Black paint on putty

[woodspiral]

Hello,

I've got a lot of windows to renovate and they have all been painted gloss black on the outside. I'm going to be painting them white.

I've managed to burn off the paint on the frames but there's a lot of black paint on the putty. I can't burn it off, so do I:

1) sand it down and prime over
2) use paint stripper
3) something else - like a filler?

With 1) I'm concerned it will take forever and I won't end up with a smooth finish. 2) might be OK but I haven't found anything about using stripper on putty. Is it safe? Anyway 2) might take a long time too. I know, I know, window renovation is slow.

I was in Bath last weekend and saw a professional decorator using a white material which he had liberally pasted all over the woodwork - frame, muntins everything. I looked like he'd made a mess but I guess he was smoothing everything out. Does anyone know what filler it might have been? I should have asked him!

Also from what time of year is it safe to use putty as I have a number of panes to replace too.

Thank you,
Woodspiral

 

[Jacob]

Hello,

I've got a lot of windows to renovate and they have all been painted gloss black on the outside. I'm going to be painting them white.

I've managed to burn off the paint on the frames but there's a lot of black paint on the putty. I can't burn it off, so do I:

1) sand it down and prime over
2) use paint stripper
3) something else - like a filler?

With 1) I'm concerned it will take forever and I won't end up with a smooth finish. 2) might be OK but I haven't found anything about using stripper on putty. Is it safe? Anyway 2) might take a long time too. I know, I know, window renovation is slow.

I was in Bath last weekend and saw a professional decorator using a white material which he had liberally pasted all over the woodwork - frame, muntins everything. I looked like he'd made a mess but I guess he was smoothing everything out. Does anyone know what filler it might have been? I should have asked him!

Also from what time of year is it safe to use putty as I have a number of panes to replace too.

Thank you,
Woodspiral

I'd be extremely cautious about burning off. In fact I wouldn't do it at all. A good wash, rub down, light sanding etc and just get painting with good quality oil based white primer.
You can use putty anytime of year it won't come to harm as long as you paint it within a few months and before a heat wave.
PS don't use sprigs, except as a temporary fix if needed on big panes. Remove before you paint. They are the first thing to fail.

 

[Ollie78]

I would sand it down to remove any lumpy or loose bits ( be careful glass scratches easily) . And prime it with something like Tikurilla Otex which is very good at sticking to anything and also covering colours well.
If I had enough time or it was very loose then I would chip off all the putty and redo it all with a polymer putty replacement.

Ollie

 

[Jacob]

I would sand it down to remove any lumpy or loose bits ( be careful glass scratches easily) . And prime it with something like Tikurilla Otex which is very good at sticking to anything and also covering colours well.
If I had enough time or it was very loose then I would chip off all the putty and redo it all with a polymer putty replacement.

Ollie

I wouldn't remove any putty at all unless already loose and dropping off. Then prime the bare bits with linseed oil and put linseed oil putty back. It can last 100s of years and be rock hard.

 

[Jorny]

We removed the putty on our windows when we repainted them, but the putty was old. We only removed the "exterior" putty, not the putty bedding the glass in to the sash. Putting the face putty on is rather enjoyable and not that hard when you get the hang of it.R emoving the glaziers points and redoing the bedding is a lot more nerve wracking, and we only did it when the glass pane hade a crack.
If you are using traditional quality putty made of chalk and linseed oil, you don't have to worry about getting it right the first time. Just removed the putty, reshape it and reapply the same putty.

If the putty is in good condition, just paint over it with a good paint. If you where in Sweden I would recommend ottossons or selders linseed oil paint. It sticks and covers very well.

If you have a lot of windows to restore I would consider getting a speedheater. They are extremely useful.

 

[woodspiral]

Hi,

Thanks for all the feedback - there's some really good suggestions in there. To respond to some of the various points:

- I will definitely not be using a heatgun to burn off any of the paint on the putty as I said in my OP. I learnt this hard lesson from experience where I got too close to the glass and caused another crack. This now means I have 29 panes to replace instead of the original 28 damaged ones.
- Good to know that no-one seems to be advocating paint stripper. I think it would be largly a waste of time considering there are good blocking primers like:
- Tikurilla Otex - looks like a great product suggestion - I've just ordered some

Re putty:
- In some cases it's entirely missing so will have to replace it
- People haven't said anything about the weather. Is it OK to use right now (mid March in the UK?) with widely varying temps (i.e. potential frosts) or do I need to wait until later in the year?
- Other cases where the putty is loose I will have to break it off and replace.
- Cases where it is solid I will leave - with 23 windows to renovate and lots of small panes it would be a huge task to take out all the putty!

