PID forge question (mainly for those who use one)

[weo]

Hello all. I've got a question for those of you who use PID controllers on their forge. What sort of temperature swings do you see when in actual use? (ie, putting cold metal in, opening and closing the forge doors, etc.)
Today I used my forge with the controller for the first time, and was a bit disappointed compared to the test run I did over the weekend where I posted the video on my build thread: https://bladeforums.com/threads/pid-forge-upgrade-videos-added.1703702/page-5
In the test, the forge was in the garage, no metal being heated and the temp only had a 5-10 degree swing from the target temp. Whereas today, I had the forge completely outside the garage, was using it to draw out some billets, and punch some holes for some hammers (also had to christen the new 25-ton press that got delivered on Friday...) and noticed a 40-50 degree swing from target temp. Now I wasn't too surprised when this happened after putting the cold hammer stock in, but I was surprised that it kept such a large swing when drawing out the billets, even after the initial heat.
Also, I tried letting the forge just idle for a little bit and the temp still had a 25-30 degree swing. Could this large swing be due to the forge being outside and completely exposed to colder temps (it was in the low-mid 40s today.)? Or do I need to fiddle with the valves and PID setting more?

Thanks

 

[Gilbert M]

I have 2 ribbon burner forges they both hold about 2 degrees. This weekend I was forging blades, while I'm working them if they don't cool to much the forge probably drops around 25 degrees and comes back to temp in a minute more or less depending on the size of the billet. Temperature doesn't seem to affect the forge but wind does this weekend's breezes were causing close to a 10 degree swing, I just tried to keep the forge more closed and that helped. It took a while to get get the first PID right (I'm no expert ) when I built the second forge I used the same PID and settings. My bypass is set to just under target temp that way I can keep the needle valve for my solenoid set pretty low with bigger billets sometimes higher. My PID(mypin) turns on at 2 degrees below and off at target temp. I keep the air flow as low as possible I can weld or get down to 1250 (some swings at1250 unless I adjust the airflow) . If I turn the air up it heats up and cools off faster and uses more gas. I hope you find something in this to help you.
Gilbert