PID Proposed Shopping List

[ranger391xt]

Good article. As it happens, I have an old gutted PC that still has its power supply. I'll use it.

I do have a couple questions:

- Why did you use a terminal block? I ask simply because the various youtube construction examples I've seen do not use one.
- What did you use to cut the openings in the metal? I suspect I'll need to buy whatever it is.

Thank you, Richard

I used the terminal block because I felt it was cleaner, and let me take all the wires to one central place if I ever need to troubleshoot or replace something. Using wire nuts is certainly another way to go. it just wasn't my preference. Plus, I already had the terminal blocks from another project.

I cut the openings with a dremel tool and filed them. There are probably better ways, based on You Tube videos that I have watched since doing the build.

Sent from my SM-N981U using Tapatalk

[HATCH]

You run into the risk of the wire nut coming lose if you tend to move your PID around.

I use butt splices to connect the neutral and grounds. The hots go to the screw terminals on the SSR

[RG1911]

Also, I used 14 ga wire for all 120 volt wiring.
I use a sabre saw with metal cutting blade, 24 TPI is good ...maybe even 18 TPI would be OK.
If you need to buy a sabre saw, look for one with variable speed, cutting slower makes cutting steel easier, also lube the blade...Oil works, boolit lube works great, but even WD40 helps, mostly you want a lube to keep the blade cool and keep the teeth from getting clogged with galled metal.

I've got a bunch of cutting oil made for aluminum. I did unearth a Skil 524 sabre saw that I must have picked up at a yard sale some time back. It says it's 2-speed, but I can get only 1 speed from it. I ordered an assortment of metal cutting blades so I'll see what happens. Or I could play with my mini milling machine.

Cheers, Richard

[nuclearcricket]

The metal in those boxes is fairly thin aluminum. Your mini mill will surely do a fine job on cutting the openings you need. You can also use a coping saw and file to fit. Still not a hard job. When I built mine I did use a terminal strip, kind of made things easy. I also installed plugs to plug in a power cord from an old computer, and the ability to plug in the power cord for the pot as well as a plug in for the thermocople. My thoughts were if I ever wanted to use another pot it would make it easier. Also if I wanted or needed to tear the set up down and move it, it would be a lot easier. What was hard for me was understanding the wireing diagram. I am a machinist not an electrician but I did find one I could understand and it has worked quite well since. I did mount my SSR on top of the box and the heat sink on top of that. I probably have gotten away with not having the heat sink but for the cost I figured why risk problems if you don't have to.
One thing I have learned is that it if very nice to be able to adjust the temp to fine tune things to your mold. I found it interesting that not all molds work well at one temp. Some like a little more, some a little less. I run both aluminum and iron molds, they are all a little different in their likes.
Sam

[popper]

Just run a plug for the entire unit, no need for a switch. I hard wired my entire unit, just unplug and remove probe from the pot when done. Used an extension cord cut in half, recepticle for the pot and plug for the PID/pot.
Beware of the thin temp probes, they break easily (wire is very brittle) and have little insulation in them (wire is good for 1200F but insulation normally isn't, I got one with high temp insulation after the first one broke internaly). Metal case may not be enough heat sink for long casting sessions, and do use the thermal paste. SSRs are rated at normal operating temp and the rating decreases pretty fast with temp so the larger unit actually does better and cost diff. isn't that much.

[JonB_in_Glencoe]

I've got a bunch of cutting oil made for aluminum. I did unearth a Skil 524 sabre saw that I must have picked up at a yard sale some time back. It says it's 2-speed, but I can get only 1 speed from it. I ordered an assortment of metal cutting blades so I'll see what happens. Or I could play with my mini milling machine.

Cheers, Richard

Richard,
I googled Skil 524 sabre saw. WOW, that's an old metal unit...don't hurt yourself.
My corded sabre saw was a Black and Decker from the 1990s, and there was a tiny speed dial right in the trigger, where your trigger finger would touch it. Newer models had a trigger that varied the farther you pulled the trigger...and the best models had the adjustable oscillating blade feature. I've had numerous sabre saws, as one job that I am retired from, required plenty of sheet metal work.

One way to use a full speed sabre saw, to simulate a slower speed is to just, punch the trigger and release, punch the trigger and release, ...repeat. with that old Skil, there will likely be some momentum as long as you don't force the blade to bite hard...and Hang on to the saw tightly and have the work piece (box) clamped to a heavy table.

[RG1911]

Well, this being Laramie, I had to order wire and connectors. (We're not at the end of the world, but sometimes you can see it from here.)

While waiting for the supplies, I reread PID threads here and watched a number of Youtube how-to videos.To be honest, these did not do much to lessen my confusion. This is partially explained by the differences among PID controllers, and images that were not as clear as I needed.

Being bored, I scrounged up some old, very thin single-strand wire in two colors to try to cobble together a mock-up using my components. This became a trial-and-error (and blown circuit breaker) project as I synthesized the different information sources to fit my components. The short story is I did get the setup to work. I am leaving it untouched so I can replace the thin wire with the 14 AWG wire I ordered and the connectors. Once the bad has been replaced by the good, I will post pictures of the wiring connections I used.

