Is it ok to use galvanized piping right out of the drum manifold?

Is the heat too high to use a galvanized T clean out right out of the drum manifold?

Purchased a galvanized one already and didn't consider that it should be stove pipe.

Thoughts, good people of the permies world?

Aaron

After looking at that picture I posted I noticed that I have a too thin drum manifold in that picture.
Rest assured I have made a larger one since the taking of the picture.

The heat right out of the manifold is likely to be too high for galvanizing to be safe as bought, plus galvanized ducting is generally thinner than black stovepipe.

You can render the galvanized duct safe for the mass by heating it in a well-ventilated area outside until the galvanizing goes from shiny to dull gray; then the zinc has turned to a more stable form that will be safe unless it is exposed to welding temperatures or the like.

It still would be thinner, and might not be as durable as you want. You will have to make your own decision there.

So run the piping through a fire until it turns from shiny to dull grey?

Here is my dilemma. How far out should I go with stove pipe before I attach to the galvanized pipe.  The piping was given to me and I can't afford to replace it all with stove pipe.
Correct me if  I am wrong, I have seen many a picture with the mass heater part being galvanized piping.
Never paid attention to it actually coming out of the manifold.

Thanks for the advice.

About five feet of black stovepipe is generally recommended. If your mass is very good cob and has sufficient layers or thickness to eliminate the possibility of leaks, you can probably use whatever you want and expect that even if the duct does deteriorate, the cob will hold up.

I will not be using cob for the mass heater.  I am creating a cement block box and filling it with pea gravel. Periodically I will be uncovering the mass heater piping to look for leaks   I will be using cob for the drum manifold to seal it around the firebrick and to create the 45 degree lip on top of the heat riser. Then the jay tube will be bricked in with perlite as the insulation.