# Window Glazing question



## Bob Mariani (Dec 1, 2008)

why are you painting the glaze?


----------



## DIY DUDE (Oct 15, 2009)

Bob Mariani said:


> why are you painting the glaze?


I've never seen a window around these parts that didn't have the glaze painted.


----------



## Bob Mariani (Dec 1, 2008)

you need an oil primer. did you use one? and the glazing should be cured.


----------



## DIY DUDE (Oct 15, 2009)

Bob Mariani said:


> you need an oil primer. did you use one? and the glazing should be cured.


Yes, I used SW oil primer, then glazed, then primed again, and painted. I'm just curious as to whether or not I should remove the glazing that has hairline cracks on the remaining windows?


----------



## Bob Mariani (Dec 1, 2008)

you should be able to flatten them out. Maybe adding 50% penetrol to the paint.


----------



## Windows (Feb 22, 2010)

I am redoing my double hung windows and I have found them to be an incredible amount of work already - so if the glazing is intact, I leave it be. No sense making work when the old glaze may last another 30 years or more, or might even outlive the sash. THe way I see it, the sash will require routine maintenance/painting every 7 years or so, and I'll catch any problems on a future cycle. If I find cracking in the paint and the paint is still well adhered to the glaze, I just put a little glaze in the cracks, smooth it with my finger, give it a few days to set up, prime and paint it. I think of it as a realistic solution for a very minor issue.


----------



## Windows (Feb 22, 2010)

One more point about not removing all the glazing -- I have found on some of my windows that they were not bedded properly, or that the bedding has fallen away with time so the panes rattle a little, and that has made me want to remove all the glazing so I could re-sit the glass. What I do instead is place the sash glazing side down on sawhorses and with a very small cut in the tube, caulk around the edge of the glass with acrylic DAP. I let it set up for a bit, then flip it over and place missing points and the rest of the repairs. Doing this has created a great seal on windows where the glass wasn't sitting right, and is about 1/100 of the work of removing the glass to bed it properly with glazing.


----------



## ccarlisle (Jul 2, 2008)

Are you talking specifically about the exterior putty? or the interior?

A good quality linseed oil putty should last a good twenty years and should be painted with an oil-based paint. If however a latex is used then the linseed oil putty has to be given plenty of time to dry out before painting. What type and brand of putty did you use?

Furthermore, the paint film should completely cover the putty and even a millimeter or so onto the glass to provide a barrier against air and water infiltration.


----------



## DIY DUDE (Oct 15, 2009)

I'm going to attempt to getting a couple of pic's on here, then you can see what I'm talking about.
This is taking the glazing knife and running it against the glass and glaze. Would you guy's remove all of it or just fill back in what has come out?


----------



## Windows (Feb 22, 2010)

The recommended method is to remove all the old glaze. 

I scrape out all that is loose and can be reasonably removed, and glaze over whatever remains.

FYI - that is not alligatoring.


----------



## Bob Mariani (Dec 1, 2008)

you need to remove all the glazing


----------



## DIY DUDE (Oct 15, 2009)

Thanks guy's.\
I've already got the heat gun and glazing knife going:whistling2:


----------



## ccarlisle (Jul 2, 2008)

Yeah...personally, I'm surprised you even had to ask. 

No question. Just replace with a good putty. Then alkyd from a paint store, like BenjaminMoore or SherwinWilliams; this is tough work, so no time to cheap out - because you don't want to come back next year with
the same problems.


----------



## chrisn (Dec 23, 2007)

Oil prime before and after.:whistling2:


----------



## ccarlisle (Jul 2, 2008)

We've had good results with DAP '33" linseed oil-based putty for the exterior, when we've had to reglaze over new wood. Now my teacher used to use boiled linseed oil as a primer as his theory was that the linseed oil primer prevented the oils in the putty from being absorbed into the wood too fast. That's the way _he_ was taught back in the 30's.

He didn't think much about using an alkyd primer over the bare wood instead as he didn't like a film layer between the wood and the putty; yet at least one preservation consultant I read seems to go along with the alkyd primer...maybe has more to do with the type of wood?

Anyway, priming one way or the other of new -or old -wood is always recommended. Good catch, chrisn...!


----------



## chrisn (Dec 23, 2007)

ccarlisle said:


> We've had good results with DAP '33" linseed oil-based putty for the exterior, when we've had to reglaze over new wood. Now my teacher used to use boiled linseed oil as a primer as his theory was that the linseed oil primer prevented the oils in the putty from being absorbed into the wood too fast. That's the way _he_ was taught back in the 30's.
> 
> He didn't think much about using an alkyd primer over the bare wood instead as he didn't like a film layer between the wood and the putty; yet at least one preservation consultant I read seems to go along with the alkyd primer...maybe has more to do with the type of wood?
> 
> Anyway, priming one way or the other of new -or old -wood is always recommended. Good catch, chrisn...!


 
I would also use the linseed oil if you can still find it,I have had a gallon container for about 20 years now and still use it.