My main concern with covering the paint is covering cracks in the black paint. In some places the black paint is solid but cracked I know the primer and final paint will go someway in filling those but if I could use some kind of fine filler either on the black or on the primer to smooth things out that would be great. My question is really, is this done and what products do people use for that which are paint compatible?

I will look at speedheater, but I've already got a heatgun which is pretty good. I have done a lot of the heating/scraping around a lot of the frames.

Sorry for all these questions, but the scale of this task is a little daunting, and I want to embark on things in the right manner!

Cheers
Woodspiral

 

[Jorny]

Hi,

Thanks for all the feedback - there's some really good suggestions in there. To respond to some of the various points:

- I will definitely not be using a heatgun to burn off any of the paint on the putty as I said in my OP. I learnt this hard lesson from experience where I got too close to the glass and caused another crack. This now means I have 29 panes to replace instead of the original 28 damaged ones.
- Good to know that no-one seems to be advocating paint stripper. I think it would be largly a waste of time considering there are good blocking primers like:
- Tikurilla Otex - looks like a great product suggestion - I've just ordered some

Re putty:
- In some cases it's entirely missing so will have to replace it
- People haven't said anything about the weather. Is it OK to use right now (mid March in the UK?) with widely varying temps (i.e. potential frosts) or do I need to wait until later in the year?
- Other cases where the putty is loose I will have to break it off and replace.
- Cases where it is solid I will leave - with 23 windows to renovate and lots of small panes it would be a huge task to take out all the putty!

My main concern with covering the paint is covering cracks in the black paint. In some places the black paint is solid but cracked I know the primer and final paint will go someway in filling those but if I could use some kind of fine filler either on the black or on the primer to smooth things out that would be great. My question is really, is this done and what products do people use for that which are paint compatible?

I will look at speedheater, but I've already got a heatgun which is pretty good. I have done a lot of the heating/scraping around a lot of the frames.

Sorry for all these questions, but the scale of this task is a little daunting, and I want to embark on things in the right manner!

Cheers
Woodspiral

I would use linseed oil putty as a filler. I use it as a filler on both small cracks as well as screw and nail holes in our wooden facade. Should work to smooth out the old putty.

The nice thing with a speed heater is that you can use it to remove putty as well. Just cover the glass with a piece of cardboard or masonite clad with aluminium foil and heat the putty to loosen it. It is a lot better and safer than a heat gun. They cost a lot of money though.

 

[woodspiral]

The nice thing with a speed heater is that you can use it to remove putty as well. Just cover the glass with a piece of cardboard or masonite clad with aluminium foil and heat the putty to loosen it. It is a lot better and safer than a heat gun. They cost a lot of money though.

Yeah, I was rather shocked at the price of them. I looked at a YouTube video review of it where this guy used it to heat old putty on a window and remove it with a chisel which had a wheel on it as a guide - came off very easily. However in the comments to that video, a couple of people said the heater was useless against really old putty which had totally dried out. My windows are very old and I suspect that is the case.

 

[scholar]

Not to add to the comments on how to deal with the putty, but one point with this job will be to get off all the black paint that is on the glass, because it will remain visible from the inside even if painted over.

I would always do this when repainting even if not changing colour, because you can then thoroughly clean the junction of the glass and the putty and apply a new sealing coat of paint running just over the edge of the putty.

Ideal tool to scrape the paint off the glass is this Window Scraper | Toolstation
the glass should be really clean to avoid scratching and it works best to lubricate with a bit of white spirit as you go.

Cheers

 

[Jacob]

Not to add to the comments on how to deal with the putty, but one point with this job will be to get off all the black paint that is on the glass, because it will remain visible from the inside even if painted over.

I would always do this when repainting even if not changing colour, because you can then thoroughly clean the junction of the glass and the putty and apply a new sealing coat of paint running just over the edge of the putty.

Ideal tool to scrape the paint off the glass is this Window Scraper | Toolstation
the glass should be really clean to avoid scratching and it works best to lubricate with a bit of white spirit as you go.

Cheers

Yes that's the tool for the job. Stanley knife blade in a holder. Or just a sharp chisel.

