Even sanding tips

[jesterbass]

Hello,

I have this nice bass body, alder back with a flamed maple top. It used to have a poly finish, which I have now stripped down to 150grit sandpaper. The basecoat from the poly finish was a good guide about when to stop sanding because of the colour change when the actual bare wood appeared. Now I have to progressively go to finer grit sandpapers. Are there any tips on how to tell when I am done with a given grit and move on to the next? So as to not miss any area but also not to oversand.

Thanks!

 

[Ruckus_Instrmts]

When I sand finishes I run successive grits perpendicular to the last grit. You'll know its time to move on when all your scratches run in one direction.

 

[jesterbass]

Thanks! Any other thoughts/pointers are welcome.

 

[bassteban]

Good lighting- natural sunlight is often the best.

 

[praisegig]

Use sanding blocks to keep everything level

 

[stanknuckle]

I've been wondering about this too. I've found that for me on my headstock that the should-be-gloss finish is "marbled". I've been using minwax wipe on. This marbled effect seems to be coming from beneath the coats. I think I may have to start again?

 

[pilotjones]

I've been wondering about this too. I've found that for me on my headstock that the should be a gloss finish is "marbled". I've been using minwax wipe on. This marbled effect seems to be coming from beneath the coats. I think I may have to start again?

Sounds like you've sanded through layers of finish, producing witness lines. The only solution I know of is to add more finish layers, and be more gentle and sand less when redoing it.

 

[stanknuckle]

Sounds like you've sanded through layers of finish, producing witness lines. The only solution I know of is to add more finish layers, and be more gentle and sand less when redoing it.

Yeah i thought so... bugger! So I simply apply more coats and that will cover up the lines?

 

[pilotjones]

That's what I did - put a few layers, and then be extra careful not to sand through the top layer. For flat surfaces, this requires that your surface be dead flat before to add the extra layers, so that when you hit it afterward with a sanding block, you're not once again removing the mountaintops from the bumpy surface.

If there's any better solution, no one has let me in on it yet. Simply sanding to 4000 did not do it for me.

 

[stanknuckle]

I put on about 12 coats of polyurethane (minwax wipe-on) and block sanded it but, it has left a lighter shade in areas around the edges and between the tuning peg holes. It's like I've gone down to the bare wood. It looks terrible. Does anyone else agree with me that I sand it ALL back to a uniform colour and start again?