Parker "51" O-Ring Hoods: Half-Recessed Or Fully Recessed?

[ek-hornbeck]

I need to replace the hood on a "51." I prefer to use hoods that work with o-rings: I don't have to screw them down hard (stressing the plastic) or use shellac to seal them against leaks.

 

I have the option of buying a shell with a fully-recessed indent for the o-ring, or a half-recessed indent.

 

I have no idea what the trade-offs are here. Could someone clue me in?

 

The half-recessed shells look a little more robust around the lip, for obvious reasons. But I am no expert. Do they completely hide the o-ring? How do the two kinds of shell work out?

 

E. K.

[FarmBoy]

Which connector do you have?

 

Even with an o-ring some thread sealant is advised.

[ek-hornbeck]

Which connector do you have?

 

Even with an o-ring some thread sealant is advised.

 

Looks like a generic connector for a Mark 1 Aerometric. I was unaware those came in different types.

 

I cannot use thread sealant because I have to tear my pen down once or twice a year to clean it. Thus is life with nano-pigment ink. But I've never had a problem with leaks, so it seems to be going fine.

 

E. K.

[Ron Z]

I agree with Todd. You might get away without sealant on an 0-ring section, but maybe not. You don't have to use shellac. Though some argue with me, I have handled NOS 51s that still had the dust from making the pen inside. I can tell you with absolute certainty that they did not use shellac, but used a rosin based thread sealant. Pen mechanics tend to use shellac because not only does it seal, but it also helps to keep the casual user from opening up the pen and screwing up the alignment of the parts.

 

If you used thread sealant, it would be much easier to open the pen when you need to. Don't make the shell tight. Just until it stops will work. The thread sealant will help to keep the hood from unscrewing on its own.

[ek-hornbeck]

I agree with Todd. You might get away without sealant on an 0-ring section, but maybe not. You don't have to use shellac. Though some argue with me, I have handled NOS 51s that still had the dust from making the pen inside. I can tell you with absolute certainty that they did not use shellac, but used a rosin based thread sealant. Pen mechanics tend to use shellac because not only does it seal, but it also helps to keep the casual user from opening up the pen and screwing up the alignment of the parts.

 

I'm going to take a delaying, if-it-ain't-broke attitude to this issue: when my "51" starts to leak, I'll turn my attention to sealants.

 

In any event, we are wandering from the actual question I've got: what is the difference & functional tradeoffs between half-recess and full-recess hoods, in practice?

 

E. K.