window putty

[plasticpigeon]

Hello

I think I have painted a window that I have recently puttied too early. I left it for about 10 days or so and the putty went a bit firm so I painted it. I have painted one coat of dulux trade oil undercoat. On one section of putty it seems to have made the putty soft, and has wrinkled slightly. Is the best bet to leave it to harden and give it a light sand before the next coat, or take off the bead of putty and do it again, and let it dry more this time? Thanks.

 

[worms]

PP, I don't know the answer, but I bet most of us have made the same mistake at some point...and will probably do so again!

 

[88v8]

In general, I would leave putty about 3-4 weeks, unless the sun's on it, and then start with primer rather than u/c.

Leave it another few days. No botox required. Just continue with your paint system.
I wouldn't try sanding it, the outer hardened skin is very thin and will not take the pressure of sanding.

Ivor

 

[DJH]

The secret is to paint over new putty with water first and a skin will form quicker.............

Doug

 

[Penners]

Is the best bet to leave it to harden and give it a light sand before the next coat

That's certainly what I would do.

 

[plasticpigeon]

I know this might sound daft, but what is the difference between primer and undercoat? The last window I painted I put on undercoat, followed by oil eggshell top coat and I was pleased with the finish. I have a primer that is a kind of vivid green stuff but i thought it was more of a wood preserver than a paint as it is very thin and sinks into the wood a bit.

Thanks Doug, I have another sash waiting to be painted. It's been sitting in my office for a week since it was puttied. I shall paint the putty with water on that one and see if it helps. Putty takes a lot longer to go of at this time of year than in the summer, even with the pathetic summer we had last year!!!

 

[DJH]

The cold clean water trick works best on freshly tooled putty Plastic, in other words straight away.... No matter how hard I tried I could never get a good even smooth finish with putty.

Doug

 

[stuart45]

I know this might sound daft, but what is the difference between primer and undercoat? The last window I painted I put on undercoat, followed by oil eggshell top coat and I was pleased with the finish.
!!

Primer soaks into the wood more and helps to seal any stains coming through. Undercoat covers any dark colours and gives a good base for the thinner gloss or satinwood.

 

[stuart45]

The cold clean water trick works best on freshly tooled putty Plastic, in other words straight away.... No matter how hard I tried I could never get a good even smooth finish with putty.

Doug

I use a flat knife rather than a putty knife. Sometimes I can get a good finish first time, other times it looks a mess. It depends on confidence with the tools I suppose like with the mastic gun. Getting the right pressure on the knife seems to make a lot of difference.
When you watch the glaziers does it they whip round it really quick and it looks perfect first go.

 

[philpjuk100]

Yes I am a bit impatient and usually paint too soon,especially on upstairs windows,"how much longer is this scaffolding going to be here?",I sand off any rough bits before a second coat.Does anybody else paint well onto the glass and then with a blade type scraper and shield scrape the paint off leaving about 1/16" on the glass? or are you more careful,or use masking tape?

 

[plasticpigeon]

I've found a small square ended knife like a small scraper to be much easier to use than a putty knife. Maybe that is the same a Stuart's knife. After a couple of sash windows I seem to have got the hang of it. I find it best when the kneeded putty will just stick to my hands.

 

[DJH]

I might get into trouble admitting this but I always bed the glass in the frames with clear mastic and then faced with putty. I find it's more resistant to water that settles on it when our windows condensate.

Doug

 

[plasticpigeon]

Its no good, I've ripped out the offending bits of putty. It is really weird but the putty is fine all round the window apart from the middle section of the central glazing bar where it wrinkled a bit. As this window is the kitchen window it is at head height when outside, so I want it to look really good. I hope I don't end up chasing the putty all round the window trying to get the perfect joint but if I have to so be it.

 

[Penners]

I've given up using traditional putty. Unless you're a professional glazier, or at least someone who uses it very regularly, I reckon it's well nigh impossible to develop the necessary skill to get a really good finish.

