Hi, I´m trying to remove a Parker 51 hood so I can change a nib and it´s impossible for me to unscrew it. I allready tryed using warmed water, but was impossible. Any suggestions on how can I open it. Thanks you all.

I'd a fondue pot and a candy thermometer in an attempt to free a couple I was having some trouble with. The thermometer is to keep an eye on the heat (someone in a previous thread was indicating that below 130F doesn't do much and 150F or above is very bad for the Lucite). One of them finally gave in after an hour in the water. The other one had two nights of three hours each and still hasn't unstuck-- I suspect a very wrong ink indeed was used in that one, but I too would like more tips.

If you have access to an ultrasounic cleaner, I would give it 10 or 15 minutes in that first to loosen up the dried ink. Try gentle heat to loosen things up after that and then try to remove the hood.
Rob

One guideline I use is 70 degree C for 20 min. and it has been successful in unscrewing a few hoods. But 150 degree F is 65.5 C so I probably give it a bit too much heat. Anyway, so far so good.

I read that a hair dryer could be used.
I have tried it on 4 hoods and each time it's worked perfectly.
It took two or three periods of heating for each taking care not
to overheat.

Chibu,

Is your pen an Aerometric or a Vacumatic?

Later Aerometric pens have an o-ring in a recessed groove, very near the clutch ring. If the rubber o-ring is really stuck, this type can sometimes be more difficult to remove than others. Patience, heat, and good tools are the keys. The plastic used in "51" pens is less sensitive to heat than celluloid. Too hot to touch with your lip is a reasonable rough measure of how hot is too hot.

Another possibility is that someone had this hood apart in the past and "sealed" it with a large amount of shellac. Heat is about the only thing that will help if this is the case. Again, slow and easy does it; many repeated heating/cooling cycles will shake things up better than one big blast of heat, although if it is sheallaced in place only heat will soften it up.

If all else fails, try putting it in the refrigerator for a few hours, then take it out for a few hours. Repeat this for a couple of days, then go back to the gentle heat and tools. Sometimes this works when nothing else will.

Cheers,
Tom

Just stick it in yer teeth and twist ... or tie a string to a doorknob and then slam the door shut ...

Thanks you all for the advice, I have three pens in the fridge and my wife is stareing me with a funny face, but afraid to ask