How to prevent medium to small bubbles in glass fusing

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.

Thermal Shock in glass.

Most Hotpotters know that glass can breaks due to rapid, uneven temperature change. Also 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 firing to fast 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 the lower heat and longer firing time it is very good possible to fuse glass with different thickness and from different suppliers together with a success rate of +80%.

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


More info on the HotPot microwave visit www.hotpotnorge.moonfruit.com

HotPot 3- HotPot Q & A

During our demonstration of the Hotpot microwave kiln wegot several times the next two questions.


And it where exactly the same questions I did have when I started to use the HotPot microwave kiln.

Where stands COE..  in fusing glass for?

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

If you fuse glass always stick to glass 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 make the glass crack.

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

At the same time it tells something about the hardness of the glass. The lower the number the harder the glass. For example a 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 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

HotPot 2-Types of glass-Dichroic

We came in contact with dichroic glass through a new fun way of glass fusing called HotPot.

Before I'll go into that a small introduction to Dichroic glass, and the many ways of using this beautifull material.



Dichroic glass is glass containing multiple micro-layers of metal oxides which give the glass dichroic optical properties. This high-tech optical coating selectively reflects certain wavelenghts (colors) of light and allow the remaining wavelenghts to transmit through.

This effect is seen in nature in opals and peacock feathers.


The word dichroic means two colors, which refers to transmitted and reflected color.Multiple ultra-thin layers of different metals (gold, silver), metal oxides (titanium, chromium, aluminium, zirconium, magnesium) and silica are vaporised by an electron beam in a vacuum chamber.



The vapour then condenses on the surface of the glass in the form of a crystal structure. This is sometimes followed by a protective layer of quartz crystal.

The character of dichroic glass is its changeability and it can be used in differend ways.


Dichroic in fused glass application;

Mix of dichroic glass

Fusing dichroic glass not only produces captivating effects, it eliminates all the vulnerabilities like scratches, damage from solvents, oils, flux and adhesives.
The fusing process moleculary binds the glass and the coating materials.





Reflective colors difficult to perceive on clear glass will intensify when fused onto a colored background.

Clear glass offers versatility as it can be fused with Dichroic either up or down.

When fused  Dichroic side down, the coating will be encased in a layer of clear.

When fused Dichroic side up, a soft metallic effect is achieved.


Leaded glass application;

Dichroic used in dragonfly wings

When making a glass panel in the Tiffany or lead came methode that includes Dichroic glass, use a glass cutter without oil and score the glass on the uncoated side.






The coating can be protected from soldering and grouting phases by covering it with low tack tape or contact paper that is easily removed when finished.

Lamination applications;

Cabouchon jewellery by F. Hebing

Some Dichroic jewels and bevels are made by laminating the clear bevel to a coated sheet of thin float glass. This process layers the coating between the glass and is in this way protected from the dangers listed above.
This kind of glassfusing is easy to do in your own microwave, int's known as HotPot.
I'll explane how this very fun process goes in a nex post called "HotPot Norge".


Fred Hebing

Foil, foil and more foil.

Foil, foil and more foil.

There are several different backings in copper foil, how and when to use them?

The backing is the adhesive side of the foil. If the foil is wrapped around a piece of transparent glass the color backing is visible if you look "inside" the foiled area through the glass. This becomes very visible you patina your solder lines in a different color than the foil backing.

So always to match the copper foil with the patina you would like to use on the finished piece.

Black backed foil for black patina.

Copper patina on the copper foil with no color backing

If you plan on leaving the solder in its natural silver color the silver foil will match.

Foil comes in different thicknesses 0,03 mm  and 0,04 mm. Which size is best to minimize foil splitting on inside curves?

Thickness really doesn't matter when it comes to foiling inside curves. You can use any of the thicknesses. The trick is to not pull the foil so tight.

Immediately after foiling the inside curve, crimp down the sides gently and ease the foil around the curve.

Fred Hebing

HotPot Norge 1

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.

Time for some show and tell.

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.glassatelier.no






Fred Hebing

Glassatelier Hebing Efteland created.

