Glassatelier Hebing Efteland's

014 HotPot Norge Glassatelier Hebing Efteland by

Q&A

From HotPotter to HotPotter

 

In this blog you will find HotPot related tips, advice and how-tos to improve your glass fusing and have an enjoyable time!

 

Feel free to drop us a question, if it's been on your mind, chances are someone else has been wondering about it too and you'll be doing everybody a big favour :o)

By HotPot Norge, Feb 2 2013 10:00AM

Bubbles can be caused by many different things.

Uneven stacking of glass can result in air trapped between layers. To prevent this from occurring, check the placement of all the glass pieces to insure they are sitting properly on the base. If possible fill up the small openings between the different glass pieces with a clear glass.

Second, check the glass prior to fusing. Some glass may already contain bubbles inside, which may or may not affect the outcome.

By HotPot Norge, Jan 26 2013 10:00AM

If the glass piece has flattened out too much, the piece is over fired.


To prevent this from happening, reduce the firing time.


During the firing process, lift the lid of the microwave kiln to see how far the fusing process is.

If the desired results have not been achieved, continue firing in 20-30 seconds intervals.

Repeat this till you have your piece fused to the level you want.

By HotPot Norge, Jan 16 2013 01:06PM

Most Hotpotters know that glass can break due to rapid, uneven temperature changes.

Mostly during cooling down and sometimes while firing.


This is known as thermal shock.


Why this happens may not be obvious.


When solid glass is heated or cooled unevenly, the part of the glass that is heated will expand (or contract if cooled). The glass that isn’t changing temperature stays the same size.


This uneven expansion creates a lot of stress inside the glass. If the stress is strong enough the glass will break. And that is called thermal shock.


A good example of this you can see in the picture.


Here I mixed glass with different thickness and in combination with rapid firing, it gave me an S shaped crack. The thinner glass got hotter faster than the thicker glass and causes thermal shock.


I repeated the experiment with less heat over a longer firing time up to 10-12 minutes and the results were much better. The pieces came unbroken out of the HotPot, that was already a big improvement.


When I came back to the studio the next morning still some thermal shock had occurred during the night.


Overall I can say that with lower heat and longer firing times, it is very possible to fuse glass with different thicknesses and from different suppliers together with a success rate of +80%.


All the glass used in this test had the same COE.


S shaped crack result of thermal shock.
S shaped crack result of thermal shock.
Different thickness of glass fired with a lower wattage.
Different thickness of glass fired with a lower wattage.

By hotpotnorge, Jan 29 2012 10:51AM

Testing out the HotPot starter pack some time ago we had lots of fun and at the same time wanted to make more pieces with “depth”.


We did see so many nice cabochons on the internet that were so pretty and delicate in appearance it was very inspiring.

Also realizing that these nice pieces were made by people with loads of experience we wanted to see how fast we could get to their level, more or less.


By looking at these pictures we concluded that the dichroic glass was a big part of the answer.


That’s strange, we used dichros from the HotPot starter pack and while it gives nice results it wasn’t what we were looking for. How to improve on this?


The eureka moment came when we combined dichroic on black with clear dichroic glass over it. Also a colored base with clear dichroic on top gives very interesting results. As with clear dichro over millefiore.


We realized that if the clear dichro is used upside down (i.e. the dichro film side of the glass faces up) the piece comes out cloudy.


We hope this info will help everybody to diversify the pieces they make and get even more satisfaction out of the HotPot.


Yvette and Fred



Picture below: "London calling"


Made on a white background with PreCuts hearts, red and black frit, two small millifiore and clear dichro. Topped off with a layer of clear glass.


London calling
London calling

By hotpotnorge, Jan 8 2012 03:48PM

During our demonstration of the Hotpot microwave kiln we got several times the next two questions. Which is exactly the same questions I did have when I started to use the HotPot microwave kiln.


What does the COE.. in glass fusing stand for?


COE stands for Coefficient of Expansion and is used in the world of glass fusing as a compatibility code.


If you fuse glass always stick with the same COE code.

For example if you put COE 90 and COE 96 in a design and fire it in your HotPot or fusing oven, the difference in expansion will cause surface tension and make the glass crack.

This will happen when the glass expands during firing or contracts under the cooling down period.


At the same time it tells something about the hardness of the glass. The lower the number the harder the glass. For example, an ordinary bottle has a COE 38 code and a lamp worker uses much softer glass like COE 104.


Can I use the glass that I’ve got in the barn in the HotPot?

The problem with fusing 'found' glass is that you have no idea what the COE is.

So it isn’t recommended to use this with the glass supplied in the HotPot starter pack.


Hope this will help and if you got more questions about the Hotpot microwave kiln let me know and I’ll do my best to answer them.



Fred Hebing


By hotpotnorge, Jan 5 2012 10:10AM

Recently we encountered a very fun new thing that's happening in the world of glass fusing.

It's called HotPot and you can fuse glass in your own microwave, how about that.


With the use of the nice dichroic glass types out there it's possible to make very nice fused personalized jewelry in a very easy way.

At the moment we are practicing this and the results are very satisfying from the start.



The HotPot is a small kiln that is designed for use in a microwave. When placed in the microwave this kiln should be elevated from the microwave floor. The kiln comes with some blocks for this purpose.


The only other thing to prepare before using the kiln is to put fiber- and releasing paper in the HotPot and you're ready to go. These papers prevent your glass from sticking to the kiln and will give the piece that you're designing a smooth finish on the back.


After this 30 second preparation, the real fun starts - designing your jewelry.

It is much easier than it sounds, more or less placing several pieces of glass on top of each other.


And there are so many nice type of glass out there.


Another nice thing to do is to incorporate milefiori or precut shapes in the design you're making.


To make it more personal, cut your own glass shapes. Remember, when cutting glass cutting for use in the HotPot, always do it with an oil free glass cutter.

When cutting dichroic glass, always cut on the back side of the glass so you don't damage the layer of dichroic film.



There's even a glue to stick glass pieces together because stacking glass is slippery business, and they can slide.


It happened several times while placing the kiln in the microwave - glass falling of each other by the smallest bump or when carrying it on the tiniest angle.


How unfortunate it happened again, maybe we should start using the glue?


We the glueless people (or are we the clueless people?) gently place the bottom part of the Hotpot with the assembled glass pieces, on the blocks in the center of the microwave

.

And be even more careful when placing the Hotpot lid on. Most of the time we end up lifting the lid just one more time to make sure the glass didn't shift. (Remember glue less)


All set and done. Time to start the microwave (750-1000 watt) and let it go for about 5 or 6 minutes. Time to have a peek. Put on your gloves and lift the top up far enough so you can see if the glass is melting. If not melted far enough give it some more microwave time.


You can look every 30 seconds if you want till you see a nice orange mound of glowing glass.


Done that's all to it.


Carefully remove the kiln from the microwave and place it on some heat resistant tiles (leftover tiles from your bathroom will do the trick) to protect your worktable surface.


Let the kiln cool down totally and do not remove the glass till after the cooling down. Doing so early will cause thermal shock to the glass and it will crack.


That's all that there is to it, time to have a drink and maybe prepare your next piece.


For more info on the Hotpot visit www.hotpotnorge.com



Fred Hebing