---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 04/27/21: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 11:06 AM - How to seal Tygon tube to barb fittings (rparigoris) 2. 01:08 PM - Re: How to seal Tygon tube to barb fittings (ashleysc@broadstripe.net) 3. 01:12 PM - Re: How to seal Tygon tube to barb fittings (Charlie England) ________________________________ Message 1 _____________________________________ Time: 11:06:33 AM PST US Subject: AeroElectric-List: How to seal Tygon tube to barb fittings From: "rparigoris" Hi Group. I have a mix of instruments that use various Barb fittings. Some 1 barb, some 2 and some more. Anything Winter or from Germany have gorgeous 2 rounded bump barbs. They don't leak at all. Some of the others with some poking I can get to leak. In the soaring community, if using old tubing or if you suspect leaking, they use a Green Latex farm animal castrating donut. I have some and they work great. Size is 5.5mm ID (.217") x 13.5mm OD (.532"). The Tygon tubing I'm using is 9/32"OD (.281") x 5/32"ID (.156") and depending on barb OD will grow in size. I can only use the Latex rings on about 1/4 of my connections because the rings are so thick (.158"). I would like to use dash 105 O-Rings. I tried a gazillion small clamps, nothing tickles my fancy. ID not right size, too much tension and point loading on wire clamps is 1 on bottom and 2 on top. I tried a double wrap of .25" safety wire, kinda OK but very fiddly to get it just right. You want a complete circle and it needs to go between the point of the barbs so has to be very thin. Anyway McMaster has A70 durometer dash 105 O-Rings in Buna-N, Viton, Silicone, EPDM and Poly Urethane. They also have harder A90 in Poly Urethane. Any input on which compound of O-Rings might keep tension better over time when used as a rubber band? Any other ideas welcomed. Anyone know of a small circular spring like those used in lips of seals with an approx ID of less than .281"? Thx. Ron P. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=501535#501535 ________________________________ Message 2 _____________________________________ Time: 01:08:18 PM PST US From: ashleysc@broadstripe.net Subject: Re: AeroElectric-List: How to seal Tygon tube to barb fittings Hi Ron; Viton will probably hold up the best. Oetiker makes corrosion resistant clamps that hold tight, are light weight, require a special tool to install, and are one-time use. There is a safety wiring tool that encircles the tubing with 4 wraps of safety wire and folds it over to clench. This is lighter than Oetiker and also one-time use. If you are interested in pursuing this, I can get the name off my tool in the hangar. Cheers! Stu. ----- Original Message ----- From: "rparigoris" Sent: Tuesday, April 27, 2021 11:05:59 AM Subject: AeroElectric-List: How to seal Tygon tube to barb fittings Hi Group. I have a mix of instruments that use various Barb fittings. Some 1 barb, some 2 and some more. Anything Winter or from Germany have gorgeous 2 rounded bump barbs. They don't leak at all. Some of the others with some poking I can get to leak. In the soaring community, if using old tubing or if you suspect leaking, they use a Green Latex farm animal castrating donut. I have some and they work great. Size is 5.5mm ID (.217") x 13.5mm OD (.532"). The Tygon tubing I'm using is 9/32"OD (.281") x 5/32"ID (.156") and depending on barb OD will grow in size. I can only use the Latex rings on about 1/4 of my connections because the rings are so thick (.158"). I would like to use dash 105 O-Rings. I tried a gazillion small clamps, nothing tickles my fancy. ID not right size, too much tension and point loading on wire clamps is 1 on bottom and 2 on top. I tried a double wrap of .25" safety wire, kinda OK but very fiddly to get it just right. You want a complete circle and it ne! eds to go between the point of the barbs so has to be very thin. Anyway McMaster has A70 durometer dash 105 O-Rings in Buna-N, Viton, Silicone, EPDM and Poly Urethane. They also have harder A90 in Poly Urethane. Any input on which compound of O-Rings might keep tension better over time when used as a rubber band? Any other ideas welcomed. Anyone know of a small circular spring like those used in lips of seals with an approx ID of less than .281"? Thx. Ron P. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=501535#501535 ________________________________ Message 3 _____________________________________ Time: 01:12:30 PM PST US From: Charlie England Subject: Re: AeroElectric-List: How to seal Tygon tube to barb fittings On Tue, Apr 27, 2021 at 1:32 PM rparigoris wrote: > rparigor@hotmail.com> > > Hi Group. I have a mix of instruments that use various Barb fittings. Some > 1 barb, some 2 and some more. Anything Winter or from Germany have gorgeous > 2 rounded bump barbs. They don't leak at all. Some of the others with some > poking I can get to leak. In the soaring community, if using old tubing or > if you suspect leaking, they use a Green Latex farm animal castrating > donut. I have some and they work great. Size is 5.5mm ID (.217") x 13.5mm > OD (.532"). The Tygon tubing I'm using is 9/32"OD (.281") x 5/32"ID (.156") > and depending on barb OD will grow in size. I can only use the Latex rings > on about 1/4 of my connections because the rings are so thick (.158"). I > would like to use dash 105 O-Rings. I tried a gazillion small clamps, > nothing tickles my fancy. ID not right size, too much tension and point > loading on wire clamps is 1 on bottom and 2 on top. I tried a double wrap > of .25" safety wire, kinda OK but very fiddly to get it just right. You > want a complete circle and it ne! > eds to go between the point of the barbs so has to be very thin. > Anyway McMaster has A70 durometer dash 105 O-Rings in Buna-N, Viton, > Silicone, EPDM and Poly Urethane. They also have harder A90 in Poly > Urethane. > Any input on which compound of O-Rings might keep tension better over time > when used as a rubber band? > Any other ideas welcomed. > Anyone know of a small circular spring like those used in lips of seals > with an approx ID of less than .281"? > Thx. Ron P. > Something like this? 7mm constant tension hose clamp You'd need to verify it this particular one applies clamping pressure to a 7mm hose, or it's closed size is 7mm. For more options, just google what I wrote as the link text & substitute the size you want. The flat wrapped springs are quite common in Japanese cars, so you should be able to find something that will work. My personal preference when using hard polyethylene tubing is to use push to connect fittings. They have a 'rubber' gasket that seals to the *outside* of the tubing, and a metal barb that catches the tubing beyond the sealing point. Easy insertion/removal, unlike barb fittings. Note that you can also find them on ebay, Amazon, etc, usually for a lot less money. If the Tygon you're using is some other, softer material, they probably won't work for you. 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