Touchdown Section Disintegration

[Jack7770]

The friend who brought me her Grandfather's TM Touchdown with the inner cap that needed re-gluing (see earlier thread), brought several other problems with it that weren't immediately apparent. As I disassembled the pen, I discovered that the sac protector was missing, but I had one my parts bin--no problem. The real problem turns out to be the section. It is discolored in the lower third and the sac nipple is very fragile, thin with some cracks. Either age or having been stored in a desk drawer for more than 40 years with encrusted ink has caused the problem.

The question: can I strengthen it a weakened section sufficiently with shellac to make it serviceable or use DaBooks' technique of a cut off cartridge inserted, or is a replacement best. I'd appreciate any advice since this is a form of disintegration I haven't seen before. Thanks, Jack

[Ron Z]

You would be better off finding a donor with a section that is disintegrating like that. I've encountered pens with a Dubiel style sac nipple. They aren't pretty, and they leak... and most cartridges are made out of plastic that things don't stick to very well. All in all, another one of the ideas that frankly I don't recommend trying.

 

If replacing isn't an option, try solvent welding the cracks. Touchdown sections are celluloid, so you can use acetone as the solvent. Gently spread the cracks just enough that the walls of the crack separate. Use a fine camels hair paintbrush to drop in in the crack and then close the gap. Allow a couple of days for it to dry before you test it and finish the repair.

 

You could try some of the Plastruct polystyrene tubing from a hobby shop. Acetone should work here as well. You may have to shave it down a bit to get it to fit after you've cut off the damaged sac nipple. Go for a snug, but not tight fit to avoid a gap that has to be filled.

[Jack7770]

Thanks, Ron, as usual. I'm trying the acetone method. I have also come to be skeptical of several Frank's suggested shortcuts--like the cut-off cartridge. If the acetone doesn't strengthen the nipple enough, I'll be looking for a replacement section. Thanks again for your recommendation. Jack (BTW, how about a trip to Colorado for next year's pen show?)