Yamasaki Congo 18cm 4.5: front element group cemented or...?

[ethics_gradient]

I picked up a Yamasaki Congo 18cm f/4.5 for fairly cheap on eBay even after shipping from Japan - mostly because it has some light haze/fungus inside. I've had good luck servicing simpler lenses before and thought it'd be a good candidate for wet plate portraiture, but I can't tell if the front group is cemented or if the nameplate ring is just on there really good (to be fair I don't have a set of those rubber grip things, so just tried using the corner of a kitchen anti-slip mat after putting it in the freezer for a few hours).

It otherwise disassembles quite readily and I can get to the other surfaces without any issues.

Does anyone have any knowledge or tips? I could try putting the front group in the oven on a low setting and seeing if heat does anything, perhaps softens a threadlocker that might be on there?

I'd also be interested if anyone's got an idea how I could get a rough date for it. The serial number is 32493.

[LabRat]

I'm guessing from the speed it is a Tessar type, which means there is an air space between the forward elements... Sometimes the front element comes out from the front or the back of front ring with 2nd element behind it...

The front ring is not supposed to be too tight on the element, as these rings can distort the glass... There is usually something to prevent the ring from undoing itself... (Set screw, thread-lok etc...)

Probably thread-lok (look if there is a gap between ring and barrel), and maybe a tiny blotch where excess has come a little out, if there is, a hypodermic needle with a small amount of acetone in it... Put the smallest micro drop possible at 4 points of it's diameter in the seam, then wait about 10 minutes, then repeat once or twice, then try removing... Go very easy with the acetone...

Sometimes you can just get the element from behind it out and clean element while in place... (Second element will usually unscrew...)

Good luck!!!

Steve K