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Leadlighting Tutorial Lesson 3: Assembly of a Leadlight and helpful hints.

The ideal bench height is around 900 mm, which is the same height as a kitchen cupboard or bench. A low table will kill your back. A piece of 1/2" or 12 mm chipboard, larger than the leadlight to be made will be needed to assemble on. Begin by nailing a length of timber beading along the pencil line of the cartoon, on the longest edge FURTHEST AWAY from you first. If you are right handed, attach the next length of beading along the pencil line on the left hand side, so that you assemble from left to right. Left handers, vice-versa. The cartoon is also nailed to the chipboard under the beads so that it cannot move. Beading material can be any size but it is usually rectangular, 12 x 18 mm is most common and whatever lengths for the job. By attaching the beading as described allows you to assemble the leadlight towards yourself, which means the cartoon line is always in view enabling you to see how it is progressing easier. Also at times you will have a hammer in your hand, if you are working away from yourself leaning over your work, dropping your hammer will have an unpleasant result.

(I have seen some instances where people haven't used beading at all, just used some horseshoe nails to hold everything in place - unfortunately they were taught this way, which is not a good idea simply because it's difficult to tighten the leadlight upon completion - (see further down, last two paragraphs) and the outside leads are never straight, bulging outwards between the nails and can cause problems on fitting into the rebate. The only time when you can't use beading is when you are making either a round or oval leadlight and you are then forced to use horseshoe nails.)

Start assembly of the leadlight with two of the outside leads, which are known as H leads - cut them approx. 25 mm oversize and place them against the beading on the cartoon, forming an L shape. As lead comes in two lengths, 1 mtr & 1.2 mtrs, you will need to butt them end-to-end if making a full side lite. Try to co-incide the length with an internal lead that goes to the outside so that only one soldered join is required. Use a lubricant for the lead knife and the knife will cut the lead easier.

Due to a question from a reader I've added the following information about knife lube. Some hardware stores sell knife lube in a tube about 90 mm diameter and 300 mm long, which may be a waste as you only need a 50 mm slice off the end. You could try a leadlight shop if you have one reasonably close to you as they sometimes sell it. Failing that if you get a cake of very soft soap, that will do the job good enough. That was an old carpenters trick when screwing a screw into hard timber - it served as a lubricant. Whether you use knife lube or a cake of soap, if you melt it into a large tin receptacle like a lolly tin it saves the end picking up dirt from your table. Just remember to run the blade into the soap to get a good coating on the blade and cutting is easier. By using a lubricant every time you cut lead with your knife, it will hold its sharpness longer than cutting dry.

Outside leads can be butted together either way as in the diagram. They don’t have to be mitred as in an aluminium window, which uses a Y13 lead.


The first piece of glass to go in is the piece belonging to this corner. The next piece is any piece that is beside it, in whichever direction you are happy to assemble, then fanning out in a natural sequence. Try to form an assembly plan in your mind before beginning by thinking ahead about 3 or 4 pieces of glass and how you will lead it up as you work through it.

Cut some 6 mm U lead into 10-15 mm lengths to use between the glass and the horseshoe nails to protect the glass. The nails and U leads are lightly hammered in place to secure the glass and lead, and stop the assembled sections from moving, particularly as you get deep into the leadlight. Sometimes you may have to pause and continue elsewhere by reasons of complexity until you reach where you’ve paused, horseshoe nails will keep things in place and they are easy to pull out by hand. Remember to keep an eye on the sizes for the leads that you've marked on the cartoon as you work as it is easy to forget a lead size change at a particular point, being engrossed in your work.

Where adjoining pieces of glass meet at T intersections, the trick is knowing how long to cut the lead that is separating each piece of glass so there are no gaps at the joins. It is easier at first, to use a small off-cut of the same leads you are using to lead up, (or whatever size lead will be used on that line) as a guide when cutting lead to the correct length. (See diagram below.) Make sure you keep the off-cut vertical, allowing it to lean in at the top means you will cut the lead you've marked slightly smaller. Use this method to avoid gaps at lead joins, until you become confident at judging by eye, but it is time consuming. Once you ‘know’ how much the leaves of each lead overhangs the glass it will speed things up. Try to have the longer line as the ‘through lead’ with the shorter lines as joining leads. In the diagram below, assembly is being depicted as assembling from left to right, not top to bottom. So the next piece of glass will go where the text beginning with 'mark correct distance' is.



