Scratches whilst sanding floor boards

[Timmypig]

Hello All

I'm sanding bare boards prior to staining & estapolling. I've had it up to HERE (!!!!) with the scratches that end up in the boards. These scratches are all perpendicular to the length (& grain) of the boards. These must occur during sanding (with a RUPES Super Stork 7000). How? And how to get rid of them?

Hand sand along the grain?

Any suggestions appreciated, cheers.

[Phil Mac]

How dissapointing!

Did you sand the boards in the direction of the scratches or were they in the boards before you started??

Basically you havent sanded enough in depth from the second and subsequent cuts, it is essential to remove all marks from the previous cut with the higher grit paper,

If you start off with 40 grit paper never sand at 90 degrees to the boards, sand at 45 degrees to remove the high spots but only the high spots!!!!, then sand in the direction of the grain till you remove all the first cut marks on the diagonals and all the other imperfections.

Then change paper to 60 or 80 grit and sand in the direction of the of the grain only untill you have removed all the 40 grit marks,

then change to 100 grit paper and sand in the direction of the boards til you remove all the 80 grit marks.

The art fo floorsanding is being able to spot the marks from the previous cut.

It may help to wet the timber slightly with a damp cloth as this will sometimes highlight the imperfections.

Most professionals do a final cut with a rotary sander (floor polisher style sander with sand paper fixed to the bottom) to remove the marks left by the drum or belt sander, this has its own problems especially with hallogen down lights as the hallogen lights high light the circular swirls left by the rotary sander.

Having spent 7 years doing floorsanding and polishing it is a real let down when you spend the time sanding and coating a floor and when you finish you see marks you have missed, and you have 2 options

1) live with it.

2) resand it to remove the marks


Phil

[Timmypig]

Phil

Thanks for the quick response. I think I might have got myself sorted out .... I tried hand sanding with course and medium grits .... not much joy.

Then I tried resanding with the sander with medium grit paper, but without exerting any downward pressure at all. Seems to be paying off.

I'll post again later after vacuuming and the fine grit sanding has been done.

Cheers

[Timmypig]

Scratches have more or less been repaired. The problem was caused by exerting force down onto the sander, instead of letting the sander's action and the abrasion of the paper do their work .....

Lesson learnt. Piccy attached.

Cheers all