Paint spec for renovated sash windows

[O'Chippy]

Interestingly you've discounted linseed paint which is the darling of the sash window brigade. Unfortunately no use in the coming months.
I feel if your definitely going to spray water based you need an air assisted airless set up. Anything else won't cut it as the temperature drops the viscosity increases making hvlp pretty useless. Even 5 stage.

Drying times of linseed paint are as I understand long, esp in winter, I dont have the time.
Plan is to use an airless set up, not sure if that presents the same issues regarding temp/viscosity.

 

[O'Chippy]

I don't think sash windows are a great subject for spraying. Lots of narrow pieces with big holes. And the paint ideally lips onto the glass over the seal which you can't realistically achieve.

Agreed they probably are not the best subject for spraying but I have seen them successfully sprayed before and they aren't that far off door frames and architraves which are commonly sprayed.

Good point on lipping the paint onto the glass.
I am aware of that technique and its benefits, I have in my mind to use Repair care putty alternative. Apparently it doesn't require to be painted over itself and I'm assuming by the nature of the material it wouldn't benifit from lipping paint over its junction with the glass.

 

[johnnyb]

Airless should work fine. It can be hard to control as to lose the horns you need a fair bit of pressure. Which results in lots of paint transfer!

 

[markturner]

I would like to pitch in here, with both my experiences and some questions. I restored, repaired and redecorated all the sash windows in my grade 2 listed house around 4 years ago. I got all the sahes removed and dipped so started from scratch with bare wood. It took about a month to dry them all out, using a sealed room with dehumidifiers running non stop....I was keen to use traditional materials etc and so went with linseed oil paints by Brouns. I have had mixed results - it goes on lovely for sure, however, I have an ongoing problem with mould and dirt accumulating on the flat surfaces of the cills and mouldings. And when you clean the windows, paint dilutes with the water and goes all over the glass. I had some areas also where possibly I was geting bleed through of the dipping chemicals and other areas just seemed to never dry at all! And this is 4 years in!

I am going over them again starting this summer and have decided to use Dulux weathershield gloss instead. I did a test run on the porch and front door last year and the paint looks perfect a year on, which is more than can be said for the 2 or 3 windows I had to do some minor repairs and redceorating using the linsdeed oil paint ay the same time. We are slowly working round the house going over with weathershield Oil based. I notice no one who responded in the thread mentions using this at all? Just wondered why that may be? I found it very nice to use and very durable so far........

Currently I am also making some replacement sash windows for our neighbour, using sapele. I planned on using the same weathershield paint, but she wants me to use Farrow and Ball exterior paint. It is water based and I really dont like it so far, it seems very thin and I am dubious about it longevity......any users got any experience of this system here?

Because of my job and teh neighbours, I have been looking into the various options for paint and did come across a very complimentary long term test on YouTube, of the Treatex classic colour - this is also water based, but flexible and seemed good....again, any one used it?

 

[johnnyb]

I'm with you linseed paint is mostly hokum smoke and mirrors. But it must have something to recommend it. Dulux weathershield I have found to be a good paint albeit trickier to use than some(it needs thinning in trade guise and tends to rapidly skin as its got lots of driers) me and another(fairly experienced guy) both used weathershield. How linseed ever got any traction is hard to say. It's like the emporers new clothes. Zinc oxide stops mould growth they say. Not in my experience. Only lead tetroxide. The op seems like he's decided to spray water based and avoid all trad materials and I hope that approach works out but you raise another point about contamination which is a known issue with water based coatings. I swear 120 year old paint is almost unaffected by stripper but will burn off. Of course caustic can have its own issues as well. It often denatures the wood meaning some bits can almost reject coatings. I'm not really keen on any plastics in contact with old wood ? Caulk,foam ,it all traps water. Especially at the bottom of stuff(say the front linings or under the sill(

 

[johnnyb]

I've worked on enough old timber to know using normal trad materials they can last just fine. But neglect and poor water management(dodgy gutters) can leave them in such a state its hard to know what to do....it must be the paint/putty/wood etc. Then the inevitable upgrades start linseed paint, accoya, heritage putty, spray paint etc. Some may be improvements but which ones. Better to fix the roof gutters drains and passively protect stuff if possible than open a new can of worms.

