Dryer Vent Filter Snout

The first step in adding a filter bag to the dryer vent requires a convenient way to attach it. Because we live in the future, a couple of hours of 3D printing produced something that might work:

Clothes Dryer Vent Filter Snout – installed

It’s made of TPU, which is bendy enough to ease two tabs into the two outermost slots you can see and a corresponding pair of tabs into slots on the wall side.

The solid model shows the part snapped inside the vent:

Clothes Dryer Vent Filter Snout – OpenSCAD show

The flared bottom takes something like three hours to print (TPU likes slooow extrusion), so I did the top ring first to verify the tab fit:

Clothes Dryer Vent Filter Snout – OpenSCAD build

Both parts come from hull() surfaces wrapped around quartets of thin circles at the proper positions; the difference() of two slightly different hulls produces thin shells.

A thin layer of JB PlasticBonder urethane adhesive, which bonds TPU like glue, holds the two parts together. I used the tan variant and, while it’s not a perfect match, it definitely looks better than black. Not that it matters in this case.

Mary will sew up a bag with a drawstring holding it to the snout. If everything survives the performance tests, printing the whole snout in one four-hour job will both make sense and eliminate an uneven joint that’s sure to be a lint-catcher.

The OpenSCAD source code as a GitHub Gist:

	// Clothes dryer vent filter snout
	// Ed Nisley – KE4ZNU
	// 2025-10-07

	include <BOSL2/std.scad>

	Layout = "Ring"; // [Show,Build,Ring,Taper]

	/* [Hidden] */

	ID = 0;
	OD = 1;
	LENGTH = 2;

	HoleWindage = 0.2;
	Protrusion = 0.1;

	NumSides = 432*4;
	$fn=NumSides;

	Gap = 5.0;

	// Centers of corner rounding circles

	InnerWidth = 3.0; // wall inside snout
	InnerRadius = 6.0; // inner corner rounding

	RR = [130.0/2 – InnerRadius,91.0/2 – InnerRadius]; // right rear corner
	RF = [112.0/2 – InnerRadius,-(91.0/2 – InnerRadius)]; // right front corner

	CornerCtrs = [[RR.x,RR.y],[RF.x,RF.y],[-RF.x,RF.y],[-RR.x,RR.y]]; // clockwise from RR

	InsertHeight = 7.0; // overall height inside the snout

	TabOC = [73.0,91.0]; // tabs locking into snout

	TabCtrs = [[TabOC.x/2,TabOC.y/2],[TabOC.x/2,-TabOC.y/2],[-TabOC.x/2,-TabOC.y/2],[-TabOC.x/2,TabOC.y/2]];
	TabRadius = 5.0;
	TabHeight = 3.0;

	TaperHeight = 20.0; // Taper holding filter bag
	TaperRadius = 10.0; // outward to capture bag string
	TaperWidth = 2.0; // wall width

	TaperCtrs = CornerCtrs + [[0,-(TaperRadius – InnerWidth)],[0,0],[0,0],[0,-(TaperRadius – InnerWidth)]];

	//—–
	// Clear inside vent opening as 2D shape

	module Opening() {
	hull()
	for (p = CornerCtrs)
	translate(p)
	circle(r=InnerRadius);

	}


	//—–
	// Insert ring locking into vent snout

	module Ring() {

	difference() {
	union() {
	linear_extrude(h=InsertHeight)
	offset(delta=InnerWidth)
	hull()
	for (p = CornerCtrs)
	translate(p)
	circle(r=InnerRadius);
	up(InsertHeight – TabHeight)
	linear_extrude(h=TabHeight)
	for (p = TabCtrs)
	translate(p)
	circle(r=TabRadius);
	}
	down(Protrusion)
	linear_extrude(h=2*InsertHeight)
	Opening();
	}

	}

	//—–
	// Taper glued to ring

	module Taper() {

	difference() {
	hull() {
	up(TaperHeight)
	linear_extrude(h=Protrusion)
	offset(delta=InnerWidth)
	hull()
	for (p = CornerCtrs)
	translate(p)
	circle(r=InnerRadius);
	linear_extrude(h=Protrusion)
	offset(delta=TaperRadius)
	hull()
	for (p = TaperCtrs)
	translate(p)
	circle(r=TaperRadius);
	}
	hull() {
	up(TaperHeight)
	linear_extrude(h=2*Protrusion)
	offset(delta=InnerWidth)
	hull()
	for (p = CornerCtrs)
	translate(p)
	circle(r=InnerRadius – InnerWidth);
	down(Protrusion)
	linear_extrude(h=2*Protrusion)
	offset(delta=TaperRadius – TaperWidth)
	hull()
	for (p = TaperCtrs)
	translate(p)
	circle(r=TaperRadius);
	}
	}
	}

	//—–
	// Build things

	if (Layout == "Ring")
	Ring();

	if (Layout == "Taper")
	Taper();

	if (Layout == "Show") {
	up(TaperHeight)
	Ring();
	Taper();
	}

	if (Layout == "Build") {
	back(55)
	up(InsertHeight)
	yrot(180)
	Ring();
	fwd(55)
	up(TaperHeight)
	yrot(180)
	Taper();
	}