Make Your Own Varnish?

This will probably sound foreign, especially if I mention that linseed oil is a key component to good varnish, and most folks will think of it as something “out of date, replaced by better things since it was used”.

However, I’d made a violin varnish recipe a few years ago and aside from the fact that the oil was somewhat slow drying, and the varnish itself needed a good dose of UV light to dry, it turned out great. That recipe can be referenced on youtube if you look up “pine dammar varnish” and that should also lead you to a recipe.

However, there was one problem with it – the combination of the two resins just don’t have the ambient temperature hardness – especially if ambient is a little warm and whatever is varnished may have slight pressure on it for a while. Translation in this case, the problem was actually the case. The case for my guitar was a woven polymer gig bag and the weave itself has lightly impressed on the back of the guitar.

There’s little information out there, and I kind of forgot about it, figuring any number of things (and guessing wrong). What the problem turns out to be is that the resin that I used is just not hard enough even though the guitar doesn’t feel soft when you play it.

So, that makes the answer to the title pretty easy – yes, of course you can cook your own. It’s not like watching Animal Trades channel and mixing three commercial products together and calling it good. It’s like heat treating by hand and eye in that you need to learn visual cues and at least where I’ll start, I will need to measure the temperature in some steps.

But, It’s Uncommon Otherwise

I don’t see much information about anyone else making varnish, except Steve Voigt (the plane maker) has taken it up as a hobby. You can also buy a varnish like Epifanes with a thinner and brush it, but it will smell like an oil refinery, and I didn’t check the MSDS, but the resin is probably alkyd – a synthetic.

There’s any number of natural resins that can be tampered with by method or used as-is that will make varnishes, and when Steve brought this up, what caught my eye was a passage in the Holtazapffel book that some hard Copal (a resin) varnish recipes are very durable for furniture and can dry in 10 minutes.

Anyone who has used varnish, i want you to think for a second – have you ever applied a varnish that dries in 10 minutes without something arcane in it? I haven’t. And maybe I won’t be able to make a 10 minute varnish, but I’ve learned enough reading in the last week or two to know that there is some fruit at the end of the process here and that my initial success in making a varnish, that was slower drying and with a softer resin, should’ve been an invitation to learn more, and not to assume that varnish is varnish (say it like “motor oil is motor oil”).

The key parts of making varnish – first off, it is an outdoor only activity as you may sometimes be cooking flammable things at 600 degrees F, and you’ll be cooking flaxseed or linseed oil to improve its qualities, and that cooking along with cooking (or running) of resins will make things you don’t want in your house.

Too, about half a decade ago, I mentioned something to George Wilson about making varnish, and I already knew to make it outside, but George said “make it outside…I’ve made a mushroom cloud making varnish” due to having varnish foam over and come in contact with a flame. It’s an activity for people with big boy pants because there certainly is the chance of a mishap. But it can be minimized.

Steve has posted some of his goings-through thus far here:

http://blackdogswoodshop.blogspot.com/2022/09/the-search-for-perfect-finish.html

Varnish making isn’t cheap, or at least it can become expensive, but even the too-soft varnish that I made had some qualities about it – the adhesion is incredible, the way it builds very quickly on the surface of wood without blotching is incredible. The turpentine smell is fresh, not oily or stinky.

It’s worth thinking about doing, as long as you have somewhere outside that you would be able to cook it.

As I experiment with it, I’ll post about it, too. I got my first big box of stuff from Wood Finishing Industries today and have some other things on order that should allow making of varnish that will have permanence like any finish, but with warmth and depth that a lot of finishes lack now, and without the odors of some of the older solvent based finishes that we’ve grown to love (like nitro lacquer). Who knows how long those will be universally available, anyway. They may have their hand forced into crappy recipes by VOC rules or some health standards.