Thread: homemade varnish

That recipe isn't varnish, but a Dutch oil mixture. Japan drier is necessary, unless you can wait a week or two as the oil and pine tar dry (real pine tar never really dries). This concoction will not have a gloss once dry and it will not have much UV protection, which is the whole point behind clear finishes on wood. You can improve UV protection (slightly) with more pine tar, but this also darkens the color.

Real varnishes are essentially, oils (tung is far better than linseed), drying agents, a vehicle which is typically a solvent, though could be water borne, pigments and possably other resins and additives, such as UV inhibitors, dies and particulates. The combinations and formulations of these various materials, can be daunting without some chemical background or a reasonable recipe, but some of the materials will be hard to acquire.

If interested in an oil mix, reduce the Japan drier percentage to 10% or less of the whole batch. Currently you have nearly 17% Japan drier, which is too much. Also the 17% of pine tar will make a dark coloring agent, so knock this back to 10% as well, if not lower. See if you can find a UV inhibitor that'll remain in suspension in oil. The addition of shellac, lacquer or amber will harden the surface and offer some shine. Most modern spar varnishes are man made or chemically modified phenolic resins or polyurethanes, which are man made versions of the original alkyd varnishes.

I don't have to explain the issues associated with playing with fire and volatile solvents do I? You can do it, but don't even think about it around an open flame. Use a hot plate or electric burner.

So my world gets a little more complicated! Okay I guess I have some thinking/searching to do.. I really appreciate your time and thoughts!#

All is not lost, the cost of the materials in a typical Dutch oil, isn't much less then a low end traditional varnish. You can "punch up" these lesser grades, with more UV inhibitors and resins to make a better quality varnish. Be careful what you wish for. I'm the owner of more than one all varnish, not a drop of paint, boat and I can assure you they're not easy to live with. I'm fortunate enough to be able to store them indoors, but most just place them under cover, which is quite different and costly. What project are you working on, that is making you contemplate the headaches of a bright finish?

Hi,
I understand that you would like to make your own but do consider whether it is worth the effort. Boat building and boat ownership are about enjoying the boat on the water, not too much "dealing with" our better halves about their kitchen (Yes, many of us have the same issue, though I have to say mine is wonderful and will let me do anything I want in the kitchen, especially if it is to cook dinner).

I have an all-bright finish Huon Pine dinghy (12 foot with electric motors) and have found that you have to choose your finish for the situation. Because my dinghy is clinker built the outside is (relatively) easy to sand and refinish so I chose a commercially available clear varnish from one of the major manufacturers. It has lasted 15 years so far, covered, though requiring a light sand and overcoat a couple of years go. Looks great, very practical and OK to maintain. BUT, inside she is a different story with steam bent ribs and too many nooks and crannies to be able to sand so I chose an oil finish (Deks Olje) so I could just overcoat when required.

That combination is working well for me, and keeps me in the shed, out of the kitchen until dinner is cooked (hopefully).