Cleaning ebonite/hardrubber

[Tywno]

Today I was listening to podcast #74: "Pen Repair Do's and Don'ts". I learned that some fountain pens are made of ebonite/hard rubber. It was mentioned in the podcast not to leave the pens in direct sunlight, as this can cause the ebonite to discolour when it comes into contact with water.

Maybe you already know this, or not, but tobacco pipes (I own several) are often outfitted with ebonite mouthpieces. Occasionally these mouthpieces need to be polished because a foul smelling discolouration appears because of sunlight. It is a compound containing sulphur, which is used during the vulcanisation of the rubber.

So when I heard some pens made of ebonite exhibit the same deterioration, I decided I wanted to share with you that a specialised tobacconist sells special ebonite polish for pipes. I've not done this myself on a pen, but I'm sure you can also apply it to an ebonite fountain pen. With minimal effort, the ebonite polish removes the sulphur contamination and restores the deep, wet gloss black of the ebonite.

As a last line of defense, diluted chlorine is also used to treat severly deteriorated ebonite mouthpieces. But this will really dissolve part of the ebonite, leaving it a little smaller and rough. But it can be polished to a nice gloss again. Be sure to mask anything you don't want to come into contact with the chlorine with petroleum jelly.

Thats it! I'm very curious to hear from you if you find this information useful.

Stefan

[KrazyIvan]

Thank you for the tip. I have a few ebonite pens but one in particular could use a shine.

[whych]

@Tywno
Do you have a name for the ebonite polish you use? My pipes are in need of a clean up.

[hari317]

Very interesting information, thanks for posting.

It is common practice in India to use white petroleum jelly to seal the threads of ebonite pens and I used to do it for years before joining FPN in 2007 where everyone seemed to be horrified at the thought, probably recollecting natural rubber to petroleum jelly reaction. But ebonite is hard rubber and it was a common material for lead acid battery containers where the lead battery posts used to be liberally coated with white petroleum jelly with no adverse effect on the hard rubber case.

Savinelli polish?

[kirchh]

Very interesting information, thanks for posting.

It is common practice in India to use white petroleum jelly to seal the threads of ebonite pens and I used to do it for years before joining FPN in 2007 where everyone seemed to be horrified at the thought, probably recollecting natural rubber to petroleum jelly reaction. But ebonite is hard rubber and it was a common material for lead acid battery containers where the lead battery posts used to be liberally coated with white petroleum jelly with no adverse effect on the hard rubber case.

Savinelli polish?

Petroleum products dissolve latex rubber.

--Daniel

[hari317]

Petroleum products dissolve latex rubber.

--Daniel

Hi Daniel, is petroleum jelly harmful for hard rubber? can you point me to some literature on this.

Thanks!
Hari

[kirchh]

Petroleum products dissolve latex rubber.

--Daniel

Hi Daniel, is petroleum jelly harmful for hard rubber? can you point me to some literature on this.

Thanks!
Hari

Well, as petroleum jelly is a petroleum product, and as hard rubber is latex rubber, and as stated (and I don't think it's in dispute) petroleum products attack natural rubber, it follows that petroleum jelly is harmful for hard rubber.

I doubt you'll find any controversy on this point from a chemical-compatibility standpoint.

--Daniel

[hari317]

Petroleum products dissolve latex rubber.

--Daniel

Hi Daniel, is petroleum jelly harmful for hard rubber? can you point me to some literature on this.

Thanks!
Hari

Well, as petroleum jelly is a petroleum product, and as hard rubber is latex rubber, and as stated (and I don't think it's in dispute) petroleum products attack natural rubber, it follows that petroleum jelly is harmful for hard rubber.

I doubt you'll find any controversy on this point from a chemical-compatibility standpoint.

--Daniel

Latex after chemical processing becomes hard rubber with the resulting huge differences in many properties. I don't know if the vulnerability to petroleum remains the same as before processing or not, If I find out, I will share here with references.

[kirchh]

Petroleum products dissolve latex rubber.

--Daniel

Hi Daniel, is petroleum jelly harmful for hard rubber? can you point me to some literature on this.

Thanks!
Hari

Well, as petroleum jelly is a petroleum product, and as hard rubber is latex rubber, and as stated (and I don't think it's in dispute) petroleum products attack natural rubber, it follows that petroleum jelly is harmful for hard rubber.

I doubt you'll find any controversy on this point from a chemical-compatibility standpoint.

--Daniel

Latex after chemical processing becomes hard rubber with the resulting huge differences in many properties. I don't know if the vulnerability to petroleum remains the same as before processing or not, If I find out, I will share here with references.

I don't think you're reading what I write with care. I clearly stated that latex rubber is vulnerable to chemical attack by petroleum products, and that hard rubber is latex rubber. I did not say that petroleum products attack unvulcanized latex.

--Daniel

[hari317]

I don't think you're reading what I write with care. I clearly stated that latex rubber is vulnerable to chemical attack by petroleum products, and that hard rubber is latex rubber. I did not say that petroleum products attack unvulcanized latex.