Remember, that with internal leads that go out to the edge of the leadlight, use the same technique, but use an off-cut of the outside lead as a gauge to cut the internal leads the correct size so that the outside lead will fit properly on completion. This is an easy thing to forget, so writing OUTSIDE LEAD in big letters outside the pencil line on the cartoon on the two remaining sides will help to remind you. In both these instances mark the lead where you will cut it with a lead knife. Remove, cut and replace the lead. There are two things to remember here, mark and cut the correct length and angle, and one more thing described further down under Helpful Hints and Further Lead Cutting Techniques.


These windows have a special outside lead called Y13. Note that when drawing the cartoon for an aluminium window, the outside cut line for a Y13 is a different measurement than what is used for an outside H lead in timber windows. (This will be covered more fully in Lesson 5, but briefly it is 9 mm in from the pencil line.) Starting assembly is similar to wooden windows except for the following. After the beads have been attached, these leads must be mitred. They cannot be butted together the same as 12.4 or 10 mm (H leads) as they will not fit into the frame. An easy method to cut the mitre accurately is to make a template from a piece of glass, 200 x 50 mm. On one end, cut an angle of 45 degrees. Use 3 mm glass.

Note: The glass template sits beneath the flat section of the lead whilst cutting, which helps to keep it's shape. Aim to cut as close to the glass as possible to avoid crushing - about 1 mm away and it also helps to get an accurate 45 degree angle. The top cup of the Y13 usually folds down a little when you cut through it, tidy it up when you finish.


Each end of the Y13 lead must be mitred on both outside leads before starting to lead up. It is easier to do this first before the glass is all in. (See diagram below.) On completion of the leadlight, the remaining two Y13 leads are cut and fitted then the outside beads are attached. (See tightening the leadlight at the end of this lesson.)


Cut a scrap of glass 300 x 7 mm and cut into 20 mm lengths. These are placed under the flat section of the lead, raising the lead up during assembly, making it level. 2 mm thick glass is perfect but 3 mm will do. Two or three pieces under each lead is sufficient. By neglecting to put these scrap pieces under the flat section it will be soldered at an angle and won't fit properly.

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Knife – always cut down onto the face of the lead holding very close to the cut so that the lead stays vertical. Don’t force the knife, as the lead will only crush, keep it sharp and remember to use the knife lube, which is like a soft wax and makes cutting lead so much easier when you use it, rather than cutting 'dry' without it. Cutting dry will also blunten the knife quicker. When using the knife, take your time in cutting through the top leaves to stop crushing, then you will feel it slip quickly through the heart and the bottom leaves. It doesn't take long to know how 'easy' to go for the top leaves, but the key is keeping it sharp. The knife that I prefer is the Leponitt knife because it is easier to see over the blade when cutting angles as your hand is not in the way like it is on the Japanese fan-out blade. Cut using a rocking motion, (backwards and forwards) but don’t allow a rolling motion, (side to side) at the same time. Prior to cutting the lead with a knife, you would have made a mark of the angle you want to cut and you need to be careful when using the knife that the angle stays constant during the cut, or you may find that the correct angle has been lost simply because you lost concentration on the cut. (See also below under cutting lead square over the side view with snips, which has more about getting the angle right.)

Whenever you cut an 'outside lead' particularly with a knife, (either a 10 or 12.4) the top leaves will always fold down or crush. Simply turn the lead over and flatten the folded leaves with the knife blade. This can also happen with the snips but usually not as much, providing you use the method described below for using snips.


Snips – always cut on the side of the lead into the leaves, the opposite to using a knife. Reversing the procedure in both instances will crush the lead.

Use the snips when cutting lead square (90) or small angles up to 30 degrees because it is quick and easy. Remember to keep the flat side of the blades towards the piece you want to keep. This results in a flat, square edge rather than an arrow point if you hold the snips with the blades the wrong way round. This is the reason not to use normal side cutters as both sides of the blades are angled resulting in an arrow point no matter which way you use them.

