Homemade raku kiln for bisque firing

[Anuhea]

Hello! 

I am new to raku and making a homemade raku kiln out of a metal trashcan. I'm just a little confused on bisque firing. I'm thinking I'll bisque fire to come 04 but I'm just not sure how slow I need to increase the temperature. Is it also possible to maybe split up the bisque firing into 2 different firings. Since I have a homemade kiln and it will be outside I don't feel comfortable to leave it alone for like 7 hours and I have to monitor the temp anyways. I'll be using a torch attached to a propane tank and I'm also wondering if I can get a bisuqe and glaze fire out of 1 tank? Thank you! 

[Piedmont Pottery]

For our raku clays we usually bisque to 06.  You will need to make sure that your pieces are totally dry, and heat very slowly for the first part of the firing.  After you get above ~600F you should be able to ramp up the heat some to get to the final temp, but not too fast so all the nasties have time to burn out.  It will be tricky to control firing rate with your setup.  Whether you can get a bisque and glaze firing from one tank is impossible to say without knowing the btu output of your torch and the size of your tank, how much insulation is on your kiln, and the volume of the kiln.  If you're using 20 lb tanks, then you may want to use two tanks manifolded together to minimize icing up.

[Started Late]

If your clay will take a cone 04 firing, you should not have a problem and your piece will be stronger than an 05 or 06 bisque. You might not get as good a glaze absorption though with the harder piece. I bisque my rake to 05 personally. 
 

I do not bisque fire in my raku kiln. I bisque in an electric where the heat rise can be better regulated and impurities in the clay burn out better in the oxidation firing.