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resin rich foam Post New Topic | Post Reply
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john rio
Posted: Jan 04, 2007 07:38 PM
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resin rich foam
Just started spraying. I took over a rig that has Grace E-20, throat seal fluid on A side was clogged and piston is leaking. I used 2/3 B side and 1/2 A side of a set of open cell. I am wondering if the foam is O.K. {Demilec 500}. I flashed the cavities and the foam is adhering, but it did shrink a bit and is resin heavy. I was wondering if the foam R value is diminished and the the effect on the chemical properties of the foam.
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Luke Kujacznski
Posted: Jan 04, 2007 08:15 PM
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simple answer, yes, and over time I think you will see more and more shrinkage. |
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Gerry Wagoner
Posted: Jan 04, 2007 10:28 PM
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"I was wondering if the foam R value is diminished." It will be. regards, olger |
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SprayFoamSupply.com
Posted: Jan 05, 2007 06:20 AM
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Sprayjack, I would rebuild your A side pump before spraying any more foam. That foam could continue to shrink over time as it will never be as hard as it should be. I thought that your E-20 was supposed to shut down if you were off ratio? What were the 2 gauges on the front of the machine reading while you were spraying? George |
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Robert Taber
Posted: Jan 05, 2007 08:05 AM
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Good call on the pump rebuild. I bought an extra A side pump for my E20 and keep a rebuild on the shelf. I've had problems with some of the guys not maintaining the TSL (not to mention one guy who rinsed and flushed the A side with water). We have had up to a 500 psi difference without the E24. Not sure why it does not shut down but it pays to check the foam regularly. |
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FirstName LastName
Posted: Jan 05, 2007 08:42 PM
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whats the max pressure diff for shrinkage on foam. most company's say a rich is fine but don't know about b. i've had shrinkage problems with soyfoam, know known problem seems machine is fine? |
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Robert Taber
Posted: Jan 06, 2007 09:07 AM
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With oc foam I've seen a few different things cause shrinkage. The most common is off ratio resin rich. But also low temps and catalyst have been a problem. We went through several manufacturers foams last year trying to find one we liked best. We've tried soy foams, sucrose, corn and several others. Not really looking for bio foams specifically, but wanted to try just to see. It is amazing what is produced out there right now. Some are decent, some are garbage. Right now we settled on Dem 500. Seems to have best all around characteristics and most consistent. However, in cooler temps, our smaller unit (E20) can't seem to heat enough and we have some shrinking at times. Warmer temps and there is no problem. We tried one that had terrible shrinking and nothing worked except to add special chemicals from the factory. Of course then we had other problems arise. Anyway, try agitating the oc b side drum first and preheating the chemicals using drum heaters or recirc. Seems to reduce shrinking for us. |
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Posted: Jan 06, 2007 09:15 AM
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..hate to be a jerkoff but... flame on... spraying a job off ratio???? spraying with equipment you know is not working properly??? knowingly continueing to spray???? thank you for your contribution to the SPRAY FOAM INDUSTRY would you like to point the gun at my foot too??? i will buy your equiment if you go back to cement work....please ...flame off |
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john rio
Posted: Jan 06, 2007 11:32 PM
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Thank You everyone, for your help. I rebuilt the A side pump, and resprayed the job. Foamdude, this is a question and answer "HELP fORUM", I am totally new to this industry and started out with a F.U.B.A.R. operation with zero training. I am, however concerned with delivering a quality product and appreciate constructive criticism and advice. I had been told it was a temp. issue, bad Iso, and a multitude of causes. I was told that off ratio is to a smaller extent was common. Besides cement chemistry is far more complicated than foam. |
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Posted: Jan 07, 2007 09:25 AM
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this is a question and answer forum.. you have been advised well,,, rebuild the pump to spray on ratio...off ratio is never "good or normal"...this product is of a 50/50 ratio to obtain design product specs and to be applying good foam you must be on ratio... this is the first thing you learn "in class" if you go off ratio you must stop spraying and remedy the situatio...this is the second thing you learn "in class".... if you spray off ratio foam into a cavity you should remove said foam and reapply when the problem is resolved,,,,this is the third thing learned "in class"... temps affect viscosities of fluids and thus their ability to "flow"...the thicker the harder to move...(the resin sides are more viscous than the iso side, so this is the side you will most commonly see drift to a lower pressure when cold)...cold fluids could cause you to go off ratio...certainly a cheesed up processor will cause you to go off ratio... |
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Gerry Wagoner
Posted: Jan 07, 2007 10:20 AM
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Amen! |
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Glenn Gamblin
Posted: Jan 13, 2007 06:51 PM
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Just make sure that it is really resin rich. Some types of foam will use different amounts from the barrels depending on the viscosity and or weight of the chemical. 9 out of ten times that you have foam shrinkage is because you are spraying too hot. On a 2x4 stud try to start at around 133 degrees and go from there. More foam will require less heat. I spray 6 inches around 122. If it gets too cold you will feel voids behind the foam. Periodically push the middle of the foam and if it is firm it should warm enough. Voids will show up instantly, shrinkage will show up after 5 - 10 minutes. I always increase my temp. until it starts to shrink and then go down 2 degrees at a time. Another very important thing is how far your gun is from the foam. Too far away will cool the foam down and too close will make it shrink. Always check your gauges and make sure they are within 100 psi or so. Also, be patient when adjusting temperatures. |
