Refurbishing Crittall windows

3 Jan 2011
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United Kingdom
Would appreciate guidance on a DIY job that's new to me...

I'm refurbishing a couple of Crittall windows installed in an outbuilding in the late 1950's. The putty holding the single glass pane into the galvanised steel frame has cracked in many places leaving lots of fine cracks - although the putty (and the glass panes) is/are secure. There are however, three or four gaps where sections of putty (~1 to 3 cm sections) have fallen out.

I'd rather not scrape out and replace all the old putty, which is rock solid, as I might (probably will) break the glass, so, two questions: first, can I use some sort of filler/sealant to fill in the fine cracks within the putty and secondly, are there modern alternatives to linseed-based putty to fill in the missing sections or is linseed-based putty still my best bet for these larger gaps?

The putty and repairs will be repainted.

Thanks in anticipation.
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I've replaced missing putty with new putty, you have to give it a while before you paint it. After its painted I can't tell where I did it. I'm so slow it doesn't matter if I have to wait weeks before painting it :) (I just leave it and do it when its firm enough)

There are modern glazing sealants (in a cartridge gun), I used to use a "proper" glass one but now I would use any paintable sealant. Fine cracks I would use caulk.

I've got wood frame windows - I've never noticed the putty or sealant repair failing; after 5-10 years the window needs repainting and that's what I notice first. I took 6 panes of 18" x 18" glass out of the garage window by chipping out the putty, replaced the frames and put them back. There was a lot of luck involved but it can be done :)
I'm so slow it doesn't matter if I have to wait weeks before painting it

Me too. No rush...

...although it's taking me much longer than I thought to strip off sixty years of paint from the metal frames so, whilst I would like to do a thorough job, I don't want to go to unnecessary lengths, i.e. removing all the old putty when the remaining putty is secure.

I like the caulk suggestion. Around £2 for a tube of external caulk which will be all I need. Thanks.

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