re-putty windows

[tsteele]

Hi everyone, I'm a new member...I've looked at this forum on the odd occassion, figured I should register.

I have a question regarding re-puttying some old windows. My house is 35 years old, and the old woodern frames are badly needing some TLC. The glass vibrates terribly in nearly all windows (you can push it out of the frame some 5mm), the putty is cracked and falling off, both front and back fill putty.... I have had one pane replaced a few years ago by O'Briens, and when they replaced it, they used white silicone to bed the glass in and then putty on the outside.....

What I'm wanting to know is what to use for bedding in the glass, silicone or putty, what's best ? Some frames also have beading instead of putty on the outside, and I'll either replace the beading or just putty instead.

Interested to hear your thoughts ?

Thanks
Tim

[Kev Y.]

Welcome aboard tsteele,

I am from the old school when it comes to windows, I was always taught to use putty to bed the window glass in, However I can see the advantages of using silicone instead.

If the windows are old and dried out, you may need to clean them up and apply a coat of timber primer paint before re-installing the glass. I would still be tempted to go with the putty, (easier clean up)

On the topic of the beading, Some windows are designed to have the wooden beading to hold the pane in place, I dont think it is a good idea to alter the fixing method ( I stand to be corrected here). Again, remove the beading, intact IF possable, remove the glass, clean up the frame, reapply which ever bedding substance you choose, refit the glass, and refit the beading.

From memory (from 25+ yeas ago) when fixing windows using putty only, we used to hold the glass pane in place with a couple of small brads, then apply the putty over them.


Hope this has helped.

[Stu]

Re did most of an old house a few years ago. Once making sure I had removed all old putty I then primed the whole window (quick and easy with the glass out) used putty in behind the glass, small galvanised brads to hold the glass in place and then putty.
Hardest part from memory was getting the putty looking right on the front of the glass, takes a bit of practice (and to be honest more than one go on some of the panes). Also important that once the putty is dry (24-48 hours from memory) it is primed before the cracking process starts all over again.
Enjoy

[markharrison]

Tim,

Unfortunately, I know a lot about this subject! I have written a brain dump of all that I learnt on the subject in an article that is published at Woodcentral. Additionally there is another article there on puttying windows.

In short, don't use silicone to bed a window. If you ever have to replace it the job will be a royal PITA. Remove the pane, use a primer of your choice (I prefer an oil base primer) and use a putty bed. Hold the pane in place using glazing points (Bunnings carry them but in the picture framing department). The ones I use do not require any special tools and they look like this.


Place the back against the glass so the tabs stick out and push down with a putty knife or paint scraper on the tabs. I find the paint scraper to be the easiest.

One problem you will face I didn't cover was removing a window to re-putty but keeping it intact. As you have noted, the putty gets extremely hard when it is old. If the window is already broken (which in my case was true) you can just use a heat gun to soften the putty and ignore the new cracks in the glass you are creating. Just using a chisel on the putty will almost certainly crack the glass trying to get the putty off unless you are very careful.

I have given this some more thought as I have some more windows to do where the glass is not already broken. I intend to use a trim router, a bearing guided pattern bit and a wood guide (stuck to the window frame with hot melt glue) to guide the bearing.

I haven't tried this yet (this job will start in February) but I think that this is the best method.

If you have any questions let me know.

Regards,

Mark

[wombat47]

Mark has said it all.

The glazing points are wonderful little animals!! They push in so easily. In the old days of brads and hammers, it was a bit too easy to accidently hit the glass with the hammer, or the brad would slip too close to the glass.

I know from experience that it is possible to apply heat to the putty, without cracking the pane. Hold the heat gun so that the hot air is directed sideways towards the timber frame - the putty feels the heat, not the glass. Use the heat gun on the lower setting, and don't take your eyes off what you are doing for one second!

It sounds as though your timber frames might benefit from an application of Penetrol prior to priming (this will stop the timber from drawing too much oil from the putty) and you might consider adding some Penetrol to the primer.

Mark .. our local glazier uses a router if reputtying a few windows. But I wonder what happens when it hits the brads??

Most of my experience with reputtying windows comes from present home, built in the 1890's, a lot of windows and I don't think any of them had been reputtied since the house was built. All of them had at least one sash cord broken, and several had cracked panes. In some of the windows the putty had had the decency to fall out completely!!

To replace a sash cord, you have to remove the sashes. And while you have it out, you may as well refurbish it - much easier to do with the sash lying flat on a bench or table. However, two rules apply to sash removal.

1. Do it on a day that the glazier is open
2. Have a sheet of heavy plastic, big enough to fit the window opening, on hand BEFORE you start. The removal of a window seems to have some effect on atmospheric pressure - no matter how blue and clear the sky is when you start, rain clouds will appear from nowhere.

[silentC]

I was a glazier for a few years. Whenever we reglazed a timber window, we always bedded the new glass with silicone. If the frame would take a bead, we would use one unless the customer specifically wanted putty. I have reglazed windows previously glazed with silicone and there is no particular problem. I'd rather remove silicone than old putty any day of the week. Putty = time = money.

