What Metal?

Advice needed. I have to make a short extension, about 1 1/2 inch, to the back bottom of my hopper. (For background, see the last part of thread DS Machine Quality Control.)
I would like to use a lightweight material that I can work easily – such as aluminum flashing – something I can pick up cheap at Lowes or HD. I don’t care if it only lasts one season, since it will be very easy to replace yearly. But I don’t know what material to use. Something I can cut with tinsnips, that won’t ignite in the coal fire (what’s the ignition point of aluminum?), that won’t evaporate and kill me with fumes (is it dangerous to heat galvanized?), that will last at least a season just above the coal bed, and that I can easily bend to shape. So what should I use? Thanks for any advice you can offer.

I would think that would melt very quickly. Probably would have to use a minimum of quarter inch steel or cast iron.

You need at least 1/4 inch stainless steel.

Instead of that I would lean toward getting rid of that brick retainer and protecting the back wall with a half brick, or heavy layer of coarse furnace cement that would hold the brick as well. Imperial would work.

rberq wrote:Advice needed. I have to make a short extension, about 1 1/2 inch, to the back bottom of my hopper. (For background, see the last part of thread DS Machine Quality Control.)
I would like to use a lightweight material that I can work easily – such as aluminum flashing – something I can pick up cheap at Lowes or HD. I don’t care if it only lasts one season, since it will be very easy to replace yearly. But I don’t know what material to use. Something I can cut with tinsnips, that won’t ignite in the coal fire (what’s the ignition point of aluminum?), that won’t evaporate and kill me with fumes (is it dangerous to heat galvanized?), that will last at least a season just above the coal bed, and that I can easily bend to shape. So what should I use? Thanks for any advice you can offer.

You've got some tough constraints.... Aluminum won't work there. If I were you, I'd make a mold (pick your favorite material), send it to the foundry and get a piece made from cast iron. Next that that, I'd use steel. Galvanized will burn off. I'm assuming this is to bridge that ledge in your hopper to get the coal to side in better? The steel piece that is burned out of the back on the photos on that thread you posted?

dj

dlj wrote:I'm assuming this is to bridge that ledge in your hopper to get the coal to side in better? The steel piece that is burned out of the back on the photos on that thread you posted?

Yes, I need the bottom edge of the hopper in back to be about 1 1/2 inch lower, so the coal will drop/slide against the firebrick below the level of the steel.
When you say the galvanized will burn off, do you mean the whole piece will burn away if it's too thin, or do you mean the galvanized coating will burn off? Galvanizing is zinc, isn't it? I don't care if the zinc burns away as long as it doesn't poison me in the process.

Galvanized coating is toxic as it burns off,but I suppose it will go up the chimney. There is no benefit of using galvanized rather than uncoated steel for that application.

The zinc will burn off, but you'd have to be breathing flue gases to get any zinc poisoning. Thin gauge metal - thin enough that you could cut with snips - likely won't last a season.

As Franco suggested, I'd see about removing that rear-side steel brick retainer and build up the top of the fire bricks with refractory cement.

With the steel retainer removed the outward pressure of the coal in the firebox will hold the bricks in place, even if the refractory on top develops some cracks.

Paul

OK, thanks for the help everybody. I'm going with some lightweight sheet steel from the auto parts store. If it burns out in a year I will replace it annually, very simple to do. If it burns out much faster than that I will make a pattern from the lightweight stuff and have a machine shop or fabrication shop make something out of heavier steel.

A year? You will be lucky to get a day out of it!

Stoker6268 wrote:A year? You will be lucky to get a day out of it!

I'm going to be more optimistic and say two days.

Paul

Sunny Boy wrote:

Stoker6268 wrote:A year? You will be lucky to get a day out of it!

I'm going to be more optimistic and say two days.

Paul

Maybe idling on low...LOL

just pull your hopper and take it to a fab shop and have them plasma cut a wedge out of the back of each side wall then heat and hammer the back forward and weld it back up.

pristo, done deal. coal will not be able to fall that far back any more and will end the whole thing.

KingCoal wrote:just pull your hopper and take it to a fab shop and have them plasma cut a wedge out of the back of each side wall then heat and hammer the back forward and weld it back up.

That does sound like a good solution. Even better, I could take the extension that DS Machine made for me, which doesn't fit, and have them do essentially the same thing to that so it WOULD fit.

rberq wrote:

KingCoal wrote:just pull your hopper and take it to a fab shop and have them plasma cut a wedge out of the back of each side wall then heat and hammer the back forward and weld it back up.

That does sound like a good solution. Even better, I could take the extension that DS Machine made for me, which doesn't fit, and have them do essentially the same thing to that so it WOULD fit.

good thinkin' I forgot you had that piece !

steve