Need help on getting rid white residue on guitar body

[Mehi]

Theres white residue after i tried to get rid of the old paint. Guitar model is behringer i-axe 393. Is there any way to remove it? 

[Bizman62]

That looks like there's some sort of clear sealer/primer/filler to me and the residue is white because you've sanded it quite rough. You've partially sanded to bare wood which looks even paler. You can easily test this by dropping water on various places and let it sit for a while. If you can easily wipe it dry, there's sealer. If you feel a slightly swollen rough spot, that's bare wood.

The next steps depend on the finish you're planning to do. Natural, dyed, burst, paint?

For a natural finish with a clearcoat simply sand through the grits so that there's no scratches. You may not need to sand the existing coat off, just make it evenly matte. The bare wood parts may or may not blend with the primer, the only way to know is to test. If that works and you leave the primer, you'll have to lightly sand the bare wood parts as the clearcoat acts as primer on the "clean" parts and raises some grain which you have to level. That will also show any scratches so sand carefully. After that apply more clear.

If you want to dye it with a water soluble dye, you'll have to sand it to bare wood all over as water will not penetrate the primer. The goal is to get a silky smooth surface up to some 400 grit, raising the grain a few times with a damp cloth. Any scratches will be emphasized with the dye!

You can also add suitable dye to the solvent of your clearcoat and add the mix to the lacquer for a translucent finish. That should stick to the primer but will it act differently on bare wood requires testing. On top of a tinted lacquer a layer of clearcoat will add protection against dents and scratches.

If you're "just" going to paint it, sand it like described in the natural finish paragraph and apply some primer and pore filler where needed and sand flush. Painting a guitar is very similar to painting a car as any imperfections in the base will show on the finish. After getting the surface as level as possible apply the paint of your choice and potentially a clearcoat for added protection.

Finally, no matter what you choose, you can always sand it back! That said, if you soak bare wood end grain with alcohol based dye, that will penetrate quite deep so do your testing on less visible places.

[Andyjr1515]

^  What @Bizman62 said!

Yes - you've got down to the 'harder than diamond' primer coat that many commercial makers use!  It takes a considerable amount of sanding to get it all off if, as @Bizman62 says, you are planning to stain it or go for a clear or trans finish.  And if you are planning either of those, then yes - it all has to come off.  But yes - it does eventually come off.

As also said above, you can usually get away with leaving it there if you are planning a solid colour as long as you prepare it and prime it adequately.

[mistermikev]

nothing to add - "you got some sandin' to do son' hehe.  get some heavy grit and get to work.  factory sealer is hard to get through and takes a lot of work.