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Pushing out non-like products Post New Topic | Post Reply

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Melvin Chandler
Posted: Dec 15, 2006 06:05 PM
Pushing out non-like products
I've purged my lines several times due to the fear of something going wrong in the lines. However, one rep says I can push out open cell with closed cell and closed with open as long as I keep the trigger pulled and don't let the materials set in the lines.

Would any of you experienced foam professionals try this or would you separate the fluids and then push out? I'm looking to push out sealection with FE wall foam.
Thomas Kasper
Posted: Dec 16, 2006 11:18 AM
I haven't heard of this. If a spray foam contractor says they have done this and it works I would have to give it a try. (A sales rep does not count) It is quite expensive to clean the lines with DOP especially when I have do this more often then I expect. I don't mind it so much when I plan to do it, compared to when someone calls and needs the opposite foam then I am spraying at the current time. I spray a lot of rim joists and certain jobs open cell needs to be used and other jobs ridgid is the way to go.
Good question, I would also like to hear if anyone chases one foam out with the other foam.
Melvin Chandler
Posted: Dec 16, 2006 04:19 PM
I hate to look like a DOPE but what is DOP? I've used diesel fuel to push out an existing chemical since that is somewhat inexpensive at 2.50 per gal and it takes me a total of 5 gal to completely purge the lines. I've heard that hydraulic fluid is also a good method especially if you are storing for a while. Good to spray under pressure and then leave it alone.
Lane Hogstad
Posted: Dec 16, 2006 07:15 PM
The company I got my rig from said switch barrels and go. I usually switch before Im done and when I finish I spray till it comes open or closed . A few times you have little waste. I only use 2 lb or 1/2 lb never had a problem. So much bad info out there let me know if I shouldn't be doing this.
Thomas Kasper
Posted: Dec 16, 2006 07:45 PM
Doictyl phthalate (dop) is a low moisture cleaner. My supplier told me to clean my lines with it if I am down for a extended time or switching foams. Maybe I can switch foams on the fly and only use this dop once in a while.
Gerry Wagoner
Posted: Dec 16, 2006 08:45 PM
We use one material to push the other out. Depending on the materials you might have a little waste (hybrid junk). Spray it out in a plastic garbage bag and toss it.

Melvin Chandler
Posted: Dec 16, 2006 11:03 PM
Og, You don't have any problems pushing out open with closed?
Posted: Dec 17, 2006 04:34 AM
if at the shop i pump the "new" resin thru the hose via the transfer pump..the fluid in the hose is returned to the original drum...after about 50 strokes of the drum pump i look at the color of the resin (closed more amber than open which is "clear karo" color),..you can see it switch...
i would rather put closed resin into an open drum than open resin in a closed drum and stop the process accordingly...(closed foam is less tolerant of water contamination than opens are effected by the 245 contamination,,,read:in a wall cavity you can "get by" with some denser foam right after the switch if shooting opencell, but thats not the case when shooting a closed cell,,the less dense foam will be obvious..)consider that you may add 6-12 oz of fluids between 50 gallons or so,,,i think our drinking water is "less pure"...
for storage:i gravity drain all lines...i push residual with compressed air into waste vessel..
i pump glycolether solvent (barsol EB) thru the hose via a diaphragm pump...i recirc from a 5 gallon bucket with about 3 gallons of fluid in it..KEEP A SEPERATE FLUSH BUCKET and pump FOR THE ISO AND RESIN FLUSH this way you can reuse the solvent without risk of ruining a hose by creating a foam slug with the residual contaminate in the solvent...remember..volume not pressure,,,circulate for a good while to get the fluids out of the hose's surface...once circulated i gravity drain the residual solvent from the hose and air dry again...i couple the proper hose ends to themselves,,put on pallet and stick up on the rack...
when switching in the field: drop pump,,,shoot till foam starts getting funky,,,shoot off into bag, box,,or other waste vessel...once proper foam comes out,,back to the wall to hammer on...sometimes i bring the hose block back to the rig and circ to drums too as outlined above...
FirstName LastName
Posted: Dec 19, 2006 09:03 PM
i never flush/chase my lines from one foam to the other.
Posted: Dec 20, 2006 06:42 AM
I always push the one product out with the other.I do it sometimes 2 times in a day with no problems.I know how many square feet I can cover with the product in the line.The problem with not doing it is introducing air into the A side lines because it crystalizes very quickly when there is not much material not willing to risk having any buildup in the lines.Can give more details elb@mtnhome.com

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