The Sheen 801 conical mandrel test apparatus available from Novasys Group is a range of conical bend testers designed to establish a coating’s resistance to cracking or detachment from the substrate as well as its elongation.
These two key properties of the coating are determined using the conical mandrel by bending the test material around a conically shaped metal bar.
Suitable for use with metal panels up to 0.8mm thick or flexible substrates such as polythene or synthetic rubber up to 5mm in thickness, the conical mandrel test apparatus consists of a steel mandrel 203mm in length and tapering from 38mm to 3mm in diameter.
The conical mandrel accommodates test panels up to 19cm x 11cm in size. A graduated scale on the clamping bar indicates the mandrel diameter at which failure has occurred. When this diameter is added to the thickness of the panel used, the percentage elongation can be calculated.
Operating the conical mandrel apparatus
As the handle rests on the test bench (the same side as the clamping wing-nuts), a panel is inserted into the clamp with the coated side on top and a sheet of Kraft wrapping paper placed on top of the coated side.
The clamp is then tightened by means of the three wing-nuts, ensuring that one vertical edge of the panel is in line with the narrow end of the mandrel. The roller assembly is then rotated smoothly through 180 degrees, with the duration of the movement based on the national standard of compliance.
- ASTM D522 (A): For cracking/ detachment 1 second and for elongation 15 seconds
- BS EN NF/ISO 6860 (BS 3900-E11 ): For cracking/ elongation 2-3 seconds