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Writer's picturePaul Urteaga

FAQ - Common Stained Glass Cutting Questions

Updated: May 8

Before we get into the common stained glass cutting questions and answers, let us address glass scoring tools and glass scoring. There are many types of scoring tools . Select the type of tool that feels and works best for you. Pictured below are the most commonly used scoring tools.


Glass scoring tools and cutters

What is a Score?

Glass cutting is a delicate art that involves creating a "score" along the surface of the glass to guide it's break. By carefully scoring the glass, we can control the direction of the break and ensure a clean cut. You should know that you’re not actually cutting the glass in the traditional sense of cutting something however, you are actually “scratching” a line into the glass.   It's important for beginners to understand this technique and practice precise scoring to achieve accurate results in glass cutting projects. Think of a score as a visible scratch in glass that is telling the glass where we want it to break.  Please note, depending on the type of glass you are scoring, a score line may not be visible.  There are other things to consider such as pressure and sound.

 

What Makes a Good Score?

Let’s talk about pressure. Pressure plays a crucial role in creating a clean score on glass. A delicate balance of around 6 pounds of pressure is necessary to avoid crushing the glass and causing additional weakness. Too much pressure can lead to creating a dusty line that is full of little nicks and glass particles. When using too much pressure, instead of causing a small fracture or separation on the surface, your glass will be more prone to errors and will create a less predictable cut (meaning you intend to create a straight line break in your glass and somehow you literally end up in left field).


Pressure on scoring glass
Click on image to enlarge

Instead of having just one stress point to direct your break, each of those little nicks cause additional weakness or stress in the glass making the break less predictable and more likely to go awry. 


Ok, you have scored your glass. Now, look at your score line - If the score on the glass looks white and dusty or powdery, it may indicate that the score is deep and too much pressure was used.  On the other hand, if the score appears smooth and almost invisible, it likely means that you’ve nailed it!  Tilt the glass slightly to one side to get a better view of the score's appearance.  Remember, let your scoring tool work for you.

 

Sound – Your scoring tool sound is an indicator.

Pay attention to the sound your scoring tool makes when scoring. Sound can be a helpful indicator when scoring glass. Different types of glass make different sounds. Transparent glass tends to make more of a clicking and popping noise while opalescent glass will often create less sound. Nonetheless, listen for a constant scratching sound. With practice, you will notice the distinct sound each type of glass makes and you will be able to adjust your pressure accordingly. In this video created by Derek Hunt, pay attention to the sound and not his glass breaking technique. His glass breaking technique is a bit advanced and will be explained in a later blog posting.



Tool tip: If you have been using your scoring tool for quite some time and you feel your tool is just sliding across your glass without creating a score line, consider the causes:

1.     Not enough pressure

2.     Dirty tool tip

3.     Not enough oil

4.     Replacement tip is needed

(A scoring tool tip will last a long time depending on your use.  A good rule of thumb is that the tip will last for about a mile of scoring – that’s a lot of scoring!)    

 

Common Glass Cutting Questions Answered

 

Should you push or pull the cutter?

Answer: 

People have different preferences when it comes to glass cutting techniques. In my experience as a teacher, I always encourage my students to try both methods and see which one feels more comfortable for them. However, personally, I believe that pushing the cutter away from you offers more advantages than pulling it. When I'm cutting glass, I like to position my elbow against my side before making the score. This allows me to have better control over the pressure applied, especially when I work close to my body. By pushing the cutter away from me, I can extend my arm at the elbow to complete the score, resulting in a more even pressure distribution. Another benefit of pushing the cutter is that you can use the notch in the tip, where the wheel sits, as a guide.


Scoring tool tip

Simply align this notch directly with your traced pattern, and your score will be precisely where it should be! On the other hand, if you try pulling the cutter along the line, you'll find it quite challenging as your hand obstructs your view of the trace line. You'll end up twisting and turning just to see what you're doing. So, give both methods a try, but keep in mind the benefits of pushing the cutter away from you. It's all about finding what works best for you and achieving precise and comfortable glass cutting.


Standing or sitting while scoring?

Answer: 

I have tried both, it is your choice. However, to enhance your glass cutting skills, it is important to focus on achieving smooth and seamless movements. By maintaining a stable posture, you can freely move your upper body, enabling better control over your arm and shoulder. This increased range of motion will help you apply even pressure and navigate curves effortlessly. With these fluid scores, you will undoubtedly see a significant improvement in your glass cutting abilities.


Cutting Curves - Glass wants to break in a straight line

Answer: 

Make the most of this knowledge for your advantage. Attempting to forcefully navigate a steep curve in one attempt will not result in the desired outcome. Instead, consider making smaller adjustments with less curve each time. By doing so, you can shape your desired outcome without the risk of unintentionally causing a disruption in the wrong area. Click on the video for a visual representation. The pliers used in this video are called Grozing pliers. See my other blog post "Understanding the Art of Using Grozing Pliers on Stained Glass" to get a better understanding of this tool.



