Beginner looking for advice!

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  • #10109
    keithg59
    Participant

    As a newcomer to the gentle art of glass fusing (I’ve had my kiln for 4 weeks), I would be grateful if someone could help me understand what has just happened.

    I ran a full fuse firing yesterday with various size items from square dish blanks to pendants. The pendants are roughly 3cm x 2cm, were all cut at the same time from the same base and clear glass with a dichroic ‘filling’. On opeing the kiln, the outer 2 pendants, which coincidentally used the same dichroic, were misshapen and on closer examination, appeared not to have fully fused. One short edge on each has fully fused, but the sides mstly look like a tack rather than full. Although they were the outside 2, they were still some 8cm away from the edge of the shelf. All other items fused to the extent that I expected given the firing schedule I used, which was as follows:

    (Temperatures in Celsius)

    Start tempEnd tempTemp changeHold
    Ambient53820010m
    53866325030m
    663804Full15m
    804482Full45m
    48237166
    End

     

    My Kiln is a Kilncare Hobby Fuser II and the glass used was Bullseye 90COE

    I suspect that the hold time at max temperature is a little bit long, but that was deliberate on my part as the plate blanks were made from multiple pieces of glass.

    Any suggestions would be gratefully received!

    #13284
    katkramer
    Participant

    (For those who are shy about converting C into F, this looks like a standard full-fuse schedule, going up to 1479°F, with a bubble squeeze at 1250°F.  Standard stuff.)

    First thing I noticed is that you’re firing pendants and plates in the same firing.  I would actually do two different firings for the two, placing the pendants in the middle of the shelf instead of on the edges.  You didn’t mention the size of the dish blanks, but I would guess 8″ or so?  Are they single or double thickness?   This will make a difference.  If you’re running a full fuse with a single thickness, the edges will pull up.  I’m guessing the dichro pendants were double thickness.

    I looked up the Hobby Fuser, and noticed that it only has elements in the lid.  My kilns either have elements in the side or both in the lid and sides.  I wonder if that might be contributing to the issue…perhaps non-even heating?  I have a small Paragon SC2 that has softer fiber walls, and it fires pendants unevenly unless they’re in the middle of the kiln.  Your Hobby Fuser has kiln brick in the bottom, but I don’t see a description of the sides and top.  I’ve found that the Paragon has hotter spots in the kiln…but in time I learned how to work around that.  I can fire pendants in the middle, or can fire longer.

    My first suggestion would be to fire a little hotter, or hold a little longer, but with dichro you run the risk of degrading the dichro if it’s too hot.  I won’t fire dichro over about 800°C…815°C in my opinion is too hot.  Your hold seems like it’s on the longer side, but I would try to address the issue by increasing the hold and holding the temperature.

    I tend to fire things that are similar together…so pendants ONLY together, and LIKE platters together.  For example, if I were doing a strip bowl that needs a full fuse with a long hold (10mm strips of glass stood on end next to each other), I wouldn’t fire that project with a double-thickness full-fuse plate.  That way you can also learn your kiln.  So if you fire pendants together and you’re having an issue, you’ll learn to fire the pendants longer.  If you’re having a problem with pendants and plates, it’s harder to figure out what adjustments can be made to address those issues.

    Congratulations on your new kiln, and welcome to the “gentle art” of glass fusing!  You’re in good company!

    Kat Kramer
    http://www.katkramer.com

    #13285
    keithg59
    Participant

    Thanks Kat

    Yes, the dish blanks were around 8″ in size, double thickness, so 6mm. The pendants were triple thickness 2mm, so again 6mm in total.

    The sides and floor of the kiln are brick and I put the items on a shelf raised by an inch or so with a layer of thin fire paper. The top is a compressed fibre of some kind and seems to be quite effective at keeping the heat in.

    It’s interesting that the two items that didn’t complete were towards the edge, but other items that were closer to the edge (the plate blanks) fired no problem. I had deliberately extended the hold time at peak by 5 minutes due to the plates being in many parts, but have previously fired successfully with a shorter hold.

    It’s clearly going to be a bit of a learning curve, so I will have a go at a dedicated pendant firing with the pendants more towards the middle and see what happens. I did wonder if putting it all in together was wise – now I know!

    When I work out how, i’ll attach a picture of the items and where they were inside the kiln.

    Keith

     

    #13286
    katkramer
    Participant

    Keith, you sound like a pro already!!

    I used to do a lot of pendants, so I would definitely recommend firing them separately.

    Also, you mentioned Thinfire.  I used to use Thinfire, but if you’re firing pendants, I would recommend shying away from Thinfire, and using kiln wash.  I always thought that kiln wash was a real pain, but I found that the Thinfire was causing a gray haze on the edges of my pendants.  If you are cutting the pieces with a glass cutter, and have sharp broken edges on the glass, it’s most likely not a problem.  But if you are grinding anything, or cutting with a tile saw, the Thinfire paper seems to get into the ground “pores” on the edge of the pendants and cause a problem, especially with full-fused pendants.  I’ve experimented and tried with and without Thinfire, and I got the best results by not using it.  But I was also building slabs of dichro with Tekta over it, cutting on a tile saw, then firing in batches (cost effective if you’re selling them!)

    Again, if it’s cut edges, not a problem.

    If you choose to go the kiln wash route, I could usually fire 2-4 times without recoating.  I just kept the bucket of Bullseye kiln wash and a haik brush near the kiln.  When it started to show cracking on the surface, I would scrape it off with a wide razor paint scraper (don’t forget to wear breathing protection), then recoat.  When I do plates, though, I use both a fiber blanket and Thinfire…I’ve never had a problem with bubbles since I started using that combination.

    A picture would be helpful, and please let us know how your experimentation turns out!

    : )
    Kat

    #13287
    Stephen Richard
    Participant

    Firing afap from bubble squeeze to top temperature does not allow the kiln chamber to fully heat and do so evenly. Slow Dow to about 330C to top

    Stephen Richard

    blogs at: http://www.verrier-glass.blogspot.com/ and  http://www.glasstips.blogspot.com/

    #13288
    keithg59
    Participant

    Thanks for that. I’ll give it a go.

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