The last part of this process is deciding whether to cut holes in the RCBS Pro Melt for the PID and SSR (assuming there is room), or have a free-standing box.

As always, I thank everyone for the assistance in making this project a success.

Cheers, Richard

[HATCH]

free standing box
It allows you to use it on a different pot and it also limits the amount of additional heat from the pot

[JonB_in_Glencoe]

I'm with Hatch, put the new electronics in a separate enclosure. Heat kills electronics...so it's best not to have then married to a Lead furnace.

[Walter Laich]

one of the problems with the Pro-Melt II is the PID is inside the unit making it necessary to run the fan for an hour(?) after the pot is turned off--think it's programed into the machine--people are making workarounds with timers in line with power cord but if you can avoid this--do so

with an external unit, you can unplug everything and you're good to go

I built a little open-ended 'box' that the PID sits in while the pot is on top which raises the spout more in line with my eyesight so I can see where the mold should be

[RG1911]

free standing box
It allows you to use it on a different pot and it also limits the amount of additional heat from the pot

Thank you for the tip about additional heat. I'll either gut my old PC power supply to use it as the PID box, or find a suitable box locally or online. (A power supply often is useful in the radio control arena.)

Cheers,
Richard

[RG1911]

one of the problems with the Pro-Melt II is the PID is inside the unit making it necessary to run the fan for an hour(?) after the pot is turned off--think it's programed into the machine--people are making workarounds with timers in line with power cord but if you can avoid this--do so

with an external unit, you can unplug everything and you're good to go

I built a little open-ended 'box' that the PID sits in while the pot is on top which raises the spout more in line with my eyesight so I can see where the mold should be

Hmmm... Had not thought about the benefit of raising the pot. I think I will follow your example.

Cheers,
Richard

[RG1911]

I'm with Hatch, put the new electronics in a separate enclosure. Heat kills electronics...so it's best not to have then married to a Lead furnace.

True. I now wonder if heat had anything to do with the Pro Melt's failure. I don't know if just sitting for a few years could contribute to the failure.

Cheers,
Richard

[HATCH]

The failure of the PID controller on the promelt is two reasons.
Poor quality PID controller and the heat.
I would of used a 1/32 sized controller with a extra partition to help mitigate the heat from the pot.

[RG1911]

This image shows my wiring connecting InkBird PID Temperature Controller ITC-106VH to the InkBird 40 Amp SSR. It works, so unless there is a drastic electrical mistake, the connections will remain unchanged.

Once I find/build a box to hold the PID, the SSR, and the On/Off switch, I'll need to change the lengths of some of the wires. I'm also contemplating various ways to be able to connect and disconnect the PID modules from the Pro Melt heating coil. Right now, inserting quick connect couplings into wires 1c, 2 and 4 looks like what I'll do.

NOTE: I am not in any way an electrician or electrical engineer; nor do I play one on TV. Some of the explanations are sparse because I may have looked up the meaning of a term, but still do not have a firm grasp of the situation. My wiring depends in equal parts on information from here, various YouTube videos, and the PID wiring diagram in the instructions. After tripping the workshop circuit breaker a couple times, I made frequent use of my multi-meter to determine which connections produced the desired results.

Cheers, Richard

Note: With a couple exceptions, Black wires are Negative, and Red wires are Positive.

Click the image to expand it.



(If you want a larger image, please send me a PM with your email address.)

The wires are numbered as:

1a, 1b, 1c - Power lead from the wall branching to one end of the heating coil and the other to the Input side of the switch. The red wire leading from the junction is simply to be able to attach the white wire to the switch.

2 - The other wire from the wall to the Input side of the switch.

3 - Ground from the wall.

4 - This wire is a little tricky to follow, so it's labeled twice. It connects the remaining end of the heating coil to terminal 2 of the SSR.

5 - One of two leads attached to the positive output of the switch. This lead connects the positive Output of the switch to terminal 1 of the SSR.

6 - Connects Input terminal 3 of the SSR to terminal 8 of the PID. Terminal 8 is identified as "NO," which I have seen explained as Normally Off/Disconnected.

7 - Negative switch Output to terminal 10 of the PID. This terminal appears to be labeled in the instructions as "IN Power." See also label 9.

8 - Negative lead from Input terminal 4 of the SSR to terminal 6 of the PID. This terminal is labeled as "NC," which I read means Normally Connected.

9 - The second positive lead from the switch Output to terminal 9 of the PID. This terminal appears to be labeled in the instructions as "IN Power." So IN Power has both positive and negative connections.

10 - Connection between terminals 10 and 12 of the PID. Terminal 12 is labeled as "COM" in the instructions.

The thermocouple has its positive lead connected to PID terminal 4 and its negative lead to terminal 3. This is in accordance with the diagram in the PID instructions. The pictured thermocouple came with the PID and is not the large thermocouple in actual use.

[RG1911]

The failure of the PID controller on the promelt is two reasons.
Poor quality PID controller and the heat.
I would of used a 1/32 sized controller with a extra partition to help mitigate the heat from the pot.

I noticed that the original components were quite near the ends of the heating coil; so would have been subjected to a pretty high temperature. The external PID assembly neatly eliminates that problem.

Richard