Friday, January 18, 2013

More on HABRAS Disks for Polishing Jewellery


Since writing my post umpteen years ago about my original 19 mm set of Hatho Hasbras Disks, I have picked up a few more tips for when using these delicious and important tool of polishing jewellery.

They are still to date my absolute favourite polishing tool in my workshop for the fine polishing requirements, especially when aiming for a mirror polish.





Important tip #1: First and foremost - do not use these disks any faster than 5000 RPM! 

They shred apart.  Bristles go flying in all directions.  It's very sad to see your expensive 4 disk wheel (High Polish wheel in this photo) reduced to something beyond useless.  Thankfully the mandrel is a screw top.  Now to find a supplier I can order replacement disks from...




Important Tip #2: 25 mm cover a lot more area and takes more metal away quickly than 19 mm wheels.  Be cautious when using the first time.  Thankfully their colour system is standard across all sets and sizes of Hatho Habras  3m Rubber wheels (except for the course bright yellow and the extra fine bright yellow!).


25 mm Set Wheel Description 
I bought what I thought were replacement wheels after a few of my important 19 mm wheels lost their spokes.  I ended up going to a store in the UK (it's been so long I don't even remember WHO I purchased the bigger wheels through) and the sales person convinced me to buy the slightly bigger wheels as the larger wheel diameter would make polishing easier.  Seemed logical.

When I received the wheels, they were individually packed with only the Hatho Manufacturer product code as a label.  From left to right, I have placed the wheels in coarsest at left to finest at right.  Labeled left to right below taken from the Hatho General Product Catalogue (pages 28) ["grit" meaning Sand Paper Grit equivalent]:
  • 909 25(3) - Colour Brown.  Extra Course, Grit 36.
  • 908 25(3) - Colour Dark Green. Very Course, Grit 50.
  • 901 25(3) - Colour Bright Yellow. Course, Grit 80. (Not photographed).
  • 905 25(3) - Colour White. Medium, Grit 120.
  • 902 25 (3) - Colour Dark Pink/Red.  Standard, Grit 220.
  • 903 25(3) - Colour Blue. Fine, Grit 400.
The best "polish" you can achieve using the thicker wheels is a course matt finish akin to what you would achieve using 400 Grit sand paper.  The Mandrel diameter was identical to my older 19 mm set.

To show how these 25 mm disks differ in size and look, here is a close up comparing the "blue" wheels in both 25 mm and 19 mm sets.

The wheel on the left is the 25 mm wheel, notice how much thicker the bristles are.  The wheel on the right is the same blue, but part of the 19 mm set and finer bristles

19 mm Set Wheel Description
In comparison, below is my older, small wheel of 19 mm set.  The bigger 25 mm wheel is just in the photo to compare the sizes.  
  Labeled left to right below taken from the Hatho General Product Catalogue (pages 29):
  • 901 19 - Colour: Bright Yellow. Course, Grit 80
  • 905 19 - Colour: White.  Medium, Grit 120 (not photographed above).
  • 902 19 - Colour: Dark Pink/Red. Standard, Grit 220 (Same colour as 902 25 above).
  • 903 19 - Colour: Blue. Fine, Grit 400.
  • 904 19 - Colour: Pink. Very Fine, Grit "Pumice".
  • 906 19 - Colour: Bright Yellow. Extra Fine, Grit "High Grade Corundum 6 microns" (not photographed).
  • 907 19 - Colour: Light Green. Ultra Fine, Grit "High Grade Corundum 1 micron".

Complete List of both Sets
 So to put both products in a complete list rated by Grit (Bigger Wheel first).

  • 909 25(3) - Colour Brown.  Extra Course Grit 36.
  • 908 25(3) - Colour Dark Green. Very Course Grit 50.
  • 901 25(3) - Colour Bright Yellow. Course, Grit 80. (Not photographed).
  • 901 19 - Colour: Bright Yellow. Course, Grit 80
  • 905 25(3) - Colour White. Medium, Grit 120.
  • 905 19 - Colour: White.  Medium, Grit 120 (not photographed above).
  • 902 25 (3) - Colour Dark Pink/Red.  Standard, Grit 220
  • 902 19 - Colour: Dark Pink/Red. Standard, Grit 220 (Same colour as 902 25 above).
  • 903 25(3) - Colour Blue. Fine, Grit 400
  • 903 19 - Colour: Blue. Fine, Grit 400.
  • 904 19 - Colour: Pink. Very Fine, Grit "Pumice".
  • 906 19 - Colour: Bright Yellow. Extra Fine, Grit "High Grade Corundum 6 microns" (not photographed).
  • 907 19 - Colour: Light Green. Ultra Fine, Grit "High Grade Corundum 1 micron".

Benefits of the Difference Sizes

The 25 mm wheels are thicker, so seem to bite more into the metal when using.  For example, say you polish the same piece of sterling silver with the same colour wheels for same length of time, just in two different sizes.  The 19 mm wheel with finer bristles will file away less metal and seems to leave less deep scratches.  The 25 mm wheel with sturdier, thicker bristles definitely files away more metal and leaves deeper scratches.

So if you want to file away a lot of metal, you are better off using the 25 mm wheels.  They are more rugged and sturdy, and won't wear out so quickly.  The other thing to remember, since the wheels are bigger, to slow the RPMs down a bit.  The larger wheel tips will travel faster than the smaller wheel tips at the same RPMs.

The 19 mm wheels are more fine and less robust, so perfect for handling filligree and delicate projects.

The important thing is while technically the large and small wheel of the same colour are also the same Grit, the larger wheel is going to take away a lot more metal quickly than compared to the smaller wheel - which gives the impression that their "Grit measurements" aren't similar at all in performance.

That said, I used both wheels while polishing up this ring and each had its benefits.  I used the thicker wheels to help file back the lip on the bezel setting, get into the sharper big corners that need filing and smooth out the bigger scratches on the ring shank.

Then I switched to the finer wheels when I needed to polish the bezel with the stone set to get rid of my scratches.  Also the bigger wheels do not go fine enough in Grit to get a high polish so I needed the finer wheels too.

Also the finer wheels are small enough to file inside the ring shank.


Hope you found this helpful!

If you have any questions feel free to contact me at amandajewls@gmail.com or visit my website www.yourjewellery.com

1 comment:

Anonymous said...

Thanks for the tips. Very valuable information!