Guide: Assembling 3D Prints

Whether you’re splitting a model because it’s too large or just trying to avoid using supports, assembling 3D printed parts is easy if you take the right steps.

Turn this…

…into this!

Note: Some of the options listed here will only be viable with ABS plastic.

 

Chapters

i. Adhesives

ii. Measuring and Cutting Dowels

iii. Prepping the Prints

iv. Assembly

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What you’ll need:

  • Low grit Sandpaper (like 60-100)
  • Adhesive of your choosing
  • dowel/rod (optional)
  • Saw (only if using dowels)

 

i. Adhesives

There are hundreds of different adhesives, ranging from surface bonds to full plastic welds. However, for this guide I’ll only be discussing the main 3 that I use.

 

Superglue (Cyanoacrylates)

Usable with most filament types, including PLA and ABS. This can come in both thin and thick variations, and there are even thinners and thickeners available. This is my preferred adhesive when I’m finishing 3D prints for molding.

Epoxy Glue

Disclaimer: I tend to only use epoxy glue on dowels or rods for added structural support and not for the actual prints themselves. While nothing is technically stopping you from using this, it’s still only a surface bond, so not ideal for large prints.

 

Solvent Cement #4 [Only compatible with ABS Prints] 

This is the mac daddy of fusing ABS prints together. While I only learned of it recently, this is now my go-to for assembling large ABS prints that will not be molded. It welds pieces together much better than acetone alone. Downsides? It takes 72 hours to cure. But, it won’t be coming apart any time soon. It also melts the plastic slightly, so it’s not ideal for molding. The upside is you essentially have one piece now instead of 2 – that thing is on there for life (unless you smash it against some steel).

 

ii. Measuring and Cutting Dowels/Rods

What you’ll need:

  • Marker
  • Ruler
  • Saw or sharp box knife (if you’re in a pinch) to cut the dowel
Figuring out how much to cut

Stick the dowel in one end of the print. Using a sharpie, mark the dowel where the edge of the print is.

 

Label it “A”

 

Do the same step with the remaining parts. Label it “B”

 

Now measure A+B and add them together (take away an inch or so to make room for glue).

 

In this particular step A was 6 inches, and B was 18. I decided to cut around 23inches. Use a saw to cut the dowel (sorry I wasn’t able to take photos of myself doing this step).

 

Now do the same for any other dowels you may need.

 

 

iii. Prepping the Prints

What you’ll need:

  • 60 or similar grit sandpaper
  • adhesive of choice
Layout

Lay your print out in the way that resembles its final form. It’s good to familiarize with how it’s supposed to be assembled so that you’re not scrambling to figure out how things fit while the glue is curing (especially if you’re putting together a long sword where pieces can look too similar). Use a Sharpie to label the parts if needed if the part will be painted later anyway.

Sanding

Next step is to sand with 80 or similar grit sandpaper. Note where the part is supposed to make contact with the corresponding piece – those are the areas that will need to be sanded.

 

Sand the contact areas until it has roughed up a bit. This makes the surface porous so that the adhesive adheres more closely. This process is like scoring 2 pieces of clay together: you want as much contact between both surfaces to bond together and for the surface to be porous.

 

Once all of the proper pieces have been sanded, it’s time for assembly.

 

iv. Assembly

Apply the adhesive of your choice to one side, and move the two parts together. Hold tightly or use clamps. I’m personally using solvent cememt, but I would recommend thick superglue if you’re working with PLA prints.

Note: If using solvent cement, keep in mind it takes over 72 hours to fully cure. It roughly has the same viscosity as water. Use a brush or nozzle to lightly brush the solvent onto the sanded parts. Just like the superglue, hold the parts together tightly for several minutes.

 

Before attaching the last piece, add the dowel. When adding a dowel or rod, I sometimes like to use epoxy glue to the rod as it gives it some more structural support when dried.

 

Mix equal parts A and B thoroughly.

Add onto the rod, then slide the piece into place.

 

I occasionally will use 2 dowels so there’s less guesswork when it comes to alignment.

 

Continue this process until you have a finished item!

 

 

One Reply to “Guide: Assembling 3D Prints”

  1. […] If you’re looking for help on how to put together 3D parts, check out my guide on ‘Assembling 3D Printed Parts’  […]

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