I recently put up ruby red glass tile, behind my range area, and behind the sink. I used the same nutmeg color grout on it, that I did the porclain mosaic's that cover the rest of the back splash. I havent found that it affected the shimmer or the depth at all. You might want to take some extra pieces, and attach them to a board, and try, half with a color grout, and half with the clear and see which you like best. Good Luck to you.

My 40 year old tub WAS pristine till I lost my grip on the hammer during the remodel. So I now have a decent sized chip on the outside of the tub. I just tried (just as in I did this yesterday) to use Krylon paint. First I used some torn masking tape to isolate the area in a less linear way, then used a few layers of primer to bring it up to the level of the porcelain. Then removed the one taping, sanded lightly, and taped again, similarly but a bit wider area and sprayed three layers of Krylon gloss white. So far it LOOKS very nice (the chip was about the size of a silver dollar) and I have "cleaned" it and it isn't budging. I won't be ready to use the tub for another month, but again my ding was outside the used area, so I think it will be fine. . .Since it seems to have worked, I have a sink given me by someone re-doing their bathroom. It is exactly the same as my current sink except less wear and tear. SO I am going to take it out to the shop (not installed yet) and try this on the sink. I'll let you all know how it goes. Just a note, after reading a few other forums about the companies that refinish bathtubs, I am less than convinced it is a good idea. Those that "just" had it done seemed pleased, but those who had it done five years or more ago, didn't think it was so great. The reasons varied and included color shifts and peeling/chipping off.

Poly Ethylene Glycol, PEG. The wood is soaked in the material and it fills in the cell structure and hardens.

"not easily read" is an understatement as I can't make out anything that resembles "1941" in that photo. If you really wanted to mark it with a date, I'd consider having a monument maker engrave a new one for you. I guess i just don't see the significance in trying to preserve it. Good luck.