Preparing your 3D printed props (Part 2)

This should’ve really been part 1, but hey, we’re all human.

This post is dedicated to how to assemble 3D printed props. There are many ways to glue things together and I’ll go over some benefits of each.

Fresh off the printer, your pile of 3D printed parts gathers dust. You’ve been keeping your printer busy but haven’t gone through the effort of assembling the multitude of pieces. Stop – breathe – and consider the following:

• Super glue
• Gap filling super glue
• Acetone slurry (ABS prints only)
• Dichloromethane
• Filament friction welding
• E6000
• Two part epoxy

Super Glue

Pros

• Easy to apply
• Strong bond
• Possible to un-bond with un-cure
• Possible to instantly set with accelerator

Cons

• Nozzle gets stuck and you have to deal with clearing out the tip with each use
• Not good for small pieces where there is very little surface area between two pieces

Gap-filling Super Glue

Everything from above, but it’s just thicker and easier to apply (in some cases)

Acetone Slurry

Made from dissolving ABS filament in a jar of acetone to create a glue made from the filament itself.

Pros

• Cheap, easy to make
• Can vary consistency by adjusting the ratio of acetone to filament
• Will remain usable as long as it’s sealed properly
• Okay-ish in strength (so I’ve heard, I don’t print in ABS so I can’t vouch for it personally)

Cons

• Difficult to apply
• Can be difficult to make if the filament doesn’t fully dissolve
• V A P O R S
• Requires filament to make the glue

Dichloromethane

A solvent (like the acetone slurry) that when applied, lightly melts each side of the gluing faces together for a solid bond. Comes in super thin and gel-like consistencies.

Pros

• The thin and gel versions have different applications – the gel is good to treat like super glue while the thin is good to drip over an already glued seam
• Overflow is easy to cleanup, the consistency of dried hot-glue

Cons

• V A P O R S
• Hard to apply (if it’s thin, you can put some on each gluing face, but if you put too much, it’ll run right off. However, you CAN apply the thin version to the seam after it’s been glued to reinforce the joint. You cannot do this with the gel version as it will just sit on top and slowly eat into the plastic.
• Not cheap
• Is it strong? My experience has been mixed – sometimes it’s been good, but sometimes when there’s a ton of surface area, it easily breaks apart when pressure is applied to the joint. This was with me applying the gel solvent to each side, smushing them together, then shearing them a little bit to spread the glue.

Filament Friction Welding

Pros

• Strong when done right
• Good for attaching pieces with small surface area as it uses the circumference of the gluing cross-section

Cons

• Requires practice (I used this video as a guide)
• Requires a rotary tool
• Cannot be used in all cases – requires the seam be easily accessibly everywhere for the best bond

E6000

Your standard craft glue, dries to a caulk-like consistency. I’d use it more for fabrics and not 3D printed pieces.

Pros

• ???

Cons

• Motherfucker takes forever to dry
• Not super strong from my experience
• Overflow is like dried hot glue, but difficult to remove at times

Two Part Epoxy

Pros

• Strong
• Can buy versions with different working times from 5 minutes to 30 minutes

Cons

• Can be messy
• Expensive
• Easy to over-mix and waste epoxy
• If working with an epoxy with a short working time, you MUST respect the time window

Alignment holes and clamps

Personally, I’ve been using dichloromethane and epoxy for most pieces in combination with alignment pegs. Alignment pegs are basically aligned holes you drill into the gluing faces and then stick some sort of support pieces in the hole, like a nail with the head cut off or for larger pieces, a steel threaded rod. There are two ways to prepare alignment holes. One is to not include them in the model and simply drill a hole into the printed pieces with an electric drill. There are two problems with this method: One is that the holes can easily be mis-aligned, or even if they’re aligned, be drilled at angles which are not aligned. The other is that you can drill a hole into the surfaces, stick a nail into the hole and BAM, the nail goes all the way through into the print and is now rattling inside, driving you insane.

The other method is to include them in the model. You can manually add the holes in the original modeling software (Fusion 360, Maya, Solidedge, etc.) or you can use Netfabb to slice the model and add pins and holes. I don’t add pins, but instead put holes on each side and use my own pins. You can’t fully customize the location of the pins and sometimes the auto-holes can get you in weird spots, but it’s worth checking out if you don’t own a drill and since you can fully inspect the model before printing.

Clamps. Clamps are great. I have a set of quick-release clamps from various manufacturers (Irwin, DeWalt, whatever the brand from Harbor Freight is) and they all perform the same for what I’m doing. I’m not applying tons and tons of pressure, I just need to smush the sides together and keep them in position long enough for the glue to take effect. To that effect, I use two different types of clamps. Quick clamps and deep throat c-clamps. At first, I only used quick clamps, but I came across an issue for large, flat pieces where I could clamp the edges, but I couldn’t reach the center surface and sometimes piece ended up being glued aligned at the edges, but mis-aligned at the middle. To solve this, I ended up just buying some deep throated c-clamps and clamping them in the middle.

Buying these c-clamps was a great investment only because of the sheer amount of fucking pieces I need to clamp (crescent rose, kill me now). I currently have four 4-inch quick clamps, two 7-inch quick clamps, a 1-foot quick clamp, a 2-foot quick clamp, two 3-inch deep c clamps, and an 8-inch deep c clamp. This set of clamps has gotten me through most gluing projects given that I glue at most, one thing at a time.

Other resources

https://www.thistothat.com

Good luck~