diff --git a/lib/Slic3r/GCode.pm b/lib/Slic3r/GCode.pm
index c7fa122d6..4173907e3 100644
--- a/lib/Slic3r/GCode.pm
+++ b/lib/Slic3r/GCode.pm
@@ -244,7 +244,7 @@ sub extrude_loop {
     
     # extrude along the path
     my $gcode = join '', map $self->extrude_path($_, $description, %params), @paths;
-    $self->wipe_path($extrusion_path->polyline) if $self->enable_wipe;
+    $self->wipe_path($extrusion_path->polyline->clone) if $self->enable_wipe;
     
     # make a little move inwards before leaving loop
     if ($loop->role == EXTR_ROLE_EXTERNAL_PERIMETER && defined $self->layer && $self->layer->object->config->perimeters > 1) {
@@ -351,7 +351,7 @@ sub extrude_path {
             $local_F = 0;
         }
         if ($self->enable_wipe) {
-            $self->wipe_path($path->polyline);
+            $self->wipe_path($path->polyline->clone);
             $self->wipe_path->reverse;
         }
     }
@@ -468,6 +468,7 @@ sub retract {
     # wipe
     my $wipe_path;
     if ($self->extruder->wipe && $self->wipe_path) {
+        my @points = @{$self->wipe_path};
         $wipe_path = Slic3r::Polyline->new($self->last_pos, @{$self->wipe_path}[1..$#{$self->wipe_path}])
             ->clip_start($self->extruder->scaled_wipe_distance);
     }
diff --git a/lib/Slic3r/Polyline.pm b/lib/Slic3r/Polyline.pm
index 5478c865e..2f14806f4 100644
--- a/lib/Slic3r/Polyline.pm
+++ b/lib/Slic3r/Polyline.pm
@@ -112,23 +112,24 @@ sub clip_start {
     my $self = shift;
     my ($distance) = @_;
     
+    my @points = @$self;
     my $points = [ $self->[0] ];
     
-    for (my $i = 1; $distance > 0 && $i <= $#$self; $i++) {
-        my $point = $self->[$i];
-        my $segment_length = $point->distance_to($self->[$i-1]);
+    for (my $i = 1; $distance > 0 && $i <= $#points; $i++) {
+        my $point = $points[$i];
+        my $segment_length = $point->distance_to($points[$i-1]);
         if ($segment_length <= $distance) {
             $distance -= $segment_length;
             push @$points, $point;
             next;
         }
         
-        my $new_point = Slic3r::Geometry::point_along_segment($self->[$i-1], $point, $distance);
-        push @$points, Slic3r::Point->new($new_point);
+        my $new_point = Slic3r::Geometry::point_along_segment($points[$i-1], $point, $distance);
+        push @$points, Slic3r::Point->new(@$new_point);
         $distance = 0;
     }
     
-    return __PACKAGE__->new($points);
+    return __PACKAGE__->new(@$points);
 }
 
 # this method returns a collection of points picked on the polygon contour
diff --git a/t/gcode.t b/t/gcode.t
index 9504bdbdc..495d90ea2 100644
--- a/t/gcode.t
+++ b/t/gcode.t
@@ -1,4 +1,4 @@
-use Test::More tests => 1;
+use Test::More tests => 2;
 use strict;
 use warnings;
 
@@ -9,6 +9,7 @@ BEGIN {
 
 use Slic3r;
 use Slic3r::Geometry qw(scale);
+use Slic3r::Test;
 
 {
     my $gcodegen = Slic3r::GCode->new(
@@ -20,4 +21,18 @@ use Slic3r::Geometry qw(scale);
     is_deeply $gcodegen->last_pos->arrayref, [scale -10, scale -10], 'last_pos is shifted correctly';
 }
 
+{
+    my $config = Slic3r::Config->new_from_defaults;
+    $config->set('wipe', [1]);
+    
+    my $print = Slic3r::Test::init_print('20mm_cube', config => $config);
+    my $have_wipe = 0;
+    Slic3r::GCode::Reader->new->parse(Slic3r::Test::gcode($print), sub {
+        my ($self, $cmd, $args, $info) = @_;
+        $have_wipe = 1 if $info->{retracting} && $info->{dist_XY} > 0;
+    });
+    
+    ok $have_wipe, "wipe";
+}
+
 __END__