A Good Fit for Stained Glass: How Close Should the Pieces Be?

​​A Good Fit: ​​What to look for before soldering

​It's a common question asked by many stained glass ​hobbyists, "How close should the glass pieces be?"

​And one would think there should be a straight forward answer, right? 

Well, in theory yes. But I'd rather talk about reality.

We're not machines. We each work differently​, learn differently and have a different amount of patience. And our tolerance for imperfection or drive for perfection​ also varies from person to person.

Although there isn't one simple answer to the reality of this question, ​let​'s discuss 4 different ​situations.

So let's see... You've cut your glass and ground it to fit. ​The copper foil has been applied and now you're getting ready to solder. You push everything together and usually come to one of the following conclusions:

  1. That doesn't look like it fits as tight as it did when I was grinding the glass...
  2. You start to question if whether that gap is too big or not?
  3. You ponder the idea of leaving a little space between everything so that the solder fills it up and makes it stronger.
  4. You look it over and say "Yep, good enough"

Let's break each scenario down shall we?

​1. There are Uneven Spaces Across the Whole Project

​Often, hobbyists will notice that foiled projects fit differently than they did before they were foiled, and they're right. It will always ​fit slightly differently as the foil takes up​ a hair width of space. You won't notice it as much on a suncatcher with only 12 pieces, but start working on a panel with 100 pieces and you'll quickly see a difference.

Th​is minor variance of one hair width will compound with the higher number of pieces in your project as there will naturally be more copper foil taking up space. Think of it this way, one hair width is barely noticeable, but the width of one hundred hairs will make you take notice.

​ For the average glass crafter, the problem with glass fitting differently after foiling isn't usually due to the copper foil. It normally stems from not realizing that things weren't quite lined up when they were grinding the glass. ​Let's say that when you're grinding, you test the fit of piece "A" next to the neighbouring pieces "B" and "C" and everything shifts ​just a little, you might think that "A" fits perfectly. When in all actuality, "B" and "C" are no longer in their ​correct ​position.

I​f this happens with a few pieces in the project, you'll be ​quite disappointed when you line everything up to solder and see that nothing fits the way you thought.

How to Prevent Uneven Spaces

There are a couple of things you can do to try and avoid the problem of uneven spaces between your glass pieces.  

  1. Use push pins or jigs to hold your glass in place while testing the fit. This will prevent other pieces from slipping out of place without you noticing.
  2. Sometimes a piece of glass may have been accidentally flipped over or upside down. A square for example, may not be perfectly square and if turned 90 degrees, could fit very differently. Avoid this by labelling your pieces clearly so you always have them in the correct orientation.

​2. There is a ​Big Gap

​Do you really need to worry about ​it? Can't you just fill it with solder? There won't be a hole anymore ​so no one will see it. Right?

Well, big gaps present their own unique problems and it isn't true that it won't be noticeable. 

When we look at stained glass windows​, they're normally back lit. The glass lets light through while the solder doesn't ( obviously!) So this creates dark lines in our designs. Well, that big hole you want to fill with solder will be visible because it's going to be a large dark space among all of your beautiful solder lines!

Also, have you ever tried to solder a large hole? You need so much solder to fill it, which gets really hot when soldering. When you try to do that final pass, it will likely melt through. You could chase that solder all day back and forth from one side to the next. It's a real pain in the neck!

Another problem which can occur when there is so much heat in one area is thermal shock. Imagine soldering your project and feeling a sense of accomplishment as you near the end only to hear the dreaded "tink" of glass cracking. 

I've been there.

Planning a repair on a piece that isn't even finished yet is heartbreaking. 

The Best Fix for a Large Gap

I'm sure you don't want to hear this but... ​simply put; you need to cut a ​NEW piece.

​If the space you need to fill is bigger than the original ​pattern piece from the drawing, make a new template of the space you need to fill before cutting a larger piece of glass.

​3. Should I Spread​ the Pieces Out?

​Many times newer stained glass workers think that more solder means the whole piece is stronger. Please don't buy into this line of thinking; it's false!

​The reality is that using more solde​r:

  • ​will make your work heavier than necessary,
  • ​will cost you more money​ (solder isn't exactly cheap) 
  • ​won't make your project stronger, only reinforcing it will​

The​re is No Reason to Spread the Glass

​​What you'll want to do it push all of the glass pieces together before soldering. They should ​be touching all along each side as best as possible. This is where getting a good fit while grinding is very important.

​4. "Yep, Good Enough" vs. "The Perfect Fit"

​Is there really such a thing as "The perfect fit" with stained glass?

It can seem ​allusive​ to many. Even experienced stained glass crafters struggle from time to time. But yes, it is out there.  You may not have found it yet​, but don't give up.

We keep pushing ourselves to get the perfect fit because it's what is going to give us the best results for our finished piece. It makes uniform solder lines in our work and, it's a challenge ​that keeps us pushing our skills.

​As with everything hands on, we learn as we go.

When you're starting out, give yourself permission to learn. Accept that things won't be perfect​ but keep aiming for perfection. ​ As you see your skills increase over time, you'll look ​at the challenge of getting the perfect fit as one you're eagerly willing to take on and you'll notice you​r tolerance for gaps in your work will decrease​. 

That's when you can drop the "Yep, good enough" and trade it in for "Ooooh, the perfect fit! Yes!"

Have patience.


And always push yourself just a little bit​.

​Never forget to look back and see how far you've come!

Leave a Reply 39 comments

Patricia - February 15, 2018 Reply

You have got a sense of humour. Thoroughly enjoyed readi g got me down to a T