Aquatica Housing & frozen set screw

I have been diving with an Aquatica AD7000 housing (Nikon D700) for a couple of years now. Rinsed it after every dive. Worked the buttons, as well.

I experinced some minor leaks recently and went about replacing o-rings. This is not hard to do, just tedious.

All of the exterior knobs are alimunimun and have stainless steel set screws. These loosen easily, except for two of the knobs, (Exposure Compensation/Reset button and the subcommand dial knob) which have set screws that are definitly frozen and bonded.

I am perplexed. The sacrificial anode is doing its job. I didn't see any crud built up on these knobs. All the other knobs and set screws are fine. The other set screws may have had some sort of compound on them. Perhaps these lacked the compound. I use Tef-gel on nautical metalic connections that might seize. But I never thought to loosen the screws on this housing periodically.

This seems like a weakness in design when plastic knobs would suffice.

Any experience getting these undone? I've tried soaking in solvent, then vinegar and critic acid.

--Stan

You might try PB 2000. However, the key is not to get the oil in the o-rings if you can avoid it so you might apply it via a q-tip and let it soak and let it do its job. However, if you plan on replacing all the o-rings and you get some oil on them just make sure there is no remaining residue anywhere since it will cause the ruber to deteriorate over time.

This stuff works good.

http://www.autozone.com/autozone/accessories/Blaster-Chemical-11-oz-penetrating-catalyst/_/N-255s?itemIdentifier=515413

The Meltdownman

Try this;

Position the housing with solid support under the problem knob. Rotate knob with set screw to top (up) position and apply several drops of WD40 (or maybe the PB 2000) to set screw. Let soak about an hour. With your assistant helper holding the housing/knob, insert the Allen wrench and apply ccw torque and soundly tap on the top of the wrench. Some times the impact will break loose the set screw.

Plan B: return to factory.

I was told by a housing technician to use DeoxIT to break lose oxidized screws of two dissimilar metals that are frozen in the housing from exposure to salt water. Apply it with the screw in the vertical position to allow gravity to help penetration, wait overnight and try to loosen the screw, if still frozen repeat the process until the screw breaks lose. When reassembling use Tef-Gel.

Elmer

Thanks for the info.

P Blaster 2000 didn't do it, trying DeoxIT.

I'll reply when I get this lossened.

Cheers,

Stan