Best Way To Fix This Crack

[siamackz]

Hi,

 

See pic. This is celluloid I think. Its a copy of a Parker vac!

 

Question is how should I fix the crack? Some kind of adhesive or MEK? If adhesive then which kind - loctite 480 or rubber based adhesive? If MEK then do I just apply some directly in the crack and then keep the crack closed for a few days with dental bands?

[Don Jr]

Perhaps it's the lighting of your picture, but to me , it almost looks like somebody tried to fix the crack with some sort of solvent, but did not utilize a dental band (?)

 

Does the crack by the tassie-end close when you pinch on it with your fingers? If so, then wicking in some MEK and then holding it shut with a dental band will likely yield good results... I've used a very fine modeler's paint brush for this fairly successfully. If you search old threads for Ron Zorn's & FarmBoy's advice for similar situations, you'll learn that you need to be patient and let it cure for at least a week or longer for the best results, not just a few days. Then go over the repair with some appropriate micro mesh to blend in/hide the seam.

 

Good luck, and keep us posted on the progress!

Edited July 24, 2018 by Don Jr

[penjog]

Hello,

 

that's interesting.

 

Would you please explain what "MEK" and "dental band" means?

 

Hansjürgen

[praxim]

Hello,

 

that's interesting.

 

Would you please explain what "MEK" and "dental band" means?

 

Hansjürgen

 

Links provided in the quoted text.

 

In the second case, look about halfway down the page for band clamp

[siamackz]

@Don, it might be a repair that has come open. Not sure. So youre saying no need to make any celluloid slurry - just use tiny amount of MEK and then hold together. Right?

[Greenie]

It looks like a seam has opened up. The green lines do not line up at the crack. So I would guess it is not a repair that came open, but the original seam from a rolled sheet of celluloid that came open.

 

First step is MEK, or Testors 3502, then hold tight with dental matrix Tofflemire band clamp. After it sets, it might stretch open a bit and leave a depression. Dissolve some clear celluloid in testors 3502 to make a viscous celluloid solution, and lay down a bead over the depression. Let cure a week or so, and sand down.

[FarmBoy]

Not a seam. Remove the inner cap if there is one first. Then clean extensively. Degreese and dry before you solvent weld. The cap is tapered so use an appropriate band clamp.

[penjog]

@ On twig

 

Thank youfor that information and the link!

 

Hansjürgen

[Greenie]

Todd,

you are often right, and often right when I am wrong! I wish you could see the confused smile on my face to see that I am trying to figure out which of us is seeing this funny. I am not trying at all to "win". Damn text always misses the tone of a comment.

 

But look at the green and black stripes! None of them line up. This does not appear to be a machined rod like a vacumatic. It is a copy of a vacumatic per the OP, and it appears to be made from a rolled sheet. I put red dots on the ends of the green layers to help them stand out.

 

Regardless, that does not change your sage advice regarding how to repair it.

 

So, check out my dots and tell me what you think. Either way, I will still buy you the beverage of your choice next month at the SF show!

 

[Don Jr]

back @ Siamackz...

 

Not exactly...

What I'm saying is that if you can pinch it closed with your fingers - and the entire crack can be visibly closed up when you pinch it - you may not need the slurry at all, and the solvent alone might weld it shut (with the aid of a band clamp). If you pinch it closed and the widest point of the crack (by the tassie) still has a gap, you may indeed need to make a celluloid slurry to 'fill in' the gap.

I've had mixed results making the slurry... I've tried 'shaving' it/scraping the piece of donor celluloid w/ a razor blade (resulting in sliver/flakes that I then added to a few drops of solvent), and I've tried sanding the donor celluloid, and carefully collecting the 'dust' to add to the solvent. Both have had some successes as well as less-than-great results. (And by "success" I mean obtaining a slurry that actually filled a gap, dried/cured well, and after a couple of weeks was ready for me to start sanding/blending with micro-mesh). Others may have a better way of making it... (?)

[FarmBoy]

Hell I looked at it on a cell phone on a train while waiting to win another $1000 gift card. All I could tell is the crack looked curved and it looked like a Vac. I can live with this being a really bad, original to the pen seam. I'll trade you a set of eagle eyes ... wait, Scotch is better.

Unfortunately that doesn't make the repair any easier.

[CS388]

What I'm saying is that if you can pinch it closed with your fingers - and the entire crack can be visibly closed up when you pinch it - you may not need the slurry at all, and the solvent alone might weld it shut (with the aid of a band clamp). If you pinch it closed and the widest point of the crack (by the tassie) still has a gap, you may indeed need to make a celluloid slurry to 'fill in' the gap.

 

 

 

Yes, I'd try solvent alone, before slurry. All surfaces to be cleaned and de-greased first.

I'd be tempted to nip it at the top, it being tapered - and hope getting that straight, would pull itthe rest into line.

I'd leave it for a week!

 

I totally see Greenie's line misalignment.

I think I'd forego the cosmetics for a strong weld.

 

There's often call for a bit of slurry during the clean-up (in my humble efforts).

I use shavings, some of which have been been in solvent, in small air-tight containers for months!

 

Nice pen, siamackz.

Good luck.

[Greenie]

Hell I looked at it on a cell phone on a train while waiting to win another $1000 gift card. All I could tell is the crack looked curved and it looked like a Vac. I can live with this being a really bad, original to the pen seam. I'll trade you a set of eagle eyes ... wait, Scotch is better.

Unfortunately that doesn't make the repair any easier.

Scotch it is! Feel free to order top shelf!

[siamackz]

 

Yes, I'd try solvent alone, before slurry. All surfaces to be cleaned and de-greased first.

I'd be tempted to nip it at the top, it being tapered - and hope getting that straight, would pull itthe rest into line.

I'd leave it for a week!

 

I totally see Greenie's line misalignment.

I think I'd forego the cosmetics for a strong weld.

 

There's often call for a bit of slurry during the clean-up (in my humble efforts).

I use shavings, some of which have been been in solvent, in small air-tight containers for months!

 

Nice pen, siamackz.

Good luck.

Thanks for the suggestions. Can you explain what you mean by nip it at the top?

[CS388]

Thanks for the suggestions. Can you explain what you mean by nip it at the top?

 

Sorry for late reply.

 

Unless you have a tapered clamp, which matches the profile of the cap, the circular band-clamp will not compess the whole length of the crack. It would have a pinch point.

I meant I'd favour the top end of the crack, for strength.

 

I've tightly bound wire around shaped caps, to compress cracks, but there are cosmetic consequence to such repairs. Strong, but wrong. These were beater pens. Your's looks more classy!

 

It will be interesting to see what movement is in the crack, once you get it to bits and cleaned up.

Good luck.

Edited July 26, 2018 by CS388

[siamackz]

 

Sorry for late reply.

 

Unless you have a tapered clamp, which matches the profile of the cap, the circular band-clamp will not compess the whole length of the crack. It would have a pinch point.

I meant I'd favour the top end of the crack, for strength.

 

I've tightly bound wire around shaped caps, to compress cracks, but there are cosmetic consequence to such repairs. Strong, but wrong. These were beater pens. Your's looks more classy!

 

It will be interesting to see what movement is in the crack, once you get it to bits and cleaned up.

Good luck.

Ah, got it, thanks so much! Ill keep youll posted!