Pumice and Rotten stone

[kerriescroller]

Being fairly new to wood work and especially finishing. I wondered if I could gather some info on Pumice and Rotten stone from you proffessionals out there. I have heard of Pumice Stone and Rotten stone but not sure what the uses are or where I purchase this. I have read a few minor mentions on here about it uses. But nothing really substanial. thanks
Kerrie

[kiwigeo]

One use for pumice is for grain infilling on open grained wood such as rosewood prior to finishing.

[Hickory]

Never heard of grain filling with Pumice but I certainly don't know everthing....

Pumice and Rottenstone are abrasives Pumice being the coursest of the two.

To use Pumice as a softening agent to bring a patina to a glossy surface or to smooth the nibs and bumps or remove brush marks from a hardened surface. Simply apply a light oil such as Mineral Oil and sprinkle a generous amount of pummice on the surface of the oil, using a soft oil soaked clothe, rub (till your shoulders and elbows cry) and polish the surface to your liking. It wears down the high points of the finish and will completely erode if you continue. Re oil and polish it dry see what a fine surface you have.

If you want a krisp shinny finish (wet look) then proceed further with rotton stone, some use water and I use more Mineral oil, Sprinkle the wet surface with the stone (WOW it is Black, yep what a mess so put down papers) rub in the same fashion as the pumice but not with the same rag. This finer abrasive will polish the surface to a sharp finish. Depends on your preference and elbo endurance.

Only on fine pieces do I make the effort but it is worth the trouble. This past spring I visited my sister and she asked me to help her refinish her diningroom table. Seems her daughter in law had sat a very hot dish on the table and scalded the finish. It was dull and lifeless and showed as a whitened area when the light hit it. I went to a local WWing store and purchased the Rotten Stone and the Pharmacy to get the Mineral oil. Spread plastic and papers on the floor. Got some old towels and in an hour or so the spot was gone and much glossier than the rest of the table , you could then see the scratches from silver ware and glasses at the other place settings as this area was perfect, had to polish the entire table but it was worth it. What a difference a little elbow grease can do and saved a refinish job.

For purchase, you must go to WWing stores or Catalog sales.

[DanP]

Go here

http://www.ubeaut.com.au/ubhome.htm

Click on Tripoli Powder on the left of screen menu.

The owner of this Forum is the man as far as finishing products go. Do yourself a favour and buy one of everything he has.

Dan

[kiwigeo]

Never heard of grain filling with Pumice but I certainly don't know everthing....

Pumice often used for grain filling Rosewood backs and sides on classical guitars. Procedure is usually to apply a few seal coats of shellac (2lb cut) and then work same with pumice and alcohol using a grinding fad.

Cheers Martin

[witch1]

Go here

http://www.ubeaut.com.au/ubhome.htm

Click on Tripoli Powder on the left of screen menu.

The owner of this Forum is the man as far as finishing products go. Do yourself a favour and buy one of everything he has.

Dan

dan we used to use tripoli in the form of a waxy bar (brick red in colour) to polish brass and copper prior to chrome plating.
the bar was applied to a rag buffing wheel spinning at 3000 RPM (melted right on to the wheel ) then you carefully buffed the brass item to a brilliant finish.
regards , ancient marathoner

[Hickory]

Pumice often used for grain filling Rosewood backs and sides on classical guitars. Procedure is usually to apply a few seal coats of shellac (2lb cut) and then work same with pumice and alcohol using a grinding fad.

Cheers Martin

Okay, so you are not using the Pumice as a filler but as an abrasive to cut the finish and force the slurry into the grain.... I've heard of that, my one track mind was stuck in one gear.

Never done it but have heard that Plaster of Paris is a good filler (they say) as well. Although it is white when dried, application of BLO (Boiled Linseed Oil) will turn the plaster transparent and matches the color of the timber. Alway wanted to try this yet haven't found the project I want to sacrifice for the trial. Perhaps I will do some scrap.

[kiwigeo]

There are a few options available for grain infilling. For guitars epoxy is popular along with hide glue and superglue.

On the classical guitar Im currently (still) working on Ive gone for grain filling using pumice (Behlans 4F grade) but its hard work and it requires a bit of skill to do the job properly. Ill probably try epoxy on the next guitar I finish.

Do a dry run on some scrap wood first. I got my hands on some opportunity grade Indian Rosewood and made up some dummy guitar backs to practise filling and frenchy polishing on.