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245 vs. Water blown Post New Topic | Post Reply
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Circle-D
Posted: Feb 19, 2007 09:46 PM
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245 vs. Water blown
In my rookie research stages I've been learning about the different foams and machines to spray them. It is my understanding that the blowing agent in a 245 foam boils at 59.5*. Everybody talks about having the material come out of the drum at 70*-90*. What stops the blowing agent from boiling off before it gets to the proportioner? What happens if it does boil off?If you leave your drums at <60* then you would theroreticcally (? spelling) have to have a machine with a Delta T of at least 60* correct? I guess my question is with a lot of these smaller 6000 watt machines the delta T is only around 50*. Are they unable to satisfactorily apply the 245 foams? Are you limiting yourself to water blown foams with these smaller machines? Please correct me if I'm wrong but I understand that most of your closed cell foams are 245 blown. I don't want to buy a machine with this kind of a limitation. What do all the other owners of 6000 watt machines do? Maybe my thinking is all wrong? Thank you for your thoughts on this. Skip |
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Glenn Gamblin
Posted: Feb 21, 2007 08:35 PM
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Almost all types of closed cell foam is applied between 105-120 degrees, I typically spray around 115 depending on many factors. Any good brand of foam will not boil until it gets over 90 degrees, and I have even had mine over 100 without boiling, as long as it doesn't get shaken up. When the resin boils,it basically looks like a coke does when you shake it up. It typically takes less heat to spray closed cell. The water blown you have to recirculate and get your barrels up to at least 100 degrees and I typically spray my sealection 500 between 125 and 135. A six thousand watt machine will be fine. |
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SprayFoamSupply.com
Posted: Feb 21, 2007 09:33 PM
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Why do you have to heat up your sealection to over 100 in order to spray at 125-135? If you have a machine with 6,000 watts of heat and a delta T of 50, you only need to have your drums 75-85 to spray, and that is when you are really keeping the trigger pulled. George |
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Circle-D
Posted: Feb 21, 2007 10:41 PM
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glenngamblin, you say a good foam will not boil until above 90*. Is my figure of 245 boiling at 59.5* an error? Thank you for your comments. Anyone else with a theory? |
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Luke Kujacznski
Posted: Feb 21, 2007 10:52 PM
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pure 245 will boil at about 60 degrees, but because 245 is so expensive it is co-blown with water thus raising the boiling point. |
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Circle-D
Posted: Feb 22, 2007 10:28 AM
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Luke,Is that the standard for 245 foams........to be co-blown, or does it vary by manufacturer? Thanks |
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Glenn Gamblin
Posted: Feb 22, 2007 11:36 AM
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Going through Demilecs school they beat it in your head to recirc. the materials and get them to 100 or better. I have tried it both ways and my yield is alway better when I do. 1 or 2 degrees will really affect your yield with open cell. |
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Luke Kujacznski
Posted: Feb 22, 2007 11:49 AM
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Almost all 245 foams are co blown. The reaason is that 245 is ungodly expensive. If the used only 245 a set of material would cost around $4000. Having your material around 70-85 is good. With cc if you get much hotter then that you will start forcing the 245 out of the foam and your yields will go down. You cannot recirc cc foam, when the b side gets that hot the density and viscocity change and you will start spraying off ratio. |
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Barry Wallett
Posted: Feb 22, 2007 12:42 PM
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Luke, Forgive me if I am missing something, I am just at the point of researching this business, here is my thought. The two machines I am looking at are the Graco E-10 and the Green machine. Both are small machines that recirculate the material inside of the unit to the small tank to keep it hot. Both machines are able to spray cc foam. What am I missing, do I misunderstand what you mean by reecirculating? Thanks Barry "foamer wannabe" |
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Luke Kujacznski
Posted: Feb 22, 2007 01:28 PM
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I would stay away from machines that have to recirc to heat material, the work for spraying small amounts of material but just touch up and small jobs, the machine I would recommend would be is the A-20. Send me a e-mail and I can get you info. Luke |
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Circle-D
Posted: Feb 22, 2007 02:11 PM
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Luke, What is your take on the Glascraft Guardian A5? |
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Luke Kujacznski
Posted: Feb 22, 2007 04:02 PM
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good machine, good heaters, good support. Haven't sprayed it personally but heard it performs well. |
