Acetone Application 0

[ldhair]

There will be no issue with residue if you use acetone properly. If you don't know what you are doing, yes, you will leave residue. 

[Miguel del Rio]

On 5/26/2019 at 5:08 PM, ldhair said:

There will be no issue with residue if you use acetone properly. If you don't know what you are doing, yes, you will leave residue. 

Please enlighten us as to the proper use acetone on coins without using a final rinse of distilled water.

Include photos of this procedure, if possible.

Edited May 30, 2019 by Miguel del Rio

[Miguel del Rio]

On 5/26/2019 at 5:08 PM, ldhair said:

There will be no issue with residue if you use acetone properly. If you don't know what you are doing, yes, you will leave residue. 

Further investigation reveals that residue is an issue regardless of the grade of acetone. Maximum non-dissolved solids after evaporation for the highest grade is 5 ppm. The next lower grade, an ACS grade reagent, is 0.001%, or 10 ppm:

Clearly, a procedure involving a successive series of diluting solvents and powerful mixing is required if acetone is to be used. 

Such a procedure is outlined in the response below: 

(In the example above, substrates are suspended in racks on metal clips.)

To accommodate acetone, one would need a ventilator hood, a probe sonication device, a temperature controlled nitrogen evaporator, supply of glass beakers, etc.

The "20 seconds sonication" for each step may require termination upon discovery of solid debris so that the solvent can be refreshed and the coin remain unabraded. Then, the sonication may resume.

A probe sonication device provides about 1,000 times more power than a tub style ultrasonic cleaner, rendering surface tension moot.

Edited May 28, 2019 by Miguel del Rio
spelling

[cladking]

Do not spray acetone.  It is far too dangerous and you could probably blow up your ventilation system if you tried (and maybe if you don't).  

In any case it is certainly highly prone to fire.   

It's a little hard to believe it would be any more effective for cleaning even a tiny minority of coins.  

[ldhair]

14 hours ago, Miguel del Rio said:

Please enlighten us as to how the properly use acetone on coins without using a final rinse of distilled water.

Include photos of this procedure, if possible.

I'll get right on that.

[Coin Cave]

Can I substitute the isopropyl alcohol with Everclear?  They sell 99.9% isopropyl alcohol at electronic stores.  I like it for cutting through cellophane residue.   

[Miguel del Rio]

16 hours ago, Coin Cave said:

Can I substitute the isopropyl alcohol with Everclear?  They sell 99.9% isopropyl alcohol at electronic stores.  I like it for cutting through cellophane residue.   

I have a number of unused 99+ isopropyl alcohol bottles which leave residue on coins.

Walmart's Equate first-aid brand is 91% isopropyl alcohol and 9% distilled water. It's inexpensive and leaves no residue. Not my first test of this brand, though you can never be too sure. Tested this coin using only the Equate alcohol and no distilled water rinse to see if evaporating the alcohol would leave a residue:

Splashed both sides of the coin with alcohol. Dried the coin. No detectable difference from these images taken afterward:

Used a manual drying bulb rather than the pressurized air since the cans of air can leave moisture on the coin in the form of ice which takes even longer to evaporate:

Placed the coin in a hard plastic basket (used for the ultrasonic cleaner):

Dried one side of the coin, then slid the backside of a clean coin flip underneath the coin. Firmly grasped the coin with the coin flip. Removed the coin, then dried the sink and basket with a cloth towel. Replaced the reverse side of the coin facing up in the basket. Gently shook and tilted basket with coin to remove most of the remaining isopropanol. Continued to dry the other coin surface and the basket. 

What appeared to be specs of debris on the coin were actually microscopic bubbles of alcohol which had not yet evaporated.

Repeated a few times until the coin was dry.

Edge of the coin was still a little wet.

Left coin to completely air dry while setting up camera for photos. (if coin is not completely dry, the alcohol will turn the capsule permanently cloudy).

Setup DLSR camera to take closeup images (entry level model cost me $399.99 with accessories). Set image stabilization, auto white balance, auto focus. Used circular polarizer and set light meter to +1 f-stop.

Took pictures under a variety of lighting conditions, occasionally dusting the coin with the bulb.

Photos shown are 1/16th the square area of the originals.

Edited May 28, 2019 by Miguel del Rio