Cleaning granite precison table

rock_breaker

rock_breaker

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I have a tracktor with wet type multable disk brakes and the left hand one seems to be locked up. After dismantling the brake I washed the disks in Stoddard solvent.
After washing I noticed a stain on the precision block which I thick is from the oil in the solvent. I used a dry industrial paper towel to wipe the stone but the stain is still there. I am considering the use of alcohol or acetone in an attempt to remove the stain. Two questions are Should I not do this and is there a better alternative? FYI The maximum warp in the disks is 0.003" in one friction disk, 0.0015" in two others and two steel fixed steel disks with 0.0015" warpage. the operating camber shaft is in a place that is difficult for oil to get to and I believe it filled with dirt or grime during the past 10 years of operation. Will know more tomorrow after re-assembly. Any help or information will be appreciated.
Ray
 
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Wash the granit plate with soap and water, rinse it off with water, wipe dry with paper towels. Any stain left will do no harm.
 
If you're asking whether the acetone or alcohol will damage a natural granite surface plate, they should not. However, simply wiping or flooding with the solvent may not remove the stain but rather drive it in further.

A more effective method is to use the appropriate solvent in a poultice. Simply put, the poultice is a dry, inert material (diatomaceous earth is commonly used) and it acts as a carrier for the solvent. As the solvent evaporates, the poultice material also dries and as it does it draws the "stain" out of the host subject. Sometimes it takes a couple tries, but if you have the correct solvent it is usually effective. I have cleaned a fair bit of architectural stone, both polished and unpolished, with poultices and various solvents. When you hit it right, the process is almost like magic. Natural granite is a very porous material, so actually responds quite well to this process.

As Tom says though, the oil stain isn't going to affect the accuracy of the plate, just the appearance. And given a bit of time, it will fade in quite a bit anyway and not be as noticeable. And in fact, if you have wiped it down with a solvent in trying to remove the oil, you may be seeing the blush left over from the solvent absorbed into the stone and not the oil itself anymore. Give it a day or so to dry before making any decision for more intervention.

-frank
 
In my considerable experience, a tractor is not a precision machine, requiring white gloves to keep it working properly. That said, they can be quite expensive, both to buy and to keep in good working condition, so your care and concern is correct. Cleaning and then rinsing the brake parts with Stoddard solvent, then letting them dry before lubricating for reassembly would likely be appropriate. The bigger concern is with scrupulously keeping contaminants out during reassembly. Not knowing the exact brake system on your tractor, I cannot comment on the diagnosis of what is causing it to lock up. The local dealer is your best source of knowledge on how to proceed. Making friends with a well respected tech at the dealership is always well worth its weight in gold...

I would not use paper to dry the parts, paper is a contaminant in a hydraulic system. I would use high pressure air only.
 
francist said:
...
A more effective method is to use the appropriate solvent in a poultice..
...
-frank
Click to expand...

Starrett has a cleaning product for surface plates that is a solvent. I think it's mostly an industrial grade of ether. Well, used to be anyway, not sure nowadays...

MK
 
Meta Key said:
Starrett has a cleaning product for surface plates that is a solvent. I think it's mostly an industrial grade of ether. Well, used to be anyway, not sure nowadays...

MK
Click to expand...
The OP is working on a tractor brake system, not a granite surface plate... ;)
 
Oops!

What would the real "precision block" be made of?

-f
 
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