For angles over 30 degrees, use the lead knife. If you try to cut angles over 30 degrees with snips, the lead will crush.



When you have cut through the lead, ensure it is square over the side view, even if the cut is an angle on the face of the lead.

If it is cut DOWN on an angle over the side view, (see diagram below) it may butt up quite well on the front of the leadlight, but when you come to solder the other side, these gaps will be very apparent, causing problems soldering. Try to remember to check this every time you cut a piece of lead either with the lead knife or snips, and it only takes a second, saving problems later. When you put a piece of lead in along the glass that that separates another piece of glass, first you will leave it a little longer than necessary, then mark and cut it. (See diagram 2nd from top.)

If the piece of glass is a curve you can either take the glass out and bend the lead to shape around the glass first, or bend the lead around the piece that fits against this piece. That way you have enough waste lead to get the first cut just right, whether it is at an angle or 90 degrees to the lead that it butts against.

It is the second cut, which is after you've determined how long it is to be, that is the most critical to get right, particularly with the side view angle. If it isn't square over the side view and you trim it excessively, the lead will be too short - leaving a gap. (See further down under 'A little trick' to fix this problem.) If you get into this habit of checking your work now as you go it will soon become automatic.

Sometimes after you've cut a piece of lead to the length you want, it may still be a fraction too long and needing trimming just that little bit to be the right size. The best way to do this is with the knife. With the lead on the bench, pare a little off the bottom leaves then turn the lead over and repeat for the other side. If you try to remove the excess in one go, the lead will crush.

How to cut square over the side view with snips:

This is probably the hardest thing to grasp to get right for the first time. Firstly, when you mark the lead to the length you want to cut, take care to mark parallel with the cartoon line, even it's a curve, this gets the angle on the face right. (This is while the lead is against the glass to get the correct length as in the second drawing.) Use the lead knife to do this and roll the knife over the face of the lead as much as possible. This makes it easier to align the snips with a longer mark on the face of the lead. Do it gently, you're only marking it at this stage, not cutting it. Then remove the lead and hold it in your hands for the next process.

This is the tricky bit, with your eye directly over the mark, hold the snips with the blades vertical or as close to 90 degrees to the lead as you can. (The problem here is the blades are at an angle to the handles, so it is the face of the blades you are concentrating on, not the handles - see also next paragraph about cradling the snips.) Take care to grip the lead with the blades so that they are lined up accurately on both sides of the mark you made on the face of the lead.

When you grip the lead at this point with the snips, only exert enough pressure to grip the TOP leaves of the lead. (You need to cradle the snips in your hand so the blades are behind or below your thumb, not below your little finger as if you were holding a dagger - this makes it easier to do the next step.) Now rotate the snips with the lead that you are GENTLY holding, 90 degrees - so that you are now looking over the side view of the lead, but still only gripping the top leaves. (If you cradle the snips the wrong way, it's very difficult to rotate your hand properly.)

Because you are only gripping the top leaves of the lead, if the blades are not quite 90 degrees over the side view on the lead, you will still be able to move the lead slightly to cut the lead square over the side view. If you had gripped the lead too tightly in the first instance you will also have gripped the bottom leaves as well, which will prevent you from moving the lead slightly in the blades of the snips. This is fairly easy to do if the angle on the face of the lead that you are wanting to cut is 90 degrees, but if it is a slight angle, take care when rotating the lead and snips together, that you maintain the angle on the face with the snips as well.

It's usually here where problems arise, as you rotate the snips and lead together, if you're holding the snips a little too loosely on the lead, it's easy to accidentally move the lead and lose the angle, particularly if you hold the lead too tight in your other hand. Try to combine holding both with a soft grip. If it does move you have to go back to the start again. When you are happy everything is OK, make the cut.

It's a good idea to practice on scrap lead while you read this at the same time. To break the above down into simple steps, firstly it's marking an angle, carefully lining up the snips, gently gripping the top leaves, rotating to 90 degrees to check the side view and cut. Taking a little care now will pay you back when soldering the second side.

