Sandpaper on Bonsai Pots?

Messages
2,776
Reaction score
15
Location
Michigan, USA
USDA Zone
5
I just read a discussion on another forum where it was recommended to use wet sandpaper 0000 grit or steel wool to remove stains from bonsai pots. Needless to say I am quite skeptical of this advice and would certainly never consider doing so on my own pots, some of which are very expensive, some of which are old, and some of which have a slight patina.


What do you think of this advice, of which it was said that many bonsaists do so?




Will
 

Tachigi

Omono
Messages
1,201
Reaction score
32
Location
PA.
USDA Zone
6b
1000 grit sand paper which is less abrasive than a scotch brite. This used for clear coat finishes on cars and boats between layers. I have personally used it on unglazed finishes with no ill effects. One day if needed I would try it on a glazed pot. To date there hasn't been a need for it. Keep in mind that a wet piece of 1000 grit will cut faster than a dry.

As for steel wool? Personally I'd stay away from it. Not because of scratching, but because of staining. I once had an employee that decided to use a fine steel wool on some fiberglass to remove a stain. He got the stain up but over the weekend the area scrubbed stained a rusty color due to the fine bits of steel wool oxidizing from the moisture used to scrub with and the morning dew. Needless to say a lot more scrubbing was needed in addition to a chemical treatment.

Will, I would suggest if you want to test this theory. Take a piece of glass and a 1000 grit piece of sand paper and sand the glass. This experiment will tell all.
 

bisjoe

Yamadori
Messages
85
Reaction score
0
Location
Sammamish, WA
USDA Zone
8B
Wet sanding is done safely on cars and other painted finishes. I use both wet sanding and steel wool at times in woodworking. If it's not overdone, with proper grits, it shouldn't harm the pot finish. Still, I think I'd first try an automotive rubbing compound which is used to remove swirl marks, it's a paste and much less likely to go too deep and scratch the surface or remove the finish. I've used it on the kitchen sink.

With expensive/rare pots like yours it's still best to try a non-abrasive approach to cleaning first.
 
Messages
2,776
Reaction score
15
Location
Michigan, USA
USDA Zone
5
Will, I would suggest if you want to test this theory. Take a piece of glass and a 1000 grit piece of sand paper and sand the glass. This experiment will tell all.
Oh, I don't want to test it at all. ;)

Pots and automobile finishes are not the same thing, by a long shot...using wet sandpaper on a automobile surface is usually a prelude to putting on the finial layer of paint or finish, I know of no body that would wet sand their car to "clean" it.

The point I think I was unsuccessful in making is that even if this did not ruin the finish of a pot, glazed or unglazed, it certainly would the patina. So you have a old pot, nice patina that needs cleaning, you would take a piece of sandpaper to it, no matter how fine?

For my pots that are not so valuable or which I could care less about a patina on, I have personally found that "Soft Scrub" works well with some good old fashioned elbow grease. I have never once noticed a mark left on any surface (including aquarium glass) using this product. For my other pots, regular wiping with a old diaper or t-shirt not only prevents such build ups, but also polishes nd creates a patina over time.



Will
 

Graydon

Chumono
Messages
717
Reaction score
7
Skip steel wool and look for bronze wool. Same "grits" with no irritating steel stains.

Mirka makes a great product call Abralon. It's like a wet paper but on a cushioned fabric backing and is designed to remove blemishes in clear coats and polish Corian. Works great on all types of finishes and I have even polished acrylic to nearly a glass finish. The "grit" rating on this stuff is not the same as regular paper (i.e. 180 Abralon is much smoother than 180 peel and stick paper).

The 3M Scotch Brite pads come in may "grits" as well.

I call the stains patina and leave them alone for now. I have waxed unglazed pots to soften the look and push back the stains. Beeswax, turpentine and linseed oil mix I use on wood.
 

BonsaiWes

Mame
Messages
128
Reaction score
1
USDA Zone
7
Olive oil and a rag works for me, the oil loosens the grit and grime, lime build up etc. Sometimes a chisel is needed to get the older and harder lime build up, but being mindfull when chiseling is easy.
 

Rick Moquin

Omono
Messages
1,245
Reaction score
8
Location
Dartmouth, NS Canada
USDA Zone
6a
A little olive oil and 1000 wet/dry sandpaper = a polish. Any type of lubricant used with sandpaper results in a smooth finish. I have done it on my pots (unglazed), and have used it extensively in woodworking. As a matter of fact I prefer a hand rubbed oil finish to any lacker or varnish.

When it comes to patina, once stain free, rub your pots with the coarse side of leather and olive oil, you won't believe the results. The side effects of this practice, the oil will harden off and fill the pores and the pot will be harder to stain. Wax on a car for the lack of a better metaphor.
 

Vance Wood

Lord Mugo
Messages
13,600
Reaction score
15,709
Location
Michigan
USDA Zone
5-6
If your issue is as Will has put it, not wanting to ruin or change the patina I would not use steel wool, bronze wool or even 2000 grit emery cloth. Regardless of how fine a product is it is still scratching the surface and in essence changing the surface. The human eye is not sensitive enough to distinguish the infinitesimally small scratches these products produce but they are scratching out and evening out the larger surfaces scratches, imperfections and, in this case, caked on salts and calcium deposits. By profession I am a furniture finisher, I work with this kind of stuff day in and day out and have done so for forty years. I guarantee you that 1000 to 1500 grit sand paper/emery cloth does indeed sand off a very small portion of the finish. Some of the finishes we are encountering today are so thin that you cannot use even 2000 grit or you run the risk of cutting right through to the wood in a couple of strokes.

