Can't Unscrew the Barrel

[Andy98R1]

Hi All,

I've just lucked in to a Triumph TD, know it's not special but I intend on keeping it for daily use. Well, I would if I could unscrew the barrel and check out the mechanism, which is almost certainly faulty. I was hoping to do this over my Christmas break but don't want to damage anything by exerting too much pressure; so does anyone know a neat trick for getting the barrel to release?

 

Many thanks

 

Andy

[psfred]

Heat.

 

The barrels of some TD and Snorkels are shellaced in place (or with Sheaffer sealant instead of shellac), so you must melt it to get them off.

 

Dry heat is best -- a temperature controlled head gun or a hair dryer used carefully will work fine, but don't get the pen too hot, the plastic will distort. You should be able to just barely hold it for 3 or 4 seconds.

 

Once you've softened the sealant, the barrel will unscrew. May be reluctant for the first few turns.

 

Snorkels have other problems, notably stuck springs, that heating won't help much with.

 

Peter

[Richard]

Gentle heat, patience, and a quick twist.

[Andy98R1]

Many thanks.

 

Looks like the wife's hairdryer is going to do some real work (said with all the bravery of a fool hardy man!)

 

Cheers,

Andy

[Andy98R1]

We are making progress! The barrel is off, boy they really glued it on, and I've removed the sac protector.

 

My next problem is that I can't find anything wrong with the sac. When I squeeze it, it draws and expels water but it didn't show any pressure when I used the pump mechanism.

 

So my question is: Is this usual or am I missing something?

 

And the very next question is: Should I just replace everything anyway?

 

Thank you to all those sharing this learning experience with me!

 

Cheers,

Andy

[Nick A]

Well, there's the O ring at the back of the barrel that could be rotted. Needs to have pressure inside to deflate the sac to fill. As long as you have it apart, I would replace the sac as well.

 

You can see where it is located in the graphic on Richard's website: http://www.richardspens.com/?page=ref_info/pneumatics.htm

 

Oh, one more thing, a crack in the barrel might cause some troubles too, but usually it's bad rubber.

Edited December 23, 2008 by Nick A

[psfred]

Given that the pen is at least 50 years old, I would replace the sac and 0-ring. Very very unlikely that the 0-ring is anything but petrified, and the sac is probably going soft, too.

 

Sac is a straight #15, available from several places, and the 0-ring is readily available from Pendemonium or Giovanni at Tryphon.

 

You will need a long, thin screwdriver to reach the screw that holds the blind cap to the TouchDown tube -- watch that you don't lose the star washer or the rubber seal found inside the rest of the bits. Remove the screw, pull the blind cap off, and push the tube out of the mouth of the barrel. When you look inside the blind cap end of the barrel, you will see the 0-ring in a slot at the end of the threaded portion when the blink cap scews on. Use a tiny screwdriver or a straight pin or very sharp thin pick to GENTLY pry this ring out of the slot. They can be quite hard, in which case a straight pin works nicely to stab into it and crack it into pieces.

 

Insert the new o-ring into the slot -- I just push the o-ring into the barrel at an angle and get the lower part started into the slot and push the rest in with my screwdriver, but some people like to use a pencil or a piece of dowel rod inserted into the other end of the barrel to keep the o-ring at the correct position.

 

Grease with some pure silicone grease - available from the above places as well as bearing supply houses, dive shops, and possibly electronics supply stores. Do not, please, use anything petroleum containing, as it will slowly melt the o-ring.

 

Push the TD tube back into the barrel, drop in the screw, re-install the blind cap being careful not to strip the plastic cap, screw it back on, and you should have a fully functional pen.

 

Do check to see, however, that the nib and feed are not clogged with ink! That will prevent the pen filling, too.

 

Peter

[Ernst Bitterman]

A quick check of the barrel pressure is to put your finder over the mouth of it and run the tube in and out-- you can feel the draw and compression. If/When you take off the blind cap, check that there's a little black seal up inside it (if it's not there, one can be fabricated from some excess sac). You may also find a little crack in the barrel compromising the seal, which can usually be put right by use of a liquid model cement (Tenax is the usual choice).

 

The seal in question, although somewhat compressed:

http://dirck.delint.ca/Pneumatic%20blind%20cap%20gasket.jpg