Test procedure and results for 2 hours, 24 hours and 3 months. Cleaning Procedure After cutting to a thickness of 5mm, the 25mm diameter disks were: Washed Ultrasonic Clean with 10% Decon 90 Rinsed with deionised water Two Ultrasonic Cleans with deionised Water Dried @50'C for ~2Hr Test Procedure Four examples of each resin (except Varian Torr Seal and the 'domestic' Araldites) were prepared immediately before pump testing following the manufacturers recommended cure time and the cleaning routine outlined above. Four samples of each resin type were loaded into the vacuum test chamber and pumped by a rotary pump (Alcatel 2012) for 1 minute followed by the turbo-molecular pump (Pfeiffer TPH240). The vacuum recording started after a pump-down time of 5 minutes by which time the vacuum was around 1e-4Torr. Four vacuum measurements were made: Varian MultiGauge Thermocouple. The gauge output was only used to monitor the backing pressure and to confirm that the vacuum was suitable to start the turbo-molecular pump. Varian MultiGauge Cold Cathode and/or Bayard-Alpert UHV gauge. Thermo (VGQ), Residual Gas Analyser. The spectra were used to characterise the different resins. Thermo (VGQ), total pressure measure. This vacuum measure was used to monitor the pump-down time. Two hour test results This pump test was performed 24hrs after the resin was mixed. The vacuum was recorded by the Thermo (VGQ) in total pressure mode and confirmed by the Varian Cold Cathode gauge and presented as the final vacuum reading. We have provided a comparison of all of the pump tests via a downloadable PDF document. Document Pump Down Rotated (46.03 KB / PDF) Resin Final Vacuum (2Hr) Pump Graph (PDF document) None 2.8e-7 Torr Document tp blank 2 hours (8.95 KB / PDF) EpoThin 8.4e-7 Torr Document tp epothin 2 (8.8 KB / PDF) TransOptic 1.4e-5 Torr Document tp transoptic 2 (10.67 KB / PDF) KonductoMet 1 4.8e-6 Torr Document tp konduct 2 (10.03 KB / PDF) Korapox 439 5.4e-6 Torr Document tp korapox 2 (10.34 KB / PDF) Epofix 3.2e-6 Torr Document tp epofix (13.38 KB / PDF) Specifix 20 5.1e-6 Torr Document tp specfix 2 (10.97 KB / PDF) Ciba Geigy 2.5e-6 Torr Document ciba pump 2 (10.36 KB / PDF) ProbeMet 5.4e-7 Torr Document tp probemet 2 (8.78 KB / PDF) Robnor Resin 3.3e-6 Torr Document tp robnor 2 (8.94 KB / PDF) Epoxicure (Room Temperature) 3.4e-6 Torr Document pump epoxicure rt (10.75 KB / PDF) Epoxicure (cured at 65oC) 3.6e-6 Torr Document epoxicure 65 (10.83 KB / PDF) Petropoxy 3.7e-6 Torr Document tp petropoxy 2 (8.87 KB / PDF) EpoHeat 4.2e-6 Torr Document tp epoheat 2 (10.2 KB / PDF) 24 hour test results The 24Hr pump test was performed ~30 days after the resin was prepared and is believed to give a good indication of the resins suitability for the practical preparation of material for SIMS analysis. Throughout the testing period the empty vacuum chambers residual gases and ultimate (24hr) vacuum were routinely monitored to check how these parameters varied over time. The results show a slight but steady improvement in the ultimate chamber vacuum over the 30 day test period. We have provided a comparison of all of the pump tests via a downloadable PDF document. Document Pump Down Rotated (421.68 KB / PDF) Resin Final Vacuum (24Hr) Pump Graph (PDF document) None 7.12e-8 Torr Document uhv24blank (68.83 KB / PDF) EpoThin 1.64e-7 Torr Document uhv24ethin (23.94 KB / PDF) TransOptic 3.10e-7 Torr Document uhv 24 topt (42.45 KB / PDF) KonductoMet 1 2.40e-7 Torr Document uhv24kmet (37.54 KB / PDF) Korapox 439 1.10e-7 Torr Document uhv24kpox (41.12 KB / PDF) Epofix 1.60e-7 Torr Document uhv24efx (71.54 KB / PDF) Specifix 20 2.10e-7 Torr Document uhv 24 sfx (43.7 KB / PDF) Ciba Geigy 1.90e-7 Torr Document uhv24cg (36.68 KB / PDF) ProbeMet 1.60e-7 Torr Document uhv 24 pmet (23.93 KB / PDF) Robnor Resin 1.11e-7 Torr Document uhv 24 rr (26.44 KB / PDF) Epoxicure (Room Temperature) 1.70e-7 Torr Document uhv24ecurert (40.9 KB / PDF) Epoxicure (cured at 65oC) 1.60e-7 Torr Document uhv 24 ecure65 (44.24 KB / PDF) Petropoxy 1.20e-7 Torr Document uhv 24 pxy (25.41 KB / PDF) EpoHeat 1.40e-7 Torr Document uhv24eheat (36.7 KB / PDF) Three month cure test results A final 2Hr pump test was performed ~3 months after the resin was prepared. The samples were kept in a desiccator and the test chamber continually pumped over this ~3 month time period and the base vacuum improved. The results show a significant improvement in the ultimate chamber vacuum after 3 months hardening. A comparison of all of the pump tests is provided via a downloadable PDF document. Document 3 month Pump (305.09 KB / PDF) Resin Final Vacuum (2Hr) None 2.8e-8 Torr EpoThin 5.3e-8 Torr TransOptic 1.5e-7 Torr KonductoMet 1 9.8e-8 Torr Korapox 439 7.1e-8 Torr Epofix 7.4-8 Torr Specifix 20 8.5e-8 Torr Ciba Geigy 5.8e-8 Torr ProbeMet 5.9e-8 Torr Robnor Resin 6.6e-8 Torr Epoxicure (Room Temperature) 6.9e-8 Torr Epoxicure (cured at 65oC) 5.9e-8 Torr Petropoxy 9.3e-8 Torr EpoHeat 6.6e-8 Torr Residual Gas Analysis The residual gases within the vacuum chamber were routinely monitored during the pump tests. These gases, although not all identified, can provide a distinctive 'fingerprint' of the resins. Discussion of Results Comparison of the final vacuum achieved for each resin under the three test conditions is illustrated in our downloadable PDF document. Document 3 test comparison (18.32 KB / PDF) The relative vacuum achieved has been calculated from the final vacuum recorded minus the base vacuum of the chamber. It demonstrates that after ~3 months the same vacuum maybe achieved that previously took 24hrs. Epothin and ProbMet both performed well under all 3 test conditions. This article was published on 2024-07-01
