My vertical slipjoint kiln

R

Randy3000

Joined
Jun 3, 2017
Messages
811
I have had a problem with warping on 1/16" blades and springs, and want to try hanging my parts. I also like to make springs 6 at a time, and currently with a kiln with a door on the side, everytime i open the door it will drop 100 degrees or so, and so i have to let it warm back up before grabbing the next spring. I feel across 6 springs, the heat treat cannot be uniform, and so have stuck to doing 2 or 3 at a time. With a vertical kiln i hope temp drops wont be so much an issue. I also really messed up when i built my heat treat oven, and i have been wanting to rebuild it. I hope to have it finished this weekend.

I am using 1" aluminum angle at 1/16" thick, and will be bolting it together with threaded rod. I like this construction technique since it is impossible for me to weld accurately at my skill level. It will get sheet metal panels, painted with krylon high heat max.

I am reusing my electric box from the original kiln. On the right is a 30amp double pole double throw switch. I put the hot on one pole and the neutral on the other pole. This makes it so flipping the switch off totally disconnects everything from power, for those worried about whether the neutral really is neutral. Also, all the wire connections can be made directly on the component terminals.
3i91aAt.jpg


(Deleted a paragraph for safety and legal reasons)

I have some leftover 1" roxul i am thinking about putting up against the bottom to help prevent the electric box from getting hot. I may also rig up a sheet metal heat barrier from the drop off sheet metal pieces i have. I wonder if any of this will be necessary? The box is 4" tall and 1 and 3/4 from the bottom of the kiln.

EwQfZ7o.jpg
 
Last edited:
Why you don t quench all 6 springs at once ? About horizontal/vertical oven... I don t see why would be any difference in temp. drop ?
 
You see, when i built the original oven, i made a lot of dumb mistakes. Due to the frame, i really needed the element leads going out the back. It never occured to me that i could run the leads through the bottom. Due to the oven dimensions, i couldnt get 4 rows of element coils on the sides. This meant i ran the leads out the back, went along bottom of each side, went to the front went to the back, and then back to the front with the middle of the coil spanning the top opening at the door. I really should have ran the leads through the bottom along the sides near the front, and had the middle of the coil at the back along the bottom. So anyway, over time, the length of coil spanning the top of the door started drooping down. This is dangerous and dumb, but it is what i did. I also planned on laying blades on the oven bottom, and had the thermocouple nearly touching the bottom. So i say all that to say, it is hard for me to grab shit out of the oven, and i certainly dont have room for a rack to hold several parts that i can grab at once. Hence, i really need to rebuild the thing.

As far as temp drop, i am expecting a 1"x2" top hole to lose less heat than a 4"x4.5" door opening.
 
I got all the sheet metal cut, sanded, acetoned, and painted. All the threaded rod is cut. I had some damaged bricks, so i cut one into a 4"x4.5" block to form the bottom of the kiln. This will give me 6.5" depth in the kiln, which is plenty deep enough for me.

I took the old element and stretched it out as even as i could, then using two pliers i started straightening sections. I made 12 sections at 5" long each. Then i put 5 and 1/2" grooves in the bricks. I space the grooves out by 1.25", which actually makes the distance between grooves in the corners 1.25". It forms a 3-4-5 triangle in the corner, for those of you that know pythagorean theorem.
lHo32Wu.jpg


I cut the bottom sheet metal to make room for thermocouple and the element leads. In the morning i will assemble it. Hope to test fire it by the afternoon.
 
I'll leave the kiln build issues to the others.

I would not mount a plastic controller box directly under the kiln. Just use some 10 gauge high temperature wire to make the power leads connect and mount the controller a foot or so away.

HOWEVER -
Making up a double male extension cord is beyond stupid. I am not sure if it is even legal in some places. Spend an extra $10 and buy a male socket for the control box and use a proper male/female extension cord. A twist lock male socket and female cord end is what is proper for such an extension.
Don't make excuses for doing something wrong.
 
Randy3000 said:
I have had a problem with warping on 1/16" blades and springs, and want to try hanging my parts. I also like to make springs 6 at a time, and currently with a kiln with a door on the side, everytime i open the door it will drop 100 degrees or so, and so i have to let it warm back up before grabbing the next spring. I feel across 6 springs, the heat treat cannot be uniform, and so have stuck to doing 2 or 3 at a time. With a vertical kiln i hope temp drops wont be so much an issue. I also really messed up when i built my heat treat oven, and i have been wanting to rebuild it. I hope to have it finished this weekend.

I am using 1" aluminum angle at 1/16" thick, and will be bolting it together with threaded rod. I like this construction technique since it is impossible for me to weld accurately at my skill level. It will get sheet metal panels, painted with krylon high heat max.

