With so many machines and so many different systems out there how do you know how to set your system yo for the best results.
There are a few different theory's out there with how a machine should be set up, one thing that is consistent with the theories is how to get the temperature set correctly.
When you pull the trigger you want to see a nice round pattern (depending on your chamber). When the material hits the substrate you want to see it look "wet" for about a second. After the second of wet looking material you should see it change color (to the finished shade) as well as rise up.
If the material is wet for longer than a second, or the pattern doesn't open up fully, that is a sign of cold material. Cold material will drop down walls creating a messy finish. It will also will not expand the same as properly heated materials. This will cause poor yield, as a result of higher density.
On the other hand, if the material comes out too hot, it will hit the substrate the same shade and color of the finished product. This is because the foam is reacting before it ever touches the wall. This will cause a lot of extra over spray as well as damage cell structure allowing shrinkage and cracking to occur much easier. Once again your finished product with look rough and terrible, because the foam does not have time to "grow into itself" and create a nice smooth skin. Another thing you will notice is how hard it is to keep a good pattern. This is because the chambers will plug up much faster, because if the early reaction time.
Typically this temperature range will be between 100-140 F. Talk to you chemical manufacture to be able to get a smaller range.
Now that you have your temperature range dialed in. This is where the theories come into play.
ISO temperature slightly lower than the others
RESIN temperature is roughly 10 degrees f hotter than the ISO
HOSE temperature is in the middle
This setting was created to help your gauges look more balanced.
The science behind this is true, and proves the pressure will be more balanced.
Because the two materials have different viscosities at room temperature, when they are heated up, the resin is will remain slightly thicker. This will create more back pressure. By increasing it 10 degrees (f) more than the ISO, you will thin it out so it's viscosity is much closer to the ISO's.
The purpose of the hose heat being in the middle, is to help maintain the Increase temperature on the resin, but not allow the ISO to get as hot as the resin.
This would be a great set up, IF the hose sensor was in the resin side of the hose...
Set the HOSE and the ISO 10 degrees (f) lower than the RESIN.
This has the same idea as theory #1 but takes into account the safety factor and the wear on the hose (this is a good thing).
The problem with having the hose hotter than is ISO side is all because of the sensor. From the factory, the sensor is located in the ISO section of the hose.
If the hose heat is set to the same as the ISO preheated there will be no issues. It will be able to maintain the chemical temperature easily, by sending pulses of 40 amps through the hose, with little to no issues.
If the hose is set higher than the ISO preheater, it will constantly be sending power through the hose telling it to heat the material. To do this the machine must send constant 40 amps of power through the line to try and increase the temperature of the ISO. If 3 amps can kill a person imagine what 40 amp of constant power will do! Sadly people have older beat up hoses. With these hoses, t's not uncommon to see a bare wire here or there throughout the hose. If this wire touches metal it will arch (potentially weld itself) and can start fires, if it touches water it will charge it and shock anyone connected to it, if you touch it your muscles will contract and not be able to let go...potentially killing you.
Setting the ISO and hose temperatures the same will avoid these safety concerns. Instead of the constant power going through, it will be quick pulses, which can still can still has its risks, but will now only give you a quick shock, instead of a potentially fatal one. Matching these temperatures will also allow your resin to cool off a little, bring the viscosity back up and allowing for a slight pressure difference on you gauges.
Set all the temperatures to the same.
This will cause roughly 100-150psi difference in the gauges. Yes it is a difference, but not one you will really see in your foam (assuming pressure are set correctly)
Out of these three theories I'm a fan of #2 and #3.
Because of the extra wear and safety hazards of theory #1 I would highly recommend staying away from this! Perfectly balanced pressures are not worth the risk of potentially killing or severely hurting someone!
When it comes to setting up the pressures, that part is pretty easy.
Pretty much all material manufactures would like their foam to be sprayed at around 800-1000psi AT THE GUN. The hose will always have some pressure lose as the material runs through it. A good rule of thumb is 1 psi per foot.
If you have 200 ft of hose, you should set you machine at around 1200psi so you can get roughly 1000psi at your gun.
Increasing the pressure and spraying at a high pressure does not exactly increase the output of the material, it simply increases the aggressiveness as it leaves the gun. This set up will cause more overspray and blow back.
If you want to increase your output, use a different chamber.