I’m printing a torso sculpture in two parts so that it stands 13" tall. I’m printing the shell thickness at 2.4mm with a 10% fill.
Anyone have a suggestion for the best way to weld the ABS parts together?
thanks!
Paul
On my ABS parts that were delaminating I used super glue.
So far, it’s held up really well. Super glue is clear, sets up REALLY fast 
and for what I used it for seems to have worked perfectly. I’m betting that super glue bond is far stronger than the bond between many of the ABS layers.
thanks for that tip. I’ll try that where it’s delaminating. I’m finding everyone is having ABS delamination problems. However, I’m talking about gluing two prints together. I noticed yesterday, I accidentally spilled a little acetone on my workbench where I had a failed part. When I picked it up the bottom layers melted and partially glued to the table… guess I’ll try that on both parts then stick together!
Superglue works well but is a brittle bond.
Acetone works very well since it is just melting the ABS together.
I set both parts in a barely wet acetone tray, waited about 2-3 minutes, then compressed them together. They seem to be bonded pretty well.
I like to use either Acetone or Plastruct Plastic Weld.
Just brushing on a little acetone to the surfaces being mated is good. A mixture of acetone and ABS seems to work better for me (just a very light mixture, only a little ABS).
However, I’d like to share my favorite way to join parts: friction welding.
It’s very easy once you get the hang of it, but practice on some scrap/junk.
Simply take some 3mm filament and cut to a short-ish length. Put that piece of filament in a Dremel rotary tool. (the piece of filament needs to be short and/or straight enough to spin fast but balanced around the axis of rotation)
The Dremel will spin the filament fast enough to melt it and your part enough to friction weld. I usually only turn my Dremel up half way (maybe 10-15k RPM).
Experiement with different speeds and pressure applied. It makes a great bond.
You can sand the weld down. Or you can leave the weld there for a cool look. I like to leave the welds on when I’m painting parts with a metalic acrylic paint.
MEK (Methyl Ethyl Keytone) is more aggressive than acetone on ABS but it is hard to find and somewhat expensive. Many plastic pipe preparation products like this one from Home Depot: http://www.homedepot.com/p/Oatey-16-oz-ABS-Transition-Cement-30925/100200776 contain MEK and THF (Tetrahydofuran) which is also a very aggressive ABS solvent. Many of these products are clear and have a water like consistency so will flow into tiny joints like layer splits and will work gluing close fitting ABS parts pressed together. Use sparingly otherwise they will just melt the plastic and never dry. Experiment with some junk parts or scraps but be aware YMMV, check the MSDS sheets for the products you find to see the chemicals they contain. New government VOC regulations are restricting the use of some of these chemicals so formulations are changing frequently (you used to be able to purchase MEK off the shelf at Home Deopt but no more), be sure to check the MSDS for the exact ingredients. If you find something that works good post it for the rest of us.
John
The trick I like to use is a combination of what everybody else is saying, I use a couple drops of super glue to hold/tack the pieces together and then use acetone or ABS acetone mix and apply it in the seam with a fine tipped brush and fuse the two parts together. The super glue will allow you to fuse multiple parts together at one time too.
@sstantz I really like the plastic welding trick! I bet it makes for some really solid connections, I have to try it. Could you possibly throw up a video of you welding something up? 
I would stay away from MEK and THF there’s a reason that the EPA is putting restrictions on them. Plus the other options you should already have lying around.
You can get this: http://www.eplastics.com/Plastic/ABS-Glue/WELD-ON-PLASTIC-ADHESIVE-GLUE-IPS-2354-PINT which works great, but if you check the MSDS it’s basically MEK.
You used to be able to buy a whole quart of MEK for a few dollars, now thanks to the EPA we have to pay $20.00 for a pint. Guess we need to keep all those young’ens from get’in high sniff’en this kind of stuff. And of course we don’t want to risk brain damage like all the plumbers in the US that use this stuff on a daily basis because it’s required on all plastic pipe jobs to meet code. But all the plumbers I know are smart enough not to inhale the vapors of all the chemicals they use. Of course we must trust the government bureaucracy implicitly because we’re obviously to dumb to think for ourselves. “That government is best which governs least.” Thomas Jefferson.
John