A harbor freight pump will probably be fine for a Hobbyists. To check it out just block the hole with your finger pump it up and make sure the gauge does not bleed down. it is a great tool for bleeding brakes by your self checking choke pull offs, Dist. vacuum advance dashpot, auto trans vacuum modulator and many other things. Normally you would watch the gauge when testing the canister but because of the check valve you have to vent it and pull of to see if it is working. when bad you will hear the hissing noise of the valve leaking. If you hear nothing let it sit for 10 minutes and pull the cap from the small nipple and you should hear the hiss of the air rushing in to fill the canister through the small nipple. And yes it would have been easier when out on the bench, it is buried under there. On second thought if you make a pull on the small nipple with the large left open the check valve should hold and then you can watch the gauge.