Really confused on Pro-Melt?

[Canuck Bob]

I have saved and decided to pull the trigger on a RCBS Pro-Melt. Then I read the current thread on temp fluctuations!

Once you got used to your new model furnace did the temp vary widely? Adding a PID to a Pro-Melt for a Canadian would be stupid expensive!!!!! Sorry for yet another question but this report surprised me.

Please don't suggest a Lee. I mean no disrespect its just that I have my two choices already. I fully understand and appreciate Lee products and have bored this forum with too many questions for too long. My second choice would be a Waage and a ladle.

[VHoward]

I have had no temp fluctuations with mine. So I can't understand that problem. Maybe the ones who have the problem got a bad thermostat in their unit? RCBS would take care of that problem for them if they contacted RCBS.

[Firebricker]

Mine always holds temp pretty steady it won't hold it to the exact degree but close. It's going to fluctuate when adding metal or running real low. Make sure checking temp with something accurate a had one that the needle liked to stick on. If you really want PID controlled there are some guys here that could set you up at a reasonable cost but I think you be fine with a stock pro-melt. FB

[btroj]

Had mine for 20 years now, no problems. Would buy another with no hesitation.

[Rockchucker]

I too have never had any bad fluctuations with mine and I've had it since 2009. I wouldn't hesitate buying another if the need ever arises. I really don't know of anyone that has a problem of any kind with their Pro Melt, and very sure RCBS would correct any problems you could have. Really don't feel the need for a PID like others on this site does, and I'm not knocking the PID as others really like the Temperature of the melt not exceeding 1 or 2 degrees. Not having one doesn't seem to affect the quality of my boolits.

[AggieEE]

Anytime you have a bi-metal thermostat you are going to have some temp variations. It may run from as low as +/- 5*F to +/_ 20*F or more depending on the quality of the thermostat and the temp range. Its harder to hold 800* +/- 5* than 100* +/- 5*. The PID controlers came about as the industrial needs required a tighter temp control on some processes. When I had industrial control in collage it was a major math fest. Last year I taught a class with PID's and it was a lot simpler. If you are seeing extreme variations you may have a bad thermostat. They are easy to change if you are comfortable with working on electric appliances. AggieEE

[mktacop]

I'll weigh in here...

I bought a new Pro-Melt about 2 months ago. When I got it set up I set the dial on 750 and let it heat up. I have a digital casting thermometer and stuck it in the Pro-Melt. Temp read about 740 degrees. As I was casting, I kept an eye on my thermometer and saw that the temp would fluctuate from 740 down to about 650 then back to 740.

I called RCBS to see if there was any way to adjust the thermostat to be a little more consistent on temps. I was told that the thermostat is not adjustable. When I asked if they thought such a wide fluctuation was acceptable, the gentleman told that the new thermostats RCBS is using are not as precise as the older ones were. He then suggested I just set the pot at 850 and cast with it set there.

When I got off the phone with them, I hooked the PID I had been using with my old Lee pot to the RCBS and haven't looked back. I really like my Pro-melt, I just wish it had been more accurate on holding temps without having to add a PID to it.

[Rockchucker]

Mktacop, I would think that a 90 degree differential would not be acceptable to me under any circumstance, that just seems to be way out of whack. I'm supprized RCBS would let that slide, and not just send you a new thermostat pronto, especially only being 2 months old.

[mktacop]

Mktacop, I would think that a 90 degree differential would not be acceptable to me under any circumstance, that just seems to be way out of whack. I'm supprized RCBS would let that slide, and not just send you a new thermostat pronto, especially only being 2 months old.

While I agree that that temp swing is ridiculous, I HAD to have a pot and didn't have time to send it back to RCBS. After talking with their representative on the phone, I'm not sure sending it back would have done me any good anyway. He seemed to not care about the temp fluctuations and even called them "normal". Fortunately, I already had a PID and now have great temp control on my Pro-Melt. If I hadn't had the PID, i would probably have just sent it back dropped the cash for a Magma Master Pot. As it is with the PID, the Pro-Melt works great.....without the PID, not so much.

[Sgt Red Leg]

OK~ ~ ~ I'll bite..............what is a 'PID' please? ?

[mktacop]

OK~ ~ ~ I'll bite..............what is a 'PID' please? ?

PID stands for Proportinal, Integral, Derivative. Fancy way of saying an electronically controlled way of determining when a heating element gets power in order to maintain a constant temperature.

There are several threads here on how to build one.


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[Freightman]

Look up to the stickies second one is about PID's

[Sgt Red Leg]

OK! Thanks. Many abbreviations going on here. I am learning slowly!

[Walter Laich]

I have the pro-melt and also built a PID mostly because I saw it as a challenge. Was a nice project for a retired teacher.

Do I need it--probably not but I do like the constant temp it holds the pot to.

w

[barkerwc4362]

I have three pro-melts. The newest hasn't been used yet. I use Thrifty-sorb on the top the melt to control heat release and reduce oxidation of the alloy. I used to use cat litter, but found this is cheaper. I use 1/2 - 3/4" to provide a barrier and helps maintain a constant temperature.

Bill

[David2011]

Mine is an older model as well, from the early '80s. It only fluctuates wildly when the pot gets low and I toss a bunch of sprue into the melt which promptly freezes.

Are your temp swings while casting or with a full pot and just sitting there doing nothing?

David

[mktacop]

Mine is an older model as well, from the early '80s. It only fluctuates wildly when the pot gets low and I toss a bunch of sprue into the melt which promptly freezes.

Are your temp swings while casting or with a full pot and just sitting there doing nothing?

David

I first noticed the temp swings while casting, but no sprues were being added back to the pot. Even with the pot just sitting there, it had the same temp swings.

[mooseman1]

mine varies about 150 degrees when i cast ,an it really suck's but like the tread starter i'm in canada so its suck it up cupcake for me

[dromia]

The Promelt is one of the better pots at holding temp, but temp fluctuations are the nature of the beast with the thermostat control.

I've used pro-melts for years with great success so a PID is not an essential piece of kit, in one of the PID threads I think Forzone states that the noticed improvement of the PID is less with the Promelt than with other makes of pot as the Promelt thermostat is one of the better ones.

I've just built one of Frozones PID kits for my Promelts, not because I was unhappy with them but because it it just another small step to reducing variables which is what casting and hand loading is all about. Will it make a difference on the target probably not but I hope that it will further reduce my reject rate.

Surely all the parts necessary are available in Canada, I'm in the UK and Frozones kit cost me £125 delivered. Buying all the bits in the UK would have cost me £80-£90 so to me the extra was worth not having the hassle of shopping blind and the instructions and templates were a godsend for a non techy like me.

So does a Promelt need one? No!

Do you need one to cast good boolits no.

But some of us boolit casters do like our kit though.

[shotman]

Find something to cover the pot and start at 850 and let it get HOT then cover and drop back to about 700. I have a piece of 1/4 in asbestos with a handle and is easy to move
If you read their instructions it says to keep half full which is hard to do with a lee 6 banger
I start at near full and with the spring Idea that was posted in another thread it works good for me
Remember that the pot is not cast iron so temps will change faster
The cat litter may work but when you add back the sprut you tend to get in mix and that can get to valve and start it dripping