How to heal split seams in ABS prints

I have recently discovered that I can effectively repair split seams in ABS with application of a little acetone and a heat gun. I use an x-acto knife to apply a tiny amount of acetone to the split seam, then wave a heat gun set at low over the seam just until I see the seam swell back together. You must be very careful not to apply too much heat for too long or your part will start to gloss and then warp. If it is a very narrow split, just the heat gun has also been effective. This method has worked quite well and the seams are holding and appear to be permanent. Try this on some of your junked parts until you get the hang of it.

Be careful with a heat gun and acetone - it can and will flash.

I just came across the Bondic UV curing bonding that seems promising. Its a liquid form, but cures when exposed to the UV LED (included). Not sure if it works well with ABS… have some on order to test.

The Bondic works well for both PLA and ABS. However, the cracks in ABS are due to stress and Bondic is a bandaid - it does not remove the stress. Using gentle heat removes or minimizes the stress and then the acetone does also, as it rebonds. I had a tall ABS vase pop a crack that I used Bondic to repair and a week later another crack popped up higher up (and it makes a loud noise when it pops!)

That’s good to know.

You’re full of great tips! :slight_smile:

A polite way of saying “you’ve screwed up a lot!” :slight_smile:

I probably should have noted that you should let the acetone dry completely before applying the heat gun… :unamused:

“important safety tip”!

Ran into what I think is split seams on my first large print. I was useing the cura quick print setting for fast abs with a bed temp of 110c and hot end at 240c. I had the 9 hour print going while I was at work so I don’t know when the split happened. Any advice on how to repair? I don’t want to waste 9 hours to try again. [Imgur](

The delamination could be due to a lot of different temperature and cooling variables. The easiest way to fix is re-print at a higher extrusion temp (+5C) and slightly increase filament flow (1-2%).

I don’t know how to salvage something like that… if you’re just interested in aesthetics, some sort of filler would work.

Enclose your printer if you haven’t done so already.


That looks like a split caused by a rapid temperature change in the air around the printer. Do you have it set up in a high traffic area of your home or perhaps the garage where opening the garage door would cause a massive air change? That is not a minor split there.

The solution is to build an enclosure around your printer to prevent air gusts and keep the temperature consistent around the print bed. I work with a Stratasys printer at my job and it is completely enclosed with a constant interior temperature of 90 Celsius. Opening the door during a print can trash hours of work buy rapidly cooling the air and inducing a split.

I have my TAZ in an independently heated rear bedroom of my house and limit foot traffic while printing. I keep the room temperature at about 28 Celsius. Even so I am currently designing an enclosure to eliminate the minor splits I still experience on occasion.

You seem to be printing at a very high temperature. I typically print ABS at 228 C and have the bed at 90 C. I arrived at these numbers after a lot of experimentation, and the extruder temperature does vary slightly depending on the color of the filament. I always use Lulzbot filament. I get very good and consistent results with this setup. I also have a PEI bed which makes for consistently well stuck down parts with zero fuss.