Soaker Hose End Plug

One of the soaker hoses in Mary’s Vassar Farms garden split lengthwise near one end:

Soaker Hose Plug - hose split
Soaker Hose Plug – hose split

Although the hose is fully depreciated, I thought it’d be worthwhile to cut off the damaged end and conjure an end cap to see if a simple plug can withstand 100 psi water pressure.

A pair of Delrin (because I have it) plugs with serrations fill the hose channels, with the outer clamp squishing the hose against them:

Soaker Hose Plug - channel plugs - side view
Soaker Hose Plug – channel plugs – side view

In real life, they’ll be pushed completely into the hose, with a generous layer of silicone snot caulk improving their griptivity.

I started with 8 mm plugs, but they didn’t quite fill the channels:

Soaker Hose Plug - channel plugs - 8 mm test fit
Soaker Hose Plug – channel plugs – 8 mm test fit

Going to 8.5 mm worked better, although there’s really no way to force the granulated rubber shape into a snug fit around a cylinder:

Soaker Hose Plug - channel plugs test fit
Soaker Hose Plug – channel plugs test fit

Fortunately, they need not be leakproof, because leaking is what the hose does for a living. Well, did for a living, back before it died.

The clamps have a solid endstop, although it’s more to tidy the end than to hold the plugs in place:

Soaker Hose End Plug - Slic3r
Soaker Hose End Plug – Slic3r

The clamps need aluminum backing plates to distribute the stress evenly across their flat sides:

Soaker Hose Plug - installed
Soaker Hose Plug – installed

Those are 8-32 stainless steel screws. The standard 1 inch length worked out exactly right through no fault of my own.

The OpenSCAD source code as a GitHub Gist:

// Rubber Soaker Hose End Plug
// Ed Nisley KE4ZNU June 2019
// 2020-05 Two-channel hose end plug
Layout = "Hose"; // [Hose,Block,Show,Build]
//- Extrusion parameters must match reality!
/* [Hidden] */
ThreadThick = 0.25;
ThreadWidth = 0.40;
HoleWindage = 0.2;
Protrusion = 0.1; // make holes end cleanly
inch = 25.4;
function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);
//----------
// Dimensions
// Hose lies along X axis
HoseTubeOD = 12.0; // water tube diameter
HoseTubeOC = 12.5; // .. spacing
HoseWebThick = 7.8; // center joining tubes
Hose = [100,25.0,HoseTubeOD]; // X=very long, Y=overall width, Z=thickness
HoseSides = 12*4;
PlugLength = 25.0; // plugs in hose channels
PlateThick = 5.0; // end block thickness
WallThick = 2.0; // overall minimum thickness
Kerf = 0.75; // cut through middle to apply compression
ID = 0;
OD = 1;
LENGTH = 2;
// 8-32 stainless screws
Screw = [4.1,8.0,3.0]; // OD = head LENGTH = head thickness
Washer = [4.4,9.5,1.0];
Nut = [4.1,9.7,6.0];
CornerRadius = Washer[OD]/2;
ScrewOC = Hose.y + Washer[OD];
echo(str("Screw OC: ",ScrewOC));
BlockOAL = [PlugLength + PlateThick,ScrewOC + Washer[OD],2*WallThick + Hose.z]; // overall splice block size
echo(str("Block: ",BlockOAL));
//----------------------
// Useful routines
module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes
Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);
FixDia = Dia / cos(180/Sides);
cylinder(d=(FixDia + HoleWindage),h=Height,$fn=Sides);
}
// Hose shape
module HoseProfile() {
rotate([0,-90,0])
translate([0,0,-Hose.x/2])
linear_extrude(height=Hose.x,convexity=4)
union() {
for (j=[-1,1]) // outer channels
translate([0,j*HoseTubeOC/2])
circle(d=HoseTubeOD,$fn=HoseSides);
translate([0,0])
square([HoseWebThick,HoseTubeOC],center=true);
}
}
// Outside shape of splice Block
// Z centered on hose rim circles, not overall thickness through center ridge
module SpliceBlock() {
difference() {
hull()
for (i=[-1,1], j=[-1,1]) // rounded block
translate([i*(BlockOAL.x/2 - CornerRadius),j*(BlockOAL.y/2 - CornerRadius),-BlockOAL.z/2])
cylinder(r=CornerRadius,h=BlockOAL.z,$fn=4*8);
for (j=[-1,1]) // screw holes
translate([0,
j*ScrewOC/2,
-(BlockOAL.z/2 + Protrusion)])
PolyCyl(Screw[ID],BlockOAL.z + 2*Protrusion,6);
cube([2*BlockOAL.x,2*BlockOAL.y,Kerf],center=true); // slice through center
}
}
// Splice block less hose
module ShapedBlock() {
difference() {
SpliceBlock();
translate([(-Hose.x/2) + (BlockOAL.x/2) - PlateThick,0,0])
HoseProfile();
}
}
//----------
// Build them
if (Layout == "Hose")
HoseProfile();
if (Layout == "Block")
SpliceBlock();
if (Layout == "Show") {
ShapedBlock();
translate([(-Hose.x/2) + (BlockOAL.x/2) - PlateThick,0,0])
color("Green",0.25)
HoseProfile();
}
if (Layout == "Build") {
SliceOffset = 0;
intersection() {
translate([SliceOffset,0,BlockOAL.z/4])
cube([4*BlockOAL.x,4*BlockOAL.y,BlockOAL.z/2],center=true);
union() {
translate([0,0.6*BlockOAL.y,BlockOAL.z/2])
ShapedBlock();
translate([0,-0.6*BlockOAL.y,BlockOAL.z/2])
rotate([0,180,0])
ShapedBlock();
}
}
}

The original doodle, with dimensions vaguely related to the final model:

Soaker Hose End Plug - hose dimensions
Soaker Hose End Plug – hose dimensions

There is, as far as I can tell, no standardization of dimensions or shapes across manufacturers, apart from the threaded hose fittings.