How to Fix Broken Resin 3D Prints

Sometimes, the worst happens when you accidentally snap your resin 3d printed parts. Thankfully, there is a easy way to try to salvage your broken resin parts and save the hours you put into the print. In the example below, a recently resin 3d printed blade model was accidentally snapped into 2 during the support removal process. (Side note – as a principle, if you could wait 5 hours for a resin part to be 3d printed, you could spend more than 5 minutes on support removal!)

This piece was printed in Monocure clear resin so why not make the proverbial lemonade with this lemon and experiment to see if using the same resin as a “glue” of sorts would work to fit it. And if so, how well it would do. Hence, we simply grabbed a small disposable cup and a pointy wooden stick to use as the applicator.

Applying the Resin into the Broken Part

Here we have the 2 halves of the broken 3d print positioned back to show how the piece should have been. Thankfully, it was a rather clean break and no smaller bits were missing.

Taking a closer look at the break shows that it’s not completely smooth, which is actually a much better thing when it comes to getting things to stick together. What with the increased surface area and all that.

Having poured out a small quantity of the Monocure clear resin (which was the resin used to 3d print this part in the first place). we used the wooden stick to grab small amounts of it to apply to one half of the broken part.

Just by dabbing small amounts of resin on the part, we tried to get an evenly thin coat of the resin over the broken edge. It helped that the wet resin is shiny and so it’s easier to see and ensure that the part is uniformly coated.

Bad camera at play here but just take our word that this end has been coated nicely.

Joining and Curing in the UV Chamber

Putting the two halves together should see a little bit of the resin coming out of the gaps. This is a good thing and also reason why a only very thin coat is required.

Next up, time to cure it in the UV chamber. At first, we had to use both hands to hold the piece in place for the initial setting but it would soon cure to be sufficiently strong to be held with one hand. Total time we left it in the UV chamber was around a minute but more wouldn’t hurt.

Fresh out of the UV chamber, it’s quite clear that the excess resin on the join has formed solidly into a sort of “weld” line.


Results of the Joining Process

And so, breaking out some medium grit sand paper, you can wet sand the excess down. For sake of comparison, we sanded only the bottom half so we can draw a comparison to the top un-sanded half.

Couple of minutes later of sanding up to 1000+ grit sandpaper, it seems that we have managed to do quite a decent repair to this resin 3d part in short order.

Here’s the piece in better lighting conditions to show the repair. The crack line is almost indistinguishable at this point with this clear piece.

Another look from another angle. As good as new!

Further Thoughts

This is is a fairly simple process to do for fixing of broken resin 3d parts so that the long hours of 3d printing which went into them are not wasted. This can definitely be applied also to assembles of models which had to be broken down into parts to fit smaller resin 3d printers.

So if you do try that out for yourselves, we would love to see your results too!

As always, happy 3d printing y’all! =)

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