Block-off Plate: would aluminum work or only steel is needed?

[yuryk]

Hi guys. I mostly see galvanized steel mentioned as material for a block-off plate. But what about aluminum? I heard it becomes softer above 400F, so not sure if it's suitable for this purpose... I just can't find galvanized steel of 26 or 24 gauge of proper size, but found 36 in. x 36 in. x 0.02 in. Plain Silver Metallic Aluminum Sheet Metal at Home Depot, but not sure whether it'll do the job...

Thank you.

 

[EatenByLimestone]

Aluminum is less forgiving if you bend it incorrectly. Steel will stretch when you bend it back, Al will crack.

Check with a plumbing supply or hvac supply. They'll have it.

 

[yuryk]

Thank you, it's very helpful. Another argument I guess that galvanized sheet metal would produce dangerous fumes when hot, right? I saw it few times on this forum... But anyway, those are just 2 options: either aluminum or galvanized sheet metal for a metal block-off plate, correct?

 

[begreen]

The block-off plate won't get hot enough to offgas. Aluminum is an option, so is sheet steel, but galvanized is most commonly used.

 

[yuryk]

The block-off plate won't get hot enough to offgas.

I was curious and asked Travis Industries about max outer temperatures for their stove. Here is a response from a tech support guy:

Our units are made to operate between 600-900 degrees optimally. They can and will peak well above that temperature 1100-1200 degrees at times but should never be allowed to sustain temperatures above 900 degrees.

And about galvanized steel I read that in long-term, continuous exposure of it, the recommended maximum temperature is 392 F. 900F sounds like a lot, so curious if it can exceed that value at a distance to the block-off plate... Did anyone use a probe to figure out?

 

[begreen]

Was the tech specifically asked about inserts? An insert typically has a convective jacket surrounding the stove body to collect the heat. The jacket temp should be well below the stove body temp.

 

[yuryk]

Was the tech specifically asked about inserts?

I have just followed up with him about it, asking specifically about an insert. Here is his response:

Those temps are to be expected at the liner base/exhaust of any wood burning unit we manufacture. It’s all relative to other factors like wood species, wood moisture content, length of venting, and outside temperature.

So, I guess, aluminium or regular steel plate would be safer to use... Not sure though, just thinking out loud...

 

[begreen]

Yes, the liner will get hotter at times but the heat disappates quickly.