NRI varnish sytsem

[AMORI]

I have received my order from NRI in the UK of their varnishing "system". That is, rosin oil(II) ground coat, A5 clear coat and then 2 coloured varnishes. Does anyone have experience with these products and what were the results?

[Mike_Danielson]

No one answered your question; so I will take a stab at it.

I have used rosin oil (Mine was from Kremer)-the idea is that because it has a similar refractive index to wood, the grain would telegraph through. If you choose to use it, add drier; otherwise, it will not dry in a reasonable time. Cover the surface using a wet fingertip (gloved, of course) because you just want it to penetrate slightly. You will probably want to add more coats until the surface is filled. Rosin oil did not perform any miracles for me--it is OK.

I can't tell if you are using the suggested Rubio method for ground. I do not like the idea of using water glass-it is a real stiffener on the top. Personally, I would skip this step.

I have never used their version of the Fulton varnishes; so I cannot talk about them. Their use of pine resins to make varnish does not jell with what Fulton uses (thickened gum spirits of turpentine) unless it is just different semantics for the same thing--this communication problem is common in varnish making. I have had good luck with my own home-made Fulton varnishes, but you have to add drier if you want them to set up in a couple of days.

[AMORI]

Thanks Mike. All the NRI products were quite expensive so I must give it a stab, I suppose. I applied unthinned Rosin oil without hardener to a test piece 3 days ago and it still feels waxy. Last night I did another test using a little turps and hardener and this morning, 8 hours later it is also still waxy.

I was told by NRI that the Rosin oil WAS the ground coat and I'm not sure what the Rubio method is? Do you think I should use a pre-ground? If so, what? I uses to use egg-white.

Maybe it is semantics, NRI have said that it is the same thing as Fulton. I just did not want to try making the volatile mixture myself - yet. I am also going to try Mr. Darnton's varnish soon, my mastic arrived from Greece a few days ago.

[Seth_Leigh]

You guys who used rosin oil ground, did you expose the rosin oil to UV light after? I have a bottle of the rosin oil from Kremer and it dries fine in the UV box.

[b sharp]

Seth, the Kremer rosin oil is a different animal than the NRI rosin oils. I have both and they are not comparable.

[Craig Tucker]

Hmm,

Rosin oil has never been one of my favorite products.

Where is everybody getting the idea to use "rosin oil" for a ground in the first place?

[fiddlecollector]

I think they are obsessed with rosin oil= higher refractive index = superb depth of figure.

I have never found the result that good.

[Seth_Leigh]

Actually, the "rosin oil" I got from Kremer I got because I'd read about the Rubio ground system, and Rubio used rosin oil after hitting the wood with the watery mineral soup and then the waterglass. This was in my readings before my first violin was finished. I didn't end up using the Rubio ground mixture at all. But I still have the waterglass, mineral mix, and rosin oil.

[Mike_Danielson]

I think the rosin oil will work just fine as the ground, but with most things in violin finishing, you should always test them first.

I was reading Zemitis' book the other day, "Violin Varnish and Coloration" and it dawned on me that the varnish problem is a two part problem. A number of people have solved the first problem which is making a flexible, clear varnish that is brushable. Zemitis' varnish is based on fused amber with linseed oil which a number of people have figured out to do (Baese, Merrill, for instance), but there are other varnishes that also work such as Fulton's oil varnish or Darnton's mastic varnish or alkyd varnishes (I suspect Hammerl varnishes are of this type) or Michelman rosinate in oil. But then part two of the problem kicks in--how do you get the color? Zemitis freely admits he never solved it. This is the issue that makes me think that Fulton has got the recipe the most correct because he can get the right color simply by the degree of cooking of the thickened turpentine.

[fiddlecollector]

Yes only joking Seth, but i do know that the rosin oil from Kremer is not the same of the stuff from NRI,its made in a different more dangerous way, Kremer themselves say that theirs is just rosin in terpentine.

[Seth_Leigh]

Yes, I believe true rosin oil is released on heating rosin, or something like that. I'll be disappointed if the "rosin oil" from Kremer is just normal rosin dissolved in turpentine. I am not sure it is, because it's fairly dark in this bottle, and the rosin I have is a light yellowish solid. At least there's got to be more to it than that.

[fiddlecollector]

According to there site its made by cooking rosin and dissolving in terpentine(so basically a simple varnish), the NRI stuff is made from distilled rosin.

