diff --git a/crates/fj-kernel/src/algorithms/approx/curve.rs b/crates/fj-kernel/src/algorithms/approx/curve.rs
index aa17fc9b7..870925bcc 100644
--- a/crates/fj-kernel/src/algorithms/approx/curve.rs
+++ b/crates/fj-kernel/src/algorithms/approx/curve.rs
@@ -291,13 +291,12 @@ mod tests {
         let surface = objects
             .surfaces
             .insert(Surface::new(GlobalPath::x_axis(), [0., 0., 1.]))?;
-        let curve = PartialCurve {
+        let mut curve = PartialCurve {
             surface: Some(surface),
             ..Default::default()
-        }
-        .update_as_circle_from_radius(1.)
-        .build(&objects)?
-        .insert(&objects)?;
+        };
+        curve.update_as_circle_from_radius(1.);
+        let curve = curve.build(&objects)?.insert(&objects)?;
 
         let range = RangeOnPath::from([[0.], [TAU]]);
         let tolerance = 1.;
diff --git a/crates/fj-kernel/src/builder/curve.rs b/crates/fj-kernel/src/builder/curve.rs
index a16324b32..9afedb650 100644
--- a/crates/fj-kernel/src/builder/curve.rs
+++ b/crates/fj-kernel/src/builder/curve.rs
@@ -11,7 +11,10 @@ pub trait CurveBuilder {
     fn update_as_v_axis(self) -> Self;
 
     /// Update partial curve as a circle, from the provided radius
-    fn update_as_circle_from_radius(self, radius: impl Into<Scalar>) -> Self;
+    fn update_as_circle_from_radius(
+        &mut self,
+        radius: impl Into<Scalar>,
+    ) -> &mut Self;
 
     /// Update partial curve as a line, from the provided points
     fn update_as_line_from_points(
@@ -37,11 +40,12 @@ impl CurveBuilder for PartialCurve {
         self
     }
 
-    fn update_as_circle_from_radius(self, radius: impl Into<Scalar>) -> Self {
-        Self {
-            path: Some(SurfacePath::circle_from_radius(radius)),
-            ..self
-        }
+    fn update_as_circle_from_radius(
+        &mut self,
+        radius: impl Into<Scalar>,
+    ) -> &mut Self {
+        self.path = Some(SurfacePath::circle_from_radius(radius));
+        self
     }
 
     fn update_as_line_from_points(
diff --git a/crates/fj-kernel/src/builder/edge.rs b/crates/fj-kernel/src/builder/edge.rs
index c05c65120..2fc232795 100644
--- a/crates/fj-kernel/src/builder/edge.rs
+++ b/crates/fj-kernel/src/builder/edge.rs
@@ -70,7 +70,7 @@ impl HalfEdgeBuilder for PartialHalfEdge {
     ) -> Result<Self, ValidationError> {
         let mut curve = self.curve().into_partial();
         curve.global_form = Some(self.extract_global_curve());
-        let curve = curve.update_as_circle_from_radius(radius);
+        curve.update_as_circle_from_radius(radius);
 
         let path = curve.path.expect("Expected path that was just created");