Double firing?

[sterling gold]

http://www.sweetwoodmaple.com/images/Building%20Sugar%20house%202002/Arch%20alone.jpg

We have an arch similar to this one...during boiling, we have removed the draft door and built a fire in the draft chamber which substantially decreases boiling time and increases steam output.

The arch obviously was not designed for this, and the sides begin to glow after not too long since there are no fire bricks to insulate the draft chamber.

Question 1. Is this bad? Will the thin sheet metal eventually warp and pop off?

Double firing can get us evaporation rates close to 45 gallons/hour, which for a naturally aspirated 2x6 ain't too bad.

Question 2. How can we obtain evaporation rates close to above without a blower and without risking damage to our arch?

And really, who hasn't asked this question after four consecutive long nights in the sugar house?

[sugarmaker43]

I use to boil on a 2x6 as well and I always was looking at increasing the evaporation rate as well and it doesn't change when you get a bigger rig. With your double firing you are probably going to warp and ruin your grates. They are meant to have cold air going up through them to keep them from warping. I did a low cost blower on mine which was a exaust fan for a gas water heater and had a sheet metal friend make a plenum to go from 4" to 16" wide or so in the back of the arch ash pan. This probably cost $75 total and it worked great. You do have to dampen down the volume of air so as not to over charge the fire box and blow ash out the door cracks. Hope this helps.

[dano2840]

ive done that before, you definetly need to brick the draft door if your going to do that, it will decrease the life of the tin on the sides of your arch, where it was glowing will start to turn white when it cools down and will rust in the off season

[brookledge]

I agree with Jim you will warp your grates
Keith