How to use this kind of putty knife for glazing?

[MrJof]

Hi all.

I'd like to re-putty my sash windows. If I look on YouTube and elsewhere for instructions the putty knifes they use are always of the rectangular style (see image attached). However, I happen to have a putty knife that has more of a machete shape (see image attached) and indeed this tends to be the type that Screwfix, Toolstation and Wickes sell. How is this kind of knife used and do you recommend it for glazing versus the rectangular style?

Thanks as always!
MrJof

 

[crank39]

I've used both in the past but the one in the second picture is used with the 45° angle is used to face the putty off, it also helps in the corners to create the mitre effect but as I say I used the straight knife to good effect too, puttying takes practice and is very satisfying when you get it right

 

[MrJof]

I've used both in the past but the one in the second picture is used with the 45° angle is used to face the putty off, it also helps in the corners to create the mitre effect but as I say I used the straight knife to good effect too, puttying takes practice and is very satisfying when you get it right

That's great, thanks. I happen to have the curved one already which I got for another task (I've since found they are called "clip" or "clipt" shaped blades) so I gave it a pretend swipe across the windows; I think I'm with you about the corners - it's somewhat easier to manoeuvre than the straight one.

Do you know what the curved side is for? Is it to get more of a concave bead versus the straight one?

I'm definitely looking forward to giving it a go! The previous job was done really badly (uneven etc) so hopefully after some practice I'll at least make it all slightly better

 

[JohnD]

I was taught to use the curved "sabre" one many years ago.

not used so much now.

I think you need a youtube vid and some practice.

The short straight edge is run along the glass, this gives a straight line and cuts off excess, you pull the knife towards you by the handle, and the putty is pushed into place as the curved edge presses along it. The point is used in corners. The knife flexes a bit.

If you get it wrong you can pull it out, mould it, and do it again, but look out for splinters or sharp paint flakes while you mould it.

Paint the rebate with oil-based primer before puttying.