[TheDad]

yep the push in brads are the way to go for "the home glazier", unless you know a glazier with a bradder who will let you use it.

I spoke to my local glazier (whom I worked for after a couple of the big hail storm we get here!) and after doing 10 or 20 panes in one day he said that to remove putty (broken of course) a heat gun helps a lot.... on site a butane one. to redoo he uses back putty not silicon, but he is due to retire this year....

A real pleasure to see him work, does it with his eyes closed almost.

his pet hate? steel frame windows, a real... to do as it is almost impossible to remove the old putty, don't know why really..

and that is my 2 cents worth.

rounded up to 5 cents including GST

[markharrison]

silentc: Bedding a window with putty is perhaps a couple of minutes work. I doubt that there is much to be gained in productivity with silicone.

The external mitred bead of putty is another matter. I'm too slow to make a living at this skill that's for sure )

[silentC]

I was mainly talking about removing old putty vs. old silicone. However, I can tell you from experience that squirting a bead of silicone around the rebate and pushing in a sheet of glass (seconds) is much quicker than kneading putty and pushing it in inch by inch (minutes). Let's get together and have a race

[GeoffS]

I've been thinking about this discussion for a day or two!
The arguments for and against bedding with silicon. Having watched some old time glaziers who could squeeze a ribbon of putty as fast as I can use a glue gun I'm not sure that the argument about speed holds. I will admit that for the amateur the silicon gun would be quicker but a bit of practice with putty might be worth the effort.
On which is easier to remove - well I have not removed glass from a 100 year old window bedded with silicon (?). On more recent windows I reckon putty is easier, silicon tends to stick like --- to both the glass and the wood. Damage to the timber is hard to avoid. This may partly be due to the fact that if silicon is used the timber should not be primed and the silicon gets into the grain.
As to the outside finish I prefer the putty. Once again an experienced glazier does it so easily and quickly it is quicker than beading. I don't like beading as such small bits of timber do not weather well. Frequently the seal between the glass and the beading does not extend to very outside edge allowing water to get to the unprotected back of the beading.
Will this extend the argument???
Cheers

[Sturdee]

I am not an expert but over the years I have reglazed enough windows at home.

I have used putty to bed the glass in but two years ago I started using silicone. Much easier and quicker. Would not use putty for bedding in again.

To remove old putty etc from the window I use my angle grinder with face protection and a dust mask. Romoves old putty, small nails and even the little bits of glass with ease.


Peter.

[silentC]

OK, you might anticipate that there is a reason many/most glaziers these days have switched to silicone + timber bead. It's less labour intensive and less training is required. Any idiot can do it.

There is a call for doing it the old (hard) way because there are still plenty of people around who a) like the look of puttied windows and b) have a perception that it is higher quality and more durable.

Let me say that if you don't keep the paint up to putty, it will deteriorate as quickly as timber. In fact, if you use cedar for the bead as we used to, the timber will probably still be looking good long after the putty has cracked and fallen out.

On the subject of cleaning old putty out vs. old silicone, I have done both and, I say again (is this the 3rd time now?) that I would rather remove old silicone than old putty ANY day of the week. Old putty is VERY hard. It is quite difficult to remove it without taking timber with it. Some times you are lucky and the old putty falls out but more likely it is like rock. I defy you to remove it without damaging the frame.

Silicone on the other hand peels off like, well, silicone off a window frame. It sticks to glass like the proverbial to a blanket but it's grip on timber is not anywhere near as strong. Why? Because timber is porous whereas glass is not. At least that has been my experience.

Geoff, no doubt you are right. The old timers were pretty quick in their day (a dying breed now) but I still bet I could get my glass in the hole quicker than them. I'd even give them a head start.

Now, how does any of this help Tim? He will have to make up his own mind. The traditional way is putty all round. A hybrid method is silicone inside, putty out, although I can't see the advantage of this. The modern way (for timber framed windows) is silicone inside and timber bead out.

Tim, are you there? Hello?.....

[zok]

I, too, am a new member to this forum. I have a question regarding old windows and new BASIX restrictions. Is it possible to replace the old panes of glass in double-hung sash windows with comfort or double-glazed glass?

Thanks.

Zok

[Ashore]

I use silicon and timber beading whenever I can but if required will re putty have not used those glazing points as I have my old dad's sprig gun and a good supply of sprigs, these are also great for picture frames .

With the silicon make sure you use an anti bacterial type as you don't want mould growing on it

Rgds

[journeyman Mick]

Zok,
welcome to the forums. You'll find you'll get more people responding to your questions if you start a new thread. Go up this page till you get to the blue link that says
" Woodwork Forums > HOME RENOVATION > DOORS, WINDOWS, ARCHITRAVES & SKIRTS ETC > re-putty windows
Reply to Thread "
and click on the "DOORS, WINDOWS, ARCHITRAVES & SKIRTS ETC " section. You'll go to the main part of that particular forum and then you'll need to find and click on the red "new thread" button near the top of the page on the left hand side.

Mick