Repairing cracks?

[chud]

As far as I can tell from doing some searching around here, the "standard" method for repairing cracks seems to be solvent-weld + clamp, right?

 

So, what solvent is the best solvent to use? Or, what are the favorite few, since I expect different ones are best for different materials?

 

At the moment, what I have to work on are a Sheaffer touchdown with an inch-long crack in the cap (ebay: "no cracks"), and a Waterman of unknown pedigree (looks a bit like a Crusader, though the cap is wrong) with a crack in the section.

 

On the Sheaffer, the crack does *not* extend to the cap lip, it's in the middle of the cap, running longitudinally - it probably got squished at some point. The waterman section is cracked from the nib down to within maybe 5mm of where the end of the barrel is when the pen is assembled.

 

What do you guys use for these? Thanks!

[Ron Z]

For the Sheaffer TD, use Tenax 7-R.

 

For the Waterman's cracked section, use another section. You really can not repair a cracked section because of the forces involved when the nib and feed are pressed into place. The crack will just open up again. You need a replacement.

[Johnny Appleseed]

For the Sheaffer TD, use Tenax 7-R.

 

For the Waterman's cracked section, use another section. You really can not repair a cracked section because of the forces involved when the nib and feed are pressed into place. The crack will just open up again. You need a replacement.

 

 

Does Amboid Pro-Weld work for Sheaffer's as well? I have used it pretty successfully on a Parker 21 hood, but I know it is somewhat limited in what it works for.

 

I would love a general guide to solvents for different materials.

 

John

[chud]

I would love a general guide to solvents for different materials.

 

Me too.

 

Thanks Ron. Other than sections, are there other kinds of cracks generally regarded as unrepairable (structurally at least - cosmetic questions may be an entirely different ball game)?

 

Thanks!

[Huffward]

Useful topic. Thanks.

 

Any surefire remedies for a crack in a casein plastic British vintage? I discovered a crack after getting the barrel off the section of one about six months ago. Might have been me but I'm pretty certain it was already there. It hardly shows at all but I don't use the pen for fear of extending it.

 

Any solutions?

[psfred]

Chud:

 

I use Testor's 3502 liquid plastic cement (it's really only solvents). It appears to contain methyl ethyl ketone and some methylene chloride. Works very well on any polystyrene or celluloid pen, with the advantage that it drys rather slowly. I've fixed "closed" cracks by just flowing some on and allowing the pen to stand undisturbed for a couple days. Cracks in Parker 21 hoods require a couple doses before clamping them shut (I often just wrap a rubber band around again and again). It will badly mark up the surface it you get it anywhere but the crack, though!

 

Sections are not repairable -- even if the solvent would adequately soften them (and it won't touch hard rubber anyway), the ink that has accumulated in there will prevent the parts bonding together well enough to withstand re-inserting the nib and feed.

 

Tenax R7 is methylene chloride. It will work very nicely, but it will also evaporate almost instantly. You will need to apply several times until you see evidence of softening of the plastic before applying pressure or it won't stick.

 

Peter

[Gerry]

Tenax R7 is methylene chloride. It will work very nicely, but it will also evaporate almost instantly. You will need to apply several times until you see evidence of softening of the plastic before applying pressure or it won't stick.

 

Peter

 

What is Methylene Chloride usually stored in? I bought some that was in a plastic bottle (evidently MC resistant, but it evaporated through the bottle over a period of a month or two. Yes, the top was on tightly. I suppose a glass bottle with a metal cap would be better....

 

Regards,

 

Gerry

[psfred]

Glass with a teflon or silicone rubber liner in the cap works pretty well. Usually delivered in gallon glass jugs with plastic, lined caps. Keeps OK in those, but it does evaporate easily!

 

Peter

[Gerry]

Glass with a teflon or silicone rubber liner in the cap works pretty well. Usually delivered in gallon glass jugs with plastic, lined caps. Keeps OK in those, but it does evaporate easily!

 

Peter

 

Thanks.

 

Next time I buy some I'll put it in another bottle soon as I get home. The supplier - a plastics company seems to dish it out only in plastic bottles - and it's a bit pricey to lose to evaporation...

 

Gerry

[jicaino]

clorophorm. Old anesthesic. That dissolves almost any plastinc (except for modern plastics like delrin, etc)

[Fox in the Stars]

What about cracks in black hard rubber, like my vintage Waterman?

 

[Johnny Appleseed]

Alas Hard-rubber is mostly a lost cause. You can try epoxy, but as the surface of the brake has a tendancy to oxidize, and the areas we usually need to fix most have very little surface area for adhesion, you can't get a very strong bond. There are some techniques that work reasonably well cosmetically, but they lack the strength needed for the usual cracked caps and barrels.

 

There are a couple of people out there that claim to have come up with a propriatary process.

 

What's up with your waterman?

 

John

[Fox in the Stars]

Alas Hard-rubber is mostly a lost cause. You can try epoxy, but as the surface of the brake has a tendancy to oxidize, and the areas we usually need to fix most have very little surface area for adhesion, you can't get a very strong bond. There are some techniques that work reasonably well cosmetically, but they lack the strength needed for the usual cracked caps and barrels.

 

There are a couple of people out there that claim to have come up with a propriatary process.

 

What's up with your waterman?

 

John

 

 

It's just a hairline transverse crack radiating from the lever at one end. Wanted to ask, tho. ^_^

[demeter]

clorophorm. Old anesthesic. That dissolves almost any plastinc (except for modern plastics like delrin, etc)

 

 

While I still worked in a pharmaceutical laboratory, over 20 years ago now, chloroform was on the suspected carcinogen list...so I wouldn't recommend that.

Any solvent, except perhaps water, I'd say use with great caution, and read the label.

Just my nosy two cents here.

 

And Fox in the Stars...what an incredibly lovely label! Good on you.

Andrew

Edited November 19, 2007 by demeter

[jicaino]

liver cancer, yes. I have no sibstitute for that, though. Works VERY well on most plastics, producing one of the most strong bonds (like a weld, actually) w/o all the discoloration disadvantage of certain ether based solvents wich works well too. Clorophorm produces less discoloration and better bonds. You can always wear a mask, and I'll tell you, that's carcinogen if you're on high exposal levels... you don't get cancer for repairing a bunch of 51 hoods or any other pen parts for that sake. Nowadays ALL is carcinogen, cancer stats are sky rocketing.

[jicaino]

as far as for hard rubber: you mix natural rubber with sulphur and minerals such as steel or iron (cast iron would do) very fine powder. You put the sulphur on a stove untill it melts, (Careful! flammable and toxic fumes) then you add the rubber then the powder, and mix it up. You use this generously over the BHR crack and then you "iron" over the cracked part with a red hot piece of steel, rubbing rapidly and lightly.

[fpfanatic5]

I have a crack on the hood of a Parker 21 through which ink is leaking. Would this be fixed by sealing the crack or is there an internal leak that needs to be fixed?