Putty advice for sash windows

[Bingy man]

Neither was my father taught or told to remove the pins before final putty up. He always used pins, as did his apprentice (and the apprentices apprentice). My dad knew about glazing sprigs but never used them. In fact in the training chain the only person who used sprigs was the last one and that is because the (Council) COW insisted on inspecting before final Putty Up and the use sprigs was contractual. And the COW did not want the sprigs removing.

Glazing only cracks where the pin or sprig is because the metal is NOT flat to the glass.

Tbh I think it was a security issue as the local crooks would happily remove the putty gain entry , rob you blind and be kind enough to refit the glass before they left ,I was taught to slide the small pin hammer against the glass and gently tap the pin home as you said the pin is parallel to the glass not angled but I do see jacobs point but I never had any issues.

 

[niall Y]

Just because, one doesn't find glazing sprigs on some old windows does not mean that this is the norm. Because, equally, one does find them used.

Where they are difficult to use, and possibly best avoided, is on very thin glazing bars, where one is in danger of splitting the thin fillet of wood left between the panes, or even worse hitting an adjacent pane of glass and cracking it. Where there is enough meat on the stiles and rails this is not a problem. And if one is so minded, then they can even be tapped below the surface, off the edge of the glass, as one proceeds with the puttying.

I find sprigs a lot easier to use than panel pins as you can slide them flush on the glass Using a heavy firmer chisel instead of a hammer also helps as the bevel can be slid on the surface of the glass which helps stop them veering at an angle when they are going in.

 

[Glitch]

Can I recommend toupret brand glazing putty. It's basically modified linseed oil putty. Easy to use, white, paint in a few days, doesn't stink to bad and doesn't crack and doesnt smear. £9 a pot from the dulux centre. I reckon those water based heritage sealants are fine for double glazing but not that easy to use and not traditional for resto work.(not cheap either.)

I've just used the Toupret putty to replace some old cracked stuff.
Much easier to use than traditional Linseed putty.
Takes a few days to skin over.
Will have to see how durable it is but the reviews are encouraging.

 

[RupertV]

Left in they can fail by rust getting at them and causing cracks in the putty.
Also being a tight fit any shock to the glass can start a crack next to the pin.
Also they are pipper to extract if trying to take out a piece of glass, especially if rusted in.
If nailed in too tight they can start a crack at any time.
I did a lot of repair/restoration, mostly sashes, as well as new stuff and found these things out for myself - firstly by noticing that original old work never ever had pins or sprigs left in.
PS but of course you can leave them in and safe a few minutes on the job, and you might get away with it!

I haven't glazed a window in years but always used copper glazing (doesn't rust and were made for the job)sprigs which are like a miniature cut nail, tapped in with the edge of a bolster against the glass to below the putty line - never had a window crack (some done more than 40 years ago still good) and easy to remove with pincers. Job done.

 

[Jacob]

Just have to be patient with putty and wait for it to skin over. As a bonus you can leave it quite a long time before it must be painted.
In the end it's the cheapest, easiest to apply, longest lasting, easiest to maintain/repair.
Good idea to prime new work with stopping in rebates, on remedial work to apply linseed oil.
You can still buy 3mm horticultural glass which is often rippled and more like old glass.

Typo - "Knotting", not "stopping"

 

[Chubber]

I hesitate to post this in such a pedantic fashion in such erudite company but feel I must ....

Glazing sprigs should not be removed when the pane is set on a thin bedding of soft putty.

Consult the link I posted earlier - examine the pointed end of the illustrated sprigs. It is not some accident of manufacture that they are that peculiar shape. Just as a farrier's hoof nail has a bias cut point to guide it, so the tapered shape and pip steer the sprig gently against the glass.

It is inserted with the flattest straight edge to the glass, and generally set (for convenience) using the side of a 1" firmer chisel.

If you have one, a case-makers sprig set (hammer) shown below does a better/similar job.

Those of you that aren't already bored to a state of catalepsy will notice that the handle is offset to allow the long face to be slid flush/flat against the glass.

Feel free to call me a pedantic old scrote, although I prefer 'curmudgeon'......

Excuse me if I have repeated any previous post contents.

 

[Jacob]

I hesitate to post this in such a pedantic fashion in such erudite company but feel I must ....

Glazing sprigs should not be removed when the pane is set on a thin bedding of soft putty.

Consult the link I posted earlier - examine the pointed end of the illustrated sprigs. It is not some accident of manufacture that they are that peculiar shape. Just as a farrier's hoof nail has a bias cut point to guide it, so the tapered shape and pip steer the sprig gently against the glass.