 

[scholar]

Yes that's the tool for the job. Stanley knife blade in a holder. Or just a sharp chisel.

Actually a chisel is probably the best tool for the job because the glass scrapers have an offset designed to leave a margin of paint on the glass.
(I just didn’t want to make such a heretical suggestion)

Cheers

 

[Jorny]

I use a razor scraper. To get a sharp line easily, paint a few millimeters out on the glass. Then I put a wide filling knife over the putty and use the scraper to remove the paint leaving a millimeter or two of paint on the glass to create a seal over the putty and the glass. This way it is easy to create a sharp line.

I have one exactly like this, and I also use one that is even longer (70cm) that is made for cutting wallpaper. A long one is quite handy on larger panes of glass.

 

[Ollie78]

A quick note about the stanley knife type scrapers. I would not recommend them, they are not sharp / thin enough and likely will scratch more than neccessary.
Instead use a single edged razor blade in a holder like this thing Stanley Window Scraper | Toolstation
I get 100 blades off ebay the American line or Persona ones are pretty good the unbranded ones can be shockingly bad.

I have used a speedheater myself, they are effective but in reality if you are only removing putty that is already cracked from the face then a chisel or putty knife will be very effective at removing any hard putty. Also the speedheater is a bit delicate and £80 for replacement bulbs is no fun, guess how I know.
One of the reasons a speedheater is good is that it doesn`t heat up the glass like a regular heat gun, so be careful as glass can just pop because of the heat, use a joint taping knife, similar to pictured above to shield the glass from the heat gun a bit.

For the filling of the tiny flaws in the paint look for the Swedish putty/Enduit or similar, Tout pret fine surface filler is pretty good stuff as is knifing putty for car paint.

I also recommend Bahco carbide scrapers I suggest a triangle blade in a 625 and a 50mm or 65mm in a 665 handle (blades are cheaper from woodford tooling or applebey woodturning). The metal handled Linbide/Stanley ones are not in the same league.

I dread to think how many miles of putty I have replaced and these recommendations are the best things I have found.


Ollie

 

[Jorny]

A quick note about the stanley knife type scrapers. I would not recommend them, they are not sharp / thin enough and likely will scratch more than neccessary.
Instead use a single edged razor blade in a holder like this thing Stanley Window Scraper | Toolstation
I get 100 blades off ebay the American line or Persona ones are pretty good the unbranded ones can be shockingly bad.

I have used a speedheater myself, they are effective but in reality if you are only removing putty that is already cracked from the face then a chisel or putty knife will be very effective at removing any hard putty. Also the speedheater is a bit delicate and £80 for replacement bulbs is no fun, guess how I know.
One of the reasons a speedheater is good is that it doesn`t heat up the glass like a regular heat gun, so be careful as glass can just pop because of the heat, use a joint taping knife, similar to pictured above to shield the glass from the heat gun a bit.

For the filling of the tiny flaws in the paint look for the Swedish putty/Enduit or similar, Tout pret fine surface filler is pretty good stuff as is knifing putty for car paint.

I also recommend Bahco carbide scrapers I suggest a triangle blade in a 625 and a 50mm or 65mm in a 665 handle (blades are cheaper from woodford tooling or applebey woodturning). The metal handled Linbide/Stanley ones are not in the same league.

I dread to think how many miles of putty I have replaced and these recommendations are the best things I have found.


Ollie

The Stanley scraper above looks just like the one I use. I agree about the blades, some unbranded are ok, some are terrible!

I have used our speedheater to remove paint from our entire facade and they are made to withstand professional use. But the bulbs are made from glass and do not like to be dropped, and I probably found out the same way as you did...

Also agree on the Bahco scrapers, they are very good. I have also found speedheaters own triangular scrapers to be good.

 

[woodspiral]

Awesome people thanks for the extra suggestions - I do have indeed a stanley type scraper with a large pack of blades. I got this tip from a car body shop and it's a great tool for windows.

What about puttying now at this time of year, is it safe, or should I leave it?

 

[woodspiral]

I use a razor scraper. To get a sharp line easily, paint a few millimeters out on the glass. Then I put a wide filling knife over the putty and use the scraper to remove the paint leaving a millimeter or two of paint on the glass to create a seal over the putty and the glass. This way it is easy to create a sharp line.

That's a very interesting technique - I would normally mask off carefully with ProDec tape to create the sharp line. I might give that a trial and see how I get on. Good tip thanks!

