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high b side gauge pressure iso rich Post New Topic | Post Reply

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Posted: Aug 25, 2013 10:42 PM
high b side gauge pressure iso rich
I have a graco e20 and its spraying iso rich with high b side gauge pressure. Switched guns to our spare gun and still the same problem. Checked the y strainer and also the gun filter. Both are clean. Pulled the manifold shut off valve an it looked fine, but still cleaned it. Pulled the manifold off and got two clean 5 gallon buckets to check fluid flow. Put the machine in jog 10. The iso side looks to be flowing twice as much. Pulled the hoses at the machine and flow looked about the same as the a side. Checked the flow at 50ft and the flow dropped quite a bit almost half. Checked the flow at 100ft and it dropped about half again. Looks like a constant drop at each of the 50ft sections. Next I used compressed air and blew back through each of the 50ft sections and captured the fluid. The fluid is clean and no problems blowing air through it. While I had each section apart I used a 12" rod and slid it into the hose to see if there was anything blocking the fittings. I couldn't feel any restriction using the rod. Not sure what the fluid flow should be but I would expect it to be about the same between the a and b sides. I put everything back together and tried spraying again and the foam looked better just spraying a small area. Once I started really spraying a lot it started acting up again. The foam is reacting but sticky on the overspray areas after the foam is cured. Does anyone have any ideas?
Posted: Aug 26, 2013 10:49 AM
Sounds like you have a restriction on the B side. Either that or you are spraying the material too cold. What kind of foam is it? Open or closed cell? What temp and pressure are you spraying at? What size chamber in what gun?
Jesse Michalski
Posted: Sep 11, 2013 09:26 PM
keep in mind that the viscosity of your Resin is thicker than the ISO. If you are setting your hose heats the same, you will have an imbalance from the word go. In order to get the material flowing equally, try setting your resin temp (B) at a minimum of 10 degrees higher than the ISO temp that you have selected. You can even go 15 to 20 degrees hotter on the B side (especially with closed cell). After your pressures balance out, then you need to be looking at the quality of your foam. Move the temps on the primary and hose heat up or down as needed, but keep the B side higher.

If the foam is pulling away from the substrate, it's too hot. If it is runny or is setting slowly, turn your heat up a bit. You will find the range you need to be in. Consider substrate temp in your thought process.

An example setting on your machine might be

Primary A- 120 degrees
Primary B- 135 degrees
Hose heat- 120-125

This is one of a myriad of solutions. If your hoses are clean and you've checked the screens on your gun and the machine, then try this.
Try this anyway.

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