--Daniel

I have attempted to. so are you saying that latex rubber is identical to hard rubber? (english is my nth language, so pardon me if i am slow)

Hard rubber is not latex rubber (latex is non cross linked rubber).

You have to hard vulcanise the latex to make it hard rubber.

[whych]

I don't think you're reading what I write with care. I clearly stated that latex rubber is vulnerable to chemical attack by petroleum products, and that hard rubber is latex rubber. I did not say that petroleum products attack unvulcanized latex.

--Daniel

I have attempted to. so are you saying that latex rubber is identical to hard rubber? (english is my nth language, so pardon me if i am slow)

Hard rubber is not latex rubber (latex is non cross linked rubber).

You have to hard vulcanise the latex to make it hard rubber.

Hari,
I don't think you are misreading it. Daniel is saying that Latex and hard rubber are the same. Somewhere along the way he is not reading/comprehending what he has said.
Indeed, if what he is trying to say is true, your car tyres should disintegrate pretty quickly.

[kirchh]

I don't think you're reading what I write with care. I clearly stated that latex rubber is vulnerable to chemical attack by petroleum products, and that hard rubber is latex rubber. I did not say that petroleum products attack unvulcanized latex.

--Daniel

I have attempted to. so are you saying that latex rubber is identical to hard rubber? (english is my nth language, so pardon me if i am slow)

Hard rubber is not latex rubber (latex is non cross linked rubber).

You have to hard vulcanise the latex to make it hard rubber.

Natural latex is not cross-linked. Latex is vulcanized to make latex rubber, also known as natural rubber or NR, which can be produced in a range of hardnesses primarily by varying the amount of sulfur added to it. This material is vulnerable to breakdown by petroleum products. The hard rubber used in fountain pens is latex rubber (with a relatively high percentage of sulfur). Therefore, hard rubber pens are vulnerable to attack by petroleum products.

--Daniel

[kirchh]

I don't think you're reading what I write with care. I clearly stated that latex rubber is vulnerable to chemical attack by petroleum products, and that hard rubber is latex rubber. I did not say that petroleum products attack unvulcanized latex.

--Daniel

I have attempted to. so are you saying that latex rubber is identical to hard rubber? (english is my nth language, so pardon me if i am slow)

Hard rubber is not latex rubber (latex is non cross linked rubber).

You have to hard vulcanise the latex to make it hard rubber.

Hari,
I don't think you are misreading it. Daniel is saying that Latex and hard rubber are the same.

Incorrect. I never said that. I said that hard rubber is latex rubber. Latex rubber is a material produced by vulcanizing latex.

--Daniel
P.S. Note that "latex" is not a trade name, and therefore should not be capitalized as a proper noun.

[Flounder]

I've recently been exploring the uses of castor oil, after dipping my toe in the "rosin based sealant" waters a while back. As a vegetable fat, castor oil is supposed to be safe for use on rubber - I recently found out it's the principle ingredient in Castrol Red, a grease I've used on brake piston seals and in other contexts where I'd rather seals were preserved by their lubricating grease, rather than attacked by it. Castor oil is also used as the lubricant in air pumps.

Anyway, I was reading a similar discussion about hard rubber saxophone mouthpieces, where castor oil was mentioned. I applied some to a BHR cap finial, an old hardened ink sac, left them in a sealed container for weeks, then washed off the oil.

I think there is an effect, though very subtle - possibly, as mentioned in that sax thread, just oil giving the rubber a wet look sheen. I've recently got some plastic test tubes, and will try filling them with the castor oil, inserting some kindly donated scrap BHR pieces, and heating them in a bain marie.

[cedargirl]

Great, Flounder - I love your empirical approach to issues.

I've also heard of people using various waxes on old ebonite - I think someone mentioned canauba. What do people think about this? Bees wax comes to mind as a "natural" non-petroleum based wax.

[kirchh]

Great, Flounder - I love your empirical approach to issues.

I've also heard of people using various waxes on old ebonite - I think someone mentioned canauba. What do people think about this? Bees wax comes to mind as a "natural" non-petroleum based wax.

Carnauba wax and beeswax contain acids and are not recommended for any artifact.

--Daniel

[Vintagepens]

Regarding petroleum jelly and hard rubber, this appears to be a case where in theory the petroleum jelly could cause deterioration of the hard rubber, but in practice such deterioration has never been observed or documented.

I'm not advocating use of petroleum jelly on hard rubber, but I'd also avoid overstating the risks.

[Jon Szanto]

Bees wax comes to mind as a "natural" non-petroleum based wax.

Note: natural ≠ benign.

[gweddig]

Bees wax comes to mind as a "natural" non-petroleum based wax.

Note: natural ≠ benign.

All natural poison oak comes to mind at the moment.

[hari317]

Regarding petroleum jelly and hard rubber, this appears to be a case where in theory the petroleum jelly could cause deterioration of the hard rubber, but in practice such deterioration has never been observed or documented.

FWIW, That is my experience too.