TD Barrel crack repair - any advice?

[parapadakis]

I have this sad little Imperial barrel that needs repairing. I am planning to attempt the fill-and-file approach with CA glue on the outside, before throwing it away. I am aware that the O-ring groove needs to stay clear on the inside. Any other advice from succesful TD barrel repairs? (besides "don't bother, find a donor pen" 😉)

 

Thanks

George

 

 

 

[terim]

We have replacement barrels, NOS ....

https://www.peytonstreetpens.com/sheaffer-imperial-touchdown-fountain-pen-replacement-barrels-fits-models-ii-iii-iv-vi-viii-new-old-stock-made-in-australia.html

 

No burgundy,  though I do have a few that are scratched up if you want to send me a message via the website.

[parapadakis]

On 12/14/2021 at 8:24 PM, terim said:

No burgundy,  though I do have a few that are scratched up if you want to send me a message via the website.

Thank you. Great to know there is a backup option, if my attampt at repairing it doesn't work out 🙂

[jspen765]

Hi Parapadakis:

 

CA will not do it.  You need to weld it. 

 

There are better people at this, you should search the Repair section for Touchdown and Snorkel repair.  There are even some online movies that would help (I have to do it wrong, then get it right, movies don't always do it for me). 

 

The actual problem is the O-ring in the back has hardened.  Someone tried to work it, and the hardened rubber O-ring put excess pressure on the plastic.  Fortunately the plastic failed before the brass tube inside gave.  That means that both the O-ring and the sac inside need replacing (or renewing as your English friends call it).   You will need a sac and a new O-ring, Shellac, plus some silicone grease, pure.  Do some searches on the repair forum for "snorkel repair" and "touchdown repair" for full details. That should also get you to sources for the O-ring and sac.  There are still some in England.

 

As I said CA will not do it.  You need to weld it.  I have successfully repaired TD and Snorkel pens with similar cracks using MEK, which is hard to get.  I believe these are polystyrene so liquid cement for plastic models should be close enough but slower to cure. 

 

So take it apart.  Unscrew the section from the body, it often requires dry heat to loosen the plastic threads.  The metal cage that holds the sac can be pulled off the section, some fit hard, some loose.  Remove the sac and its remnants on the section end. Trim the new sac to length and put on the new sac (15 1/2 if I remember right, 16 will do) with shellac as cement.  Let it dry and snap its cover back on. 

 

Then take a long slender flat screwdriver up the inside of the brass tube in the body and unscrew the screw that holds the cap. Pull the cap off. Next push the chromed tube out the bottom.  Take something moderately sharp (I usually use a large straight pin) and convince the old O-ring to come out.

 

Now repair the body crack. Apply the cement and let it cure under pressure.  I use a dental clamp or clothes clip to hold the crack closed.  This will need to thoroughly cure, 2 days is not too long. 

 

Then put the new O-ring in, which is an exercise in dexterity.  I dip the O-ring in silicone grease (pure, go to a dive shop or use the grease for spark plug wires).  Reverse the steps to put it back together.  Technically there is a third seal between the pressure tube and the cap, a scrap of  sac from the excess length can be used for this if required.  Out of about 100 Sheaffer Touchdown and Snorkel pens I have done, I have changed this seal no more than twice.  And I am still not sure I needed to.  Just make sure it is there.

 

Finish re-assembling, and check the tube movement.  You should feel slight pressure and hear a small hiss if held up to your ears. Pull it back, put the section in water, then vigorously close it.  It should take up some liquid. Squirt the water out, and repeat with ink.  Write.  You are in business!

 

Good luck,

 

Jon The Eclectic Penner

 

 

[3rdlakerobert]

A cure is more dubious for Touchdown TM models than Snorkels, PFM, and TD-filling Imperials like yours since the older Touchdown TMs were made of a plastic resin that it turns out is prone to shrinking. In my experience, Touchdown TMs shrink at the place your Touchdown Imperial is cracked and solvent welding is not a lasting solution for those pens. The stress on the material at the point where the plunger tube runs through the O-ring soon causes another crack. You however will be able to do a satisfactory repair using the procedure described below.

