The successful joining of PVC
pipes and fittings larger than 2 inch and all
non-interference type joints require the use of solvent
cements that have higher gap-filling properties than the
minimum viscosity (90 cps) cements permitted in most
specifications. The ability of solvent cement to fill gaps
in a pipe joint can be determined by considering it's wet
film thickness. A guide to the proper selection of solvent
cements for the various pipe sizes is given below. Cements
are classified into three types or groups, regular bodied,
medium bodied, or heavy bodied based on minimum viscosity
and wet film thickness. Manufacturers' recommendations for
pipe size should be followed, guidelines shown in the table
are general ones. Note that solvent cement properties may
vary considerably among manufacturers. There are also
situations where joint fits vary for different applications
of the same nominal pipe size. In such cases, variations for
these guidelines given may be satisfactory or desirable.
Medium bodied and heavy bodied cement can generally be used
for smaller pipe and fittings than shown in tables
below.
Product
Viscosity
The method of measuring the
thickness or body of products.
Wet
Film Thickness
Wet film thickness of solvent
cement can be measured by using a Nordson Wet Film Thickness
Gage or equivalent. To use the gage, dip a short length of 1
inch pipe vertically into the cement at a temperature of
approximately 73 degrees F (23 degrees C) to a depth of
1-1/2 to 2 inches for a period of 15 seconds. Remove the
pipe from the cement and hold the pipe horizontally for 45
seconds Measure the wet film thickness on the top surface of
the pipe with the end of the gage about 1/4 inch from the
end off the pipe.
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