let's make some mastic varnish

[Seth_Leigh]

I just got a pound of mastic tears from the Woodfinishing Enterprises company in Wisconsin. I saved off 115 grams to send to Tim up in Canada, and put the rest, which amounted to around 339 grams, into a glass olive jar. I filled it with turpentine (quite a lot of turpentine, was glad I had enough) until the turps level was maybe 1/2" above the top of the mastic tears. I've shaken it up a couple times since then. I'm including, in this first post, three pictures. As time passes and I move into the next stages I'll post more. I may post a couple pics after a day or two or three of dissolving. I plan on letting this dissolve for a good week or two at least before moving to step 2, so the thread may go unupdated for a while as nature takes its course.

Remember, no heat is used in making this varnish! I hope this little photo essay on mastic varnish making can help some of you who have read about some of us making this varnish before, but have never done it, and are curious how it happens. Well, here's how it happens. This is the easiest stuff in the world to make, and there's really not much reason not to dig in and make some, if you're interested in a good oil varnish.

First pic is my jar with 339 grams of mastic tears, next to a can of turpentine from Home Depot. 339 grams of mastic is about 3.39 times as much as I've ever done at one time before. I've made this varnish a couple of times before, and I didn't want to save any aside or anything like that, so I just made it all. This will make quite a nice quantity of varnish, and it oughta last me for a good long time. If you're a first-timer, it's probably a good idea to just buy 100 grams and try that first. It's not really any easier with only 100 grams, but if you somehow manage to find a way to mess this up, it won't have cost you as much.

Here's the mastic covered, and with an additional 1/2" or so of turpentine in the jar.

Here's the jar about three or four hours later. I've shaken it up thoroughly a couple times since I poured the turpentine in. You can see the mass of mastic is sort of consolidating and dropping in the jar. Also, the liquid is starting to be fairly syrupy already when you slosh it around.

In a week or two there will be a layer of gunk at the bottom of this jar. I'm going to estimate it will be a half inch thick or so. With luck all of the little specks of wood and dirt and stuff that you can see in the jar, with the mastic, will be trapped in this gunk. The gunk that will be left when this has dissolved well is all stuff you don't want in the varnish, so the next step will be to decant all the precious syrupy liquid into a clean jar and get rid of the gunky jar. I doubt I'll bother trying to clean this jar out - it'll probably end up in the trash.

[mcarufe]

Hi Seth,

You have the "motherload" of mastic. I think you will end up with a super concentrated mastic solution as you have too much resin to turps. I could be wrong and someone who has more experiece can chime in. In other words you can make more ecomical mixture and it will be clarify better with more turps.

Mike

[Andres Sender]

Mike, this is how the recipe goes. You just cover the mastic with turps. Gives you lots of room to play with consistency later if you so wish.

[Seth_Leigh]

Here's a picture from this morning. At this point the mastic has been in the turpentine around 12 hours. For reference, I made a black line with a Sharpy indicating the original level of the mastic in the jar before adding the turpentine, so you can see how much the mastic has gone down in the jar. Some of the difference is just the mastic coming together in more of a solid mass without all the spaces between tears, and some of this represents actual dissolution into the turps.

For comparison's sake, I photographed this new batch this morning next to a plastic container I have from Kremer Pigments containing what's left of my previous batch of mastic varnish in 2004. Michael has said before that this varnish only gets better with age, and I believe it. Experiments I've done with this three year old mastic varnish showed it working perfectly. As you can see, this stuff, at least using my turps and my linseed oil, comes out crystal clear but with a yellow, pilsner beer color. If you guys could see what this stuff looks like compared to "clear" Fulton varnish you'd think this stuff may as well look like water. It's many orders of magnitude clearer and less colored. With no coloring, a thin coat of this mastic varnish is as clear as it gets.

Mike, I totally understand why you'd think that this is too much resin in too little solvent, but as Andres said, this is the recipe, and it works. The varnish on the left, in this picture, was made the same way, albeit in a smaller jar, in 2004.

[Tim McTigue]

Seth, thanks for posting this photo-essay! This gives me a real clear idea what to expect - can't wait to get the stuff you're sending. Soon as I get it, I'll start the process, so that whenever I need it, it'll be ready...

[mcarufe]

Seth And Andres,

I stand corrected. Wow that really clears up and like you say, you can have the option of thinning or not as needed later.

Mike

[Roderick Quiros]

hi seth, nice post... it is a handy reference, and nicely written.

rq

[EarlyRetiree]

Seth, thank you for documenting this. I've been intending to try the DMV and even tried to make a very small amount using mastic purchased in capsules at a health food store (WAY too expensive and I ended up with enough to varish a scroll!).

