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Here's a question I have about finishing the Stew-Mac electric guitar kit I got for Christmas).

I usually finish my acoustic guitars with a rattle-can nitrocellulose (Mohawk Instrument Lacquer from Woodcraft), and I've used Tru-Oil for that purpose once with good results. This is because it results in a thin, hard finish that doesn't interfere with the wood's resonant qualities. (All my necks are finished with Tru-Oil, and I intend to use that on the neck of my new guitar as well.)

But for the body, I'm thinking of using just a wipe-on polyurethane after filling the pores of the mahogany. The reasoning is that except for possible esthetic reasons, the finish on a solid guitar body doesn't affect the acoustic properties, or so I've been told by other guitarists. Unlike an acoustic guitar body's ability to resonate and affect the tone, the only variation on a solid wood body that matters is its weight, the theory being that the greater mass minimizes the effect of a string's vibration being dissipated through the bridge, thereby increasing the "sustain" of the string. On an acoustic guitar, you want that vibration to go through the bridge into the top of the guitar, because it's the top that transmit the vibration into the air. But there is no soundboard on a solid-body, hence no effect of that guitar's finish on the production of sound.

But I may be overthinking this, as I am wont to do. Is this reasoning sound? Should I go on with the wipe-on poly, or should I get out the rattle-cans again and use them on the body?

From the way you've described the situation, it doesn't seem to make any difference one way or the other. So do it
whichever way you want.
If you really want a reason to choose one or the other, pick the method you haven't done before, to learn a new skill and gain experience.

That makes sense. I'm going to go for the wipe-on poly. According to what I've read on the other forums, the trick is to apply a lot of thin coats rather than one thick one... kinda like the Tru-Oil stuff I've used.

Not that I've used it on solid bodys, I was going to suggest Osmo or Monocoat, quick, easy. Three coats of TruOil would be easy too if you've got it on your shelf.

Rummaging around in my finishing materials drawer, I found some water-based rosewood stain from Minwas, some water-based rosewood pore filler from LMI, and a bottle of Stew-Mac water-based wipe-on poly. So that's what I'll probably end up using. I wish I had some mahogany to use as a test-strip, but I do have some sapele which is pretty close to mahogany, so I'll make a trial run with that.

Update: There is some feeling that water-based wipe-on poly finishes end up "cloudier" than the oil-based ones. I did get some mahogany for testing from Exotic Woods, so I'll test it to see what it looks like.