Finishing Buttons and Small Plastics
Buttons are manufactured in several different plastics or can be made from animal horns. It is important to determine the material used in order to apply the correct finishing procedure.
The operations involved include:
- Cutting to remove tool marks or parting lines;
- Refining the surface to remove scratches or roughness;
- Polishing to produce luster;
- Wiping off to remove excess waxes and deposit a sealing coat.
Wet cutting is used for heavy stock removal, using Pumice Grit as the abrasive along with a few ounces of Kramco 1010 General Purpose Cleaning Liquid Finishing Compound to prevent the residue from sticking to the button or clogging its holes. Often a Ceramic Triangle Media 1/4” x 1/4” is added to smooth inside the depressed center. Triangles are added at a rate of 1/3 of the load of buttons. Pumice Grit is added at a rate of 11/2 lb per gross of buttons. Water is added to cover the load by about 2″. Time of run is overnight in a standard 30″ x 36″ wet barrel tumbler or 24 hours in a smaller barrel. When using this process to produce a dull finish on a processed button, the run can be reduced to 2-3 hours and should be followed by a 1-2 hour run in corn cob grit treated with silicone oil.
Dry cutting is used for softer plastics, such as acetate, or materials that will not tolerate an extended exposure to water, such as animal horns or urea. Hardwood Tumbling Media Pegs are loaded into the barrel at a volume rate of three parts Hardwood Tumbling Media to one part buttons, filling the barrel to the 50% level. Dry Abrasive Cream Finishing Compound should be added at a rate of 1/4 cup per 50 lbs of media. Run time is overnight. When using this process to produce a dull finish on a processed button, the run can be reduced to 2-3 hours and should be followed by a 1 hour run in Corn Cob Grit treated with a small amount of silicone oil.
This operation fixes the surface and prepares it for polishing. Shynolyte Pre-Polishing Cream is added to the Hardwood Tumbling Media Pegs at a rate of 1/4 cup per 50 lbs of Hardwood Tumbling Media Pegs. The buttons are added at a rate of 3 parts media to one part button to bring the barrel load to the 50% level. The run is overnight. For harder plastics, such as urea, Walnut Shell Grit is substituted for Hardwood Tumbling Media Pegs because it is heavier and harder.
This operation abrasively polishes the surface of the button so that if the wax is removed the button does not lose its shine. The Hardwood Tumbling Media Pegs (or Walnut Shell Grit for harder plastic) are treated with 1/4 cup of Microlyte Polishing Cream Finishing Compound per 50 lbs of Hardwood Tumbling Media Pegs. Add 3 parts media to one part buttons and run overnight to 24 hours.
After polishing, there will be a wax film residue on the button that must be removed. Hi-Glos Final Cream Finishing Compound is used most commonly with Cob Corn Grit since Hardwood Tumbling Media Pegs will sometimes remove the wax, but deposit a hard film of its own. Using three parts media to one part buttons and running 1-2 hours will finish the button and restore the shine to buttons that have been dyed.
Make sure your barrel is filled to the 50% level. Running a barrel less than 50% full produces more action and may scratch the buttons. Your buttons should have a film at the end of the run. If you do not see a film, use more Cream Finishing Compound.