Please continue to add pics periodically until you've completed the process. Thanks.

[Seth_Leigh]

Thanks for the comments, and Bob, I'll definitely post more pics as the process continues. I think it'll be very interesting to show the process after the linseed oil has been added, and the cloudiness starts to settle down to the bottom of the jar over a period of days, leaving a crystal clear varnish on top. Another reader contacted me offline with some questions he had prior to making some DMV himself, so I'm glad this thread is serving its intended purpose.

Here's how it looks this morning, the 2nd morning after adding the turpentine. It's been dissolving for about 36 hours already. I could already decant this off and add oil and make a useful varnish, but I'm going to let it keep dissolving for another five days or so. If I were more patient, and not wanting to take pictures and show active progress in a short time, I'd just put this up on the shelf and leave it alone for a month or two. But there's a point of diminishing returns. Obviously most of the reduction in the mastic level occurred in the first twelve hours or so, and it's a lot less change each day from there on out. I predicted a final gunk level of 1/2" and it's already down to 3/4".

By the way, I've been shaking this up a couple times a day. Last night before I went to bed I turned the jar upside down (make sure it's well-sealed) and waited until the mastic glob had sort of broken up under the force of gravity into smaller globs and fallen from the top of the jar back into the liquid. At that point I shook it vigorously for a minute or two and then let it sit and went to bed. I'll do that again a couple times today. I'm guessing that by tomorrow it will have reached a 1/2" thick layer. I now don't know what the final gunk layer thickness will be. Maybe 3/8"?

One comment about the photography. This photograph's background looks very different than yesterday's because this one was taken earlier in the morning. There wasn't enough daylight coming down through my basement window to properly backlight the dissolving mastic, so I used one of the workbench incadescent lights to do it. Yesterday's picture was taken with just indirect daylight and no in candescent lighting. The first night's pictures were taken at night with only the incandescent lighting. In all cases, white balance was set on my camera using my collapsible gray card, so the color of the varnish is fairly consistent, but the background lighting appears totally different. I kind of like this almost eery blue cast to the background of this morning's picture. It shows starkly just how blue daylight is, when you've set your white balance based on incandescent light.

[carlkenyon]

Seth,

I want to make some mastic varnish also . I got the catalog for

wood finishing enterprises and I am going to place an order. Are

there ingredience that I will need to order beside mastic tears

(gum mastic, 4 oz&nbsp. Turpintine is available at home depot

.

carl

[Seth_Leigh]

You'll need some linseed oil. You won't want the "boiled linseed oil" from Home Depot though. And there have been posts in the past by people who tried various flax oils from health food stores and whatnot and had trouble getting their varnish to dry. The safest bet seems to be just plain old cold-pressed pure linseed oil from a place that intends it to be used as a drying oil.

I bought and used, and still have some left, a liter of cold-pressed linseed oil from Kremer Pigments back in 2004. It didn't cost that much, and can be used to make a lot of varnish and other experiments. Kremer just got bought by some other company, and I'm not 100% sure the new combination company still has all the old Kremer products. If they do, I don't think you'd go wrong using their oil.

Oh, and you'll need a couple of glass jars. :-) Spaghetti sauce jars are nice, but I'm partial to olive jars, because I get to eat the olives first. :-) By the way, Carl, don't worry about having a scale or anything. This method doesn't require much precision in measurements. Mark a line up the jar indicating the top of the mastic when you first put it in the jar, and then divide that volume by three and mark a line 1/3 of the way up from the bottom of the jar, and that will indicate a good amount of oil to use.

[Craig Tucker]

Seth

I cannot improve on this wonderful post, so I'll only add an interesting tidbit.

I will say that I always disolve my mastic in the jar out in the warm (usually) 80 - 90 degree sun.

Often it is completely dissolved within 24 hours...

I have always wondered if the UV has any effect?

What thinks ye?

[Seth_Leigh]

Well, I wish Michael would post and answer this directly, but he's AWOL at 9999 posts, so I'll just say he has warned of the effects of using any heat to assist in the dissolution of the mastic. He says that the gunk at the bottom of the jar, that will dissolve if you use heat, is not stuff that you want in the varnish anyway, so that it's better not to use any heat. I followed this advice strictly the previous times I've made this varnish and the varnish has always dried very quickly and completely on test strips or a violin.

As I recall, you had some drying problems with your mastic varnish, Craig. Can it be that the heat of the 80-90 degree sun exposure dissolved the gunk that you didn't really want in the varnish, and now it results in drying problems? I don't know. One interesting experiment would be to take a quantity of mastic and divide it in two and make two batches at once. Dissolve one indoors at room temperature, and dissolve the other outside in the sun in 90 degree weather. I just used up all my mastic, so I can't do that experiment, but it would be interesting.

