Foam Testing | Ask Mason Knowles - SPF Consultant | Spray Foam Technical Questions and Answers | SprayFoam Magazine Q&A Forums

Q&A Forums

Author	Comments
Dave Strnad Posted: Oct 20, 2007 08:07 PM	Foam Testing Mason, Are there methods a spf contractor can use to check quality on jobs. I imagine that this could be done be taking random core samples. My question is what test can be done to confirm quality? density is easy enough, but what about closed cell content, strucuture, r-value, etc. I have been told by several different people that for the most part if it looks good it is good, but it would be nice to be a little more exact. Thanks
mason Posted: Oct 21, 2007 10:00 AM	You can test the compressive strength of the foam with a foam sample. Cut a foam block about 3-4 inches in diameter, take a one inch diameter solid wood or metal rod and place in the center of the foam sample, stack weights up to 20 lbs on the rod. A 2 lb closed cell foam should compress at around 15 to 25 pounds. Experienced foamers do the "thumb test" After years, an experienced foamer can depress the foam with their thumb to determine to a remarkable accuracy whether the foam is up to its rated compressive strength For adhesion, take a core sample from the substrate, the foam should not come off clean but leave little pieces of foam stuck to the surface. This is called cohesive foam failure and is the optimum adhesion that you are striving for. A mechanical bond is acceptable, this is where the foam comes off clean but is difficult to remove. If the foam comes off easily, it is unacceptable. Cell Structure: A visual observation can typically tell you if the foam is mixed well, but to verify in the field, take an optical comparator that can magnify the sample and observe if the cells are of fairly uniform size without voids, splits or cracks. The Canadian Urethane Contractors Assocation has a field testing apparatus for testing adhesion of foam. You may call them for more information. Hope this helps.

Author

Comments

Dave Strnad

Posted: Oct 20, 2007 08:07 PM

Foam Testing

Mason,

Are there methods a spf contractor can use to check quality on jobs. I imagine that this could be done be taking random core samples. My question is what test can be done to confirm quality? density is easy enough, but what about closed cell content, strucuture, r-value, etc. I have been told by several different people that for the most part if it looks good it is good, but it would be nice to be a little more exact.

Thanks

mason

Posted: Oct 21, 2007 10:00 AM

You can test the compressive strength of the foam with a foam sample. Cut a foam block about 3-4 inches in diameter, take a one inch diameter solid wood or metal rod and place in the center of the foam sample, stack weights up to 20 lbs on the rod. A 2 lb closed cell foam should compress at around 15 to 25 pounds. Experienced foamers do the "thumb test" After years, an experienced foamer can depress the foam with their thumb to determine to a remarkable accuracy whether the foam is up to its rated compressive strength

For adhesion, take a core sample from the substrate, the foam should not come off clean but leave little pieces of foam stuck to the surface. This is called cohesive foam failure and is the optimum adhesion that you are striving for. A mechanical bond is acceptable, this is where the foam comes off clean but is difficult to remove. If the foam comes off easily, it is unacceptable.

Cell Structure: A visual observation can typically tell you if the foam is mixed well, but to verify in the field, take an optical comparator that can magnify the sample and observe if the cells are of fairly uniform size without voids, splits or cracks.

The Canadian Urethane Contractors Assocation has a field testing apparatus for testing adhesion of foam. You may call them for more information.
Hope this helps.

You need to login to reply to this topic. Please click here to login.