Problem with cloudy edges – need advice

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  • #9608
    redcaw
    Participant

    I am fusing glass cabachons, and have started having a problem with the edges – they have a haze on them, and are not forming a rounded shape.  This is a new problem, I’ve fused for years using the same glass and haven’t had this.  I assumed it was a temperature problem, but checked my kiln throughout the last firing, and it was ramping correctly and heating to the correct temperature (1450).  I am using Bullseye shelf paper and was wondering if this could be part of the problem – although there is no dichroic glass in these pieces.  The tops of the cabachons are perfectly clear, it is just the edges that are cloudy.  To add to the mystery, sometimes they fuse perfectly, but every other time I fuse it does this. I have etched and then refired these to fix this, and it doesn’t seem to change anything.  I use moretti glass for these. Has anyone come across this problem?   Any suggestions?  

    #11972
    bookie13
    Participant

    Don’t feel like the Lone Ranger. Almost everyone who does cabs runs into this.

    Are you grinding the cabs before the final firing and getting gray at that point? If you are, that is the main contributor to the problem. I use progressive grits for grinding, being sure to keep the piees in water between each grinding. I use 180, then 400 then 600. At the end I still use a homemade brew of devit agent (see my tutorial on that). Do not have the problem any more.

    I use thinfire and do feel that is a contributing agent, but you can ignore that if you do the better grinding and devit agent.

     

    Barry Kaiser

    Web Site    http://www.kaiserglass.com

    Glass Classes:   http://www.Kaiserglass.com/classes.html

    Tutorials      http://www.kaiserglass.com/tutorials.html

    #11973
    redcaw
    Participant

    Thanks for your response – actually I am not grinding.  And the cloudy-ness isn’t gray, it is clear – as if it has been etched on the edges.  Almost as if something is rising from the shelf and affecting just the edge of the cabachon. 

    #11974
    redcaw
    Participant

    Thanks for your response – actually I am not grinding.  And the cloudy-ness isn’t gray, it is clear – as if it has been etched on the edges.  Almost as if something is rising from the shelf and affecting just the edge of the cabachon. 

    #11975
    Anonymous
    Inactive

    How are you cutting your cabs and are you firing on shelf paper?



    Paul
    FusedGlass.Org
    Helios Kiln Glass Studio
    PaulTarlow.com

     

    #11976
    redcaw
    Participant

    I am cutting the cabs with a glass clipper (not sure what it is called – the ones with 2 circular edges).  Then I etch it before firing.  I am firing on bullseye shelf paper.  Thanks!

    #11977
    Pam B
    Participant

    Pam B

    the etching is probably causing the problem.  Don’t etch the edges and see if this works.  that is why grinding the edges was brought up.  when you grind the edges it looks like you etched it causing a cloudiness unless you thoroughly clean the edges and-or coat with a kiln fire .

    #11978
    redcaw
    Participant

    Thanks – I’ll try these suggestions!

    #11979
    SL
    Participant

    I too just took out some student work and had 1 piece have the edges look cloudy I am not sure why as all the other pieces have turned out perfect, in the same batch. I have to say it must have been the glass, or the student grinding the glass before firing. What other explanation could it be?

    Hopefully we will be able to lap it and it will come off and she can polish it.

    I also think sometimes you can have an area in your kiln that might just be hotter, thus the devit.

    Good Luck in your search for glassy looking pieces.

     

    Just a thought. You said you are using Moretti? If that is true you will run into problems with that sheet glass. It is not as well made as BE, SPEC, and the other fuseable glasses. It does cloud up

    Stacy.

    #11980
    katkramer
    Participant

    I used to have this problem…I was cutting my Bullseye cabs on a tile saw, and firing on thinfire.  I frequently got the cloudy edges.

    I found that if I use a “glass brush” or even a toothbrush and dishwashing detergent to clean the cabs before firing, then fire directly on kiln wash, I get perfect results.  The glass brush is used by enamel artists when they grind down cloisonne enamels, and it gets the tiny particles of glass out of the ground edges.

    #11981
    redcaw
    Participant

    Thanks for all of the great suggestions, I will definitely try the glass brush.

    #11982
    katkramer
    Participant

    I wrote earlier about the glass brush being helpful, but after many different experiments, I’ve found it’s not necessary.  A toothbrush with dishwashing detergent is all I use.

    I also do not do progressive grinding.  I am using a Ryobi tile saw with the QEP Glass tile blade from Home Depot, about $26.  The disadvantage is that the “kerf” (width of blade/cut) is a little wide, but you’ll probably not ever cut your fingers on it.  I do NO GRINDING on my pieces whatsoever.  (I also cut on a small diamond glass bandsaw, but I follow the same cleaning steps for flawless results.)

    I put the pieces in a bowl of water with Dawn detergent in the sink, run the water, scrub the edges of each one with a toothbrush, then rinse, and put into another bowl in the sink full of clean water.  When I’m done scrubbing them all, I rinse the bowl full of glass, pulling out pieces, and putting them on a clean kitchen towel (not paper towels, although this would probably work).

    I now ONLY use a kilnwashed shelf.  Although I religiously use Thinfire shelf paper for other projects, I do not use it for pendants.  I don’t know what happens, but my guess is that the Thinfire creates dust that is attracted somehow to the ground areas of your glass pendants.  I’ve tested this many times, and each time I use Thinfire, I have at least some of the pendants come out with gray haze.

    Although it’s a little more work, the results are worth it.

    Pandora Pendant with Fused Glass

    Kat Kramer
    Kat Kramer Design/Glasskatz
    Denver, formerly Austin!

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