Btw, I doubt it's the UV that's making the difference in your varnish dissolving. I think it's just the 20-30 degree temperature difference.

[Craig Tucker]

D*mn, your probably correct about that.

(!)

[Seth_Leigh]

Craig, was your completed mastic varnish crystal clear like the stuff in the plastic jar on the left in some of my photos? I'm curious, since you've made varnish with complete dissolution of the tears, and the varnish in this jar was not. When I say crystal clear, I mean it. Take a light beer, put it in a glass, let it go flat, and that crystal clear yellow look is how this varnish looks.

[Craig Tucker]

Yes, it looked EXACTLY like what you show, but it was made from food grade mastic tears from Chios, not the Kremer stuff, so I'm not sure how well they compare.

It was extremely clean to start with - with no visible impurities.

I did wind up with drying problems (imprinting in the case up to about four months after which it seems to have dried permanently.) but, I started using Japan Dryer in the same batch, and had no further drying problems... exactly as the instructions on the can say to mix.

I would have preferred not to have had to resort to a metalic dryer.

[Collin]

Seth - why wouldn't you want the boiled linseed oil? just

curious....

Edit - I should have been more specific - why is cold-pressed

linseed oil preferred to boiled when boiled will dry faster?

[Matej_Kliman]

I also think Seth is right,

I had similar experience with raw pine resin. I used heat once to dissolve all of it for my varnish and the result is muddy undrying varnish.

Matej

[Berl Mendenhall]

Seth,

Aces as always. Really a great thread. I'll be checking daily. I appreciate you taking your time to put togeather the photos and information.

Berl Mendenhall

[Seth_Leigh]

Collin, the boiled linseed oil I've had from the hardware store before a thin, watery stuff, not at all like raw linseed oil. But more than that, The Michael said not to, so I don't use it for this stuff. :-) Maybe next time I buy some mastic I'll set some aside for an experiment and make some varnish using the hardware store boiled linseed oil instead, and see how it turns out. But really, I don't have a good answer to your question. Maybe someone else does.

[Andres Sender]

The rumor is that the hardware store stuff is late pressings/steamings full of dreck which you have to wash and even then may only 'dry' because it has added dryers.

[Seth_Leigh]

I thought about not taking up anymore bandwidth with a new picture just to show some incremental change, but finally decided to just go for it. This picture does show a meaningful incremental difference in the mastic level and will help people unfamiliar with the process form a good idea of how this goes, and how quickly it goes.

This is the mastic dissolving on the third day following the night when I first poured in the turpentine over the mastic tears.

The snot at the bottom of the jar isn't actually in an even layer right now because I shook it up enough to break it up and let it settle again. It's in more like ragged chunks right now. All told, it's less than 1/2" deep, and my revised guesstimate of 3/8" of non-dissolving gunk at the bottom of the jar looks like it'll probably be pretty close.

At this point, it looks like almost all the soluble mastic is dissolved. There are a few little clearer pockets in the gunk, though, which I think may be mastic which will dissolve, so I'm going to force myself to be patient and give it more time. I'll shake it up again tonight, and then tomorrow a couple times, and then I'll pour the mastic syrup into another jar and add the linseed oil on Sunday morning. I'm going to add 100 grams of the washed linseed oil that I have left from Kremer. I washed this a few months ago, and there's a thread about that, actually, if someone's interested in seeing the washed versus unwashed oil.

Recall from the original post that I weighed out the original mastic tears at 339 grams. Given that some of these original 339 grams will be left unused at the bottom of the jar, the 100 grams of linseed oil will likely represent pretty close to an even 3:1 ratio of resin to oil, or 33% oil - in other words, well within the "probably a pretty good amount of oil" range. It could have been more oil, it could have been less oil. But this will be a pretty good amount of oil, I won't spent one minute fretting about the precision with which the actual oil ratio can be measured.

If I felt no particular rush I'd probably just let this stuff sit on the shelf for a few weeks and get to it later. But as it is, I'll do it on Sunday. That's enough time, and it will produce a very nice varnish.

[Seth_Leigh]

Here's the mastic on the 4th morning since adding the turps. At this point it's more or less just gunk at the bottom of the jar that's left, with probably not much soluble mastic left. I could definitely pour off the mastic syrup now and add the oil, but I said I would do it on Sunday morning, and I'm going to force myself to hold to that.

It's interesting to me that the gunk layer at the bottom is even thinner than my revised projection of 3/8". At this point it's probably going to be less than 1/4" thick. I'll see if I can get a good closeup showing the nature of the gunk itself.

[Seth_Leigh]

[Craig Tucker]

"The Michael"

Guffaw!