Wednesday, 15 May 2013

Rosin Based Thread Sealant: Safety Second!

Here's a second attempt at mixing "rosin based" fountain pen thread sealant, this time eschewing the safety of the bain-marie. This gave encouraging results using a cake of dark "A.B." brand rosin, so, using more heat, I gave the amber coloured "Theodore" rosin another chance too!

After some very helpful input from the wider community of enthusiasts - see these threads at the Fountain Pen Network and Fountain Pen Geeks forums - I think this second batch is an improvement. I've some harder amber rosin on the way, so I will save the results of the Frontier thread test for when that's cooked up.

This has been a fascinating few days! I was a very poor chemistry student, with "a rudimentary knowledge of some areas... [and] great gaps in his understanding", so it's not often I turn my hand to natural philosophy. I've been particularly surprised by the powerful stickiness of the resultant rosin/oil sealant. By means of heat and castor oil, the shade of the original tree's rosin-locked spirit is lent a grasping vitality, as if seeking to lay down roots anew!

Let's Be Careful Out There
This remarkable stickiness is something for the plucky amateur to be cautious of. Though the turpentine is removed, rosin is still flammable. It won't dissolve in water (thanks for that Kristine!), and as shown in the clip above, this mixture is very sticky indeed. Add an open flame to a spillage and one might well say "horrifically" sticky. It brings to mind Anna Comnena's description of a hand held variant of Greek Fire used during a counter-sapping effort  in the defence of Dyrrachium;

"Now this fire was chemically prepared in the following manner. From the pine and other similar evergreen trees they gather resin, which burns easily. This is rubbed with sulphur and introduced into reed tubes. A man blows on it with strong, sustained breath, as though he were playing a pipe, and it then comes in contact with the fire at the end of the tube, bursts into flames and falls like a flash of lightning on the faces of those in front of it."

I don't usually write imperatives in this blog, but with that awful image in mind, please use every precaution if heating this stuff.

Diverting MindThots
 A few millennia-connecting details I found kind of neat during this wee project:

  •  According to the September 1st, 673 - August 31st, 674 entry of the Chronicle of Theophanes, "In this year the expedition of the enemies of God anchored in Thracian territory...At the time Kallinikos, an artificer from Heliopolis, fled to the Romans. He had devised a sea fire which ignited the Arab ships and burned them with all hands." In the entry for 812-813, it's spare underpants time, after "The Bulgars took Mesembria and Debeltos as well, in which places they found thirty-six bronze siphons and not a little of the liquid fire shot through them".
  • 21st Century - describing the qualities of Parker's rosin based thread sealant, Ron Zorn mentions that this sticky stuff will dissolve in naphtha.
  • In the Administrando Imperio, his handy 10th Century guide to empire maintenance, Constantine Poryphyrogenitos warns of the "care and thought you must take in the matter of the liquid fire which is discharged through tubes", and goes on to list the locations of numerous "naphtha wells", "some of them being red, some yellow, and some blackish".
  • Writing in the 1st Century, Pliny references Pytheas' On the Ocean, who reported Germanic tribes using amber for fuel.
  • Anna Comnena's 12th Century Alexiad includes a short note describing the use of tree resin in the preparation of a portable version of "chemically prepared" fire.

Safety first.

See you next time!



  1. Very interesting testing you've done on a possible alternative to shellac sealant. Your mention of soldering flux reminded me that during the summer when I worked with electricians and electronics techs, some who worked on very fine and delicate soldering jobs would add extra flux made from the stuff. The rosin would be dissolved in a type of alcohol and applied with a fine tipped squeeze bottle. The electronics techs would use isopropyl alcohol, as it was readily available, but I'm sure the denatured (or methylated, as some say) spirits would most likely work as well. This may be an easy way to clean off your pens if you haven't found a better way by now (and they aren't damaged by the alcohol, of course). I'd be cautious about getting methylated spirit on the hands though, as the methanol added is quite toxic and can be absorbed through the skin. In this regard, the isopropyl ("rubbing") alcohol would perhaps be a safer bet.

  2. Hello. Thanks for this great article. thread sealant


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