Stabilize Loose Cap Bands?

[markh]

I have a celluloid Duofold with 3 thin cap bands that are loose enough to wiggle and rotate.

 

Any suggestions for the best way to stabilize them??

 

Thnx

 

 

.

[tryphon]

If it is celluloid, you could try expanding the cap under heat. It is not as difficult as it sounds, as long as you proceed slowly and with caution. If the bands are not too lose, you can stabilize them with some clear shellac.

[alexro]

you can stabilize them with some clear shellac.

this solution always worked for me perfectly, though I used just ordinary (brownish) shellac as it not seen under the bands.

[markh]

If it is celluloid, you could try expanding the cap under heat. It is not as difficult as it sounds, as long as you proceed slowly and with caution. If the bands are not too lose, you can stabilize them with some clear shellac.

I've tried this before. Disaster - lip cracks. Is there a trick to lower the risk??

 

.

[markh]

this solution always worked for me perfectly, though I used just ordinary (brownish) shellac as it not seen under the bands.

 

So I paint shellac over the bands, and presumably wipe it off before it sets. The visible parts get wiped away, shellac under the band stays...

 

 

.

[tryphon]

I've tried this before. Disaster - lip cracks. Is there a trick to lower the risk??

 

.

Try using an inner cap extractor to expand the cap from the inside. You may want to use some electrical tape around the puller threads. Go slowly and use enough heat.

[FarmBoy]

I'd reswage the bands onto the cap to tighten them.

FB

[kirchh]

I'd reswage the bands onto the cap to tighten them.

FB

 

Concur.

 

--Daniel

[tryphon]

I'd reswage the bands onto the cap to tighten them.

FB

How? I am curious.

[Ron Z]

I find that stretching a cap lip to tighten the band is more than a bit risky, especially if you aren't used to heating celluloid. I prefer to swage them, which when properly done allows you to tighten the band and secure it without any shellac or adhesive.

[tryphon]

Ron,

are the bands loose because:

a. the cap has shrunk

b. the bands have expanded ?

I am not aware of metal bands spontaneously expanding... If the cause is a., shouldn't the solution be to return the cap to its original diameter? Risky: of course: these are old pens. Swaging is also risky: compress too much and you can have ripples or breaks in the bands or crack the cap.

I'd like to know what swaging tool can be used: I must have a thousand vintage, never used cap bands and I would love to find a way to use them.

Thanks,

Giovanni

Edited February 16, 2015 by tryphon

[kirchh]

Ron,

are the bands loose because:

a. the cap has shrunk

b. the bands have expanded ?

I am not aware of metal bands spontaneously expanding... If the cause is a., shouldn't the solution be to return the cap to its original diameter? Risky: of course: these are old pens. Swaging is also risky: compress too much and you can have ripples or breaks in the bands or crack the cap.

I'd like to know what swaging tool can be used: I must have a thousand vintage, never used cap bands and I would love to find a way to use them.

Thanks,

Giovanni

 

I'm sure Ron will respond, but I will give you my experience. You are correct -- surely the cap, along with all the other celluloid parts of the pen, has contracted as a result of the small degree of curing that the material undergoes after the article is manufactured. This is quite common with celluloid pens, and it explains loose cap bands and also such phenomena as the commonly-seen gap between the top and bottom of Sheaffer celluloid pencils. Though some dimensions can be restored, it is only at the expense of others -- locally expanding part of the cap will not only increase the outer diameter in that region, it will also increase the inner diameter, which may result in a loss of mating between the cap and barrel threads as well as the appearance of a swelling at the expanded area. Shrinking the cap bands to match the shrinkage of the celluloid is a better solution, and less risky if skillfully performed with the proper tools.

 

--Daniel

[lcoldfield]

I prefer to expand the cap, because it is rare that the barrel has shrunk too - the hard rubber section will have prevented that. Only a small expansion is usually required, but it can be risky, like swaging, if you do not have the proper tools. I make a mandrel with a small taper and cut a shoulder so that it does not ruin the threads. I heat the mandrel and ease it in very slowly whilst also using hot air on the cap. The job is finished using a swaging technique and a spot of shellac. A small degree of swaging can be done using wrapped steel shim and loggerhead pliers gripping and rotating. I leave the mandrel in so that considerable force can be used without risk to the celluloid.

Laurence Oldfield

[kirchh]

I prefer to expand the cap, because it is rare that the barrel has shrunk too - the hard rubber section will have prevented that. Only a small expansion is usually required, but it can be risky, like swaging, if you do not have the proper tools. I make a mandrel with a small taper and cut a shoulder so that it does not ruin the threads. I heat the mandrel and ease it in very slowly whilst also using hot air on the cap. The job is finished using a swaging technique and a spot of shellac. A small degree of swaging can be done using wrapped steel shim and loggerhead pliers gripping and rotating. I leave the mandrel in so that considerable force can be used without risk to the celluloid.

Laurence Oldfield

 

While the inside diameter of the barrel will likely not have shrunk appreciably where the section has prevented that, the outside diameter will decrease simply by virtue of the loss of volume of the material. In addition, barrel threads may be somewhat worn. I will also observe that the pens I've examined that have had the lower part of the cap expanded show an unavoidable swelling as a result. Careful swaging with a purpose-built tool or a suitably chosen repurposed collet and semi-compliant non-marring sleeve or bushing can produce outstanding and undetectable results.

 

--Daniel

[markh]

I prefer to expand the cap, because it is rare that the barrel has shrunk too - the hard rubber section will have prevented that. Only a small expansion is usually required, but it can be risky, like swaging, if you do not have the proper tools. I make a mandrel with a small taper and cut a shoulder so that it does not ruin the threads. I heat the mandrel and ease it in very slowly whilst also using hot air on the cap. The job is finished using a swaging technique and a spot of shellac. A small degree of swaging can be done using wrapped steel shim and loggerhead pliers gripping and rotating. I leave the mandrel in so that considerable force can be used without risk to the celluloid.

Laurence Oldfield

 

Wow - way beyond my skills. The shellac I can handle. Making a mandrel and swaging gold rings not so much. Maybe the complete set of lessons are somewhere on YouTube....

 

 

.

Edited February 16, 2015 by markh

[lcoldfield]

The choice of technique depends so much on the condition of the pen. If the bands are merely a bit loose then shellac is probably good enough. If the bands are falling off, then cap expanding or swaging methods are needed (in the hands of an experienced person). If the cap is obviously tight on the barrel, I would expand the cap, but not to the extent that it becomes obviously larger in diameter at the lip than elsewhere. If more than marginal expansion is required then it probably means that the bands being fitted are not original. The swaging method is handy for fixing replacement bands (preferably softened first).

Laurence