Sunday, November 2, 2014

Kiss My Glass! (Slumping a bottle to make a cheese-server)

Holy sh*t! This post contains CONTENT! (and minimal rambling)

Okay, maybe a little bit of rambling!  Been doing a fair amount of "Art Glass" dabbling - whenever I can find a Groupon for Bay Area Glass Institute (Love BAGI!).

One project that intrigued me was glass slumping.  I have a kiln, so might as well try it!

Been thinking about it for a loooooong time - which is probably a good thing because it allowed me to "hoard" quite a few Skyy Vodka bottles in the garage!

Much web-surfing was done, and many bottles were hoarded.

A few sites with good info:
-Warm Glass
-Big Ceramic Store  - I mostly followed this one
-Fused Glass - Quite a few simple projects here

If you Google glass-fusing and/or bottle-slumping, there is a ton of info out there.

I wanted to keep it simple, so I figured I'd start with bottle slumping.  No need to worry about COE's and other "details" - just bake a bottle 'til it's flat.

And since my kiln is a ceramic kiln (as opposed to a glass kiln, which has more heating elements - including elements in the kiln-lid), I mostly stuck with the info from Big Ceramic Store.  I started with one of their "recommended" firing profiles (but I tweaked it, a bit).

Okay, so anyway, here is what I did for my Very First Bottle Slump:

  1. I'm using 1.75 litre bottles, and the height of the bottle - laid on it's side - was pretty much *exactly* the diameter of my kiln shelf.  This made me nervous because, as the bottle flattens, there's a strong possibility that it's gonna extend beyond the edges of my *round* shelves.
  2. As I was Googling "Bottle Slump" Images, I really didn't like the way the base of the bottle slumped upward, and flopped over.
  3. Being cognizant of #1 and #2, I decided to buy a bottle cutter from Amazon (Affiliate link - but I've yet to see a penny!) and sliced about an inch, to 1-1/2" off the bottom of the bottle - figuring I'd end up with a nice flat cheese-tray, and a nifty round disk that could be used as a trivet, or wall-hanging, or something.

    So I have to say that - even though I was dubious of this cutter - it did a pretty good job of scoring the bottle properly on the first try! It was a little nerve-wracking to put together, and the included instructions were a little wonky, but it did the job!

    Important hint:  Do the boiling-water/ice-water dunk after scoring it.  Mine broke off clean after about 3 dunks.

  4. Remove the labels from the bottle (no, they aren't painted-on, they're clear plastic labels that *will* turn black if you leave 'em on).  Google has dozens of different suggestions for label-removal.  I found that scraping the label off (after soaking in hot, soapy water), then hitting it with rubbing alcohol did a pretty-good job.  Keep rinsing, drying, inspecting, re-alcoholing (lather, rinse, repeat) 'til you confirm you got ALL the residue off.  You want NO adhesive residue and NO finger oils on the glass.

    Add'l helpful hint: Remove the label *before* you cut the glass.  That raw edge was kinda scary!  I also wore Nitrile surgical gloves for the final cleaning and kiln-loading - so no finger-oils to smudge things up!
  5. Prep the kiln shelves.  I had previously slathered my kiln shelves with kiln wash from the local Clay shop - but much of it was flaking off.  I chose my "smoothest" shelf, and mixed-up a fresh "light-slurry" of kiln wash and re-applied it.  Then dried it with a propane torch, then attempted to smooth the surface using a green scruffy pad.
  6. Load the kiln.  I knew I couldn't fit both the bottle and the base on one shelf, so I put the base on it's own shelf - toward the middle of the kiln (it didn't get as warm).


    Okay, so I was *super* paranoid about squish-age and glass-running, so this is on 2 pieces of fiber-paper, *and* a mini kiln-shelf, *and* a regular kiln shelf (with extra kiln-wash splooged-on!)
  7. Load the top shelf - leaving extra space at the "bottom" end of the bottle.  Insert a high-fire-wire into the neck (optional - if you want to have a hanger).

