The yellow flame is what we call a reducing flame, as it can reduce the the more reactive metals to their elemental state. The flame lacks oxygen, your fan is not giving enough air for the amount of fuel you are using, either a bigger fan or using a smaller gas orifice will fix.
The flame Yellow is giving off un-burnt gases full of carbon 9which makes it a good reducer of the metal salt to metal elements, sometimes we want this type of flame but it really depends on what we are doing. (this flame can also introduce more pollutants into the air). Normally not what you want in your furnace, but their are times it is very useful.
The Blue flame can be a neutral flame. A very hot flame with just right on oxygen to fuel ratio, this will produce the best heat. We call the flame here stoichiometric combustion or chemical reaction exactly how much of both chemicals needed in the chemical reaction, or just the right amount of fuel with just the right amount of air for complete combustion, this will also be the cleanest flame and will produce the least amount of pollutants into the air...
We can also provide more air or oxygen than gas it will also be a blue flame but different at burner, and less heat. This is an oxidizing flame it will make salts of metals that oxidize more easily, make rust out of iron for example.
See the reactivity series of metals, carbon is added to the chart as a reference, to which metals can be reduced with carbon.
High pressure regulators are normally where you have larger burners, most high pressure regulators can be adjusted down to a low pressure, many or most of the low pressure propane regulators can not be adjusted and have a fixed setting.
Fuels can attack hoses and become very dangerous, different fuels nee different types of hoses, be sure your hoses are rated for the fuel (and pressures your using them with). a fuel leak or busted hose is not something you want to happen, a leak can fuel an area with fuel making a dangerous situation to be in.
Using the improper hose for the fuel you are using is just an accident waiting to happen.
Looks like you are making good progress, adjustments or tweaking your design is all part of the game when you are building your homemade burner, learning what it needs and what makes it work is an important part of that process.
Sorry I was having trouble seeing the pictures you posted. But this is probably what you were talking about.
The flame Yellow is giving off un-burnt gases full of carbon 9which makes it a good reducer of the metal salt to metal elements, sometimes we want this type of flame but it really depends on what we are doing. (this flame can also introduce more pollutants into the air). Normally not what you want in your furnace, but their are times it is very useful.
The Blue flame can be a neutral flame. A very hot flame with just right on oxygen to fuel ratio, this will produce the best heat. We call the flame here stoichiometric combustion or chemical reaction exactly how much of both chemicals needed in the chemical reaction, or just the right amount of fuel with just the right amount of air for complete combustion, this will also be the cleanest flame and will produce the least amount of pollutants into the air...
We can also provide more air or oxygen than gas it will also be a blue flame but different at burner, and less heat. This is an oxidizing flame it will make salts of metals that oxidize more easily, make rust out of iron for example.
See the reactivity series of metals, carbon is added to the chart as a reference, to which metals can be reduced with carbon.
High pressure regulators are normally where you have larger burners, most high pressure regulators can be adjusted down to a low pressure, many or most of the low pressure propane regulators can not be adjusted and have a fixed setting.
Fuels can attack hoses and become very dangerous, different fuels nee different types of hoses, be sure your hoses are rated for the fuel (and pressures your using them with). a fuel leak or busted hose is not something you want to happen, a leak can fuel an area with fuel making a dangerous situation to be in.
Using the improper hose for the fuel you are using is just an accident waiting to happen.
Looks like you are making good progress, adjustments or tweaking your design is all part of the game when you are building your homemade burner, learning what it needs and what makes it work is an important part of that process.
Sorry I was having trouble seeing the pictures you posted. But this is probably what you were talking about.