In reality it's easier to do than describe but once you get the hang of it, it really is easy. As already mentioned only cut angles up to 30 degrees with the snips, with angles over 30 degrees, simply use your lead knife and cut on the mark already made.

(If you're unsure of what I mean, have another look at the diagram 2nd from the top, as well as the one below and relate this text with these diagrams.)


Packing the lead to get the glass close to the cartoon line:

If the glass pieces are less than the right distance from the cartoon line during assembly, i.e. the glass is too small, (and you should be checking for this on every piece of glass as you put it in) by cutting the heart out of some scrap lead with snips; the channel of the lead can be packed with these pieces thus moving the glass toward the line in 1 mm increments. To cut the heart out, cut a piece of lead no longer than the blades of the snips, (12 mm max,) and place the flat face of the snips directly under the leaves on one side and snip it off. Repeat for the other side and this section of the heart will fit inside the channel. (If after cutting and fitting a piece of scrap heart and you find that the glass piece is on or even over the line, don't put it in, the glass needs to be slightly over 1 mm too small for this method to be effective. If the leadlight continues to 'shrink,' it will still be possible to use this remedy further into the leadlight or it may even rectify itself on another piece of glass that was cut slightly oversize.)

Suppose you had a rectangular piece of glass that is 1 mm further away from the cartoon line than it should be, you will only need two lead hearts – one at both ends to move the glass 1 mm closer to the line. If the glass is fitting OK at one end but not at the other, i.e. it may be crooked, packing that end only will fix the problem. You can do this on any shape; I’m just using a rectangle shape so you can understand the idea.The smallest lead you can pack is 4.6, and both sides can be packed if necessary. You will find until your accuracy improves this will be your best assembly trick.

It won't take long to realise how close to the cut line the glass needs to be so that shrinkage of the leadlight is kept to a minimum. Just make sure you check this before cutting the lead that separates the glass pieces because if you've already marked and cut the lead, then discovered the glass is a little short of the cut line, putting a 'scrap heart' in moves the glass but now the lead is 1 mm too short! Remember to do first things first.......

A little trick: Suppose you did cut the lead a little short, perhaps a millimetre or so, take it out and stretch it between your fingers and this usually fixes the problem. Don't worry if the lead is following a curve, you can soon bend it to shape again after gaining that millimetre. In case this sounds contrary to what I've said about stretching lead in lesson 2, you're only trying to gain a fraction, not inches.

If you find you have to almost continually pack the lead during assembly, the real problem is your cutting technique - cutting too far away from the line. (Go back to lining up the wheel housing on the edge of the cartoon line and cutting slowly – are you using the right pen, did you paint the face of the cutter white?)

If the glass is too big, which is rarely and is definitely your cutting technique, you are either cutting too fast or not taking enough care and you reduce by grozing or grinding.

I'm including this paragraph as an afterthought - by now you should have discovered that leadlighting is easier if you pay attention to accuracy. In the spirit of making things easier for yourself, I apologize for my bluntness - if you're a 'near enough's good enough' person, you may need to rethink that! In the end result, no one will know but it goes together so much easier if you try to be as accurate as you can in the cutting and assembly steps. You will see in the next step, soldering, that too is easier if your assembly is accurate in regard to minimal gaps at lead joins.

When leading up, treat the cartoon as if it were a road map. Where a lead line meets at a T intersection and is close to a right angle, that's where the lead for that line stops, (see diagram 2nd from the top) it does not bend around the corner. It will butt up against the lead that is on this line.


However, at Y type intersections as in the diagram above, instead of three separate leads, try to have one lead running all the way through on the lesser angle, it’s a lot easier and faster.

2nd. best assembly trick:

Sometimes when you are leading up and you put your next piece of glass in that is a curved shape, but it appears a little larger than it should be, i.e. it is on or over the line instead of being just inside the line. Don't just assume it's the edge that is over the line that is causing the problem as it could be the other side next to the lead. With the glass in place and using your cartoon pen, trace around the lead onto the glass, then take it out and examine the line on the glass and compare it to the actual shape. If it is irregular, i.e. it has some high spots, grind these high spots off and check again to see if the problem has been solved.