  8. Program the kiln:  I took one of Big Ceramic Store's profiles and added a couple extra segments - to include an annealing phase (annealing is where the glass is "held" at a high-ish temperature.  It should prevent the glass from cracking from thermal shock during the cool-down).
  9. In case you're interested, this is the firing profile that I plugged-into the controller:

    Segm# Rate      Degree     Hold
    1          500       1100         10m
    2          250       1300           0m
    3          300       1425         10m
    4          500        970          20m
    5          120        750          10m

    My kiln is an AIM model 1413/2 (runs on 2 x 120V, but will reach Cone 10), with a Bartlett V6-CF programmable controller.  No clue what the capacity is, but definitely less than 3 cubic feet, I'm sure.  Nevertheless, it's not a tiny kiln - there's a fair amount of "space" to heat-up in there...

    BTW - I don't recommend this firing profile (for reasons described below).  But I'm keeping copious notes and tweaking as I go.  Eventually, I'll hit on the *Perfect* firing profile!
  10. Run the kiln and try to find something else to occupy your mind for the 7+ hours it takes to cook (and another 5-6 + hours to cool-down!)
  11. Get impatient in the wee-hours of the morning, grab a flashlight and run out to the studio to sneak a peek!  Then close it again and allow it to cool naturally!


    Ooh! Ooh!  Looks encouraging!
  12. Wait til morning to get a GOOD look at it - and confirm that you don't have glass FUSED to the kiln shelves! (Yay!  I didn't!)


    Indoor shot.
Bottom-side
(No, I have no idea why the picture placement is wacky!)

Top-side, in the sun.

Thoughts/Observations:

For this being my first attempt at slumping a bottle, I'm actually pretty happy.  No, it's far from perfect - but I did err on the side of caution (better to have an under-slumped bottle than a ruined kiln!).

The bottle got more heat, so it slumped more - but not quite enough.  I do like how the handle "folded" as it slumped (at the neck).  I don't like the "fold" about 2/3 of the way up.  Also, the bottom end (where the bottle was 'open') didn't really slump/seal together which would make me hesitant to sell this as a food-serving piece (No, I won't be selling this one!).  Lastly, I did get some pesky air-bubbles (which can almost be seen in the sunshine shot).  Not sure what I'm gonna do to prevent those.

I like how the base collapsed into a circle.  I was afraid it would be more lopsided.  The disk didn't get nearly as much heat as the bottle/cheese plate did.  On the bottom-shot, you can see the circle-of-dots that were part of the original bottle - so this is grossly under-slumped.

Add'l note on the bottom-shot (of the bottle/cheese-plate), you can see the brush-strokes from the kiln-wash on the shelf.

Bottom Line:  I think I need to increase the top-temp, and extend the "soak" at top-temp.  I think my annealing phase was fine (segment 4 @ 970* for 20m).

This bottle is my prototype - and I plan to use it to create a ceramic-bisque mold for future slumps.  I'll put an "edge" around the mold so that the outer edges of the cheese-plate will have a lip (I hate runaway cheese!).  As for the disk, I may already have a round plate mold someplace.  Although I think it might make a nice trivet, if I can figure out how to *easily* slump-it further (maybe epoxy some flat, clear marbles to the bottom?).

And I'll plan on mixing up my kiln-wash a little thinner, and using a spritzy-spray-bottle applicator - rather than a brush - so hopefully I'll get smoother coverage (resulting in a smoother bottom).

I have some other ideas I want to try out:  Bought some "dichro-slides" which is dichroic (shimmery/rainbow) finish on a fusible decal.  Once the bottle is fused flat, I'll apply the dichro-slides to the glass in some kinda cool pattern/design, then re-fire in the kiln to fuse 'em together.  Not sure if that should be a "tack-fuse" or what.  More research is needed...

In any event, I wanted to share "What I did" - in case anyone is interested (at the very least, I can reference back to this - next time I slump!).  And *when* I do achieve a "Successful" bottle slump, I'll post the firing profile (with the requisite "YMMV" - since kiln performance may vary).

I'm actually quite happy with it - and feel encouraged enough to try more :-)


1 comment:

Olivia Princess said...

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