Many months of thoughts, spending much time on a business plan we took the dive. Quitted our jobs, must say that always gives a good feeling, and started to look for a place to start our glassatelier.

We looked at a lighthouse on an island, run down buildings, some were appealing some were not, great locations to less nice locations.

From out of budget to totally out of budget.

Then we stumbled upon an incentive from the Stavanger commune to get some activity in a very nice old part of town. With nothing to lose we entered the bid for one of the properties on offer.



We were very pleasantly surprised when we got a positive answer from Stavanger commune when they offered to lease us Mellomstraen 4.


We jumped on it, a location and building that will fit in very good with what we have in mind and what we want to do.

Soon we'll receive the key and can start putting in work tables, paint the walls etc. We hope to open the premises in the second half of October. If you're in the neighbourhood or passing by Mellomstraen 4 feel free to enter and have a chat and look around.



Yvette and Fred

Lead came color glass set in double glazing.

Some time ago we were asked to restore some lead came colored glass in an older house and upgrade it at the same time.

We happily accepted this project because we just extended our skills with this double glazing technique.

We started this restauration project with removing all the old layers of paint from the woodwork.

After this we removed the window and took the stained glass piece out of the frame.

Not too bad we only broke 3 pieces of clear glass.

In the double glazing technique, the stained glass is put in a y-profile making the original size of the piece a wee bit too big.

This means that we will have to take the whole piece apart, clean it, re-cut it and put it back together again.

In this case the owner wanted to incorporate more transparent glass to get more light into his house.

After putting the lead came piece back together again, it was time to start making the aluminum frames that go on both sides of the y-profile.

This aluminum profile is filled with a drying agent that will get all water molecules between the layers of glass out to prevent condensation when the temperature goes down and the heating goes up.

You always must use different thickness of glass on either side of the lead came piece to prevent mirroring of items in the finished product. For example 4 mm complemented with 5 mm etc.

When all of this is done it's time to clean all the glass and fill the space between the outer pieces of glass with rubber putty to get an airtight seal around the whole piece.

This putty has to dry out for about a week. Then the time comes to place the piece back into its frame and see the results.

The last thing to do for us is to put sealant on the glass frame connection to make it waterproof for years to come.

Fred Hebing

Types of Glass - Uroboros

Maybe our favorite glass is made by a company called Uroboros.

Uroboros glass is hand mixed and rolled sheet by sheet, in doing so every sheet of glass they produce is unique.

To see the production process we can recommend a visit to their website ( www.uroboros.com ) and click "about us" and then "video library". A good few minutes spent.

 
The diversity of color combinations and surface textures makes this glass perfect for lampshades and other items made in the copperfoil (Tiffany) technique.

Typical for Uroborus glass is not only the natural colors but also the balance of transparent and opalescent glass for the field of glass fusing.

Because of the uniqueness of the glass it's best to go to your supplier and pick their glass on a project base. The pictures of Uroboros glass on websites or in catalogues don't do justice to the real splendor and translucency of their product.

Despite this, I'm going to put some pictures of their glass on this page.

Fred Hebing

Soldering Problems and Tips 1

When you start soldering you will see things happen that makes you think mmhhuu??????? 
Is it supposed be like this?

To answer that here are some pointers and actions to take to improve your soldering technique. As usual practice makes perfect (most of the time).

Beading of seams is too flat.
Not enough solder.  

Beading is lumpy or peaks instead of flowing.
Iron is too cold. 

Can't seam to get beading smooth.
Did you flux? Iron too cold or too hot. Too much or not enough solder. 

Solder won't stick to copper foil or lead.
Did you flux? Copper foil may be oxidized.

Solder splatters into little balls all over the glass.
Iron too hot: purchase rheostat for your iron. This will control the current to your iron and control the heat output.

Solder falls through seams to other side when soldering copper foiled pieces.
Soldering iron is too hot or you are holding the iron in one area too long.


Try to solder in a well ventilated space, or even better, do it outdoors if you have space and the weather is on your side. It's not very beneficial to breate in the fumes from the soldering process.


Hope this helps.
Fred

Coming soon: The different types of solder and lead-free solder.