Nowadays I bed the glass in butyl putty, then secure it with a quadrant moulding on the outside, also bedded on a thin strip of butyl putty. This seems to be the way that a lot of glazing is done nowadays, and I reckon it's a hell of a lot easier to get a good, neat job.

Butyl putty is much less sticky than linseed oil putty, and easier to mould into a strip. It's available just about anywhere - here's one example: http://www.toolstop.co.uk/index.php?option=shop&page=shop.product_details&product_id=41537&l=uk&utm_source=google&utm_medium=base

 

[MatthewC]

I've got some sash windows to repair later this year, so here's an idiot's question: should one apply linseed putty to bare wood or should it be painted? If so, with primer, undercoat or gloss? (To my thinking, gloss might make the putty less liable to stick...)

NB Much as I like Penners' idea of butyl putty and a quadrant moulding, I don't think my frames have sufficent depth to take a moulding (although I could be tempted to try).

 

[88v8]

To get a good finish on linseed putty, dip the putty knife in water, then it won't drag.

When painting, I use a cutting brush and lap the top coats only - not the primer or u/c - slightly onto the glass.

Ivor

 

[plasticpigeon]

I've managed to get a decent finish, I'll put up a picture. I'll persevere because I like the finish and it's traditional. Matthew, the frames have to be sealed with something otherwise the oil in the putty sinks into the wood and it will crack. I have painted mine with undercoat before doing the putty. On one rebate I wanted to put the glass in quickly so I used knotting compound, as I had some, but I think any shellac based polish would seal in a short time. However as you can tell I'm not an expert as I had trouble with a section staying too soft and I don't know why!! All part of the fun I suppose.

 

[middi]

Glazing putty ( or linseed oil putty) has been on " death row" since the advent of double glazing and the extinction of the commercial wooden glasshouses of yesteryear. It is one of those materials that is hardly ever used in the building trade nowdays and like the traditional buildings of yesteryear we can figure out how they are put toghether but do not really understand what make them " tick ".

As Penners mentioned, glazing nowdays is mainly silicone and beading ( single or DG) simply because the transition ( evolution if you like) has been made from one building method to another.
We, the custodians of single glazed listed buildings, are left " holding the baby" with little understanding as to how to look after it.
Putty needs to be of a certain consistency and texture for a speedy application ( a putty glazier would always "adjust" the texture of HIS putty that is best suited to his method of application ). The tool ( or putty knife) are as varied as there are glaziers and would have ranged from plastic strips of the late 50's, broken table knives and purpose made soft and hard " putty knives". Experience in understanding and application was the "key" not the utensil.
As to painting putty after application ( linseed oil putty), This should be done after the" crust" has formed in the top layer of the putty. This " crust" is the slow drying and evaporation of the oils within the top layer and is reasonably firm to the touch. This drying process may take a few days to a few weeks and dependant on the 4 seasons and temperature. The Drying rate of the putty is also dependant on the type of wood and if it has been primed or not. A primed wooden sash bar will delay the drying process ( and reccomended). The intention should be to paint the putty when a hard exterior skin has formed but still maintaining a slightly malleable interior. If putty is not well maintained with a covering of paint that seals those oils within the core of the putty it will become bone dry, it will crack and eventually fall off leading to deterioration of window frames etc..

( I learned all this from a putty glazier in the 60's whilst glazing the 200 ft long glasshouses at my father's cucumber nursery in the lea valley area)

Middi

 

[worms]

I've got some sash windows to repair later this year, so here's an idiot's question: should one apply linseed putty to bare wood or should it be painted? If so, with primer, undercoat or gloss? (To my thinking, gloss might make the putty less liable to stick...).

I've always run a a little linseed oil over the rebate before applying the putty - I guess on the same principle as wetting the wall before doing lime pointing. The oil requires a coffee and kit-kat break to give it time to soak in, though, so it does slow down the process.

Temperature of the putty also makes a difference and my recollection of traditional glaziers is that they worked it with their hands a bit first to soften and warm it.

 

[Penners]

The oil requires a coffee and kit-kat break to give it time to soak in

WARNING - do not regard the putty skinning-over time as a Kit-Kat break.