Can I lean my cutter as I score glass on curves?

Answer: 

Angles make a difference - Ensure that your cutter is held perpendicular to the glass. If the handle of your cutter tilts to the left or right during cutting, the glass edge will likely mirror that same angle after breaking the score. As a result, the front and back sides of the glass will have different sizes, impacting how the pieces align when fitted together.


With regard to textured (uneven surface) glass, should I always cut textured glass on the ‘back’ side?

Answer:

It is recommended to cut on the non-textured side for most applications. However, if the textured side provides a smoother and better cutting experience, then it is advisable to use that side. Just remember to flip the pattern over if you want the texture to be on the front of the finished panel.

 

Should I cut all my glass at the same time or should I work in sections?

Answer:

I have tried a few of these ideas:

  1. Cutting in Sections - Performing these steps in order per section. Cut glass, grind, foil, and solder in sections.  i.e. 10’’ x 12”  glass piece divided into two sections. STOP!!  This method is a mess and you will have many tools everywhere.

  2. Cut, Grind, Foil as You Go - Cut glass, grind each piece, and then foil as you go.  You can work with this method, however, depending on the size of your piece, you will want to pay attention to the length of time your foil will be exposed to air to avoid oxidation on your foil. Although some glass enthusiasts swear by this method, I personally do not care for it.

  3. Cut, Grind, and Foil from the Middle - Cut all your glass according to your pattern pieces before any grinding. Now, here is where glass enthusiasts and artists differ but for me personally, I use this method. 

    1. When it comes to grinding, I personally like to start on the center pieces in my pattern and work outward towards the edges of my pattern. Doing so helps keep grinding too much off your center pieces.  When working your way outward as a beginner, you may notice your border pieces extend past your border edges.  Not a problem!  Simply grind your edges of your border pieces to fit your pattern piece. Lastly, foil your pieces, flux, and solder.      

 

What kind of oil can I use in my cutter?

Answer:

As you know, there are many types of oil.  You can choose to play it safe and purchase glass cutter oil which can be pricey depending on where you shop.  Others have used sewing machine oil or lamp oil and they will work as well.  However, do not use cooking oil, olive oil, WD-40 etc… 

 

Some have discovered that they like to fill their scoring tool with oil, only to discover that it leaks and leaves a pool of oil in it’s storage container.  There is a workaround with this. 


Tool Tip: Instead of filling your scoring tool with oil, you may opt to use a very small Tupperware container with a lid (2"x2" or similar works perfectly).   Simply cut a sponge to fit the inside of your container and then trim this sponge where it raises no more than a half inch in height.  Pour some oil on this sponge and prior to scoring, glide the tip of your tool over the sponge.  If too much oil transfers from your sponge, to your tool tip, simply roll your tool tip on a napkin to remove any dripping oil and get to scoring.  When you are done scoring, seal your cutting oil container for future use.

 

I have gaps in my pieces! Can I just fill them with solder?

Answer:

Practice and experience will reduce gaps between your pattern glass pieces. The more time you spend working with glass, the better you will get.  So when starting out, just know there will be gaps and then there will be some LARGE gaps.  Some gaps you can fill with solder and it will still look OK but some gaps may need a filler to help your solder stick, and then there is the least liked solution.


Let’s start with the least liked solution, yet the better solution of them all. Recut the pieces so they fit properly. I know it sounds like a pain in the you know what - but I did say it is the least liked solution. Recutting a piece with a parge gap helps make you a better glass artist and you will end up with a piece you can appreciate. Otherwise, one will never learn to cut precisely if you think you can fill the gaps with extra solder or a filler. It bites to have to pull out the scoring and glass breaking tools again but believe me - Just do it! You will thank yourself once it is all done. 

 

But what if I do not have enough glass to recut a piece to fit properly?

If the gap is more than 3mm wide, you can use copper foil to fill the gap.  Depending on the length of your gap, cut a strip of foil that is double the length of your gap.  Peel the backing off the foil, stick the ends of your foil together (sticky side to sticky side) and flatten out the foil.  Some areas of your gap may be wider in the middle and may require you to fold your foil again. Insert the foil into the and press in any foil that is protruding above the glass.    

 

Gaps that are smaller than 3mm, you can simply fill them with solder.  Doing so with may cause your solder to melt trough to the other side of your piece, causing your solder line to go flat.  Don’t worry about this, simply let this area cool down and then resolder your line. When you finish soldering your first side, you will turn your piece over and notice a flat blob of solder where it had melted through.  Simply touch up this solder blob and create your solder line.


Side Note:

Show off your love for stained glass with apparel and accessories from Caveman Glass Store. Browse our Stained Glass section for shirts, sweatshirts, hoodies, bags, thermal bottles, and more. Our products are perfect for avid crafters who want to sport their hobby with pride. Don't miss out on the chance to showcase your creativity and passion for this beautiful art form. Visit our eBay Store today to get your hands on our stained glass merchandise.


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