Tuning Advice on separating Air Gun parts...

I previously put 2 power plenums on my .25 Dream Classic, but wanted to remove one of them to put on my Dream-Tac Compact. I have both rifles tore down and when I removed the power plenum, both came off together and now I can't get them apart. There was nothing but silicone grease used on the o-ring when I installed them, so no loc-tite used. What is the best way to get them apart without damaging any thing? Will heat word without damaging the 0-ring? It's hard to get a good grip on either end to try and unscrew them with just my hands. Thanks...
 
Had the same thing happen to me. I used a bench vise on one (with the PP wrapped in an old bicycle tube) and channel-lock pliers (jaws padded with old bicycle tube) on the other.

After the initial 'break' between the 2 parts (the o-ring seal) occurred, they easily unscrewed by hand.

Have no idea why the initial break was so hard.

Strap wrenches with the rubber band type strap were on no good to me in this case.
 
Thanks for all the advice! I got them apart! I ended up just spraying a little Kroil at the seam between the 2 and let it sit for about 30 minutes. I was then able to get a better grip using a couple of those round rubber things you use to loosen jar tops. Once they broke loose they came right apart very easily.

All that, and after I put the other Power Plenum on my Dream-Tac Compact, the barrel would fully seat because I have one of the early model with the larger diameter shrouds! Oh well, I wanted to bring the Dream Classic back to just one Power Plenum anyway.

Now another question... I loosened the gauge on my Dream Classic to degas it and when I went to air it up after reassembling everything, the gauge didn't register, even the regulator gauge showed the prober regulator pressure. I lightly twisted the gauge by grabbing the body of the gauge and then the needle jumped up showing a reading. The problem is, I can twist the body of the gauge either direction and the reading goes up and down proportionately. So, since I don't really trust the gauge on my compressor, I have no idea what the actual pressure in the air cylinder is. Is my gauge toast? Should I just replace it with a better one?

Thanks again for the help.
 
I have found in the past that if you tighten the gauge too much on FX guns then it won't register at all. Just loosened it a little bit and all was good, without any leakage.

IDK about whether yours is toast due to the body being loose/twistable. Just for FX gauges I bought a thin 11mm wrench from Amazon. It was pretty cheap, and having the right tool for the job is priceless.
 
I have found in the past that if you tighten the gauge too much on FX guns then it won't register at all. Just loosened it a little bit and all was good, without any leakage.

IDK about whether yours is toast due to the body being loose/twistable. Just for FX gauges I bought a thin 11mm wrench from Amazon. It was pretty cheap, and having the right tool for the job is priceless.

☝ he is RIGHT!