Try WD40, I think you will be amazed at how well this works.
 

Vance Wood

Lord Mugo
Messages
13,600
Reaction score
15,709
Location
Michigan
USDA Zone
5-6
A little olive oil and 1000 wet/dry sandpaper = a polish. Any type of lubricant used with sandpaper results in a smooth finish. I have done it on my pots (unglazed), and have used it extensively in woodworking. As a matter of fact I prefer a hand rubbed oil finish to any lacker or varnish.

When it comes to patina, once stain free, rub your pots with the coarse side of leather and olive oil, you won't believe the results. The side effects of this practice, the oil will harden off and fill the pores and the pot will be harder to stain. Wax on a car for the lack of a better metaphor.
By doing this Rick you have changed the original Patina. Patina being the resulting small scratches and smudges produced by years of use that are not considered objectionable.
 

Rick Moquin

Omono
Messages
1,245
Reaction score
8
Location
Dartmouth, NS Canada
USDA Zone
6a
By doing this Rick you have changed the original Patina. Patina being the resulting small scratches and smudges produced by years of use that are not considered objectionable.
Patina is a fancy word for the build up of crud by manipulation, if it is wanted as such then by all means. On the other hand a patina can be built as suggested, and most unglazed pots go through the process I described before being exhibited anyway.

... the last time I checked no one views pots under a microscope. Sooooo if these minuscule scratches are not discernible by the naked eye, what's your point, besides being argumentative. Fine French polish on furniture is in no way related to an unglazed (rough textured) pot, regardless how smooth the surface may appear. If you have been a furniture refinisher for 40 years then you know a "French polish" is the act of raising the grain, removing the filaments raised with mild abrasion and then burnishing with a suitable medium and applicator. These types of finish are in no way as hard as let's say a polyurethane but extremely durable, and smooth, free of blemishes if done correctly and corrected with the original method should they become marred.
 

Vance Wood

Lord Mugo
Messages
13,600
Reaction score
15,709
Location
Michigan
USDA Zone
5-6
First of all Rick I was not being argumentative, second of all have I done something to raise your ire? I get the impression from you that I am not entitled to voice my opinion,--in your eyes.

Thirdly the way I apply a French Polish does not use an abrasive in the process. The polish is achieved by very light smooth applications applied one on top of another, with a lightly saturated pad until a glass like finish is achieved. The only time an abrasive is used is when you get in a hurry and wind up with some debris in the finish. I might add that most of the time in today's market a French polish is too expensive a process due to the labor involved to make it commercially viable. Fourth point a furniture finisher does not spend most of his time applying a new finish to a piece of wood but gets the unenviable task of trying to repair a finish that has become damaged but may still be salvageable.

Fifth and final point was to point out that an abrasive no matter how fine it is, is still removing a portion of the original surface regardless of how fine it may look in the end or how miniscule the removal of product is. If this makes no difference to you by all means sand away, some people may find it to be a critical bit of information to understand what is really happening.

As to the WD40 by all means be carefull not to apply it to your prized pot and then strike with a five pound sledge. Just for the sake of saftey never ever check to see if there is gas in your gas tank by throwing in a lit match.
 
Last edited:

Rick Moquin

Omono
Messages
1,245
Reaction score
8
Location
Dartmouth, NS Canada
USDA Zone
6a
Thirdly the way I apply a French Polish does not use an abrasive in the process. The polish is achieved by very light smooth applications applied one on top of another, with a lightly saturated pad until a glass like finish is achieved. The only time an abrasive is used is when you get in a hurry and wind up with some debris in the finish. I might add that most of the time in today's market a French polish is too expensive a process due to the labor involved to make it commercially viable. Fourth point a furniture finisher does not spend most of his time applying a new finish to a piece of wood but gets the unenviable task of trying to repair a finish that has become damaged but may still be salvageable.
The use of a mild abrasive was in conjunction with a lubricant as I previously mentioned, to remove the stains. As we both know adding lubrication will reduce marring of the finish. When it comes to "French polish" of course no abrasives are used after the initial final sanding which is normally carried out wet (oil). Then the wood is polished (burnished)to a high gloss with the medium contained in coarse cheese cloth. Although not an abrasive as such, cheese cloth does hold some a certain abrasiveness nonetheless. When it comes to a pot an application of oil with the back side of the leather will indeed render beautiful results. These results will become richer and deeper over time.

... and yes the time it takes to render a "French polish" is unmarketable these days, hence the use of polyurethanes and lackers.
 
Messages
271
Reaction score
2
Location
Scandinavia
USDA Zone
3b
A "french polish" sure isn't cheap in some parts of Amsterdam, but I wouldn't call it unmarketable:eek:

Lighten up!
 
Messages
2,776
Reaction score
15
Location
Michigan, USA
USDA Zone
5
In the end, mineral buildups, stains, and other discoloration of the pots is the result of lack of care, I think. Taking the time to wipe down your pots with just a plain Cotton cloth on a regular basis will prevent having to use such drastic measures.

Sandpaper of any grit seems a little drastic, I think I'll stick to Cotton and elbow grease.


Will
 
Messages
1,773
Reaction score
12
Location
Ottawa, KS
USDA Zone
6
Patina is one thing. Large lime deposits is something else entirely. I envy Boon in that he lives in the Bay area, where one day of frost a year is a rough winter. All his pots remain under the benches, where runoff from watering gives them a soft glow over time. A good patina is a beautiful thing.
 
Top Bottom