I am reusing my electric box from the original kiln. On the right is a 30amp double pole double throw switch. I put the hot on one pole and the neutral on the other pole. This makes it so flipping the switch off totally disconnects everything from power, for those worried about whether the neutral really is neutral. Also, all the wire connections can be made directly on the component terminals. I use a 20 amp outlet that i can hook up power to with a double male cord. Double male cords present a shock hazard if you unplug from the box while still plugged in to an outlet. But i have to use a 15' extension cord to reach a 20 amp outlet, and so it is nice to be able to detach the cord when i need to, just unplug from outlet first.
3i91aAt.jpg


I have some leftover 1" roxul i am thinking about putting up against the bottom to help prevent the electric box from getting hot. I may also rig up a sheet metal heat barrier from the drop off sheet metal pieces i have. I wonder if any of this will be necessary? The box is 4" tall and 1 and 3/4 from the bottom of the kiln.

EwQfZ7o.jpg
Click to expand...
A few things:
  1. Double male - NO! JUST NO! There are plugs for such applications, use them.
  2. Double pole switching neutral - Also generally no. The two poles generally don't contact at exactly the same time and there are devices that will be fried by having no neutral. There are special switches that disconnect live and then neutral and connect neutral back up before live. Or just leave neutral connected.
  3. If it's connected while you're not there at times you may want a fire retardant enclosure
 
I did not realize it was illegal, but it sure is. I will edit my post.

My temper oven has an identical electric box. I will get a transfer box that i can use for either oven.

I cannot understand how it is possible for a pid to fry if only hot or neutral is connected, for any length of time. Besides, i used it for a year like this no problems.

I will be connecting the element leads with high temp wiring. The wire i got has 29 ampacity. This element pulls about 10 amps.
 
Last edited:
It isn't a guarantee that it will ruin an electronic device instantly , but switching the neutral/ground leaves the hot line connected. This is the line that voltage spikes travel along. Voltage spikes can be in thousands of volts in some circumstances. These are normally discharged and nothing happens. Without a discharge path through the neutral/ground, these spikes can fry a TV or computer … and a PID. It is always best to have the hot lead switched.

When you use a DPST switch to switch both the hot and neutral/ground wires, it may cause a spike as they disconnect at minutely different times. The preferred way is to put a SPST switch in the hot line.
 
Last edited:
I had hot only switched once and someone told me that if someone wired the outlet wrong i could get fried if i touched the element. I dont really know what to do now. I am at the hardware store now. I am going to stick to the traditional power cord idea and just have a small power cord i plug in to the extension cord.
 
You can never be 100% sure an outlet is wired right, but it is a safe assumption that if it was installed in a building under inspection codes and by a licensed contractor it is right. If someone does his own wiring of outlets he should be 100% familiar with all codes and proper wiring procedures … or hire someone who is. It is an easy test with a meter or cheap plug in "fault detector" to check any outlet you are unsure of.

BTW, I have been assuming you are in the USA. If overseas, wiring can be very different. Overseas there can be two hot wires and a ground. In that case, switching only one leg is dangerous when dealing with coils. If you are not in the USA or places where our power system is used, please tell us. This is one reason your location is important in your profile.
 
Fitting this thing in here is the hardest thing i have ever done. Another hour or so and i should have it finished.
bn03oUD.jpg
 
Broke the dadgum element. I always heard elements were brittle after firing, but it seemed to have plenty flex to it. Ordered a new element. I have seen people do elements like what i was trying to do, but fitting that sucker in there is near impossible. I left plenty space on the bricks to make curved tops and bottoms, i will do that and save my sanity.
 
That was one of the things I didn't go into. Never try and re-use elements. Just get new ones and install them. Once fired, they will break if re-used.
 
My phone is past the 5gb limit and so uploading pics to imgur takes about 5min each, but i finally got my first test fire. I will mount this to a cart along with my tempering oven and quench tank. It works great! I used the bricks from my old oven that broke and sanded them rectangular on my disk grinder and can adjust the top hole to whatever i need. So glad i did this. Thanks for the safety info everyone.

bOxXTDu.jpg
 
Last edited:
It's not clear to me how you make the opening/door ? Another note ........you have element on all four side ? How you will protect them from unintentional touch with steel ? I understand that there is no current when you opening the door , but still .......
 
There is no door. I have loose bricks on top i can arrange to make a small hole and lower my parts into the kiln on a wire. The part of the wires sticking out have a loop i can hook onto and pull the part out when i am ready to quench. My wire hooker thing is nonconductive. I also kill power when removing parts.

Worst case scenario is the element pulls 12 staples loose and a section of the element leans over onto the hanging parts, creating a short. This situation could happen with any kiln except for maybe the $1200+ kilns with a hard ceramic type setup holding the elements securely.

I will post more pics when i can. My phone is hanging for a long time, i dont think i can upload any more for a week or so.
 
R Randy3000 you mentioned something about you like to HT/quench multiple blades springs at the same time.
how do you do this? hold them together with some wire or rod?
what material is this wire?

and then do you just dunk them in the quench oil all at the same time?
 
HSC /// said:
help me understand this, practically how would you go about doing this? how would you place them? hold them?
thanks
Click to expand...
Yes , with bare hand .....it s only 800 degrees :) Seriously , by heart I can think on several type of stainless rack that would do that job ..........
 
You must log in or register to reply here.
Back
Top