This is 11 coats of PC Petrifier, to which I have been adding a little, very fine paulownia sawdust.
I am not really using this product as it was designed. What it was designed for is hardening rotting wood. The paulownia I am using is obviously not rotting, but it is very soft. Also, they recommend using 2-3 coats, so I am using a lot more coats than they recommend.
It's one of the few water based wood hardeners that I have found, so that is one reason to use it. According to it's SDS it's mostly water, a very mild solvent (glycol ether TPM) and a proprietary hard urethane. Very low VOCs and toxicity. But my off-book use goes beyond that.
When I first used it I noticed that it dries relatively quickly and hard. It seals the wood well and is about the consistency of normal water, although it is milky white. Since paulownia has huge open grain, I thought it might be interesting use a sanding pad with it, and add some sawdust. From there the idea was to just keep adding a little sawdust and building it up until the grain was pretty well filled. So I have been putting a coat on once a day for almost two weeks. It's now fairly hard, the grain is mostly filled. It dries completely clear with no yellowing. Coats are super thin, and it's only $10 for 8 oz.
Stain won't penetrate, but I have tried it in swatches with colored shellac, with which it seems to work pretty well...although I am still gaining experience with that.
Also, putting a coat on every day has kept me from feeling bad about putting off sanding my Tele project...