Darnton's mastic varnish...alternatives?

[polkat]

A few years back Michael Darnton posted here about a mastic varnish he likes to make and use on violins. I am fairly new to making my own varnishes, or understanding resins for that matter (although another maker has offered me good advice lately). I am wondering, due partially to the rising cost and dwindling availability of mastic, what I could expect if I used Michael's recipe, but substituted dammar instead of mastic? These resins are both similar, but I hear apparently somewhat different in results. Can anyone advise me? Thanks!

[Melvin Goldsmith]

How poor are you?....20 bucks extra & a bit of internet research can get you mastic....Damar & mastic are not the same.

[polkat]

Yea, I realize they are not the same, but regardless of the cost of mastic, at this point I'm wondering what would result if dammar were used?

[wmeng]

I recall a discussion on this a few years ago...apparently, it doesn't wear well, but I haven't tried it.

[Oded Kishony]

Many differences between damar and mastic. Flowing/brushing qualities, wear resistance, clarity, solubility between coats, drying properties. In my (limited) experience damar has a tendency to remain sticky for a long time unless the resin is first cooked. As far as I know mastic is not particularly scarce.

Oded Kishony

[Andres Sender]

Or to put it another way: MD's mastic varnish recipe is a rather unusual and simple one, and it seems to work specifically because of the mastic's properties.

Oh and by the way there have been a lot of posts about it in the last few years, including sources of supply and some people having problems getting it to work right. Worth a read.

March of '05

March of '05 2

March of '05 again

April of '05

April '05 2

April '05 3

November '05

May '06

This is the direct source for mastic some of us were using. My varnish from the stuff I got HERE (link) dries fine, I used Utrecht brand linseed oil.

[polkat]

Well, I finally made a batch of this stuff using the best turps and linseed oil I could find on these posts, but it resulted in a varnish that after two weeks was just as wet (it seemed) as when it was applied. I think the problem was in adding too much oil to the mix. As I understood it from the recipe, you add about as much oil as the amount of mastic that has dissolved. To me, that can be a problem to determine. Do you go by the weight of the mastic that has dissolved? The volume? And then use the same weight or volume of oil?

And how about determining the amount of mastic that has dissolved? Mark off the original amount in the jar and then determine from what's left? And is the weight or volume of a fixed amount of mastic the same as that amount of oil? I realize that some of these questions may seem obvious, but I'm just trying to understand. Thanks!

[Salieri]

Did you put your violin out in the sun, or under ultraviolet

lights? My understanding is that mastic and oil need UV light to

polymerize.

[fiddlecollector]

As general rule probably about 5% of the mastic will be gummy impurites that you dont want but it varies by how clean the mastic is and how large the lumps are.The larger the better,less surface area thats been oxidised by the air and this outer surface is probably a good proportion of the stuff which doesnt seem to like to dissolve. I would just weigh the mastic and add around 5 % to the amount to account for the stuff that is not wanted.The general way is just to weigh the solids in grams and the liquids like terps ,linseed, as cc`s or cm3. The terps isnt as critical as the oil volume as you will probably use a bit more to thin it.

Even the oil amount doesnt seem to be to critical as long as you stay within a sensible range,ive found with this varnish that i dont seem to have a drying problem at all ,unlike quite a few people on here who seem to have similar problems to you.

Mastic is a strong dryer,it polymerises any other resins that you may want to add.Something like dammar doesnt seem to exhibit this property.It also seems to bind completely with oil.