It is inserted with the flattest straight edge to the glass, and generally set (for convenience) using the side of a 1" firmer chisel.

If you have one, a case-makers sprig set (hammer) shown below does a better/similar job.

Those of you that aren't already bored to a state of catalepsy will notice that the handle is offset to allow the long face to be slid flush/flat against the glass.

Feel free to call me a pedantic old scrote, although I prefer 'curmudgeon'......
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View attachment 185191

No need to apologise for being a pedantic old scrote I'm one myself! So I'm told.
Yes to the sprig flat side for better holding - panel pins have a head which means a very local point of contact and they take more force to tap in. That sprig hammer is a novelty! The point about sprigs is that they are easy to tap in with a pin hammer or heavy chisel, and they are easy to pull out.
You can leave them in if you wish but I never found them in original old work - I did loads of period windows including reclaiming the glass.
I also never used them in new work unless done in situ, where some support becomes necessary with bigger panes temporarily, but not permanently once the putty has gone off.
If left in they can become a problem and if sashes not maintained can rust and loosen putty.
Rusty panel pins are worse than sprigs to remove and I always associated them with badly fitted replacement glass, not original work.
But I hardly ever took glass out of any modern windows later than Edwardian, where big panes are common, but still without pins left in.
PS sprigs impossible to use with thin glazing bars such as you find in Victorian stuff, but completely unnecessary anyway with small lightweight panes.
PPS "Sprig hammers" seem to be a picture framers thing according to google. I'd never heard of them I'll have a look in Salaman.

 

[Fonix]

I’m pretty sure you can paint toupret putty after 7 days - at least that’s what I’ve been doing! Available from Screwfix.

 

[Jacob]

No need to apologise for being a pedantic old scrote I'm one myself! So I'm told.
Yes to the sprig flat side for better holding - panel pins have a head which means a very local point of contact and they take more force to tap in. That sprig hammer is a novelty! The point about sprigs is that they are easy to tap in with a pin hammer or heavy chisel, and they are easy to pull out.
You can leave them in if you wish but I never found them in original old work - I did loads of period windows including reclaiming the glass.
I also never used them in new work unless done in situ, where some support becomes necessary with bigger panes temporarily, but not permanently once the putty has gone off.
If left in they can become a problem and if sashes not maintained can rust and loosen putty.
Rusty panel pins are worse than sprigs to remove and I always associated them with badly fitted replacement glass, not original work.
But I hardly ever took glass out of any modern windows later than Edwardian, where big panes are common, but still without pins left in.
PS sprigs impossible to use with thin glazing bars such as you find in Victorian stuff, but completely unnecessary anyway with small lightweight panes.
PPS "Sprig hammers" seem to be a picture framers thing according to google. I'd never heard of them I'll have a look in Salaman.

Yes, Salaman says picture framers.

 

[Chubber]

Yes, Salaman says picture framers.

I'll take that, nice though, innit?

 

[duke]

I hesitate to post this in such a pedantic fashion in such erudite company but feel I must ....

Glazing sprigs should not be removed when the pane is set on a thin bedding of soft putty.

Consult the link I posted earlier - examine the pointed end of the illustrated sprigs. It is not some accident of manufacture that they are that peculiar shape. Just as a farrier's hoof nail has a bias cut point to guide it, so the tapered shape and pip steer the sprig gently against the glass.

It is inserted with the flattest straight edge to the glass, and generally set (for convenience) using the side of a 1" firmer chisel.

If you have one, a case-makers sprig set (hammer) shown below does a better/similar job.

Those of you that aren't already bored to a state of catalepsy will notice that the handle is offset to allow the long face to be slid flush/flat against the glass.

Feel free to call me a pedantic old scrote, although I prefer 'curmudgeon'......

Excuse me if I have repeated any previous post contents.
View attachment 185190





View attachment 185191

Now I have to look up three words which I have never read or heard before.

 

[Adamprince2]

Glazing sprigs are just for temporary use to hold glass in place if necessary whilst the putty goes off. Then should be taken out and made good with a dab more putty.
With small panes you don't need them at all. Bigger panes or windy/warm weather, then yes.
Leaving them in place is a common mistake, then if the glass is stressed any cracks are likely to be started by a sprig.
Putty goes off faster and is easier to clean off the glass if you give it a quick fine spray of water straight after finishing.
Putty can be thixotropic and soften if warm and manipulated. I found this out on windows close to a steep hill, where warm weather and vibrations from passing HGVs caused new putty to slump away. Cromford hill for those who know the place.
Soften cold or old putty by popping it in a microwave for 15 seconds or so.

