my yakiire clay ;) .

I can post pics of mine if you want.


Keep up the good work and thanks a lot for sharing.


PS. I know what you're saying about using more time building tools than making blades, I haven't forged a blade in over a year now. :blink:

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thanks for the tips.


Art~ sadly, the diagram thats attached there isnt for the same sort of setup as i have.

but thanks for trying. :)


Mike~ ill do as you say.

i dont believe i have the ssr wired wrong ... mainly because it is clearly marked input/output and +/- so i double and triple checked and made sure that it was right.

the TC is a k-type ... which the pid is meant to be set to as default ... but i should check that.

and as for the wiring in of it ... yeah, its set the right way ... i mark it with great big symbols to make sure of it :)

i did check it over with a multimeter before going to work .. and it seemed like the ssr wasnt putting anything out ... ?

but i have to double check that once ive had some spleep.


i had an absolutely awful night at work.

so, rather than go out there now and get fed up and probably dismantle the thing in frustration and fury ...

im going to have myself some pasta for dinner and get in a nap before i start at it.


..... thats if i can stop thinking about it long enough to fall aspleep .. :D


thanks for the help guys ...

i appreciate it greatly.


D, the confuzzled but not beaten.... until later in the day. ;)

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Just a thought, but you know all new electrical devices are made or overseen by humans. We all tend to screw up occasionally, and it wouldn't be the first time I've encountered a new part that was DOA from the box. :( If you have a switch inline with your power feed to the SSR try bypassing it by putting both wires under the same terminal. If your elements start heating up it would indicate that your SSR isn't responding correctly, and there is a good probability it was bad out of the box.


If the SSR is the problem get another and you'll be all set. Of course you'll just have to deal with wasting your time troubleshooting and tracking down the replacement :P


You're on the right trail - keep on posting ;)



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yes, i think humanity is rearing its ugly head here ..

but i have a feeling that it might be in the product selection rather than faulty craftsmanship.

read on.



i wired it all back up ... made sure that the connections are all secure ...

still not working.


did like you said Mike .. wired the connections onto the same connection on the SSR ... and the element buzzed into life ...

so .... thats ... annoying.



oh, and i checked that the TC was set properly ... which it was set for a K-type still ... ok, good there.


so .. i switched to another SSR .. (i bought two from the same place a while back) ... tried it again ... nothing still.

so .. i checked the connections with the multimeter .. there is a DC reading coming from the controller ..

it comings through as a pulse to start with .. and when i switch to the intelligent learning setting, it comes through as a constant feed.


so, all good there.


but .. still nothing out the element side. it goes into the SSR .. but doesnt actually do anything.

im thinking that maybe i have bought the wrong SSR(s).

so ive taken a piccy.

lemme know if this is the right thing.


essentially, in my ignorance, i emailed a supplier and told them what PID i had ... what element i was getting .. and they said that they had done this before and they had exactly what i needed and sent me two small black boxy things ..


but ... maybe they arent what they should be?

piccy inclosed:



if not ... not too sure what to do now..


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annnnnd i know what the issue is.


stupid people.


me for one.

and the guy who sold me things for the other.


now to sort the solution.

which from what i have managed to find thus far... is not going to be easy.

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You've found the problem. :) Now you have to find a way to get them to exchange the AC input SSRs' with DC input SSRs' :( You will need an SSR with these inputs Crydom_SSR.JPG

I've sent you a PM with an option.




edited with picture size change...sorry Don :o

Edited by Mike Barton
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Sadly i cant switch the SSR(s) for ones that work .. because i got them so very very long ago ..


let this be a lesson to you about waiting too long before getting started on your builds .. ;)

oh well .. live and learn.


ok .... so .. where were we...


carefully feeding the element around the ceramic and brick supports .. slipping the stainless rod inside the brick/ceramic supports ... and then feeding the elements through the brick and out of the inner chamber.


i have two smaller ceramic tubes that the element passes inside of as it exits the brick .... these are to make sure that the element doesnt end up cutting through the brick... as they are soft afterall.




next i put in place the glass rope.


i need to cover about 3m of bricktop ... and they had already cut the rope into lengths of 2m.

so .. i bought two.

i bought the 9mm thickness .. because that was the size that they had two of.


but .. when i get them home ... and try to put them in .. i notice that they have sold me one 9mm one and one 12mm one ..


