Applying a colored polyurethane finish

Discussion in 'Hardware, Setup & Repair [BG]' started by Groovecenter, Aug 7, 2003.

  1. If I were going to stain a swamp ash body a white transparent color like the one in the picture attached, what would be involved?

    I used a nitro cellulose last time, and liked the results, but wanted to go with somethign a little cheaper. If things are mostly the same going from nitro to poly, the steps would go as follows-

    1.- If needed, sand body to around 220 grit dry. Wipe down with Naptha to remove any oils from handling.
    2. Since Ash is pourous wood, apply an oil or water based grain filler (a natural colored one)
    3. Apply the white tint to color.
    4. Seal the wood with a sealer of some sort. (open for recomendations)
    5. Apply about three somewhat thin coats of poly and wet sand.

    Now, all of this is pretty much guesswork, so feel free to edit my post until it is correct.

    How many coats of poly are recomended for good protection without blanketing the wood?

    Between coats I assume one should wait about 3 hours or until the poly is dry to touch correct?

    Thanks in advance, Steve Q.
  2. Oh yeah it's needed and I wouldn't stop at 220 either. If you've got good wood you could easily go to 600 and greatly improve your finish.
    An ideal filler/sealer is simple amber shellac. 2 coats - dried, cured, and wet sanded between coats. Stop the coats when you've filled the grain to your liking. Sand to 600 grit finish.
    Some sort of hand rubbed dye or stain would allow control of application and depth of tint.
    No real need here if the stain/dye went on smoothly. Even it if didn't, a few passes with some 0000 steel wool will smooth it to the point that clear coat is all the needed.
    All depends on how much of the grain you want to be able to feel. 3 coats might come up short unless you are using a real "high solids" product. Most rattle can poly's are a bit thin. I would estimate 6+ coats with wet sanding between coats is what will be needed. You'll be whipping out grits exceeding 1200 for the best finish. Your last coat should be your "flood" coat that dries with the highest gloss. You won't sand this coat - you'll just buff it to remove specks.

    As for what is "dry", "cured", "dry-to-touch" - I use these simple rules - It's cured if I can't smell the solvent in the finish. I'll sniff it daily to get a reading on how much longer it will take to cure. It can be days but until you can't get a whiff of the finish, it's not "cured". Something is dry to the touch if I can take my CLEAN finger and lightly drag the end across a small area of the coating and have my finger "squeek" as it shimmys along the surface. That's when poly's can be recoated. How long this takes is anybody's guess since drying time is determined by spray mixture, humidity and temperature.

    Hope this helps.
  3. thanks for the reply hambone. You mentioned three coats wouldn't be enough depending on how much I wanted to "feel the grain." Did you mean actually feel the wood, because I don't want to feel the wood at all. This is going to be my fretted 5 warmoth in swampash, so I thought I'd give it a nice hard finish as it will most likely become my main gigging bass. Your recomendation is 6 coats with wet sanding between each coat after it has dried to touch?
  4. Wet sanding should be done when the coat is cured. For Poly's that shouldn't be too long. Maybe a day or so.

    If you want that glassy type of finish, be prepared to keep at it.