Just about every joint I made with barbed fittings and ss worm gear hose clamps leaked on a gravity system with at most 15 lbs of pressure. Are better fittings available or does my installation technique need improving?

Well, we use barbed inserts all the time with hose clamps, and never have a leak with pressures up to and exceeding 60 psi. They do make compression fittings, but they only work on certain grade of pipe. Is your pipe thin or thick? With the compression fittings, there is a stainless steel sleeve that slides into the pipe before putting on the fitting, but I really think barbed inserts should work just fine here. Are the hose clamps the right size? We always use two hose clamps per fitting, with the hose clamps screws facing opposite ways. Are you heating the pipe to insert the fittings, if so, don't overheat it, and if you can get them in without heating it at all, that's your best bet. Can you tell me exactly how you are putting the stuff together? Ill try to help out if I can.

I am using thinwall black plastic pipe rated 100PSI that comes in 400 foot rolls. The stainless steel pipe clamps are about 1/2 inch wide and have a max range of 1 inch pipe. I have only been installing one clamp over the barbed portion of the straight coupling or tee. I did not heat any pipe to install on the barbed fittings. In one case, even two hose clamps failed to stop a leak.

Hi Propfool...

The trick to these fittings is to heat the tubing a little bit as MGD77 suggested.

You don't want to overheat, but slightly soften the plastic so that when you drive the SS clamp home it embeds just slightly into the plastic tubing and causes the plastic to take the shape of the barbed fitting.

Give it a shot and let us know how you make out, OK?

Mark

How do I heat it... with a propane torch or with a container of near boiling water?

Propane torch... just wave it by the last inch or two of the tubing until the fitting can be inserted without deforming the pipe. Then cinch the SS clamps down... should see just a little bit of plastic come into the clamp when all is tightened.