It depends on your set-up. Some variation will need to be made to compensate for hose size and length.

Pot pressure 125psi
Gun pressure 85psi

Wow Fred. that's a lot of pressure to put on the pot. I use my pot with Du-Bois 301 glue which is very thin, but I run my pot at 5-8 psi and gun at 65-80. I know the weldwood will need a higher psi. but anything above 20 on the pot sounds dangerous to me. I have not run weldwood through my pot so maybe that much is required to make it spray properly.

Be safe and look at manual for the pot you have, and do not exceed what is specified. I don't recall what brand it was but when I attended Wyo-Tech we had a test on pressure pot usage, and for that brand the maximum pot pressure was something like 15-17 i think. (forgive my memory that was in 1999)

Fred Knows what he is doing & I'm not questioning him. I'm sure his glue pot is a really good purpose built setup, and can handle those pressures.

I'm Just hoping no one puts that much psi. on a cheapo harbor freight pot like mine. The harbor freight pots absolutely need modification to work properly for glue. Low psi regulator for the pot side and absolutely add a relief valve. I use a 25psi relief valve on mine

yup now ive had a mess about I find 8 psi for glue and 40 psi for gun works for me

I can't even say that. I work with an operating pressure of 6bar/87psi on all compressed air connections. For all other tools like the airbrush gun and the glue gun I adjust as needed.
I also use only one gun with one cup on the gun. For me, this turned out to be the best solution, because I often have to adjust the thickness of the glue to the different jobs and therefore always have to adjust the air supply and the amount of glue.
...So its all about the feeling :love: