By no means trust me. Sure I have done a lot a lot of reading. But I have never had this issue.
Try a search for fixes connected to freezing it. I recall back in December a recomendation for a similar issue (not with a kayfun) regarding freezing the atty.
Again…don’t trust me. You gotta find a post regarding that…id hate to see you ruin your kayfun.
I would take the 510 pin out pull the afc ring off the bottom
Remove the top ring that holds the glass tank section on and remove the glass
wash what is left off good and let it dry
wrap masking tape around the base and around the area of the chamber for the build deck to protect them
use 2 pairs of pliers to get them unscrewed
Sorry to hear that. It’s a bummer but it will give, as @Chrispdx has recommended, would stick it in the freezer for a while, doing this will contract the metal parts and hopefully release it.
If you can i would try and take it apart from the top down, take the top fill off and disassembled the tank section peice by peice, then on the chimney section wrap a rubber band round it and use that for leverage.
Try and take the top sections off first before you put it in your freezer, protect’s the glass.
Let me know if that works for you. 
I like what @wvsanta and @Pattie Said take off the glass… You can also use 2 ( small ) Strap Wrenches https://youtu.be/eoRT8UvYraI
I’m trying to like things and i keep getting the message 'try again in 3 hrs’
I’ve used a cpl today but thats all and it won’t let me like anything! Hmmmm🤔
Anyway here ya go @Rob62 
You and me both 
Imine are back now for some reason?
Mine too 
Good. Were back in business. 
Thanks for all your suggestions! I am only able to remove the 510 pin, bottom base, airflow ring and the top cap. I’m not able to unscrew the top ring in order to remove the glass.
It’s in the freezer now. I’ll post an update in an hour or two. Thanks again!!!
When you take it out of the freezer see if you can take off the glass first
It sounds like you may have tightened everything up way to tight. When I put my tank together I screw the top on until it just makes contact with the glass and then only a very light snug after that. Same when I close my juice control and when mounting on the mod.
Progress - was able to remove the top ring and glass after an hour in the freezer. Taking @wvsanta’s advice and washed and letting dry. Masking tape and pliers next…
Let us know how it goes
@Chrispdx Well, it worked for removing the glass so contrary to your advice, I do trust you.
If it does not come apart easy I would try this next.
Heat water to a boil turn off the heat holding the base where the air flow ring goes with a pair of tongs or pliers submerge the upper half in the hot water all the way to where the glass mounts. Keep it in the water for a few min then using a pot holder or oven mit try unscrewing it immediately.
Yay!!! I was just worried because it was so long ago that I read the tip that I wasn’t sure.
Masking tape and pliers didn’t work. Dipping in hot water didn’t work either. 
Then my husband tried with rubber and pliers, then leather and pliers, then wrapped it in leather, put it in a vise, cursed a great deal* and then asked “Are you sure this is supposed to come apart?” lol (needless to say he’s not a vaper).
Any machinist/vaper in the SF bay area reading this thread?
*I’ve cursed my fair share as well.
Try putting it back in the freezer and try again the cold should shrink the o’rings a little. If you have the air flow ring off you may be able to put a small rod in the big holes of the base