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#145-1 Blanca P., Spain
I work as an engineer in Spain. We have a great problem, as we use polyol, and after isocyanate to form polyurethane. We are looking for any solvent in order to remove isocyanate, polyureas (generated from
isocyanate in contact with air) and polyurethane generated in process. We do not really know how to clean our machines and molds, which are exposed at high temperature (130 ºC) and pressure. Does anyone know the way or any product to clean our machinery?.
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#145-2 Pete Rushing, Gusmer Corporation to #143-8 Sid S, California
Why do I always have POLY 'B' left over? It's not a lot left over. maybe 1-2 Gallons. I usually just save the excess 'B' and after a while I'll get a Drum of 'A' and all is well for another few months.
In actuality, you no doubt started with less "A" vs. "B". Next time you open a new drum of "A" and "B", measure the distance from the top of the bung hole to the liquid surface of each drum. There is a good chance you have less "A" then "B". Hence, you will deplete the "A" drum first, if your Proportioning Pumps are of volumetric displacement design and of equal size or 1:1 ratio.
Most Proportioning Pumps are of volumetric displacement design and determine the ratio in which the "A" and "B" materials are pumped.
Since they are designed to pump a given volume, in general, how much the volume weighs is not a consideration. Having less volume in the drum to start with, is.
The material looks/sprays fine. It performs well over time but the reality is that I am off-ratio.
So, can we open up this discussion again? Has anyone else noticed this happening. I use Glas-Craft machines and the guys I have talked to also use Glas-Craft. Is this just a Glas-Craft/machine mechanical issue. For example- Glas-Craft uses 2 different size fittings on their hose assemblies. I assume that they do this so folks can not cross-over hoses when changing/repairing. In principal this is a good idea but, in reality the orafices of these fitting have different diameters which I beleive can effect output.
Or is it more complex than that?
The use of two different fitting sizes are intended to prevent inadvertent connection of the "A" material hose to the "B' material hose. This will not have an effect on material ratio and have little effect, on the total output of machines using volumetric displacement design Proportioning Pumps.
A friend of mine says he thinks it has to do with "Fluid Mechanics" He said that different liquids have different "flow-ability characteristics". Since ISO is generally thinner than Poly it would stand to reason that it would "flow" better.
It is true that materials that have lower viscosities also have less resistance to flow. One might ask what effect, if any, does this have on ratio. Perhaps the better question is, will this make the lower viscosity materials' Proportioning Pump, pump at a faster rate than the Proportioning Pump which pumps the higher viscosity material? If the answer is yes, then the material in fact will be dispensed off ratio. On the other hand, if the two Proportioning Pumps are connected to a common drive...........the flow characteristics of one material has little influence on the volumetric rate or ratio of the Proportioning Pumps, as neither of the pumps cycle rate changes as it would if driven independently.
It is important to keep in mind that the size of the volumetric displacement design Proportioning Pumps determine the ratio in a common drive system. Pressure balance is determined by the size of the "A" and "B" fluid orifices in the gun.
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#145-3 Ross K, New York re #144-10 Rudy C, California
I don’t think you can mix old and new Gusmer hoses because the new electrical connectors on the new hoses. So if you blow one hose, you gotta buy all new hoses. How about that?
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#145-4 Dirk Benthien, Forum Moderator re #145-3 Ross K, New York
Sorry, Ross, to contradict: there are adapters to mix and match old and new hoses, and no hose needs to be discarded due to incompatibility. For full details, visit CPI’s web site at http://www.cpillc.com/prd-gu-powerlock.htm and read about the PowerLock system.
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#145-5 Ron S, Alabama
Is it okay to spray roofing foam in the walls inside a private home for insulation. I think roofing foam is cheaper and offers higher r-value than typical insulation foam like Demilec.
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#145-6 Howard S, Florida
What happens if you spray studs with closed cell foam? Do it encapsulate mold and does it keep growing. Would it be any different with open cell foam?
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