((yes, thats right ... the only person who hasnt stuffed up my supplies thus far is the person who sold me the temp. controller .. and that guy is from the states.

i mean ... i am the first to admit that i dont know what the heck im doing ... but when i ask for something specific...i kinda figure thats what ill be getting. maybe im silly, i dont know. heck, maybe i talk funny and they cant understand me.... ))




so ... ive put the thinner rope at the back .. and the thicker one roughly at the front ... with a little bit of coaxing i was able to get them about the same thickness ... (read: squish on clean cement floor with a large flat bit of metal and then stand on it all)


ive put them in place with nails. its just a matter of pushing them through the rope carefully and then into the brick itself.

it holds pretty tight ... though i would watch when working with this rope stuff ... i noticed a bit of fibre coming off of it all as i worked it .. so i put my respirator on and hit my dust extractor too.


next is the lid.

ive lined it all up and used self tapping screws to affix two hinges onto the frame and then onto the lid.

the screws go into the square tubular steel ... which is a lot thicker and stronger than the angle iron stuff.




i tried out the lid and felt that it was realllly quite heavy compared to what i thought it was going to be ..

so ive affixed just a bit of scrap metal onto the side of the lid ... its a little offcut of the angle iron .. with a hole through it .. and then a square tube that i had left over from my recent grinder build...

i had a little bit of overhang that i left in order to create a locking mechanism on the frame .. but it will now work as a lock and also a prop.




works pretty spiffy :)




i then had to do my hercules impersonation in order to get the whole furnace up onto the table where it will be living ..

geez, for some light bits and bobs, this thing ends up darn heavy.


i welded some of the tube steel onto the end where the elements come out of .. so that i could make a housing for the element ends.




this is where i got to and found out that it didnt work ...



the thing that actually prompted me to figure it out was sitting here and refeshing the page... hoping that Mike had replied to my cries for help .. :lol:

suddenly i noticed that there was 240V on the input as well as the output.

now ... i specifically asked for a SSR that was compatible with the PID that i handed over ... but apparently the guy who i spoke with didnt understand or whatever.


so ... some searching on the internet lead me to a electric supplier in the city ...

some begging and pleading got me some info ... and lead me to the SSR that would work ... yippeee :D


but i figured id wait and make my dad and gf some dinner before i tried it all out etc.

which leads on to my next post ... :

the new day. :)

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Great going!! :D I knew you'd get it, and I figured that the electrical supply house would give you grief that you had gotten the SSRs from originally. Sadly that is normal policy with purchasing most electronic components...no returns on electronics unless it is in a sealed package or you are well known to the vendor :( I'm eagerly looking forward to the conclusion of your epic saga HOW TO GET ZAPPED 101 :lol: Now please show us the rest of the story :P



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The New Day Dawns.



ok .. so ..

today it is ... its make or break time.

ive got my serious face on ... i put my Abney Park albums on the repeat... cause nothing says scratch building like steampunk music.


and off we go.


i didnt want to use bricks to house the elements because i didnt want the reflected heat to burn out anything ..

mainly the hookup wire is my concern .. i know that its insulated .. but i just dont like the idea of things burning out or frying in the middle of some delicate process.


so .. i looked around the scrap piles in my workshop .. and couldnt find anything too suitable ..

but what i did find as i was thinking was one of the many toolboxes that my mum had bought at the auctions in order to fuel my tool addiction.

so .. i went at it with an angle grinder and cut some holes through it .. and drilled a couple holes into the top or the hookup wire to gain access.

i flared the end so that it would sit on the metal i had welded on the bottom ... and could be affixed by use of more of those self tapping screws.




this will allow me to check things by opening the covers door and make sure its all going ok ..

and if needs be i can do repairs or (heaven forbid) replace the elements without too much issue.


i also remembered that i needed to create some way to lock the lid down...

so i drilled a hole into the support bar and put some chain onto the end ...

that way when the support is down i can hook the chain over the end and the lid wont come up when people pry and stick their nose into places :)




so ... now i had it all pieced together ..

i put an extra self tapper through the door of the element cover... again, to make sure that nobody can open it when they shouldnt.




by all accounts .... that would be it ... right?

hopefully ... yeah.


i double checked my wiring ... triple checked it ..

then remembered i needed a hole for the TC to go inside ..

i didnt like the idea of going through the sides .. because no matter where i go i come out near the element ... so i went with a hole in the roof ...

i went right in the exact middle of the lid ... in between two bricks ..

i didnt trust the drill to be careful enough with the drilling of the hole ..

so i used a screwdriver to drill the hole ...

just twisting it with light pressure .. and there we go.



also used some of the offcut brick to make a little detail to stick on the top ... it helps hold the TC in place .. and ... well .. makes me happier to look at it all :)

(kinda like painting Goliath, my press.... for those who know Goliath ;))


all up the unit has two power cords coming off of it ... one for the controller itself ... and the other to the element.

plugging in the controller unit ... i set it to the learning mode .. and switched on the element .... from afar .... with a broom handle .. ;)

there was a buzz ... as i could hear the element kick over. :D


the little light on the SSR (my new one has a little red light to show activity...its very star trek :)) .. shows that it was all good .. and accepting the controllers influence ..