 

To repair the crack on a Snorkel, PFM, or on a Touchdown-filling Imperial:

1. Disassemble the pen. Be sure to remove the blind cap, plunger tube, and O-ring from the barrel. 
2. Clean the barrel, preferably with an ultrasonic cleaning unit (used for cleaning jewelry) and a couple drops of dish washing detergent.
3. Open the crack carefully and apply Tamiya Extra Thin Cement (Amazon), which is used in modeling.
4. Clamp and let set for 24 hours. Then without unclamping, reapply Tamiya over the repair. The theory here is that the second application penetrates the previous repair and when cured makes the repair stronger. Don't worry about cement drying on the surface at this point. 
5. After one week, remove the clamp and clean up the repaired area with fine abrasive, finishing up with something like 700-1000 grit sponge-backed abrasive. Buff.

You will probably still be able to see the repaired area but it will be inconspicuous.

 

[parapadakis]

On 12/17/2021 at 8:44 PM, jspen765 said:

As I said CA will not do it.  You need to weld it.  I have successfully repaired TD and Snorkel pens with similar cracks using MEK, which is hard to get

Thanks @jspen765 for the detailed explanation. I have restored a few dozen touchdowns and snorkels, so I'm familiar with the process. It's only the barrel repair that is new to me. Can you please explain what you mean by "welding"? The process you are describing is the same as I was planning to use (use liquid CA as the bond, stretch the crack to allow to penetrate the gap and then clamp together to let it cure, then additionally groove the crack area on the outside, fill with CA for additional strength and file down to polish). Why will CA not do it? Is it incompatible with this barrel material? I'm happy to use Liquid Poly cement if it will create a stronger bond.  I appreciate your thoughts on this!

 

Regards

George

[parapadakis]

Thanks @3rdlakerobert that is the technique I was planning to use, but you are suggesting that Liquid Poly (like Tamiya) would bond better with the plastic, than liquid CA?

 

thanks

George

[jspen765]

Hi Parapadakis:

 

Cyanoacrylate is a great glue, but it has problems in pens.  First it bonds by surface tension.  As a result, it is weak in tension. This joint will have lots of tension stress.  And I discovered after trying it in pens that water (ink) defeats it.  Water hastens cure but continual exposure results in the CA glue bond expanding then crumbling. Experts told me that, such as Farmboy and Ron Z.  But I had to learn the hard way. 

 

So we need another way.  One could use heat and melt it, press it together while melted, and when it cools you would have a perfect bond. In metals that is called welding. The result would be smaller than the starting product which is counterproductive, as 3rdlakerobert says, part of the problem is that the plastic may have shrunk.  But a chemical equivalent can do the same thing by melting the plastic slightly with solvent, then forcing the melted surfaces together until the chemicals evaporate and the material becomes solid again.  MEK is the best but I can't get it in California any more and I doubt you can in England (also dangerous to use). So a lesser light such as Tamiya Extra Thin Cement or the equivalent Testors cement will do something similar, though since they are milder they take longer.

 

Jon the Eclectic Penner

 

[Ron Z]

CA is the LAST thing you should reach for in pen repair...  if ever.   Really.    It will not hold, and because you have contaminated the surface, solvent welding is more difficult and the repair weaker.  The contact area is too thin to have any strength.

 

The best solvent is really hazardous to use.  Here in the US  most companies require that you have a Federal EIN to prove that you are a business before they will sell it to you.  If you can't get MEK, actone will likely work.  Allow it to cure 24 hours before you test it or try to blend the repair.  The initial bond is fairly quick, but it takes several days to approach full strength.

[parapadakis]

@jspen765 and @Ron Z - Many thanks for the detailed advice and explanations. Looks like I need to sacrifice another body first, experimenting, before I commit to fixing this one. Or perhaps accept that I may trash this one in the process and will have to replace it. Either way, good learning experience! Thank you.

[Ron Z]

I should add that you want to apply the solvent and make sure that it wets the sides of the crack, close it down, open it and apply the solvent again.  Then close it and hold it with a dental band clamp or electrical tape stretched and wrapped around the barrel.  Scotch 33+ is best if you use tape.  You can also look for Tofflemire matrix band clamps on Ebay.  There are disposable ones too.