I have a 1930s house with all single-glazing in South London. This is a painting problem but I have to explain the context.
I have decided to fit all these casement "lights" (which I believe is the correct term) with vacuum glazing. This involves routing to make the lights' rabbets deeper and wider, and also, in the case of lights which will be opening, routing grooves for weatherstrip.
The question I have though relates to painting. I have chosen to go all-oil-based: oil-based primer, oil-based undercoat and oil-based topcoat.
I am on my second "light" (fixed in place, non-opening), this is an "upper light", with the visible pane measuring about 420 mm wide by 250 mm high. The first light I did (also a fixed in place upper light) fitted back into the gap in the fixed frame easily enough.
But this second one, after priming (where required), undercoating and topcoating of both the edges of the light and of the fixed frame edges which the light's edges will come into contact with, won't fit properly. Not by much, no doubt, but it means I'm going to have to do some quite disruptive adjustment.
So the question is: when I know that the light is fixed, i.e. non-opening, is it OK to skip the topcoating on those edges (on the light and the fixed frame) which are going to be touching one another? In fact, in future, I plan to plane these edges a bit on the light (before doing any priming/painting), because I want there to be a small but distinct gap, which I will then fill with acoustic sealant: so there will be a thin bed of sealant between the light's edges and their facing parts on the fixed frame.
In other words, does (oil-based) undercoat play a big role in preventing water entering the wood? Or is it necessary in all cases to have topcoat on it, even (as in the case I describe) where the parts of the wood which I'm potentially going to leave without topcoat are going to be bedded in sealant?
NB as extra protection against lashing rain, it just so happens that these casement lights are storm casements, i.e. they have an extra wood "lip" around the outside (incidentally making the routing technique quite interesting).
I have decided to fit all these casement "lights" (which I believe is the correct term) with vacuum glazing. This involves routing to make the lights' rabbets deeper and wider, and also, in the case of lights which will be opening, routing grooves for weatherstrip.
The question I have though relates to painting. I have chosen to go all-oil-based: oil-based primer, oil-based undercoat and oil-based topcoat.
I am on my second "light" (fixed in place, non-opening), this is an "upper light", with the visible pane measuring about 420 mm wide by 250 mm high. The first light I did (also a fixed in place upper light) fitted back into the gap in the fixed frame easily enough.
But this second one, after priming (where required), undercoating and topcoating of both the edges of the light and of the fixed frame edges which the light's edges will come into contact with, won't fit properly. Not by much, no doubt, but it means I'm going to have to do some quite disruptive adjustment.
So the question is: when I know that the light is fixed, i.e. non-opening, is it OK to skip the topcoating on those edges (on the light and the fixed frame) which are going to be touching one another? In fact, in future, I plan to plane these edges a bit on the light (before doing any priming/painting), because I want there to be a small but distinct gap, which I will then fill with acoustic sealant: so there will be a thin bed of sealant between the light's edges and their facing parts on the fixed frame.
In other words, does (oil-based) undercoat play a big role in preventing water entering the wood? Or is it necessary in all cases to have topcoat on it, even (as in the case I describe) where the parts of the wood which I'm potentially going to leave without topcoat are going to be bedded in sealant?
NB as extra protection against lashing rain, it just so happens that these casement lights are storm casements, i.e. they have an extra wood "lip" around the outside (incidentally making the routing technique quite interesting).
