Pid temp control finished !!!

[calaloo]

A suggestion on mounting thr thermocouple.

A thermocouple is notjing more than two wires of dissimilar metals with the ends FUSED together. When this fused junction is heated a very small amount of electricity is produced. The thermocouple supplied with the PID controller should be modified. I used a stainless steel
1/4 inch bolt 1/2 inch long drilled through with a 1/8 th inch bit with only the last fraction of an inch drilled with a tiny bit just large enough for the fused junction to fit through. The thermocouple junction is silver soldered to the end of the bolt. The original rig on the thermocouple is very easy to remove, Just be careful. I silver soldered a 1/4 SS nut to the bottom of the pot then drilled through the nut and the pot. Tap through the nut and the pot. Use a copper crush washer to prevent leaks. The silver solder used is the high silver content high temperature type.

[Alex]

I think this thread needs to be "stickied". There seems to be a lot of interest in PID controllers now and everyone seems to be using more or less the same components. Maybe a GB would be in order. Basically, the only difference I see between mine and all the others is that I use a flexible RTD (resistance temperature detector) instead of a K-type TC on my Lube/Sizer for finer control.

[Frozone]

I decided to show my rendition of this theme.

It's built using a PC power supply case.
The lights on the Lee unit are over/under warning lights and a fuse holder.
The red light comes on at 15 below set temp, the orange at 15 above.

In back the 20# pot can be disconnected and other units plugged in.

I use 20 cuft/min forced air cooling on the SSR for up to 15As of power, the internal wiring's limit.

I use this 20# pot 80% or more of the time, so it seemed to make sense to connect the two and just use longer wires on other pots.
( that and I ran out of room for the warning lights )

I still have just enough room in the case to add a thermostat to only run the fan when needed - the next upgrade.
That and increase the load capacity to the full 25A.

Why put the controller on the side, instead of the top where it can be seen easier??? To protect it from lead splashes.
You can also see the spring I added to the spout control. It's very effective in preventing drips.

[walker77]

Thats a good idea!

[blikseme300]

Frozone,

Very nice.

Bliksem

[blikseme300]

Well folks, it has been a month since I decided to build a PID temperature control system and a large melting pot. During my research I came across a MOAM - Mother Of All Melters. Mine is the Electric version, hence the E. I thank everybody here for their sharing on this forum that made these projects possible. OK, here are the pictures:

This is the completed PID alongside the MOAM(e). The enclosure was supplied by Auber Instruments together with most of the other parts used.


Here we have the MOAM(e) alongside a Lee 10lb pot. Dwarfs it a little.


The naked pot. I decided against using stainless as I am concerned that the thermal movement by the material may crack the welds. The basic dimensions of the pot is: 6.75OD x 6.5H The pot easily handles 60lbs of melt. It can, at a push, handle 70lbs.


Dressed with a band heater. This is a combined 2420Watt at 240V.


The melt after some fluxing. Here you can seen the insulation used. It is kaowool and aluminum sheeting. I will be replacing this soon with wider aluminum to cover the exposed insulation. The thermocouple was inserted into the mix and once the set 710*F was maintained I started casting boolits. The large mouth of the pot makes it easy to stir in the flux.


The final product. 180grn .401 LSWC. I cast one session with no stopping to add ingots or waiting for temperature to stabilize. I weighed the pan after I was done and had just over 25lbs. This means I did approx 1000 boolits non-stop.


Bliksem

[walker77]

Thats really cool! How much did it cost to build the pot?

[Frozone]

Sweet!!!!

[blikseme300]

Walker77

It cost me about $60 and my time. The heater band was $35 off evilbay and the aluminum sheeting, pipe clamps and electrical plug made up the balance. The other pieces of metal used came from the scrap metal bin at work. The kaowool was scored from a local power station (thanks Billy).

If anybody is interested here is the link to my personal website where I have more information about this build. http://bliksemseplek.com/boolits.html

Be warned: If you are PC sensitive don't visit. Also, my site is undergoing alterations so all the pages are not yet active..

Bliksem

[Charlie Sometimes]

Nice web site blikseme300!
I might try to build me one after Christmas- looks like fun!
I just need a BIG dipper pot- this looks like it would do nicely, and be quick and easy to construct.

Thanks!

[gefiltephish]

I decided to show my rendition of this theme.

It's built using a PC power supply case.
The lights on the Lee unit are over/under warning lights and a fuse holder.
The red light comes on at 15 below set temp, the orange at 15 above....

Yes I know I'm dragging up an older thread.

I have the 2362 PID, 25a ssr w/heatsink.
What amp fuse and where in the schematic do you place it? Fast acting (GMA), yes?

Google search came up with this: "700 watts at 120 volts is how many amps?
5.8 amps" So, fuse for 6 or 7 amps?

Based on 110v schematic on page 1 of this thread, place in L1 between ssr and heating element?

[lurch]

If a fuse is used, it should be the absolute first thing in the circuit, even before any type of main power switch. The fuse should be sized so that thermal fatigue is not a factor causing nuisance trips. It will not save or protect anything in the circuit from failure should a overload gross enough to blow the fuse occur. It's only effect should be to disconnect power from the circuit before the branch circuit breaker trips. 6 or 7 amps is too small. Running a fuse this close to it's rating will result in a blown fuse somewhere down the road for no good reason. As a rule of thumb and unless there is some compelling reason to do otherwise, select a fuse double the current rating that the circuit is expected to draw, or at the rating of the components connecting to the branch circuit of the house. I'd use a 12A to 15A fuse for this, and I'd think pretty hard about using a slow blow at that.

[gefiltephish]

Thanks for the reply. So it appears that while fusing is not a bad thing, it's not a necessary thing either, especially if it's not going to protect the items within the circuit. It simply (possibly) saves me a trip to the breaker panel, but my pid would probably be toast anyway. Have I got that right?

[lurch]

Correct. If the fuse blew, something died. I was thinking more you were trying to save the SSR in the event that the pot shorted out. There are some things a fuse will protect (motors and in some cases speaker coils for example) but a semiconductor junction isn't one of them. There is no way on earth a fuse in the power line is going to protect the controller. Until a purpose for a fuse is defined and one selected that can actually accomplish that purpose, it's just something else to have problems with.

[gefiltephish]

Yep, that's exactly what I had in mind. I'll save myself the bother and omit the fuse. Thanks again!

[dkonrai]

I need to build one of these.

Sent from my LG-M210 using Tapatalk

[oley55]

For certain this is an old thread, but I am seriously looking at putting one together to accurately control temps in a Lee pot for salt-bath annealing.

I am wondering how well the components hold up after more than a couple years.

[HATCH]

I know one panel I built in 2012 that contains one of the PID controllers I use is still working.
why wouldn't it be working?

[oley55]

why wouldn't it be working?

I dunno, just wondering about chinesium electronic components (PID, SSR, thermalcoupler, and etc) I guess. Didn't want to spend 150 bucks for everything needed for salt-bath annealing and end up with a "one off" that often fails just when I need it.

That's pretty much WHY.

[HATCH]

Buy quality parts and you don’t have that issue.
It’s when you buy the cheapest parts you can instead of buying quality parts is when you run into those issues