Gravity cup leaking

[ian12]

Hi All

Anyone have any tips for keeping a gravity cup air tight - I clean around this area every use and there is a new gasket but it seems no matter how tight I turn the cap it leaks.

Now the leak is not lots but it means that I am losing pressure and this affects the fan.

Ian

[johnnparchem]

Hi All

Anyone have any tips for keeping a gravity cup air tight - I clean around this area every use and there is a new gasket but it seems no matter how tight I turn the cap it leaks.

Now the leak is not lots but it means that I am losing pressure and this affects the fan.

Ian

I am confused, a gravity cup cap should actually have a hole in the cap to let air in or the finish will not be able to flow because of a vacuum. I have the opposite problem you are describing. Sometimes the vent hole clogs and I get no or little spray. In any case my gravity cops do not rely on pressurizing the cup rather they let gravity feed the finish.

You also my need to thin your finish.

[B. Howard]

I am confused on the type of gun you are using. A true gravity feed cup requires a bleed hole of some type to allow air to enter as the fluid exits. These type guns may always dribble a bit depending on spray positions. It is a good idea to leave a 1/2" or so head space when filling the cup as well. If it is a pressure feed cup that is a different story and the leak will cause a loss of performance. Keeping the top of the cup clean is first. Also inspect it for any nicks or gouges that may cause leaks. If the gasket is neoprene you may be over tightening the cup which pinches the gasket and causes leaks. Cork gaskets can tend to dry out, especially if not in daily use, hydrating them with some of the proper thinner before use can help.

[ian12]

When I said air tight I meant a good tight seal to stop leaks - this is my gun http://www.hvlp.com/guns_7500mt3.php

Ian

[B. Howard]

Try my suggestions in my previous post. Unless there's is a pressure transfer hose that goes to the top of the cup a small amount of leakage will not affect performance. Also there should be some type of air bleed to allow air to enter the cup as fluid exits, that may always leak at times. The best solution to this its to convert to Devilbis D-kups or 3M pps cup systems.

[Dan Bombliss]

May try thread tape, for air compressor attachments?