White Spots on Spruce Top

[Palo-Kai]

Hi, I'm working on an old (1970's) Laminate top guitar. I sanded the top and now I have these spots on it. Any idea what they are and how I can get rid of them? Thanks.

[charles Tauber]

Are you talking about the large lighter-coloured areas? If so, you have sanded through the finish to expose bare wood. The bare wood is a lighter color.

The "fix" is to either remove the rest of the finish or apply an appropriate finish to the bare spots.

What work were you doing that you sanded the top?

[Palo-Kai]

Thanks for replying Charles. This “guitar” is just parts at the moment. The neck is attached to the top and part of the sides. The top was in very bad shape. I did wet sanding, 600, 1200, & 1500 grit. I am putting a new smaller body on it to make it a travel guitar.

[mirwa]

As charles has mentioned you have gone through the finish and into the spruce.

Spruce when freshly sanded and cut has a very white colour to it, with exposure to UV light it starts to go a shade of amber, also application of shellac or some finishes exasperates this colour change faster.

The black areas to me look like damage that has pierced the protective finish over the years and has dirtied muddied the surface.

Avoid wet sanding raw wood, it makes the fibres swell and they tear out real easy when being sanded

Steve

[ClaptonWannabe2]

would the darkest spots in the center be old adhesive from a laminate top? can it seep through into the top piece? then wet sanding discolor or burn it?

[runamuck]

It looks to me that you've gone through the spruce veneer and into the layer of glue adhering that to the next layer down.