PID Controlled Forges... my viewpoint

[Ed Caffrey]

In the past three days I have fielded no less than 6 phone calls from people about PID controlled forges. These calls are from folks who are either in the process of building a PID controlled forge, or have built it, and cannot get their forge to work the way they want.

I have talked until I'm blue in the face, trying to convince these folks that while a PID is a great little gadget, with a lot of great uses, it has no place on a "forge", and by trying to "force it", they are only creating problem for themselves.
I've also seen several images on various knife forums, of these types of forges, that simply scare the daylights out of me! Forges with copper tubing that runs up and over the top of the forge, nearly touching the forge body.....regulators with rubber hoses mounted only inches from the forge body..... and electrical wires even "clipped" to the exterior bodies of the forge(s)! These people either have a death wish, or no common sense!

Now don't get me wrong....I built and run a PID controlled "salt tank", but it is NOT used in the same manner as a common forge, and all of the components are either in "safe" locations, or shielded from the heat. There is also a HUGE difference in heating and maintaining the heat in a thermal mass the size of what's contained in a salt tank, versus a 1/4" X whatever piece of bar stock.

I'm gona try to explain my reasoning here, and hopefully I can direct folks to this thread, rather than spend hours on the phone, trying to convince them of something they don't want to hear.

OK, There are a couple of MAJOR reasons that a PID controlled forge doesn't work well.... First, folks have the idea that they can "dial in" a specific temp on the PID, and the forge will run at that specific temp. To an extent, that is true, but because of the lag between actual temp(s) being read by the thermocouple, thermal mass of the forge (and the work piece), and the difference between "heat up" and "cool down" times, there will always be a fairly wide variance. The calls I've fielded go something like "I set the PID at 1475F, and the temp varies from 1300F to 1550F!" What can I do to make it "dead on?" Short of experimenting with ALL the variables, and "sizing" EACH component to "match", which is a lengthy and expensive process, there's nothing you can do. So many things come into play.....the question is impossible to answer!

Secondly.....a forge in nothing more than a controlled explosion. It's no more dangerous than anything else....if you understand it, and respect it, you will be safe. Where I have issues with PID forges is that building, setting up, and using one of these forges requires you to add MANY more parts, lines, wires, valves, etc., and in the process of doing this, many folks do not pay attention to detail....mounting devices and parts in dangerous areas where they will either be exposed to the intense heat of the forge, or where they will very likely be "in the way" of hot steel while using the forge.
Every time you add a device/part to a forge, it's one more chance for something to go amiss. In other words.....KEEP IT SIMPLE! The more you overtake the plumbing....the easier it is to stop up the drain!

Whew! Now that I've spoken my piece, let's look at another aspect.....I can't be certain, but my instincts tell me that many who are attempting to build these PID controlled forges are seeking to overcome the learning curve associated with forging. While technology has without a doubt made many areas of our lives simpler and easier, there is simply no compensatory measure, nor "quick fix" for learning and experience.
Forging, and everything associated with it is a "manual" skill, requiring time and practice to learn and understand.
Rather than try to compensate for a lack of patience by spending lots of money on pieces and parts that will only cause frustration and anger (and in many cases make the forge down right dangerous)...my advice is to build a "simple" forge, concentrating on making it work well, and train yourself to concentrate on what your doing while at the forge....with emphasis on learning/understanding how the steel heats and cools in relationship to being place in, and taken out of the forge.

On the surface, a PID controlled forge might sound like a good idea, but since it's advent, the amount of conversations I've had, with people seeking advice about how to make one "work" the way they want it to, has lead me to the conclusion that it's far less stressful, and more beneficial to just build a "regular" forge, and exercise the patience to learn the art of forging.

Hopefully I've not offended too many folks with this thread.....that's not it's intent. The intent is to make folks realize that when it comes for forging, the only way a person is going to get "better", is to take the time and effort to learn and UNDERSTAND what it is, and how it "works."

[brucegodlesky]

Ed, yuo told it like it is. Some folks want the easier softer way and think thay money can buy that way..... just sayin..... :-)

[Ed Caffrey]

I think it was just frustration that made me write that post. It just gets my goat when someone seeks out my input or advice, then, if it's not what they want to hear.....they argue with what I tell them, or try to convince me that I'm wrong. If you don't want the answer....don't ask the question.

Another reason that I wrote what I did.....some of those calls came from folks that have/had the attitude that they could circumvent the "learning curve" buy building/using that type of forge......sorry, as I said, NOTHING.. period, will compensate for hands on time.

[brucegodlesky]

YEP!! (BOG)
Sometimes ya just gotta say it! I've gone round and round witha fella for the past yr on a certain subject. he's taken polls upon polls with other much more capable smiths than me and still comes back with the same question... and he gets the same answer from me :-) hehehe

[Karl B. Andersen]

Originally Posted by Ed Caffrey

......let's look at another aspect.....I can't be certain, but my instincts tell me that many who are attempting to build these PID controlled forges are seeking to overcome the learning curve associated with forging.

On the surface, a PID controlled forge might sound like a good idea, but since it's advent, the amount of conversations I've had, with people seeking advice about how to make one "work" the way they want it to, has lead me to the conclusion that it's far less stressful, and more beneficial to just build a "regular" forge, and exercise the patience to learn the art of forging.

Yep.

[robertmacveigh]

I can't be certain, but my instincts tell me that many who are attempting to build these PID controlled forges are seeking to overcome the learning curve associated with forging.

Good job Mr. Ed: - I feel certain that you can be "certain" about your instincts... You just saved yourself a phone call from me

very best regards,
Robert

[BrianAyres]

Ed, I wanted to thank you for your well thought out reasoning here.

I built a forge recently and found that I was able to get it to run at 1489 degrees for over thirty minutes while heat treating a couple 1084 blades. I didn't have to adjust it once. Originally I had planned on the PID controlling it but using it to monitor seems the best way to go. AC Richards was the one who helped me with this decision first. I spent a couple days at his shop over the last year and we went long periods of time both forging and heat treating with little adjustment needed to control the temps.

[Woodchuck Forge]

I agree Ed completely. I did set up a PID controlled forge for a very short time. It did not perform any better than a properly tuned forge. Like Brian mentioned, my forge will run at a given temp, plus or minus 10 deg. The lag from the turn off of the gas to the relight will vary a lot. Even with the new fangled PIDs with the smart technology to reduce the fluctuations. I can effectively heat treat in my forge, at least for most blades. Really long blades, 12" plus, give me fits at times. I do have a salt pot also and it gets used with my damascus and full harden blades. I tell everyone who comes over to set up the forge right and the PID will not be required.

I do like to see the temp my forge is running. So I use a PID as a read-out nothing more.