Amateur "rosin based" sealant trials and tribulations

[Flounder]

The last few days, I've been trying my hand at making some of this elusive "rosin based" sealant that sounds so handy. It's not something I've seen for sale domestically, or, in truth, at all, ever! I've come across various clues about consistency, proportion of rosin to castor oil, and so on, but with no experience of the stuff, I'm not sure if I'm getting close or way off the right track.

Today's test threw up a lot more questions than answers, so I'd like to ask anyone who's got ahold of this stuff how this DIY mix differs from theirs!

Today's FP test:



Yesterday's BP test:



Mixing the stuff up:
http://flounders-mindthots.blogspot....n-sealant.html

[HughC]

Looks to me you need to heat the mix more, it should be a clear honey colour. Put the rosin and a bit of oil in a jar, heat and mix until clear and let cool. If it sets hard just add a bit more oil and heat again. When it's a tachy liquid at room temperature it' right. It's the same as used for violin strings and like, again the hardness of is determined by the amount of castor oil in the block.

Regards
Hugh

[Flounder]

Thanks Hugh, that's a great help. It looks like there are at least two different types of this mysterious sealant, going by the descriptions - one thin and honey coloured, the other very thick and dark. I'll modify this lot to try matching the qualities you've described, and make up a separate pot of the dark thick stuff.

As a rough guide, should I shoot for the same level of liquidity at room temp as shown here while it was hot?

[HughC]

Mine is a very thick, tacky liquid at room temp. I would think thicker than you show would be better.

Regards
Hugh

[Flounder]

I was given some very hard, dark rosin, and gave that a go. It seems to cook and mix far better with the castor oil, and the resultant goo is much more adhesive too. I'm thinking maybe the last rosin cake I used - the "Theodore" brand stuff - was too soft. Does that make sense?

[PSmith]

Interesting experiment.

I have two questions though:
- When would you use rosin based sealant instead of shellac.
- How do you remove it should you wish to do so. Does it dissolve in alcohol?

[Flounder]

Hi PSMith, from what I've read on various FPN threads and websites, the idea seems to be you would use this in circumstances where shellac would make future disassembly risky. Rosin sealant is also supposed to release at a lower temperature than shellac does. I've found that olive oil gets it off your fingers very well.; as for pens, Ron Zorn says "naphtha or mineral spirits" will dissolve it. BTW - Main Street Pens in the US and A sell premixed rosin sealant.

This has been a very interesting exercise for me on many levels. The surprisingly adhesive quality of the rosin/oil combo, combined with a PM about its resistance to water based solvents, Mr. Zorn's comment about naptha, and the flammability of rosin itself as reported by Pytheas a bajillion years ago have all combined to lend me more respect for Anna Comnena's dry and somewhat embittered Alexiad. I'm off to reread her comments about tree resin in Greek Fire.

Anyway, here's today's report:

[PSmith]

Hello Flounder,

Thank you for the informative answer.

If memory serves me right, I should have some chunks of colophony stashed somewhere. It seems that colophony is the same thing as rosin, so if I can find some castor oil, I'll give it a try myself. Although I do not currently need this type of sealant, it seems interesting to make. Bearing in mind your comment regarding Greek fire, I'll keep a fire extinguisher within reach.

Incidentally, home made soldering flux is made by dissolving rosin in isopropyl alcohol. Perhaps isopropyl alcohol could consequently also be used, instead of naphtha, to remove the sealant. Unless the castor oil somehow interferes of course.

[HughC]

Interesting experiment.

I have two questions though:
- When would you use rosin based sealant instead of shellac.
- How do you remove it should you wish to do so. Does it dissolve in alcohol?

Use rosin sealant where you want an air tight seal ( semi permanent) on threads. Some examples are screw in nib/feed units ( like Sheaffer Triumph nibs on Snorkels ) , section threads on Sheaffer TDs and any threads that come loose when you don't want them to. The benefit over shellac is that it remains a liquid for a long time so can be undone easily or with minimum heat. it does dry out in the long term, I've never undone an early Sheaffer TD and found the sealant still a liquid and in those cases it needs heat to release. Alcohol should remove it. If you want a seal that's not permanent ( like an eyedropper that's leaking around the treads) use silicon grease.

Flounder's "brew" looks about as good as it gets !! Well done.

Regards
Hugh

[whych]

Incidentally, home made soldering flux is made by dissolving rosin in isopropyl alcohol. Perhaps isopropyl alcohol could consequently also be used, instead of naphtha, to remove the sealant. Unless the castor oil somehow interferes of course.

