Cold Working a Murrini Vessel

May 03, 2018 2 Comments

Cold Working a Murrini Vessel

Cold working glass is an art that can be learned and finishes your work. I will walk you thru my process. I am sure there are many other ways to do this on a wet belt sander or by hand but I prefer a wet lap. After a learning curve it is my go to method. My wet flat lap is a 12 inch variable speed unit from covington engineering. I had them make the stand higher as I am so tall. Flat laps are a big ticket item but worth it for me as I use it on most of my work.

The story of a funky vessel.... You may want to repeat !

This vessel happened because I did not watch the controller after I asked it to stop heating. (I was writing a blog). so I was left with a funky fun shape with possibilities. When I fused the original blank it also had a blow out as the ring was a small amount off the kiln shelf. No issues, as I cut the peg off with a tile saw.

You can look closely on the bottom left  how the round ring slid over the shelf a very small amount before I closed the kiln.  Take pictures of your kiln pre fire and you can figure out issues like this,
You can see how the design was distorted on the right side.

Here is the bottom of the blank and how the glass flowed over the kiln shelf.
This is easily fixed with a tile saw, but in hindsight double check your blanks before firing.
You can see what happens when you overheat.  Make sure when you advance your controller that it accepts this  command and do not walk away. ( or concentrate on writing a blog)  I think I may repeat this over drop in the future. Beware that the sides of the glass vessel are very thin and can crack easily. 

So lets get this finished and see what happens.

If you look closely at the rim of this vessel you can see the polishing compound has migrated into a stretched bubble.  If you know how to remove this please let me know. I have tried a spay jet and soaking it in water and alcohol.  No luck so for this reason I do not polish edges to a mirror finish and stop at a 220 g resin wheel or cone. 

This u-tube video show how I use a diamond wet saw, and how not to use a flat lap( way to fast), and then how to cut rim with a diamond cut off disk. Here is where I buy the diamond cut off disks.  click on link and it will redirect you to amazon.  Be sure if you use a Dremel or Foredom tool you keep water and the motor separate.  Be sure it is grounded and wipe water off the tool when done.

The wall thickness is very thin as you move away from the top.  Here I use a jewelers caliper to measure the rim thickness.  If it is to thin it will make the likelihood of a break in the glass when you try and cut it off.  For those thin vessels I leave a rim and cold work the edges.  Below is a digital version I like because you can measure deeper into a vessel and its digital. Click on links below and it will send you to Amazon if you wish to buy.

There is a new video by Nathan Sandberg found at AAE glass videos on his technique for finishing a drop ring vase. It is excellent and came out after I wrote this blog.  Well worth watching.
Here is the link if you are interested in buying this saw.
I find that if I center the vessel on the disk I get less chatter than if I put the vessel eccentrically on the disk.  Try and move around the disk as you want even wear.

Next I install a diamond fine cone 

A diamond water cone is a great way to finish the insides of vessels. Be careful to keep cone cutting on one  the side of the glass.  Never try and cut around the entire cone as it will become stuck and may throw your work and worse! A conical cone will not bind as easy.
If you do not have one you can do this by hand with diamond pads.  They come in many different sizes, I like these as they are flexible and work on small vessels. ​If you click on the link below you will be sent to amazon and cay buy these.
I decided to sandblast the interior so that I would get a backdrop for the murrini pull.  I like the effect and it adds a softness to the work.  I have a blog on sandblasting that may be helpful to watch.  click here and you will be redirected to this blog.
If you click on the link below you will be sent to amazon and you can buy these.
I would love your feedback. Leave me a comment and I will get back to you. Thank you.

2 Responses

Al Heilman
Al Heilman

July 30, 2019

You can buy cones for the Covington flat lap from Covington engineering or HIS Glass. I am sure glass sellers may sell cones as well.Here are the links

Merryl Sacher
Merryl Sacher

May 09, 2019

Hi Al
Thank you so much for sharing your knowledge and process. I am currently learning how to finish drop vessels, and this has been very helpful. Do you know where I can buy cones from? I was struggling with finishing the inside of the vessels well. Thank you! Merryl

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