 

[Jacob]

The technique is called cutting in. Get it right first time. Sign writers use a Maulstick.
So I'm told - not that I can do it myself!

 

[Ollie78]

The technique is called cutting in. Get it right first time. Sign writers use a Maulstick.
So I'm told - not that I can do it myself!

I agree but cutting in takes a good bit of practice and a steady hand, some people just can`t do it ( even so called professional decorators ).

One thing that will really help with cutting in on window frames is a nice sash brush ( ie round and shaped to a point ) this is really much better in the corners and is easier to control. Do not cheap out on brushes, get good ones and keep them clean or in a brush mate if using oil based, they will last years if looked after.

Ollie

 

[baldkev]

In an attempt to answer the op question on putty.... I used to work for a builder who did emergency glazing and we often used putty in the winter..... we would keep it in the truck footwell and have the heater blasting warm air at it on the way to a job so it was supple when we needed it. I cant honestly say if it harms it being cold as we were doing emergency repairs and didnt need to go back afterwards.

A google shows that putty should be used between plus 5° and 35°c, but again, if its warm when it goes in the frame, i dont know if the cold would actually do any harm

 

[mwinfrance]

You can run a long line ( horizontal or vertical using a mahl stick ) but traditionally they are round in section and the technique of following the round cross section takes some learning.easier is to make a mahl out of a piece of straight square section ( aluminium or wood) about 10 to 15mm section.much easier to follow a flat edge with one finger one a hand ( usually the little finger ) while the others hold the brush parallel to the stick and pull across or down using it to guide the line.for this technique you don't use a sash brush, you use a signwriters "pencil brush" , a sort of "rigger" or lettering brush.Flat brush, long hair, square ended. Various sizes traditionally designated by the birds names that the quills ( ferrules ) were taken from. Smallest was a lark, largest was a swan.I used to get mine from JT Keep , who were based in Holborn ( old Mr Keep himself worked behind the counter ) then, after he had died ,they were taken over by Bolhams or Bollams ? Now there are many companies selling signwriters brushes. Here in France I live 15km from the largest brush makers in France if not Europe, Two companies within 1km of each other .My preferred one ( owner is a real nice lady Stéphanie BULLIER ) has a huge catalogue from miniature brushes, lark brushes upto huge paint brushes ,various hair and bristle and synthetics, including scrubbing brushes and make-up brushes , she exports world wide.

Leonard Brushes of St Brieuc ( pronounced san bree yuh )
http://www.leonard-pinceaux.com/en/https://leonard-brushes.com/The best brushes are still hand made, Leonard used to do tours of the workshops where they are made, maybe they still do.

There is also Raphael at St Brieuc
https://www.raphael.fr/en/Raphael-since-1993_2.html

To make a mahl stick, take your stick( wood or aluminium ) about 800 to 1000mm long, take an old piece of soft cotton ( old tee-shirt ) make it into a tight ball about 40 to 50mm, whilst wrapping it around the end of your stick, when done you can tape it to the stick, wrap that ball on a stick in another piece of cotton so it is like a ball in a tiny bag on a stick, then wrap that in a piece of soft leather ( pigskin or lambskin, you can use PVC but it doesn't work so well ) and seal it off where it meets the stick.it must be firmly attached and not feel at all loose , nor wobble.

That is it, the pad end rests on the surface you are working on nearly parallel to it, without touching any fresh paint.your non brush holding hand holds the non pad end of the mahl and voila you have a "rest" that allows you to work over the surface without touching it by resting your brush hand or arm on the mahl. That with a little practice you can also use the mahl as a guide to run your fingers against while holding a brush in order to get straight smooth line.
Coach lining requires a different technique, different brushes with longer hairs or bristles , and is done free hand, no mahl.pin striping is done with different brushes gain and can be done with or without a mahl, usualy without , the steadying and pivoting is done by touching the surface with the little finger of the hand holding the brush.french pin striping brushes do not look like the flat pointed but bellied brushes used in the USA or UK known as swords and daggers, here in France they are round not flat, but still full bellied with longer hairs protruding.I can use them, but prefer swords or daggers.Otherwise signwriters brushes are similar between the USA, UK and Europe.

Not about putty, but if you have to repaint and want to be accurate it may well be useful, and I hope interesting.
Ps ..Handmade french make-up brushes are not as expensive as you might think, and are great presents for SWMBOs ..Stephanie's website has a shop.