----------



## jce (Apr 2, 2010)

*Chris*

I would have to dbl check , but I believe your local SW store could get you some linseed oil through sher-source ordering program.


----------



## Skuce (Nov 2, 2009)

That glazing putty looks to be getting close to the end of it's life.

How I'd go after that would be:

Remove old glazing.
Remove Glass.
Clean glazing rabbet.
Brush good quality Boiled Linseed oil w/ maybe 10% turpentine in the rabbet. You could also heat the Linseed oil instead of the turps to get the pentration.
Let that cure overnight at least.
"Lightly" prime the rabbet with a good oil primer.
Bed layer putty, set glass, points, top layer putty. Use a good Linseed putty. Something like SARCO M or Dap "53" (Linseed based) in the USA. Not a fan of Dap "33" since it's Soya oil and Petroleum Oil based.
Let the putty Skin for at least a week.
Prime with same oil primer.
Paint as you like.



Never use anything that comes in a caulking tubes. It will give you nightmares later on down the road.


----------



## chrisn (Dec 23, 2007)

Skuce said:


> That glazing putty looks to be getting close to the end of it's life.
> 
> How I'd go after that would be:
> 
> ...


Good advise:thumbsup:


----------



## ccarlisle (Jul 2, 2008)

I just found it difficult to obtain less than 5-lb quantities of Sarco M putty, hence the 'DAP 33' choice - for _our_ purpose which was small...

Again, I bow and defer to professional glaziers and restorers out there but IMO, I would see very little *practical *difference between a putty based solely on linseed oil and one based on soyabean oil+solvent especially when alkyd primers are involved. Traditionally and historically, yes, then linseed oil-based putties are the choice, but once you add a 'good alkyd primer' then automatically, you're into the "modern-day approach, aren't you? 

I don't know enough about the advantages of modern-day putties vs. the linseed oil-based ones - if pushed I'd say both are equivalent - but the technicalities of using one or the other are way out of my league.:laughing:

Very interesting thread however!


----------



## ccarlisle (Jul 2, 2008)

Succinctly put, JMPainting...what, the thread blew you away, we're all full of it - or what?


----------



## JMDPainting (Sep 7, 2009)

ccarlisle said:


> Succinctly put, JMPainting...what, the thread blew you away, we're all full of it - or what?


No, I posted my response before seeing the pic's of the windows , so my info no longer fit the situation.


----------



## Skuce (Nov 2, 2009)

ccarlisle said:


> I just found it difficult to obtain less than 5-lb quantities of Sarco M putty, hence the 'DAP 33' choice - for _our_ purpose which was small...
> 
> Again, I bow and defer to professional glaziers and restorers out there but IMO, I would see very little *practical *difference between a putty based solely on linseed oil and one based on soyabean oil+solvent especially when alkyd primers are involved. Traditionally and historically, yes, then linseed oil-based putties are the choice, but once you add a 'good alkyd primer' then automatically, you're into the "modern-day approach, aren't you?
> 
> ...



True enough.

If it was a full restoration. I would just soak the glazing rabbett in a protein-free mix of artist grade raw linseed oil, non-metal dryer boiled linseed oil and a small amount of turpentine.
Makes the oils stay in the putty instead of migrating out to fill the old, dry wood. If the oils leave the putty...you get it failing far too soon.

The primer is more of a redundant measure.

If you Don't do a linseed mix on the glazing rabbet...you MUST seal it. So the oil primer or shellac is imperative. 
If you Do put on a linseed mix to saturate the wood...you can go either way.

Putting the linseed oil mixes on the raw wood with/without an oil primer is a good policy. It stops the wood from taking on water. It also makes the wood more similar to being "fresh wood" than the 60, 90, 150 year old wood that it actually is. It also acts as a minor stabilizer in the wood by refilling the cells.

The Practical difference between the putties is the drying/skinning schedule....which also dictates is overall lifespan.

True Restoration grade takes about 50-70 years to fully cure. You can leave it out on the table for weeks and it won't skin over enough to paint with Modern paints. The drying oils in it are so slow to oxidize that modern petroleum paints wrinkle the surface. They shrink when they dry.
So a historic Linseed Oil Paint has to be used. It will skin over the putty in a day. It also can be painted on the putty as soon as you lay it down!!!

Next you have the DAP 33 putty. It's a Soya oil based putty with a non-drying petroleum oil added to it. It takes forever to skin over (ie: about 4-6 weeks). It's nice to work with...but I don't like the idea of the added Petro Oils on my hands all the time. It also gets really sticky in hotter temperature in the summer.
DAP has also just recently changed thier putty formula. It used to be the awful mix that actually contained a CEMENT in it! You want a putty to be slightly flexible for years...not turn to concrete.
This new mix is better....but it hasn't been on the market long enough to see how it fails after 10,20, 40 etc years.