You want to stay away from alcohol if you can - it damages some pen plastics and cellulose.

[Flounder]

Thanks Hugh, that's very encouraging! The new rosin is here, but I still need to find something to store it in after mixture. In re: naptha versus alcohol considerations, in the link above Mr. Zorn says alcohol will damage the celluloid P51 jewel.

ps - as an aside, I have two late 51s (O ringed hoods, open clutch caps) that strangely hadn't any sealant at all applied to the jewel threads, rosin, shellac or otherwise.

edit - pps, I would be very interested to hear how easy/difficult the touchdowns with dried out rosin sealant were to open after heating. Oh - and how much sealant had the factory applied? Was a mere insinuation enough, or did they go heavy on the stuff?

[Flounder]

Here's the last batch of sealant, this time using a hard amber brand called "Hidersine", and the results of the Frontier thread test using the dark "A.B." rosin applied in the last video.



Based on the last week or so, I think I'm happy to put an end to the experiments and just start using this stuff. Thanks for all the help, you fellows!

[HughC]

Thanks Hugh, that's very encouraging! The new rosin is here, but I still need to find something to store it in after mixture. In re: naptha versus alcohol considerations, in the link above Mr. Zorn says alcohol will damage the celluloid P51 jewel.

ps - as an aside, I have two late 51s (O ringed hoods, open clutch caps) that strangely hadn't any sealant at all applied to the jewel threads, rosin, shellac or otherwise.

edit - pps, I would be very interested to hear how easy/difficult the touchdowns with dried out rosin sealant were to open after heating. Oh - and how much sealant had the factory applied? Was a mere insinuation enough, or did they go heavy on the stuff?

Hi,

I store mine in a glass jar. The touchdowns open easily, a lot easier than things stuck with shellac. I try using as least heat as possible, heat a bit, try, heat again and so on. There seems to be a reasonable amount on the old TDs, but it may be the case of a "little bit goes a long way", anyway I don't use much and it does seem to grip well and spreads out over the threads if you apply near the start of them.

Regards
Hugh

[grandmia]

Hi Flounder
Great experiment, thanks it was fun watching.

[cedargirl]

snip

Hi,

I store mine in a glass jar. The touchdowns open easily, a lot easier than things stuck with shellac. I try using as least heat as possible, heat a bit, try, heat again and so on. There seems to be a reasonable amount on the old TDs, but it may be the case of a "little bit goes a long way", anyway I don't use much and it does seem to grip well and spreads out over the threads if you apply near the start of them.

Regards
Hugh

Hi Hugh

What brand of rosin did you get hold of in Australia and where did you get it?

thanks
Claire

[HughC]

snip

Hi,

I store mine in a glass jar. The touchdowns open easily, a lot easier than things stuck with shellac. I try using as least heat as possible, heat a bit, try, heat again and so on. There seems to be a reasonable amount on the old TDs, but it may be the case of a "little bit goes a long way", anyway I don't use much and it does seem to grip well and spreads out over the threads if you apply near the start of them.

Regards
Hugh

Hi Hugh

What brand of rosin did you get hold of in Australia and where did you get it?

thanks
Claire

Hi Claire,

I picked up some from a music shop, it's the same as used on violin and other string instruments. I'm not sure of brand, I bought "powdered" to make mixing easier. I'll look and see if I've still got the tin and see what brand. You only need a small block as you use very little.

Regards
Hugh

[cedargirl]

Hi Claire,

I picked up some from a music shop, it's the same as used on violin and other string instruments. I'm not sure of brand, I bought "powdered" to make mixing easier. I'll look and see if I've still got the tin and see what brand. You only need a small block as you use very little.

Regards
Hugh

Thanks - I'll see what the local music stores have.

[Flounder]

And thank you for watching Stef, it was fun to do!

ps - greater surface area and all that, please be extra careful if using powdered rosin Claire.

[cedargirl]

snip ... please be extra careful if using powdered rosin Claire.

Thanks for the warning, Flounder. I'm guessing because it is flammable, when in powdered form it would be quite combustible. So make sure it is mixed with the oil before moving to the heat. Is that how it works?

Claire

[Flounder]

I can't really say Annie! The first dud batch I powdered, then mixed in some oil, then heated in a bain marie. The batches that actually worked, I broke up the rosin into little chunks, melted them to a liquid, and then added drops of oil while mixing. Then I allowed to cool, and checked the consistency with the darning needle.