I do 99% of my firings in my shop at night while I am away at home. But my building is all concrete, so there's not much that can go wrong. I think if you have all the proper clearances and such then there is very little that can go wrong aside from an electrical fire. But even then, if everything is done properly there's very little chance of that happening either. If you've got the money to do it, then go ahead and get the Nest alarm. It wouldn't hurt, and it will give you the piece of mind you need to sleep at night with the kiln running.
The big question here is why did it sit at temp for 9 hours, unable to reach peak temperature, without putting up an error code? Review the program to see if there was a program error. Were you doing a cone firing or a custom ramp/hold?
Depends on what you're going to use the photos for. For online sales on Etsy or something like that, using other objects like tables, drapes, etc. can put the item in context, which helps the buyer see it in its intended habitat. But for entering juried exhibitions or art fairs, you just want the traditional backdrop of gray fading to black. All white or all black is not good, because the piece will look like it's floating in nothingness.
Alpine burners are made with off the shelf pipe fittings, plus a retention tip. The burner pipe is an 8" long 2" black pipe nipple, threaded into a 2" coupling. I would not use anything shorter than 8" for the burner pipe, because the gas and air don't mix as well in a shorter pipe. On the other side of the coupling is a floor flange, onto which the blower is attached. The coupling has a hole drilled on each side, through which the gas orifice is inserted. The coupling should be black pipe, not cast iron, as it is much easier to drill through for the gas orifice. If you can't find the black pipe kind, the cast ones are drillable, it's just more difficult (see photo below). The gas orifice is a 1/4" black pipe with a cap on one end. The orifice pipe goes through the hole in the coupling. Alpine drills 3 orifice holes in the pipe, with the holes aimed toward the kiln. A 3/4" reducing coupling connects to the orifice. Large washers can be used to fill any space between the 3/4" coupling and the 2" coupling so that the orifice pipe is held tight and can't turn. You could also weld the orifice pipe to the 2" coupling once you've determined that the orifice is the correct size. It's a very simple setup that you can make without any welds, and it's easy to adjust the orifice size by simply replacing the 1/4" pipe or drilling the holes larger.
In the photo below you'll see that I put a pressure gauge below the burner, then a shutoff valve, the the Baso valve, then a solenoid valve which is connected to a digital high temp shutoff controller and thermocouple. After the solenoid it connects to the 2" main gas line.
1/4 tsp copper carb won't change color?
Granted its super low percentage....
Super low percentage. If you used the whole gallon of gum solution to make a brushing batch you'd have 1/4 teaspoon, a few grams, in a 3 gallon batch of glaze. So figure 6,000 grams for the batch, about .75 grams of copper = 0.01% give or take.
If you want to do it safely, the safety systems will cost you more than the burners. For power burners, at bare minimum you'll need Baso valves on the gas lines. Ideally you'll also have solenoids on the gas lines to turn off the gas in case of a power outage so you don't have pure gas pumping through the burners. I've seen a kiln shed catch fire from that. And in addition to that you should also wire up a digital high temp shutoff controller, which is also nice to have because it can display the current kiln temp so you can see your rate of climb. Some codes don't consider Baso valves and thermocouples to be sufficient, since they are slow to react compared to more technologically advance devices like flame sensing rods and UV scanners. But it gets really expensive when you get into that stuff.
Add 2 tablespoons CMC Gum to a gallon of water. Add 1/4 teaspoon copper carbonate as a preservative, otherwise bacteria will eat up much of the gum within a few days. It will not affect the color of the glaze. Let it sit overnight, then blend with a hand blender. When making your glaze, substitute the gum solution for about 1/3 of the water.
No they are not interchangeable. Custer is a potash spar for high temperature work at cone 9/10.
A soda feldspar like Nephelyn Syenite, if substituted directly for Custer will bring the glaze temperature down to Cone 6.
If that is what you want, then test,test,test.
Changing the feldspar from potash to soda won't necessarily bring it all the way from cone 10 down to cone 6, but it will definitely bring it down. How far depends on the rest of glaze formula. But it is a good first step to lowering the melt. Potash spars can be used at cone 6, but they do melt differently than soda spars, and give a different surface look as well.
Work smart. Really pay attention to your body position while you are working. Sometimes just moving the piece higher up so you're not bent over makes a work of difference. Check how you hold your shoulders while working. Are they shrugged up, or loose and relaxed? When working for hours at a time, small stresses have huge impacts.
I just started throwing standing up 2 weeks ago. Makes a world of difference. And my work table is at standing height, too. Makes glazing a lot easier when I don't have to reach down all the time. If I need to do some sort of detail work, I put the piece on a banding wheel and sit on a stool, which puts the work at chest or shoulder height depending on the stool. This allows me to keep my back straight and shoulders back while working.