The DAP *53* or the Sarco M, Old Time Putty or LPL Putty/Mastic are all Linseed Oil based putties. They skin over in 1-2 weeks. So Painting with an alkyd primer is easy. Same with a water based primer. It will bite after a couple weeks no problem. It also bonds with the traditional Linseed paints (obviously. lol)

I'm going to stick with the Linseed putty in my business. I will use the restoration grade putty when I know I will be using a linseed paint on a very historic window. Otherwise, I'm going to stick with the linseed putty my Grandfather used to use ( I do have a small tub of DAP 33 in case of emergencies though ;-)


----------



## ccarlisle (Jul 2, 2008)

Very interesting! Are you saying, Skuce, that old putties never skinned over for 50-70 years? and if so, did they use linseed oil-based paint for that reason? i.e to keep it flexible? If so, why is old putty so hard to get off?

And, does that mean that old _painted-with-linseed-oil-paints _putties were somewhat flexible for most of their lifespans?

I had the idea that the clays in the old putties had something to do with moisture retention...a bit like they do in saltilo tiles... or adobe. Hmmm.:huh:


----------



## Skuce (Nov 2, 2009)

Ok. Old putties did skin fairly soon. Especially if they had metal drying agents (japan dryer, etc) in the mix. The Skin then also acts as a barrier to prevent the core putty from oxidizing. Adding paint on it too helps keep the oxygen out that makes the oils harden.
The 50 years is the length of time that a high quality putty should stay flexible. Not the flexible in the sense that you think of like silicone caulk, or a car tire. The flexible in the sense of moving with the expansion and contraction of 2 dissimilar materials (wood & glass) during temperature changes.
So yes. It should be flexible in that sense for years and years and years.

There is a neat little trick here.

If you paint your linseed putty in a linseed paint, you can do something very, very cool. (Alkyd and Latex/Acrylic paints can't do this)

Every 5-7 years go over all the putty with an artist grade, boiled linseed oil. It basically renews the oils in the putty to near-new condition. So your putty should last you 300 years+ if this schedule is kept up. There are plenty of examples in Europe and a few in New England of original putty still being on windows that is over 250 years. All because of the scary word "Maintenance".

Same goes for traditional Linseed Oil paints. Re-coat every 5-7 years with an artist grade linseed oil and you will never have to repaint in your lifetime...and probably not in your kids lifetime either.

Also...it isn't a Clay that is in putty. It's Chalk/Calcium Carbonate powder.

When you see putty that is failing. It's probably because it's had Zero maintenance done to it since it was put on. So the putty has completely oxidized, gone hard. It also has probably had the paint finally fail on it so the water has gotten in and washing away hardened oil and chalk powder. When you actually think about it, it's pretty amazing how well it does perform with that kind of negligence for decades and environmental abuse.

Keeping up the 5-7 years treatment of linseed oil on the putty. No reason whatsoever that it won't last centuries. 

Try getting that kind of performance out of some goop in a caulking tube!


----------



## ccarlisle (Jul 2, 2008)

Oh, OK then I stand corrected on a number of fronts. Thanks Skuce...

Do you see a lot of linseed oils paint jobs in Ontario? Not necessarily historical jobs, but just for thr long-term economics of them?


----------



## Skuce (Nov 2, 2009)

Starting to see them here and there. Especially after the whole "Alkyd Paints are Evil" thing going around all the box stores.

Acrylic/Latex tech just hasn't caught up to where Oil paints have been for wear resistance and overall longevity.

It's funny. I'm restoring a set of windows right now from a 1937 house. Taking them down to the original wood and starting over.

The original paint that is on the very bottom is this nice Blue linseed paint. The 2nd layer looks like a very early 1/2 linseed 1/2 Alkyd paint. All others are a typical Alkyd. The most modern is an exterior latex.

The Latex and Alkyds all are peeling and cracking and falling off. Takes nothing to strip them off. The very bottom layer of linseed paint will NOT come off at all. It looks like they repainted just for the fact that there was no maintenance done to the linseed paint and it literally wore out. No cracking, No peeling, Nothing. It's right into the wood. All the other paints that came after it are no where close to the original paints' durability.

The problem with modern paints is that they are simply plastic films that covers the surface . They do not penetrate to "root" into the substrate at all. They just skin the surface. That's fine and dandy till the first crack shows up.

Linseed paints go into the wood a LONG way. Sometimes up to 0.5" or farther. So it functions a part of the wood, instead of a sheet of plastic.

The term "Paint failure" is a very modern term. Over the last century we have gotten use to paint lifespans getting shorter and shorter. Now people are used to repainting every 4-6 years because of complete paint failure. A hundred years ago people were pissed off if they had to re-paint every 40-50 years!!

I can guarantee you there will be a resurgence in the use of Linseed paints in the next couple of years. I love the irony that it was 130 years ago that Linseed paint was the be-all and end-all. We're right back there again...cause it's simple...and it works!!!


----------



## Skuce (Nov 2, 2009)

Bumping back up


----------



## restorationdude (May 28, 2015)

Sorry for necroposting everybody, but I feel it is warranted since the durability issue has come up...The Allback paints and putty started making their entrance in the US market about ten years ago. Skuce, can you report on their durability since you began their use? Thanks in advance


----------

