What's the best way to make a barb fitting that's a bit small for the tubing give a water-tight fit? [See details].

I’m thinking teflon plumber’s tape might do the job. Would that work? It seems like it would give you a nice seal, if understand what you are trying to do. I’m not good at math at all, really, I’m a math moron, but you need to build the ¼ up to 5/16ths right? That’s .0625 inches. Is that too much, to thick a build up to use teflon tape? How thick is .0625 inches? LOL, other than being .0625 inches thick? I get that part. :-) I need a visual; I’m having trouble picturing how thick that is.

I did that calculation on google; not by myself. That’s the only way I could do the math.

@lillycoyote What a great idea. A layer of teflon tape, a thin layer of caulk, a layer of teflon tape, a thin layer of caulk, etc would be worth a try. I like it better than caulk ridges. It would be much more rigid.

Silicone might work here. Just make sure that you put the hose on the barbed end while the silicone is moist yet, and give it at least an hour to dry so it seals correctly. I can’t think of a better way since you’re going with this type of setup. People won’t see the silicone either.

@lillycoyote & @Adirondackwannabe Sounds like a simple and workable solution. Since the hose is opaque, it will be invisible from the outside. Fortunate that, because the 3/8” hose is clear plastic tubing.

@Paradox25 Would the hose still be removable or would it adhere to the silicone?

@ETpro You can easily remove the hose by making a small slit near the top, and cut it off. The silicone shouldn’t be too difficult to remove from the barbed fitting. It is an inconvenience, but I can’t think of a better way, unless you decide to use different fittings altogether, or go with a different set up.

@Paradox25 OK. Thanks.

There are also self fusing silicone tapes available. I’ve used this stuff before, but not for what you’re trying to do. It seemed to thick for your purposes though. However you might be able to find something thinner.

And, if you really want to lock that baby in, use heat shrinkable tubing, though make sure you put on one of the hose ends before you make the connection with the barb coupling! :-) Actually, I’m kidding on that one. It think that’s maybe overkill and I’ve never used the fabric kind, on hoses, I’ve only used the plastic kind for electrical stuff, and the fabric type in the link, well, I imagine you would want to purchase it in a quantity of less than 25’.

@lillycoyote The challenge is the tubing is already there and I want to preserve it. That’s why being able to uncouple the two devices then just slide the hoses back together after repairs to either device is a must. However, shrinking heat shrinkable tubing onto the ¼ inch barb just might work to build it up to fit 5/16 ID Hose.

@ETpro There’s always some little bit of something, out there somewhere, that will solve just about any of these little problems. And you have to either think of the solution yourself, or ask, or talk to someone, who might have an idea. That’s the great thing about both neighborhood hardware stores, and I am lucky enough to still have one near me, and Fluther, of course. :-)

There is generally a solution out there, to these kinds of problems, unlike so many of the problems we face, which often seem so intractable. Philosophy and hardware; you can’t beat that combination. :-)

@lillycoyote Well, my neighborhood hardware store is a True Value. It’s only a couple of blocks up my street, and I know the guys in there very well. On many things, they are really knowledgeable. This didn’t happen to be one of those things.

When I went in there and asked the guy in that section if he had a plastic 5/16 to 3/8 reducing barbed fitting, he had no idea what a barbed fitting even was. When I told him it was a plumbing fitting for connecting tuning, he took me to where they had the plumbing fittings, but said they had no plastic fittings—just brass. I said brass would be OK (I just hadn’t wanted to pay for brass if I didn’t need it). But looking through his collection I found a 3/8” to ½” brass reducing barbed fitting and guess what, a 3/8” x 3/8” plastic barbed coupling. I took them over and educated him in what barbed fittings are. :-)

@ETpro With barbed fittings your hose will always need to be cut to remove it, so there is no way around that. I still think that the waterproof silicone is your best bet here because of this, and it works. Just make sure you purchase the right type of silicone or caulking. Here is an example of the type of silicone you should purchase.

I did manage to find the fitting you were looking for through a company that I’m very familiar with since I work in industrial maintenance. You might be interested in checking this page: http://www.grainger.com/Grainger/THOGUS-Reducing-Coupling-3XUX6?cm_mmc=CSE:GoogleBase You’ll have to order it online though.

@Paradox25 Not so in this case. This is a drain. It’s gravity fed from a low height. Very low pressure. Press on and pull off works fine.

But THANK YOU for pointing me to this. As well known as Grainger is, why couldn’t either Google or Bing point me to this. Very much appreciated. This will be much nicer and more permanent than something I jury rig. I know Grainger well from my previous life owning a prototyping shop for electronics miniaturization. I should have thought to just go to their site and search on it.

@ETpro I wasn’t entirely sure what you were trying to do, and plumbing isn’t necessarily my strong point, so I tried to give you several options. I’m glad I was able to help.

@Paradox25 Much appreciated.

I already sent @Paradox25 a thank you message, but I wanted to share the outcome of this search here for others with similar needs for obscure parts. Armed with the URL for the exact part I needed on Grainger’s site, I pulled up my own home location on Google maps and used the search nearby feature to find a Grainger store. It turns out there’s a Grainger store less than 3 miles from my North End, Boston pad. I called them this morning, and they will have a bag of 10 of the right size reducing coupling in hand and ready for pickup tomorrow at less than half of what I paid for 1 wrong-sized reducer plus shipping. So check the Grainger site for obscure parts and then search to see if there’s a store near you. If not, you can always order online, pay for shipping and endure the delay.

Now I wonder if I can shake Grainger down for a paid testimonial and get my $4.10 bag of 10 reducing couplings free. :-)

@ETpro good… and good for @Paradox25. I’ve never ordered anything from them or been to one of Grainger’s store’s, but when I went to the link I did remember that one time I was looking for something and when I went to their site I was glad to find that they had a store about 20 minutes from my house. I just don’t remember what I was looking for. :-) I know I didn’t place an order or ever go to the store.

@lillycoyote Thanks. I sent @Paradox25 a thank you note. I already switched the jury-rigged reducer. It looks so much better.

@ETpro I got your messages. I’m glad it worked out, so you’re welcome. I had to work the long 4 day stretch through the weekend, so I usually don’t log on here during that time.