Leading up a circular piece of glass without any gap is very easy with this simple method. Firstly start with a piece of lead that you know is a little longer than necessary to go around the glass. I find the best way to do this is to mark the glass and start rolling the glass along the lead channel until you've gone full circle and just past the mark about 10 mm, ensuring you have enough lead.

Then hold the glass and lead together at this mark securely so the glass doesn't move as you wrap the lead around the circumference of the glass until the lead is completely around the glass and overlapping where you started.

Then peel back the lead that is now overlapping the other end at the mark - enough so that you can now open up the other end of the lead that is closest to the glass, but don't let the glass move and then bend the overlapping or 'longer' end around the glass. Mark the lead with a lead knife just a fraction past the mark, now unwrap the lead enough to remove the glass and cut the lead where you've marked with your knife and wrap it all up again. You've now wrapped up a circle.

The only thing to be certain of is that neither the glass or lead doesn't move from where you've marked as you first begin to wrap it up.


Most leads are structurally strong within themselves and looking at the chart of lead cross sections in Lesson 2, some leads have a lot of ‘meat’ on them in the leaves – some more than others. One lead to definitely avoid in your leadlights is 4.2, as the leaves on this lead are very thin making it the weakest structural lead. The next weakest leads that I avoid are 4.7 then 5.0, all the rest are OK and there are quite a few to choose from. It is odd that a 4.6 lead has a lot of meat on it and is a very strong lead, yet a 4.7, a slightly larger lead is not as strong because it hasn't got the same amount of lead in the leaves. (You only have to look at the lead profile chart in Lesson 2 and you will see there are 116 x 4.7 leads in a 15 kg box, but only 77 x 4.6 leads in a box, so there is a lot less lead in a 4.7 making it a weaker lead. Same with a 5.0, there are 114 in a box, 5.02 has 70, which makes it a stronger lead and a better choice. What I'm also saying here is you won't pick the difference between these weaker leads than the stronger leads with the naked eye when you are looking at the leadlight, but the leadlight will thank you for it. Yes there are more leads in the boxes of these weaker leads if you are buying it by the box, but it is false economy.)

There is another unwelcome side to these leads that have very thin leaves and that is the problems caused in soldering - thin leaf leads are so easy to melt so beware! The 4.6 lead is the easiest lead to solder, and 4.7 is the worst. Just another thing to consider when choosing your leads.

(If you live in a country other than Australia, you may want to have a look at a lead profile chart of lead that is produced in your country, but if that's not possible, when you buy your lead just remember to refer to the above paragraph and the chart in Lesson 2 first and select appropriate leads in regard to strength.)

I can only think that making the leads with more or less meat on them stems from an earlier time but I see no reason for it today. Whether a lead has less or more meat on the leaves does not, in my opinion add visually to the leadlight, one would never know when looking at the leadlight square on to it, but it is a strength issue. Just another thing I will never understand.


I am definitely NOT in favour of tapping the glass pieces into position as you go because narrow pieces can be broken. I prefer to ‘tighten’ the leadlight after putting on the last two pieces of beading one at a time. Most people who tap the glass do so because the pieces are usually too big and/or poorly cut, or the lead isn’t fitting correctly and they tap hoping to get near the cartoon line. This should never be necessary if your cutting is accurate.

In most cases, for leadlights in a timber frame, when putting on the last two outside leads, the one that is closest to you goes on first after removing the horseshoe nails that are holding everything in place along this side. Make it also longer than necessary by about 25 mm and leave the horseshoe nails and U leads on the remaining 4th side to keep everything in position. Now put the 3rd bead in place but don’t nail it down until you tap along it to 'squeeze' it up to tighten in this direction, checking to see the pencil line as you go. When all is OK nail the bead down. The next thing is to cut the last outside lead to fit in between the other two outside leads, then tighten up in this direction with the last piece of beading the same way. Again check to just see the pencil line then you know it will fit. If you don’t cut the outside leads this way you can’t tighten the last side.

Leadlights in aluminium frames are still tightened using the same method when putting on the two outside Y13's, but because the Y13's are mitred, it doesn't matter which one goes on first.

