Thread: Just a quick mention on varnish

Since posting about the asphaltum, I have made my fourth batch of resin varnish including the first one I made years ago. this doesn't include the "run" version of the asphaltum - that makes five.

I haven't yet run sandarac, but that would be something that could be done in australia. The resins that I've run are limed rosin, black india and pale india.

this is a territory in woodworking that isn't touched on much. A plain pine rosin varnish that's not limed (liming increases the film hardness, but if you think of lime powder, it reacts with the resin and is dissolved in - the finish is still bright and clear) isn't really suitable for anything but utility work. As in, it will protect a piece, but it will not be very hard for a very very long time. Like decades. You certainly can't polish it.

The reason I mention this is that it's considered difficult to make varnish, but it actually is not. From discussions here before, I recall that you can't get commercial turpentine as we can here, and that makes it so the portugal supplier of turps that I mentioned is probably not a great idea for importing.

However, I've also learned that you can make resin varnishes with mineral oil and naphtha, or use linseed oil and resins, which I'm sure you can get and use just naphtha instead of turpentine. there are other terpenes of fruit that are used in the food industry (like D-limonene) that are actually cheaper in the US and a stronger solvent than even turpentine, so they would be usable.

Point is, it's something a hand tool woodworker can do and make with nothing more than a pair of junk pots and a cheap imported two-burner hot plate. It *must* be done outside, no exceptions. if you have ever seen a french polish in person, you will have seen the look of the finish vs. the more typical modern spray on films. There is a life to the finish and color and depth that things like consumer polyurethane just doesn't have. Natural resin varnishes have this tone and depth and can be applied by hand and will have far better longevity than anything you're likely to buy in a can.

I kind of hope this sort of thing makes a comeback. I believe that it was squelched partially due to cost and partially due to lobbying, and at this point, you do it on your own, so you're certainly not going to find retailers telling you to eschew the latest and greatest "only a little cold looking and only a little bit of durability issues" water based finish and make your own.

Reading older texts lets on just how common this was before hydrocarbon and synthetic finishes, but it also makes it sound more difficult than it is because a professional maker (the viewpoint the texts are written from) would be forced to try to evenly heat very large batches and do it without something simple and cheap that we can find now - an imported thermocouple that prevents the one big error - overheating. Varnish making over an open flame with 15 gallons in a pot would be very dangerous. Doing this with small batches, perhaps a pint to a half gallon at most, not nearly so dangerous and temperature control and even heating of a large batch doesn't apply.

i'm not going to go deep on it - I suspect few people would want to try making their own finish just as I've found almost nobody actually wants to work by hand and will follow through doing it. However, you might find the test pictures of the varnishes interesting. It'll be a little while before I'm making something like a guitar where you'd get to see the finished result in a format that isn't "varnish distressed vintage look".