 

[Doug71]

@markturner I have used the solvent based Dulux Trade Weathershield system quite often and found it good, the flexible undercoat is rated highly by some decorators I know. I do generally avoid the Preserver Primer though as it's water based and raises the grain, I prefer to use their Aluminium primer instead.

I paint all the exterior woodwork on my property with Dulux Trade Ultimate Opaque (solvent based), it's basically an opaque wood stain that they can mix up in any colour, it goes on like a stain but looks like paint if that makes any sense. It seems to last well and is really easy to overcoat when needed.

https://www.thepaintshed.com/dulux-trade-ultimate-opaque-all-colours

 

[Ollie78]

Interestingly Mighton, (who do all things sash window-ish) seem to have some arrangement with Ankerstuy where they sell their paints under the Mighton brand.
I follow Bradshaw Joinery on Youtube, he did a sash window build series, he used the Mighton/Ankerstuy paint and sang it praises.

I tried the Mightons primer and was pretty much unimpressed. But I am comparing it to my normal Tikurilla Otex primer so I guess it depends what you are used to.

 

[Jacob]

I'm with you linseed paint is mostly hokum smoke and mirrors. But it must have something to recommend it.

Basically it sticks like **** to a blanket - on bare wood, old paint, metal, glass, etc etc. It never flakes or peels. Instead it very slowly wears off from the surface and goes chalky. Can be revived very easily with oil alone, or just repainted. Never needs burning off or removing before repainting, just a wash down.
Also very easy to apply, as long as you brush it out thin and don't try to lay it on like modern paints.
Good coverage and dense pigments makes it much cheaper than it seems (pricy by the tin) and has very long shelf life.
Needs no primer or thinners other than linseed oil, but knotting in glazing rebates (and knots of course) is a very good idea.
I've been using it for about 12 years on a lot of projects and wouldn't use anything else on external joinery

..... How linseed ever got any traction is hard to say.

Gained traction through hundreds of years of successful usage. No prob once you get into it - you'll never use anything else!

....Zinc oxide stops mould growth they say.

It does. But an occasional wash down will remove it. Seems to a slight prob sometimes on shaded joinery - north or east facing doors. Not a prob with windows if they are cleaned in the normal way.

.... I swear 120 year old paint is almost unaffected by stripper

and is invariably linseed oil paint - can have a very long life if routinely maintained i.e. a bit of attention at say 5 to 10 year intervals

but will burn off. Of course caustic can have its own issues as well.

Burning off and dipping are kiss of death to joinery - probably the single biggest reason for the switch to plastic. Mainly because new paint won't stick for long. I found this out the hard way, several times! Odd how modern paints can peel off with the flakes still in good condition but the wood behind it getting water logged.
But linseed paint colours are all on the dull side compared to modern stuff and not so shiny.

PS forgot to say - linseed paints have near zero VOC and the oil itself non toxic, though probably not the pigments. Also very environment friendly - organic material with very low carbon footprint - and prolongs the life of wooden joinery.

 

[johnnyb]

I love traditional materials but was linseed on its own ever used as exterior paint? Does it indeed extend the life of exterior joinery? Is it ever worth stripping alkyd gloss to replace with linseed? All questions that need a scientific answer rather than opinion. A previous poster suggests linseed is fraught with issues.

 

[Jacob]

I love traditional materials but was linseed on its own ever used as exterior paint?

Linseed oil plus pigments is very traditional and has always been widely used. It's often thought that lead was the critical feature of long lasting paints but it may well be more to do with the linseed oil, or both perhaps.
https://www.solventfreepaint.com/info/history_linseed_paint.htm

Does it indeed extend the life of exterior joinery?

Seems to - though my experience lies the other way, in that using modern paint on old stripped joinery very quickly reduces its life.

Is it ever worth stripping alkyd gloss to replace with linseed?

My feeling on this is that if it's in good nick and sticking well, then do not remove it, just paint over, after a good wash down of course.
But stripping can be done very carefully with hot air gun - no burning.

All questions that need a scientific answer rather than opinion.

Experience counts too.

A previous poster suggests linseed is fraught with issues.

Takes a bit of getting used to.

 

[johnnyb]

http://www.vam.ac.uk/content/journa...ss-house-hold-paints-by-20th-century-artists/
This goes some way toward explaining how different oil/alkyd paints were formulated and the time periods.