What am I doing wrong....

[ChrisF]

Turned these bits down nicely round, all looking good, sand gently 240 through to 2500 and somewhere in that process these dirty marks appear......any clues as to what's occurring? It didn't happen at all on the first few pens I made but now it seems to crop up on every one. It's getting a bit expensive on tubes......

Any and all thoughts very much appreciated.

 

[Scots Bill]

Looks like spalting to me Chris, it is a fungus that runs through the wood. Thing it stops when the timber is dry. It is highly prized among woodworkers. I have actually induced the process with sawdust from infected wood put into a plastic sack with turning blanks. The time taken varies, and different wood are more or less liable to spalting, beech is noted for it. Just carry on and the pen will look super.

 

[ChrisF]

Ha, yes, the spalting, I'm aware of that. It's the mucky looking marks down in the grain that I'm talking about rather than the spalt lines.

 

[Buckeye]

Are you sanding your bushes and spreading the metal residue over the wood? When does it happen, is it after you have finished turning or after sanding?

Peter

 

[billyb_imp]

As your sanding the blanks it is likely you are also eroding away the bushes, so you end up with microscopic particles of steel transferring onto the blank & being ingrained into it as you continue to sand away.

so, try and keep off the bushes as much as possible, wipe down the blank & bushes at the very least with a cloth at every change of grit, change your bushes every now & again.

 

[Buckeye]

If it is happening with the sanding then put plenty of sanding sealer on the wood before you start to sand and keep applying it as you wear it down until you get to the finish you want.

Peter

 

[ChrisF]

Thanks guys, metal residue from the bushes could well be the problem (the bushes you understand, not my careless sanding ).

Much appreciated.

 

[bassethound]

Yep all been said I reckon!

 

[Bob Ellis]

I overcome this problem by turning some disposable bushes out of delrin. I use the metal bushes to turn the blank(s) to size and then exchange them for the delrin bushes before I begin sanding. I also use abranet and micromesh to prevent bits becoming detached from the grit and embedding themselves in the wood. This solves the problem.

 

[Bill Mooney]

As Peter says .

 

[Vic Perrin]

I agree with the metal pick up from the bushes

 

[Woody]

It could also be contamination from the spalting in fact I would be more inclined to think it could be that in which case sanding sealer is still your answer also a wash before and after you sand with Meths

 

[Penpal]

Methinks at this late stage the residue in the lines is transferring stainless steel bushes dont transfer like the old brass bushes used to I agree with Woody.

Peter.

 

[21William]

Methinks at this late stage the residue in the lines is transferring stainless steel bushes dont transfer like the old brass bushes used to I agree with Woody.

Peter.

I assumed the bushes were plated steel or brass. The ones I've seen don't look like SS but I suppose they could be?

 

[ChrisF]

Thanks all, some good food for thought. Bearing it all in mind I escaped to the workshop this morning and bashed out this little lot, taking great care to sand only wood and applying a little sanding sealer in between each grade.....and not a sign of the previously ubiquitous dirty marks (I know they're not perfect, but that's what practice is for eh!)

What a great resource - really appreciate the help.

 

[yorkshireman]

Five beauty's there Chris

 

[21William]

They look good to me Chris!

 

[Penpal]

Cris nice to beat a problem and have fun turning beaut pens.

Peter.

 

[wm460]

That is a set of beauties Chris.

 

[ChrisF]

Thanks guys - many a sin can be hidden by careful photography :wink: