Would sanding sealer prevent this?

[areevesnc]

I’ve been working this weekend on turning a bandsaw bowl. The piece is made of Peruvian walnut, maple, and cherry. I’m not thrilled with the result, but I can chalk it up as a learning experience.

One of the problems — I think — is that when sanding, dust from the very dark walnut filled the pores of the lighter woods, leading to the streaks and discoloration shown here.

Is my suspicion correct? Would the use of sanding sealer or shellac — I’m thinking something to fill the pores before sanding — have helped to prevent this? Any other hints or suggestions?

 

[Oka]

My experience the best sealer I have found to prevent wood staining is resin. Take a 30-60 min resin and thin it down with acetone to make watery and use that as a sealer. That works fantastically. Other sealers also can work, but for me this has been my go to.

 

[Bill E]

I think you are on the right track. Resand the entire bowl from 80 up to 320 ; vacuuming or blowing the dust out between each grit and also raise the grain with water starting @180 .If you are sure the dark dust is out of the light wood.Try using a Tack Cloth. Seal with a wash coat of sanding seal ( water/clear 60/40 or apply a turning wax or Shellac to seal. Bill E

 

[Dee2]

Having exposed end grain compounds the problem, IMHO. Sealing can be helpful. Sometimes, fine woodworking requires a bit of experimentation. Once you know, you know.

 

[Rwe2156]

A hand plane would be able to return it to pristine condition.

Don't use a random orbital sand parallel to the strips.

 

[Mike Davis]

I get in trouble every time I say this but it is true, a sharp tool and proper technique will take care of that.

 

[Wiley's Woodworks]

I agree with your assessment of the cause of the problem--walnut dust polluting the maple next to it. I can't tell from the picture if this is the inside or outside of the bowl. If it is possible to get a card scraper with an appropriate radius on the cutting edge, a few light scrapes might clean it up. Do everything you can think of to clean the surface afterwards--tack cloth, water wash, mineral spirits, air hose, bubble gum, artist's eraser. Finally, your choice of sealer.

 

[Charlie]

I have prevented this by vacuuming/blowing off the bowl to remove the sanding particles.
Then I apply a coat or 2 of sanding sealer (dewaxed shellac) by blotting it on, not wiping.
If you wipe on the sealer or any finish it will carry over particles from the adjoining woods.
The worst problem I ever saw was bloodwood next to maple. The maple turned pink. But blotting on the sealer prevents it.
Once there are a couple of coats of sealer you can continue your normal sand, finish schedule.

 

[areevesnc]

Thanks, everyone, for the advice. It is more of an issue on end grain, which makes sense, and explains why it’s not been much of a problem on my segmented turnings where really only side grain is exposed.

I can’t use a plane on the inside of the bowl, but I can use a card scraper. I’ll give that a try. I have yet to complete the outside of the bowl, so I’ll try a few of the other suggestions. This particular piece has enough problems that it will be relegated to a back shelf in the shop to hold spare parts anyway, so it can’t hurt to experiment with a few techniques.

I definitely take Mike’s point: had this been done well to begin with, it wouldn’t have been a problem. Part of the purpose for the project was to get more practice and eventually get to the point that I can consistently do it well!