Fireplace Heater Tube 5

[thexporter]

Were are building a fireplace tube heater.
Need to know the material and wall thickness recommendation.

The fire (wood) will be in direct contact with this.

The photo is something like what we are building but not exactly this shape.

 

[rustbuster]

304H or 310 Stainless steel may work for you. Higher nickel alloys would last longer but at higher cost.

 

[EdStainless]

Don't overlook using 430. It should work well for this.

310 is great, but will be expensive.
309 would work also and should not cost as much
I would prefer 430 over 304 but either should work fine.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[thexporter]

I want to thank both of you very much for your advise for the correct material and heads up on the cost of each, that is always a concern on a project.

Regards,

Dennis

 

[IRstuff]

One consideration is color. No matter what your starting material, the eventual color will be black, so anything with a typical SS finish will not retain that finish for long in a fireplace.

TTFN

FAQ731-376

 

[thexporter]

IRstuff

Thank you, I figured that would happen.

One other quick question is your thoughts on wall thickness??

 

[EdStainless]

I would start with 3/4" sch 40 pipe and see how that works.
The lower part is heavily loaded, but not very hot and you can provide support. The upper part that is the hottest is only trying to support itself. A couple of lateral tie rods across the back and top would allow the cooler outer tubes to assist in supporting the center ones.

A heavier wall may be stronger and last longer with scaling, but it will suffer more distortion from heating and cooling and have a greater risk of cracking from thermal cycling.

You need to allow some distortion as it is less damaging than cracking.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[ornerynorsk]

I've built a number of similar heat exchangers out of 1020/1026 erw tube with wall thicknesses in 16 gauge. You can expect years out of them before burnout. Consider that stovepipe is something between 26 and 20 gauge.

 

[IRstuff]

Not sure how well SS holds up compared to what's usually used for fireplace gratings, but I find that in my gas fireplace, the metal nearest the burners tend to get pretty rusty; I assume that it's coming from the water resulting from burning the gas.

TTFN

FAQ731-376

 

[stanweld]

The tube in my fireplace is 3/4" std wall carbon steel. I replaced the original one ten years ago and I don't know how long the previouis one had been intalled; the house was built in 1973.