[Mike_Danielson]

According to Kremer, I purchased the last two bottles of rosin oil that were created by distillation of solid rosin. They discontinued this process saying that it was too dangerous--decomposition of peroxides was cited as the problem.

I can tell you from my making of the Fulton varnish that the initial heating of the thickened gum spirits of turpentine in which the peroxides decompose is tricky (and could be considered dangerous). Now that I know how to handle it, it is a "piece of cake," but the first time I tried the process it started on fire--that is how quickly it overheated.

[Seth_Leigh]

Mike, do you recall when you bought your rosin oil? I bought mine from Kremer in the first half of 2003 sometime.

[fiddlecollector]

So the trick is long slow heating and something to cool it slightly to prevent it getting carried away.

I don`t think Kremer have sold the Rosin oil proper for at least 2-3 years but not certain.

[Mike_Danielson]

Seth, I cannot recall when I purchased rosin oil--it could have been three years ago--there is no date on the bottle. It has a part number of 79280 which is no longer in the Kremer catalog. The lady salesman said I got the last two bottles on the self and there would be no more.

Fiddlecollector, the trick is to cook the varnish in a stainless steel pot over a hotplate (outdoors, of course). When it starts to boil, place the bottom of the pot into a bucket of water, swirl it around until the boiling stops, and then reheat. Do this over and over until the violence becomes tame enough that you can raise the temperature. Fulton told me that the type of turpentine does not affect the varnish color. Color appears to be affected by the duration (temperature) of the cooking--you can go from yellow to very dark brown with a reddish-brown color just before it gets dark brown. The color of the reddish-brown varnish is so dark that it appears black in the bottle or the pot (during the cooking) but that would be expected if a few coates are to have an important affect on the instrument's color.

I think it is important to keep good notes on what you are doing when making varnish. It is especially important to know how much oil is added to the cooked resin. Gum spirits of turpentine is added to make it brushable.

[Michael Darnton]

I did this once. You can not believe how quickly things get out of hand. I had a thermometer, and suddenly it started going straight up, fast. By the time I moved my container to the bucket of ice that was right there, waiting, it had gone up about 30 degrees!

Plus, it stinks. My wife was not pleased. :-)

[AMORI]

NRI say that research done by Cambridge University indicates that the Grand Masters may have used rosin oil. These notes are interesting http://www.nrinstruments.demon.co.uk/Varn.html

There is most definitely no heating involved.

[AMORI]

Report back. 3 days later the rosin oil seems to have dried on my test piece. I have now done the next clear layer of A5 and waiting for that to dry. This violin couild take months to varnish, I hope it is worthwhile.

I do need to darken the wood a bit first I think, I did a test with strong tea last night and that has given the white wood a nice warm "pinkish" colour. Is tea okay?

[Michael Darnton]

You talking about rosin oil? Here's what the page you refer to says:

"Rosin oil is made from the distillation of Rosin. Alternative names for Rosin are Gum Rosin and Colophony. Rosin is the residue after turpentine is distilled from the sticky fluid collected from tapping pine trees. When the Rosin is distilled at about 350 degrees C., three types of Rosin Oil come out."

[Seth_Leigh]

Regarding the heating, Amori, Mike and Mike were talking about Fulton's turpene resin varnish, which has an exothermic chemical reaction during the making process.

[Andres Sender]

Amori? No heating involved in which? There's heat in the distillation process making the rosin oils, and in the preparation of stand oil, and in the coloring of the resin for the varnish, and most likely the oil and resin are brought together at a high temperature and likely also cooked for a while.

[AMORI]

I meant to say that NRI do all the preparation, heating boiling and the like. The dangerous stuff. My main concern right now is that I chose the righty ground coat. John says that I should not use the rosin oil as supplied by NRI because it is not fast drying and has given me a recipe for a ground using bow rosin.

[Seth_Leigh]

Amori, I think you'd be well advised, if you've bought the NRI varnish system, to keep to the system with respect to the use of rosin oil. Some direct sunlight or UV from black lights in a box will dry that rosin oil in a day or so.

[b sharp]

To Seth:

Just to be clear, the rosin oil described by Rubio on his website is the NRI stuff. You will see that he specifically refers to the number 2 and 3 rosin oils.

To Amori:

NRI rosin oil goes on better if heated slightly. It flows better and the resulting film is thinner and dries quicker. I've never used it on a violin, mainly due to the greenish tint it leaves. It is difficult to get rid of the green in the colour layers. I think that might be a problem of most rosin-based grounds/varnishes.