Varnish differences

[Matt P]

After all the talk about varnish types and ingredients and how different they look on the finished products:

e.g.
phenolic/alkyd/poly
soya oil-based/tung based/linseed based

I compared MinWax Poly and Heirloom varnish on several different types of wood, and I cannot discern ANY appreciable difference in the appearance of the final finish. (The MinWax and Heirloom certainly look different in the bottle - MinWax is much lighter and clearer.) Sometimes I think that people get carried away with all the ingredient talk, etc.. when there is not much of an appreciable difference in the final appearance.. In other words, sometimes The Emperor Has No Clothes. I realize this kind of talk may be heretical, but what do you think?

[John Schreiber]

Did you notice any difference in how they went on or was that the same too? Any guesses as to differences in durability?

[Matt P]

They went on pretty much the same. I assume that the MinWax poly will be somewhat more durable than the Heirloom..

[Jim Becker]

They went on pretty much the same. I assume that the MinWax poly will be somewhat more durable than the Heirloom..

Not a good assumption to make. Polyurethane does add a little abrasion resistance...which is why it's great for floors...but there isn't an appreciable difference in so-called "durablity" otherwise. Poly may be a little softer even than many other varnishes and it often has less clarity.

[Steve Schoene]

I've made several sets of similar tests. What I have found is that there are quite a few variables that affect the appearance. On one or two coats most oil based varnishes are going to look quite a bit alike. Some phenolics will be a bit darker. Some soya/alkyd (such as the Heirloom) will be a bit lighter. Differences become more pronounced if another coat or two are added. Then, the clarity of the traditional resin varnish will be more apparent, at least at some angles and in some light.

As far as durability, I'd bet that unless you are talking about floors you would find less difference in durability than in appearance between varnishes which have some polyurethane added and other which are completely formulated with a traditional resin.

Where the traditional resin varnishes make a more noticeable difference is when it is time to rub them out. The traditional resin varnishes are generally easier to achieve an even sheen than varnishes which have polyurethane in them.

[Matt P]

I see, maybe if I add more coats of each a difference will emerge..

[Kim Spence]

I took a finishing class recently and we discussed this topic. Over time you may begin to notice a difference in the finish based on the ingredients. My memory is failing me right now so I'll have to check my notes from the class, but one of either Tung or Linseed oil will darken more as it ages on the wood, but I can't remember which one off the top of my head.

[Matt P]

Yes, I've heard that linseed darkens more with age than tung..