What is the difference? I've used polyurethane to varnish boards. How is polyester varnish made?

Hello 357mag,

I'm gona give you the quick answer
All Fender bodies are polyester primed with a
product called Fullerplast. You can paint on top of
polyester and the coat will stick.

Polyurethane on the other hand can't be successfully
painted over. but is far more durable and can be built
up quickly. Also it has a quicker cure time which
industry is quite happy with. Polyurethanes are less toxic
to produce, again industry is happy.

There's lots more too.but hopefull this is where you were going.

Cheers.

Don't you paint the body first then apply the varnish on top of the paint? I thought it was:

1. Paint the body.
2. Apply polyester varnish on top.

Or...

1. Paint the body.
2. Apply polyurethane varnish on top.

Mmm. This is where a lot of words such as "varnish", "paint" and "lacquer" all get mixed up. There are in fact correct technical meanings of all those words, but as far as guitar finishes are concerned they are all the same thing.

Polyester, polyurethane and nitrocellulose are all "carriers" or "mediums" ("media"). They are more or less transparent "binders" that carry the solids that make up the finish, which may or may not include colored dyes, pigments, metallic flake, etc. There is frequently also a solvent which evaporates during drying. Different solvents have different levels of toxicity.

These finishes each have their own characteristics. The benefit of these is something we could debate for pages, and everyone has their own feelings about it.

The simple guide as far as Fender are concerned is that polyester finishes tend to be rather thick and are found on most (all?) Mexican Fenders and Squiers. Polyurethane can be applied more thinly and is found on most American Standard and American Deluxe models. And nitrocellulose tends now to be restricted to American Vintage type models and some Artist guitars, such as the Eric Johnson Sig.

Much more to be said on all of that.

Cheers - C

Now, about Nitro..., on second thought, we won't go there yet!

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