Halloween Themed Acrylic Slump Bowl

I rushed the slump and didn’t quite pay attention to all the sides but wonky is ok for Halloween and spider webs.

I tied it again to see if I could get a more regular deformation in the sections, but didn’t really improve its regularity. This design had even larger open voids so that made it twist a bit more. My original design from a few years ago that was more even in the cutouts and smaller areas of detail constrained the deformation better. This design with the large transverse cutouts make the deformation less controllable. One section collapses and the other section stretches. I am sure some materials scientists on this forum could give hints as to designing to get even deformation. I’ll keep thinking about it. Still looks ok but I do like the even deformation of my original lace bowls.

I need to get a form or buck that is actually a bit bigger than the shape so that it all stretches rather than collapses at the edges. This material is slightly thicker too and is a bit more resistent.

Here the the SVGs. Right clicky to save!



Saw a candy bowl on my hospital rounds today and the volunteer at the information desk who is one of my chief collaborators in getting use out of my Glowforge suggested I make a slump bowl like the purple plastic one. Challenge accepted. I have a rare evening free and I haven’t done a new project for a while.

There are PLA slump bowls on Thingiverse, but that would take too long to model and it would be too fragile.

Here is my earlier topic on how I form the bowls.

Here’s how I did it in Inkscape. Might be more efficient ways but there is something relaxing about playing with nodes. Make a horizontal line 10.75 inches wide. You could go bigger but this size works well with Corel flat bowls.

Duplicate the line (ctrl + d) and then do Object > Transform > Rotate 45°

Do that two more times.

Group the lines (ctrl + a; ctrl +g) and then do one more rotation of 22.5° so you will be able to fit the web into the max cut area with a bit of room to spare.

Turn off view gridlines. Drag from the top margin a guide line and double click it to get its properties and make it 67.5° and - 67.5°. move them over your drag lines. That will allow you to snap the connector lines. Make a bunch of horizontal lines in one section. Use ctrl + line tool drag to constrain to horizontal.

Click on each horizontal line and switch to node edit mode (F2). Drag it down in the center of the lines.

Drag a box select to get all the connecting lines and Group them together. Then Duplicate the group and then Transform 45°. Drag it to the next section. Rinse and repeat.

Now you have a spider web.

Next comes the fun part. You are going to get those lines thick so you can turn them into a filled shape. Then we will take the fill out and define the stroke. Then we will do a union of all these shapes and you will have a nice spider web to cut out.

Select all and then ungroup (ctrl +a; shift-control + g) everything. Keeping everything selected, we are going to define the width of the stroke. I am using .22 inch thick acrylic so I want something that is a little less than the thickness of the acrylic. It will hold the shape a bit better. If you are using thinner acrylic, you might want to make a smaller bowl in proportion to everything so you don’t have a lot of delicate strands.

Select all and then define the stroke width to about .18". (Object > Fill and Stroke > Stroke Style

Next we are going turn those wide strokes that are still single paths and turn them into fat filled objects. Select all.

Path > Stroke to Path

In node edit view you can now see that there are corner nodes. Set the stroke style width to .5 pixels and set the color of the stroke to black and then remove the fill.

I use the shift key and the bottom color swatch to quickly set stroke color or just click on the swatch and the fill is set. Click the wide X on the left of the color swatch ribbon at the bottom to remove the fill and shift click the X to remove the stroke color.

Next is to get all the lines connected.

Select all. Path > Union

Now your web is ready to cut. But first we are going to add some spiders. Or you could do a spider and a fly.

Find a silhouette of the insect and arachnid of your choice. Copy it and then paste it into the document. We are going to turn the bitmap into a vector since we want to engrave it and cut it out but also join it to the web.

If you do brightness cutoff with 2 scans, and you have a well-defined silhouette, you won’t have multiple objects and paths to deal with. You should have a filled shape. Remove its fill and define its stroke and now you have a spider outline.

You can now delete the bitmap of the spider and then resize and position the spider on the web. You’ll want to pay attention to the ends of the legs to ensure that they are supported. This one has one leg that might be a bit delicate.

Next we want to duplicate the spider and remove the stroke and add the fill. It’s a good idea to make the fill a color like red so you can distinguish the outline spider object which we will join to the web and the filled object spider which will just stay on the web to engrave the spider to make it noticeable.

This one is a bit better positioned for joining to the web.

Select the black outline spider and shift select the web.

Then Path > Union

The outline will disappear into the web and you will be left with a filled shape for engraving. Here it is without the red spider for engraving to see the shape is now joined to the web.

And now we are done with the design.

I hope someone can learn a few things from this write up. Open to suggestions as to improvements. I printed it with a little more power than usual. I didn’t want to mess with incomplete cuts and having a thicker kerf made it much easier to pop out the swarf.

Happy Halloween! My tricks for making a slump bowl and I hope a treat for you!


Bookmarked–as someday I will read through the write up on how to actually create the web!! (and the link to slumping the acrylic).

Very cool bowl and glad you accepted the challenge, and I like yours better than the one you copied! The less than perfect slump gives it more character!


Thanks for the file and the (far more valuable) detailed write up!


Love the design and the write up, makes me feel good you do things that way because i use a lot of the same tricks so i must be doing something right :).


It’s perfect! I might have to make one for next year. Thanks!


Thank you ever so much for the Idea, got a smidgen of an idea to do something similar for Christmas with snowflakes. =)


I love the bowl! And the write-up was great too - I’m going straight home to play with Inkscape today to try some of the tips you mentioned!


Sooooo…maybe i missed it (i am SURE i did ) but is the shaping i see provided by the heat gun (just making sure) i happen to own a nice one as i work in resin as well and use it rather than a torch to disperse bubbles in my resin


If you click through on the link to my topic from a few years ago on making acrylic slump bowls it will demonstrate the forming process.

Heat guns don’t do too good of a job. Best is an oven and some bowls for forming.


Great writeup! And the bowl is a keeper on the list of things to do in the future. Thanks for the share!


Thank you so much for this write up and all the other contributions you make to this forum!


That is awesome! I haven’t tried thee yet. On my list!


That would be really cool


Thank you for taking the time to share this.


Yay!! Thanks for the fun project and awesome tutorial @marmak3261!


Great tutorial! Really nice of you to write this up! Thank you!


Love the write-up AND the result!
Personally, I think the irregularities should be considered a “feature.” Brings it to life, I say!


‘Tis the season! Still great.