Sanding Pre Varnished Surfaces To remove Undulations and Ripples

[Deleted member 36384]

Hello,

I will be sanding the interior doors, bulkheads and panels on the Rival; the current varnish finish is gloss. The surface finish is not that good and one can see undulations and ripples, in the varnish.

I suspect that the existing varnish can be sanded to a nice flat surface, or at least sufficiently flat to allow the new coats to fill the valleys for a very flat finish.

What would be the best way to sand with 220 grit sandpaper: sheets glued to a flat board of ply, a DIY duty Bosch Flat sander, DIY duty Bosch Random Orbit Sander or a special aluminium sanding block for attaching standard length sandpaper strips to?

I suspect that the DIY duty Bosch machines' backing pads may be too soft and not help much in the end. The finish will be a matt or satin varnish, have not decided yet.

Thanks,

BlowingOldBoots

 

[tillergirl]

Be very very careful. You will have a thin veneer on those pannels and excessive sanding will take you through to the layer below the top veneer very very qucikly. My advice would be not to use any mechanical sander at all and be very gentle. Build up the coats to achieve smoothness. 4 or 5 will soon start to fill the 'valleys'

 

[machurley22]

I'm no expert but I think I would be wet sanding by hand using one of those hard rubber pads.

Edit: I see that your boat is quite a bit bigger than mine!

 

[Deleted member 36384]

Okay thanks for the replies. So if I understand just get the exiting varnish high spots flattened off and then build up with new varnish to fill the valleys, sanding again between coats. Powered sanders may remove to much material.

I will now use the aluminium hand sander for the larger areas: http://www.decoratingdirect.co.uk/Tools/Sanding_Block/. I have a nice flat cork block for smaller areas.

Gluing bits of sand paper to a ply board sound like a lot of gaffing about although I have sen this used by others a long time ago.