You will likely get advice form the true experts here but here’s
some from a fellow struggler. You need to approach this a little
like a science experiment to get consistent results. You have a good
start by doing your research. One of the reasons you get differing
when you do research is that there is more than one way
to make mokume. Also some may be a bit dated although
still comepletely doable. And different metal alloys and different
kilns behave differently and you need to make adjustments. If you
melted a billet then your temp was too high and/or firing time too
long. simple. the burnt spots are likely from the zinc in the brass
burning up or possibly lead depending on the alloy.
My advice first is to know your kiln. Every kiln is different.
Anytime anybody uses a kiln for anything they need to ask these
questions. Is your pyrometer accurate? Probably not. Are there hot
spots and cold spots in the kiln? Always!! What direction is the
heat coming from in this type of kiln. Front opening kilns have the
problem of being hot in the back corners and colder by the door. You
need to place your billets in the same place each time. You can find
out by trial and error where to place your billets and what
temperature to set your kiln, you already have a good start!
Know exactly what metal alloys you are using. Order from companies
that can provide this it may cost more but you have to.
If you didn’t do this you may have more than one kind of brass in
you billets. The many different brass and bronze alloys will have
different working characteristics and different melting/ fusing
temps. and some could be problematic.
Its true that there is a lot of out there to get you
started but beyond that it is up to you to adjust things for your
set of variables.