My house has wooden sashes that are at least 100 years old. Some of the windows used flat metal "sprigs" and others did not. My area is very windy. I have seen glass fallout due to the worn putty without sprigs. I had plenty of cracked glass but have not seen one start at a sprig. The 100 year sprigs don't rust as long as they are covered by putty.

When reglazing glazing points as we call them in the USA have caused problems when trying to get a tight sight line.

I could see them rusting if they were not completely covered by putty.

 

[Cabinetman]

I've never really got on with using the timberglaze type stuff for pointing, I do use it sometimes but find it really hard to get a neat finish, it's just so sticky. I do use it (or similar) for bedding the glass in though as Olly describes above.

Hodgsons do a rapid set putty which does skin over and harden quicker than the multipurpose stuff. It seems like normal putty but comes with a little bag of white powder and no instructions.....

To get normal putty to set quicker I find the sashes are best stood outside in the fresh air, always seems to take longer if they are just kept in the workshop.

I suspect Doug that the bag contains whiting, it could maybe be added to the putty for a more solid mix, but I think the rapid set already has it added. But more likely the bag of powder is for poncing on or even brushing/dusting on to the surface of the putty, this would certainly make it less sticky.
Ian
Edit, I realised after that some might get the wrong idea when I used the word poncing, isn’t Ai good, I doubt I could have found the following without it.

In French polishing, "poncing" refers to the act of applying a fine abrasive powder, typically pumice, to the surface of the wood by lightly tapping it onto the workpiece with a cloth bag, essentially "pouncing" the powder onto the wood to fill the pores and create a smooth base for the shellac layers; it's a key step in the process to achieve a deep, even finish.

Key points about poncing in French polishing:

• Function:
  The pumice acts as a very fine abrasive, lightly sanding the wood surface while also filling the grain with the shellac that adheres to it.
  
  
• Application method:
  A small amount of very fine pumice powder is placed in a cloth bag, which is then tapped gently against the wood surface to evenly distribute the powder.
  
  
• Importance:
  Poncing helps achieve a smooth, even finish by filling wood pores and providing a better surface for the shellac to adhere to, especially on open-grained woods.

 

[Chubber]

My wife 'ponced' a talc-like powder onto cloth for making waistcoats having run over the lines of tissue patterns with a pointed star wheel.

 

[mwinfrance]

"Ponçe" in french means "to sand" as in abrade. what in English is called "sanding" in French is "ponçage" , note the "tail on the letter ç , it is a c cédille , that "tail" changes the c sound to an s sound . In English in those words, it already has an s sound.

Pouncing used to be the way that one would transfer a design onto dry plaster for fresco-secco ( fresco on dry plaster )
https://en.wikipedia.org/wiki/Fresco-secco

The design is drawn on large sheets of paper or light cloth, holes are then pierced along the lines of the design at close intervals.The cloth or paper is then placed against the wall, than tapped all along the lines with a small cloth bag ( into which has been packed coloured dust, nowadays chalk ) the bag has been tightly sealed , it is about as big as a fist. The coloured dust is forced through the holes by this tapping, thus transferring the design to the wall as a series of dots.the dots are then joined ( as in some children's "join the dots books" . The cloth or paper can be re-used multiple times if required.

These cloth or paper "preparatory drawings" are called cartoons*, from the Italian cartone ( meaning large sheet of paper or cardboard ) .The technique is very old .
https://www.royalacademy.org.uk/article/daniel-maclise-what-is-a-cartoon

This is the origin of the technique that your wife used, it is widely used in tailoring today.
It dates back to Raphael and beyond.

* the origin of the word cartoons as is used today for comedic / funny drawings, or animated drawings, 3D animation.

Btw ..the ç is the first thing that a signwriter learns in France. Because of the following.
In modern French, a builder or Mason is called a Maçon ( s sound ) he produces Maçonnerie or Masonry .
The word Maçonnerie contains çonnerie ..
If you don't put the "tail" on the c , it becomes connerie , which is colloquial / slang french for f*ck up
So Maçonnerie becomes maconnerie which means "my f*ck up" .

French masons are not happy when a semi-literate signwriter for gets to put the tail on the ç when signwriting the mason's vehicle or the boards that they place on their sites.

"Wags" , sometimes remove the "tail" from the adhesive letter ç on Maçon's vehicles or sign boards.

A female Maçon is known as a Maçonne ..there the ç is vital..

I'll leave you to use the search engine of your choice to find out why..the filters here would not allow my explanation.

 

[Cabinetman]

@Chubber and @mwinfrance most interesting, thank you, the things I learn on here!
- wonderful.