Even The Hulk sometimes needs a little help... this time from hot glue.

Forget the Avengers… assemble my legs!

I’ve developed a little trick for using hot glue to rescue a 3D print that is going wonky while it is in progress. Nothing replaces starting with a good model, having the right equipment, and using good practice while printing. Still, this technique has come to the rescue a few times, especially for large prints where I would otherwise have wasted a lot of time and plastic.

One of the first things I printed when I got my 3D printer was a filament spool holder for my Printrbot Simple Metal. I was printing on a non-heated bed with PLA, and the print had a large footprint. I prepped the print surface using painter’s tape and rubbing alcohol, and started my print.

Initial adhesion was fine, but as the print progressed it began to curl and started coming off the table surface at the far ends. I only had the small amount of starter filament that Printrbot included with the printer. I didn’t want to scrap it and start over, especially since I really couldn’t do much at the time to improve the situation.

So I grabbed my hot glue gun and used it to try to secure the print to bed. This kept the lifting from getting worse and coming loose from the table as I feared it might.

The hot glue helped hold the separating layers together.

The hot glue kept the print on the table, and held the separating layers together.

The print continued, but several layers later, I was running into a different problem. The continued warping of the print was causing separation of layers at the ends. Encouraged by my earlier success, I used hot glue to fill the gap where the layers were separating. You can scoff at this technique if you like, but it worked great and I still use that spool holder to this day.

It worked! I'm as surprised as anybody.

It worked! I’m as surprised as anybody.

Another time I used this trick for a “no support” Hulk model by Kolo33 I found on Thingiverse. The model prints in four parts: the head and upper torso, the lower torso and legs, and the left and right hands. It looked like everything sliced correctly when I set up the print, but part way through one of the legs started messing up just above the ankle. Hot glue to the rescue!

I started to apply hot glue to fill the gap above the ankles.

I started to apply hot glue to fill the gap above the ankles.

Once the filament successfully bonded to the hot glue below, the print was able to continue.

As the print progressed, I could see the filament begin to adhere to the hot glue filled gap.

As the print progressed, I could see the filament begin to adhere to the hot glue filled gap.

Another gap appeared in both legs at the knee level, and I was able to use the fix again.

"Hulk's legs feel funny… like partially made of hot glue."

“Hulk’s legs feel funny… like partially made of hot glue.”

I successfully completed the print, and with a little clean up afterwards, my son was able to present a finished Hulk to his friend as a gift.

So in summary, hot glue can sometimes be used to rescue prints in situations where:

  • The print is losing adhesion to the print bed
  • The layers of the print are separating
  • A gap starts between layers due to a model error or slicing issue

I’ve searched around on the ‘Net, and haven’t found anyone else using this technique, which really surprises me. I assumed someone else must have figured this out before me. Perhaps my Google Fu is weak; I’d be happy to hear about other examples of people using hot glue during the print to fix something going wrong. Please comment if you have an example, or to let me know your experience if you try this for yourself!