Hi , let me start saying my english may not be good enough , so let me know if something is not clear .
I been forging with my charcoal forge for half a year now , but wanted les time consuming , so i'm starting my first gas forge build.
Resources are not really available in Argentina , so I been doing some research and trying to pull out some design that may work with what I have.
First gas . Propane is too expensive here so , it has to be methane. People here use bottled methane for their gas forges , and works pretty well but a 10kg bottle is a bit out of my budget so i'm gonna give a shot at a natural gas forge. From my research a gathered 2 thing about Natural Gas , is not that hot , and doesn't have much pressure, so insulation and burner performance are key ( as in every other forge , i know). For this reason I've chosen a Forced air Ribbon burner.
Now , insulation , I know you probably are not gonna like this . For my insulation Im using K-26 insulating brick and that's it . Being my first build I didn't want to spend much so I bought 8 k-26 bricks( the factory gifted me 3 extra so I have 11 ) , and 10kg of 60% alumina castable refractory to coat the inside .
The build . my idea is making a box forge with 6 bricks (2 for the sealing 2 for the floor , 1 for each wall ) and cast a 1/2 inch in the interior. The box made with the bricks ( without the refractory ) would have a volume of 161 cubic inches. For the burner my first idea was to cast it in refractory but then I had the problem as to where attach it to the forge , and the fear that it will lose to much heat because it will have no insulation behind it , so my new idea is to carve one of the wall brick , drill it and insert the plenum there , and then seal it with refractory (I thought high temp silicon my work to ) and make some kind of support so it doesn't puts to much stress in the brick an the refractory .
the forge is rather small so I was thinking of a plenum of 2x2 inches with a 3/4 mixing tube . I am under the impression that more flare holes will make shorter flares , so i was thinking of making as much as I can , without surpassing the 13:1 ratio for the burner block , and without surpassing the area of the mixing tube , to not lose pressure.
So let me know what do you think