Flying, homebuilt airplanes, working with wood, riveted aluminum, welded steel tubing, fabric, dope and common sense. Gunsmithing, amateur radio, astronomy and auto mechanics at the practical level. Roaming the west in an old VW bus. Prospecting, ghost towns and abandoned air fields. Cooking, fishing, camping and raising kids.
Friday, December 1, 2006
AV - Flying On The Cheap -- Hose Fittings
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A fellow homebuilder spotted a female air-hose quick-connect fitting on a fuel I'd just finished sloshing (riveted aluminum tank) and told me he hadn't bothered to pressure-test his tank since it was gravity feed and he figured just filling it up was enough of a test. He went on to say that it hadn't leaked so I guess he was right.
I didn't bother to tell him the fitting wasn't there for the purpose of pressure-testing.
Heat the end of your 2-ply fuel line in oil, you can push it onto an air-hose quick-connect fitting. Safety wire or even a hose-clamp for the rich bastards, you got yourself a fuel-line fitting.
Why? Because it costs less than half a buck and works perfectly well. Gettem from Harbor Freight. Two male fittings, one female and a quick-connect coupler. Wait for the sale, you can pick up the kit for $1.39 (otherwise, it's about $3).
No big deal? Maybe not, if you got lots of money to waste.
Personally, I prefer aluminum tubing for fuel, vent & vacuum lines. Old habits, etc. But if you have to squeeze ever nickle until the buffalo farts, hose is makes pretty good sense. When properly installed & supported, frequently inspected and periodically replaced, hose can be made to serve for the plumbing in a minimum-cost, VW-powered puddle jumper. Assuming you've got a drawer full of fittings.
Back around Thanksgiving I reached in the drawer and came up empty and the local auto-parts place wanted something like three bucks for one 1/4"-NPT to hose fitting, I needed four of them and they only had the one in stock. I could turn them up on the lathe faster than they could order them but on the way home I stopped by the Harbor Freight store in Escondido and they had a whole bin of air-hose fittings on sale. Bought a bunch. Worked fine.
They're cast brass rather than extruded. And only come in straights, male or female. But a gravity-feed system doesn't see any pressure to speak of and space isn't at a premium in this particular airframe so straight works okay.
Yeah, it's outside the box. No, it isn't unsafe; not when properly installed. And the proof is no farther away than testing it for yourself.
-R.S.Hoover
Could you elaborate on the use of safety wire instead of hose clamps?
ReplyDeleteI fear cutting through the hose, but I guess it's hard to get the wire that tight with the twisters before it snaps.
Here's how another cheapskate does it.