For circular or oval, wooden or aluminium windows, see Lesson 5 for tightening instructions.

After soldering the second side, trim to length the three outside leads that were cut originally 25 mm oversize. (See next lesson for turning leadlights over.)


Leadlighting Tutorial Lesson 1: Cutting Glass for Stained Glass Leadlights the Right Way

Leadlighting Tutorial Lesson 2: How to make a leadlight. Get started with a simple clear glass leadlight. Design choice.

Leadlighting Tutorial Lesson 3: Assembly of a Leadlight and helpful hints.

Leadlighting Tutorial Lesson 4: Soldering a leadlight and using the right flux. Making a tinning pot.

Leadlighting Tutorial Lesson 5: Measuring and other things you need to know.

Leadlighting Tutorial Lesson 6: Advanced Glass Cutting - methods for difficult shapes.

Leadlighting Tutorial Lesson 7: Puttying and how to repair a broken leadlight

Leadlighting Tutorial Lesson 8: Reinforcing - how, when, where and why.



John Jackson (author) from Australia on February 20, 2018:

Hi Zelda,

I am assuming, by maximum glass size - 300 x 150mm, is referring to an individual piece, in fact there is no maximum or minimum size to any individual piece. As you would understand there are many door panels, sidelights, windows that only have one piece of glass, so it makes no difference.

The text that you are referring to - 'cut out as much lead as you can' isn't a reference to glass sizes, it is merely to say that sometimes a design can be too lead dominant and by considering what lead lines can be eliminated will more often improve the overall design. That isn't to say that you MUST do that for every design, sometimes the lines are necessary for interpretation of the design - which is your call but it is still a good idea to run your 'eye of consideration' over the cartoon before inking it in.

In consideration of the design, it must be remembered that a door is the hardest place for a leadlight to survive slamming in wind, if you haven't protected it with a good door closer that works - softening the impact of a door slamming shut.

At this point I would suggest you look at Lesson 8, which is re-inforcing where door panels of the size you mention, 400 x 600, (as it is over the recommended 500 in at least one dimension) should be re-inforced with a 6mm zinc came. However, not knowing your design, I know that the straight line of a zinc came might tend to destroy what your design is representing. In this case you have to decide whether the straight line is acceptable to you and if it isn't, then a very good door closer is mandatory.

Hope this helps and best of luck in your endeavours,


Zelda on February 19, 2018:

Hi I am leadlighting a 4 panel (400mm x 600mm) door.

What is the maximum glass size you would use? Is no greater than 300mm x 150mm correct? I am trying to reduce the amount of lead used to reduce weight and I think I read in your information - cut out as much lead as you can? Thanks for the helpful tips.

John Jackson (author) from Australia on January 03, 2014:


I used what is referred to as knife-lube and I used to buy it in a tube about 70mm in diameter and about 300mm long. (That was some time ago now and I can't even remember where I used to get it.) I would then cut it up into 50mm lengths to sell to my students. Some hardware stores sell it, but as you don't need a lot of it, it may prove a waste to buy a whole tube.

If you live near a leadlight shop that does teaching, I'm sure you could buy some through them.

Failing that, you could use a very soft soap, which is an old carpenters trick when screwing a screw into a hard timber - it acts as a lubricant and will be just as good. Just remember to run the blade into it to get a good coating on it every time.

As lead is already a greasy metal composition, using an added lubrication will greatly help your lead knife to hold its sharpness reducing the amount of time spent sharpening your knife. You will find using some form of lubrication, the knife will slip through the lead so much easier than cutting dry.

Sorry I couldn't be of more help to you but if you can't source it, the soft soap will be just as good. Hope I've been of some help to you and thank you for the question.

Best regards,


lead lubricant on January 03, 2014:

What do you use as a lubricant when cutting the lead?

John Jackson (author) from Australia on May 05, 2012:

Hi Michael,

Thank you for your comment and glad to have revived your interest in leadlighting.


Michael on May 05, 2012:

Great advice, haven't done leadlight in a while, thanks for gr8 tips & jogging my my memory again.

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