Register plate fixing

[Tonythecat]

Hi hoping someone can advise. Im curently attempting to fit a register plste (closure plate might be best description as i have a liner fitted) plan was just to attach alluminium angle around the inside of the chimney and then screw the to the angle (or angle to plate) pics show what I've done so far. Note plate is just an offcut to get measurements. The angle is bolted to the masonry with m5 thunder bolts. I've just suddenly started thinking about how all this will work when it starts to get hot. Aluminium is probably not the best material as its expansion is 2.3mm per m per 100 deg. But even if I swap it to steel surely there will be some expansion and warping of the plate and angle iron. Would the expansion be likely to crack the bricks where its bolted in

 

[Tonythecat]

Here's pic

 

[Burnerman]

With the dozen or so register plates I have made, I've never experienced any issues with the fixings into the side of the chimney.
I do tend to use 3mm thick mild steel for the plate and maybe 5mm steel angle though - just for costs really.
Expansion has never been an issue for me, and if there is room I incorporate a door in the plate big enough to get a vacuum cleaner nozzle in.....just to collect any soot debris that comes down on the outside of the liner.
John

 

[Tonythecat]

Thanks for the reply. Ok how do you generally attach the angle iron. Also do you use plain or galvanised steel. I've been doing some research snd I think as you said that normal steel may be a better option as the thermal expansion is less than

With the dozen or so register plates I have made, I've never experienced any issues with the fixings into the side of the chimney.
I do tend to use 3mm thick mild steel for the plate and maybe 5mm steel angle though - just for costs really.
Expansion has never been an issue for me, and if there is room I incorporate a door in the plate big enough to get a vacuum cleaner nozzle in.....just to collect any soot debris that comes down on the outside of the liner.
John

Thanks for the reply. Ok how do you generally attach the angle iron. Also do you use plain or galvanised steel. I've been doing some research snd I think as you said that normal steel may be a better option as the thermal expansion is less than aluminium at less than half its value

 

[Burnerman]

I use standard plastic wall plugs and there's never been an issue with them.
As for steel I use BDMS (bright drawn mild steel) and cold rolled angle - I don't mind a bit of surface rust as it's rarely seen and there's no way it will corrode through!
I'm fortunate that there is a Metals Supermarket near me so supply isn't an issue.
John

 

[Tonythecat]

I use standard plastic wall plugs and there's never been an issue with them.
As for steel I use BDMS (bright drawn mild steel) and cold rolled angle - I don't mind a bit of surface rust as it's rarely seen and there's no way it will corrode through!
I'm fortunate that there is a Metals Supermarket near me so supply isn't an issue.
John

Thanks for the advice its very much appreciated