Powder Line Medium

Richard La Londe: Fused Glass Art and TechniquePowder Line Medium (PLM) is the generic name for a material that compares with the commercial product "Liquid Stringer".

This recipe shows how to make your own PLM for a fraction of the price of the commercial version.  Credit for this recipe goes to Richard La Londe who is widely credited with refining (if not originating) this technique.


  • 1/4 cup CMC
  • 2 cups water (distilled preferred but not required)


  • Boil water.
  • Add CMC, stirring in slowly to minimize clumping.
  • Stir until mixed.  There will be lots of lumps at this point - that's okay.
  • Allow the mixture to sit and cool for 24 hours.


  • CMC is used as a food additive and is non-toxic.  This recipe can be safely prepared in your kitchen.
  • CMC consistency varies among manufacturers.  You may need to experiment if you are not getting the consistency that you want.
  • This mixture can be thinned by adding water.  It cannot be thickened by adding CMC. This is why many people choose to intentionally mix the PLM extra thick and thin as needed.


  • Mix the PLM with glass powder in a squeeze bottle.  Squeeze to apply onto sheet glass.
  • Exact ratios of powder to PLM will vary due to the inconsistent nature of CMC, the variety of powder particle sizes and more. More powder and/or PLM can always be added to adjust viscosity.
  • When firing the glass consider adding a 30 minute hold at 900°F to allow the CMC to burn completely before the glass softens significantly.



What is the full name of CMC? Where do you purchase it?Bev

Hi Bev.  CMC is Carboxyl

Hi Bev.  CMC is Carboxyl Methyl Carbohydrate.  You Asked!

Some have found it at a local bakery (it is used as a thickener in foods).  It is also available at most Ceramic supply houses.  Tip: buy the 1lb bag, not the 5 lb.  From my personal perspective, the 1lb bag will supply 3 generations of glass artists.  The LaLonde recipe using 1/4 cup of the CMC powder will make enough to last the rest of your lifetime. 

Note also that since this is an organic gel, it will develop mold in a few days if left to sit out.  Some keep it in a Rubbermaid container in the refridgerator.  When I mixed my batch 6 months ago I added 1 tablespoon of isopropyl (rubbing) alcohol just before the "let it set 24 hours" step and stirred it in.  I keep it on a shelf in the shop with my glass powders and it has not developed any mold. 

If you use the CMC gel, without thinning it with water, you can make a glass "clay" that will add a whole new dimension to the stuff you can do. 

Have fun!!!

Joseph 2bears, Lomita, CA

 Excellent! I can't wait to

 Excellent! I can't wait to try this! Thank you!


Hi Joseph, Thanks for the info on the CMC. My next trip to the big city, I'll see if I can find some to experiment with. Another question that pertains to Ledger Art. Do you know what that is? I want to paint some Ledger Art on some glass discs as I  am intrigued by Native American styles of art, of which there are many.There is a Native American Artist named Michael Horse who lives in the San Francisco area who has added Ledger Art to his many other talents.There is a collection of Ledger Art housed at the Southwest Museum of the American Indian in Los Angles. Michael does his Ledger Art on old sheet music or maps. I thought how cool it would be to do some of this art in glass, that would last a lifetime.I'll send you some pics if I am ever able to develop this. Bev

Hi Bev.  To my knowledge

Hi Bev.  To my knowledge the Southwest Museum does not have any of Michael Horse's ledger art.  The ledger art of Howling Wolf (Southern Cheyenne) and Ho-Tom (Kiowa), both in the 1870's, is housed at the Autry National Center, which is affiliated and linked with the Southwest Museum. 

Michael Horse is a current artist, and his work is, of course, copyrighted.  If you want to copy his work you should seek permission from the artist.  The much older works, which are in the public domain, such as those of Howling Wolf, are preserved in museums.  I would suggest that you work with the museum housing the collection rather than just striking out on your own out of respect for the art, artist, and those working to preserve the art. 

I do have to admit that I have had a desire very similar to yours.  My personal approach is to study the ledger art from different nations, understand the symbols, subjects, costumes, and nuances, and then create my own art in a particular style, or composit style that is uniquely my own, but readily recognized as ledger art.  My feeling is that this approach honors the work of the grandfathers without "stepping on toes" so to speak.  It also avoids the possibility that my inadequacies as an artist would desicrate the work of others.  And I would be blessed and guided by their Spirits if I took the time and made the effort to understand and fully appreciate what they have left for us. 

While I have thought about this, I have barely begun the study phase.  I am busily chasing other rainbows at the moment.  I was not aware of Michael Horse until I saw your response.  Thank you for bringing his work to my attention.  Good luck with your endeavors.

--Joseph 2bears

ledger art

Hi Joseph, Thanks for your wonderful and informative words. No, I know that Michael Horse has no work in the SW Museumof of the American Indian. He has only gone there to research ledger art. His current work is probably in some gallery that represents him. He began doing Ledger Art in 1996.I have only been able to research Ledger Art on the web, as most of it is in collections far from where I live in Texas. The work is all copyrighted for sure and any work on my part would be my own personal interpretation of the Art. I found out about Michael Horse in the August 2008 issue of Southwest Art Mag. I am still toying with just how to apply my ideas of Ledger Art to glass, but, right now, I'm trying to work out the problem of too many bubbles in my glass with copper inclusion. Your Fusing Friend,Bev

Problems with the liquid medium

Hello everybody,

I am trying to use the powder line medium (CMC based one) and my lines keep shrinking.  Does anyone knows what I am doing wrong?


Ana Paula


Is CMC Gum the same thing  ? Can I use it the same way? Does it change the recipe any? Thanks a million



CMC Gum is a misused very confusing term.  I think it started in the food industry where CMC Gum is mostly defined as Sodium Carboxymethylcelluose.  That is CMC with salt added.  Today you can find CMC Gum with sugars added in the food industry.  And then there is the ceramics industry where CMC Gum can be anything from plain CMC to CMC with Xanathan Gum or even Gum Arabic additives.  And finally we get to Glass where Delphi Glass is selling "CMC Gum" which appears to be just plain CMC.  I think what we want for Glass is just plain CMC without salt, sugars, or other adhesives.  CMC is derived from plant fibers, mostly cotton lint.  It burns out cleanly, leaving no residue at fusing temperatures.  Gum Arabic will also burn out cleanly.  It is used in glass painting.  Salt and sugars will not burn out cleanly so stay away from that stuff.

If you are buying "CMC Gum" inquire as to what you are getting, particularly if you are getting it from the food industry.  If you are getting it from a ceramics or glass supplier you are probably OK, but you should still ask what you are getting so there will be no surprises.  Realize that with all the confusion in terminology between at least three industries, your supplier may not know just what the heck they bought and are reselling.

--Joseph 2bears, Lomita, CA


I just baught some CMC from Columbus Clay, they didn't have the powder, they called what they had GEL. Do you think this stuff will have ingredients listed since it is not from a food supply?



Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.