Montblanc Junior 620

[stez]

Hi,

I have an MB junior 620 with a badly cracked cap. I want to repair it. Does anyone know what type of plastic these were made of? If I can find that out, then I might be able to find a glue that will work, or do a solvent weld on it.

stez

[karmakoda]

You will likely want to replace the main part of the cap. My Junior 620 had the same problem, replaced the cap completely with one from a Montblanc 22, which creates a "Frankenpen", but it continues to function. Caps for the juniors in particular are delicate.

 

Caps from the Carrera, 12, 220, 320 may also work, but any with an identifying cap ring, bearing the model number, will create a frankenpen, functional but no longer a true 620. There is the metal cap from the 622 to consider, probably rare.

 

My pen was a piston filler with a gold plated steel nib, very pleasant writer. There was also a cartridge filler version made and Juniors with polished steel nibs.

You might begin your search for parts at Penboard.de, but you will notice the cap problem is not rare.

http://penboard.de/shop/searchdb?srchvaluedb=01484&db_seller=0

[stez]

I don't want to put a lot of money into it. Plus I like the challenge of repairing the cap. So my question remains. What kind of plastic resin was used to injection mold them?

stez

[karmakoda]

American Plastics Corp, locations in California, may be able to help you out.

https://americanplasticscorp.com/products/

 

In Canada, we have Industrial Plastics and Paints. They provided me with a solvent that is used for this type of plastic bonding/welding. I am skilled in material manipulation, but not in applying these particular chemicals.

It would have been necessary to build a specific mould with a clamping feature and a safe heating element to perform the task.

The result of my attempt: the Montblanc Junior cap has been resting in a landfill for four years.

I wish you well with your efforts.

[Maxpens]

I don't want to put a lot of money into it. Plus I like the challenge of repairing the cap. So my question remains. What kind of plastic resin was used to injection mold them?

stez

 

Should be Polycarbonate

[stez]

The cap repair won't be too hard, even though there are multiple cracks. It won't look pretty, but it will be useable as a cap. Although I discovered that the rolled gold cap from my UK made Parker 45 fits perfectly. And it looks nicer too.

A bigger problem is it's leaking ink at the piston knob, which tells me the piston is damaged. I need to replace, or repair, the piston. I have no idea how to disassemble this pen. A pic of one taken apart would help a lot. Does anyone have pics of a disassembled MB 620 junior?
Thanks,
stez

[karmakoda]

My MB Junior is long gone, but you may find the Japanese repair video for a Montblanc 22 interesting. Not sure if the piston knob removal is the same for a 620, would hope it would be more simple than the method used in the video. There are comments about various repairs scattered throughout the Fountain Pen Network.

https://www.fountainpennetwork.com/forum/index.php/topic/236096-how-to-repair-montblanc-no-22/

In 2010 I asked similar questions here concerning the MB Junior, no replies yet.

There is a material called Weld-On 16 that can be used to adhere polycarbonate.

The solvent given to me for repair was methylene chloride, it may, or may not be the correct solvent for chemical welding of polycarbonate.

Hope your efforts are successful.

 

https://www.youtube.com/watch?v=oMu2Vm4UH_o

Edited April 17, 2015 by karmakoda

[mrparkerbrook]

I have a Montblanc Junior 620 as well that I bought in 1975. Its cap also cracked but when I took it to Fountain Pen Hospital here in New York, they couldn't repair it but they gave me a cap from another Montblanc of a different number but I don't know what number that is but the cap fit perfectly. It's a slip cap rather than a screw on. The clip was different from the original; I think it came from a Junior 622 but I'm not absolutely sure. Check the net and you might see the cap I'm talking about. As I said, it does fit quite well and keeps the nib wet and ready to write! Ebay also offers some Junior's along with other Montblanc styles along those lines! It still amazes me how smooth this extra fine 14K point is after 40 years and I paid $6.48!! I wish you good luck in finding a good cap!

[stric75]

While I cannot offer you a good repair advice (I have to say I've experienced the same cap-cracking problem with my old 620) I would recommend you get a replacement cap. The Jcaps that Juniors came with were their weakest point and many tend to crack rather easily. There are some eBay sellers who offer old or NOS Junior plastic caps. The metal cap from 622 will fit just fine as well and will not crack.

You could also try interpens.de (they are a professional pen repair shop in Germany with many parts available) and penboard.de and see if they are selling any spares.