i set the controller just to a small temperature ... about 60 degrees C ..

it made the temp in short order ... and the controller switched the power off .... the little light on the SSR turned off .. and i waited....

i started sweeping up all the brick dust ... waiting for the temp to come back down ... but after 45 minutes i gave up.

so ... it for sure keeps the heat inside ..

though it will take some fiddling to get it sorted in terms of being able to reach the temp without overshooting it.


but ill deal with that once i have something to temper in it.


so ... now was time to wrap up and come and report in ..

so the only thing left now is to name it .. and to paint it ..

i dont have any paint at the moment .. and im out of money :)

so i will have to wait until i can get it painted ...


and as for name .... iron butterfly gave me inspiration there .. .;)




the ende.





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Did you clean the interior of the furnace prior to initial burn in? Are you going to test the heating elements with another run with temperature increase set to normal operating range? You might want to read this Paragon pdf for a Paragon KM HT furnace. Some of it is model specific, but there is a lot of good information in the start up and preventive maintenance sections that can prolong the life of any electric furnace/oven. ;)

You also want to consider finding a couple of ceramic insulator rings for the power wiring going through the top of the junction box you made for the element connections.

i.jpg This looks like an eventual short circuit...

smoke and flying sparks, at the very least, with people running wildly about crashing into things forgetting there is a power kill switch handy. Ask me how I know :D Be sure to check into the paintability of those soft fire bricks, I'm not sure if they would like that, but I don't know for sure.


I've been told that I'm real anal about safety, double checking, and testing stuff. I don't really care though, as I have all my fingers and toes (whole too), both ears and eyes, my nose and mouth are working fine, and I am fully mobile without back pain issues :lol:


Please show us something you've made using your new furnace when you can. I love your sword work you have posted on your website.


Edited by Mike Barton
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Did you clean the interior of the furnace prior to initial burn in?





ok ... sounds like a plan @ the ceramic inserts ... good thinking there. :)

ill have to find some that will stay in place and not end up slipping through and gumming everything up.


yes, i did clean out the interior ..


and i am slowly going to build up to a full heat ... mainly because i want to make sure that the cement that is inside in places doesnt crack up from the stress of going way up ..

but also because its my widdle furnace and i dont want to hurt it any .. tehehe

so baby steps.


but first i want to quench the wakizashi that im working on and get that ready for tempering ... that way i have an excuse to waste electricity. :)


i dont plan on painting the bricks ... though the brick i made the flame icon out of seemed to take it in stride.

i just want to cover up the zinc metal is all.

i find it ugly looking ... but think that some nice black fire paint will go well with the white bricks.

or it could just be my inner goth talking again. :P


i value your input and welcome any suggestions people have ... just so long as they are made for good reason.

if someone messages and tells me that i need to put bunny ears on my furnace ... i might say no to that one.


...... hmm ... bunny ears ...




ive learnt a lot from Mike too ..

but, remain blissful in my ignorance at that same time ...

so .. all in all a wonderfully successful build thus far .. lol


i am glad you liked my write up ..

but i think ill stick with just boring people around here ... im hopeless at writing when it counts.




(thus far resisting the urge to bake kiln cookies)

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(thus far resisting the urge to bake kiln cookies)


Give in to your inner voice... :ph34r:


Use the force Dee, use the force..umm use the kiln...bake cookies.


Me luv coookies :lol:



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Great build, Dee. I'm gonna steal some of your ideas. ;)


How many Watts do you have per cm³, and are you using it for tempering only or normalizing and hardening too?

Mine runs on ca. 3700W and is currently (I'm gonna fire it and check how even the temperature is before i glue down the bricks so i can widen it if i need more volume) 115cm long, 10cm wide and 11.5cm high. So I have ca. 0.28W/cm³.

I'm going to use it for normalizing and hardening.


Please keep us updated on how it works :D

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Great build, Dee. I'm gonna steal some of your ideas. ;)


oh dear gawd .... are you that short on ideas?



ive tried to set it so that i can reach hardening temp if i want to do so ..

but i already have a forge that does that ... and quite frankly .. i prefer flame to electrical.


i just wanted to make sure that if i ever want to do something without flame, i can.

and then there are some steels that normalising or annealing might be easier if i used the furnace...

but really ill have to wait and see.


cant say that i know the specs as to how you put it.

ive no mind for the electronics really.

and have enough of a figure so that if someone sells me the right equipment .. i can piece them together and get something that works.


but really, the electronics side of things kinda only serves to scare me .. tehehe

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B)B)B)B):D I think that says it all...well maybe the rock on smile, but I don't see one. :D
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