sanding shellac before filling ?

[eiopago]

very 1st warmoth project.
i have stained the mahogany body with deep mahogany stain,
then a wash coat of shellac (1 part shellac and 2 denaturated alcohol).
the plan is to fill with black filler and finish with clear polyurethane gloss.
the wash coat seems a bit too thin to stop the black colour of the filler to "contaminate" the koa or the mahogany stain.

i always heard that it should be enough but i feel a bit uneasy,
should i apply a coat of pure shellac, without cutting it to just be safe?
also,
should i sand the shellac smooth before filling?

thanks

 

[-CB-]

I'm not big on grain filling before staining, as you're probably going to sand off some stained area before you get the grain level.  That said, sure, go for another shellac coat.  No need to cut radically after the first coat.

 

[jackthehack]

+1 to what CB said if mahogany is the wood in question, but what type of grain filler are you using? If using the StewMac type water based filler on mahogany, I'll pretty much guarantee you'll be sanding through stain. Oil based filler you may get away with it.

 

[eiopago]

the filler i`m using is an oil based one (the original colour wasd ebony which turns grey as it dries up, that`s why i mixed it with an artist oil based black paint).
anyway,
to clarify, i stained then applied shellac (1 wash coat and the another one with pure) and filled the pores.
how comes that i might get away with sanding through the stain if i use an oil based filler as opposed to a water based one?

 

[jackthehack]

The StewMac water based stain dries hard as a rock. Or at least as hard as a hard plastic rock. Anytime you apply a colored filler you wind up getting some residual color spread over the wood that needs to be sanded back; in the case of the dried hard water based filler you have to start with #220 sandpaper and it's very easy to sand through stain or dye, especially on the edges of the body's contours.

I'm in the process of finishing my first body using oil based filler; it can kind of be a pain as it takes a LOT longer to completely dry, but it does not dry out anywhere near as hard as the water based filler, and you can use Tonar's technique of using burlap in lieu of sandpaper to "sand" back most of the excess before it dries completely. Also, you can wash back some of the excess that may dry with lacquer thinner and a rag, but that might affect the coloration of the base stain coat.

With mahogany I'd be more worried that the shellac wash costs might interfere with the filler adhering to the teeny tiny mahogany grain pores; this can be a pain and it's too easy to sand filler out of those little pores even when starting from bare wood. Try the above, if it doesn't give you the result you want you can always sand back to bare wood and start over. Always be prepared to sand all the way back to bare wood at least once when learning to apply a new finish technique, that's the nature of the game.

 

[DangerousR6]

The StewMac water based stain dries hard as a rock. Or at least as hard as a hard plastic rock. Anytime you apply a colored filler you wind up getting some residual color spread over the wood that needs to be sanded back; in the case of the dried hard water based filler you have to start with #220 sandpaper and it's very easy to sand through stain or dye, especially on the edges of the body's contours.

I'm in the process of finishing my first body using oil based filler; it can kind of be a pain as it takes a LOT longer to completely dry, but it does not dry out anywhere near as hard as the water based filler, and you can use Tonar's technique of using burlap in lieu of sandpaper to "sand" back most of the excess before it dries completely. Also, you can wash back some of the excess that may dry with lacquer thinner and a rag, but that might affect the coloration of the base stain coat.

With mahogany I'd be more worried that the shellac wash costs might interfere with the filler adhering to the teeny tiny mahogany grain pores; this can be a pain and it's too easy to sand filler out of those little pores even when starting from bare wood. Try the above, if it doesn't give you the result you want you can always sand back to bare wood and start over. Always be prepared to sand all the way back to bare wood at least once when learning to apply a new finish technique, that's the nature of the game.

So if you're going to do a stain you should do the grain fill first, then the level sanding , then the satin.... :dontknow: