3d printed tank exploded

[Tom Dulski]

 I had purchased a 3d printed tank and painted it up. It’s been sitting on my shelf for over 3 years now. I just noticed it somehow exploded. The turret split apart and there was all gunk and liquid inside and underneath it was as if some of it kind of melted. Has anyone heard of anything like this before?

[Major_Gilbear]

Yes; apparently, it's uncured resin trapped inside the models. When they are printed, the design does not permit the excess resin to drain out, and the post-printing curing stage is only "skin deep" so to speak. Making some small holes in the solid peices and flushing them through with some isoprop apparently helps afflicted models, and you can then fill and paint over those drainage holes afterwards.

It happened to Rick in his recent thread here (link).

[Tom Dulski]

 
 Ok thank you. It’s just so strange that it appeared fine for over 2 years

[Aethelflaeda was framed]

Hot summer?

[Mammoth miniatures]

 Ok thank you. It’s just so strange that it appeared fine for over 2 years

If the print wall is thick enough it can stay together for a long time, but eventually if enough resin is left in the model it will burst. The more resin in the model, the worse the results will be. Perhaps this one only had a small amount of liquid resin left inside and thus it has taken a while for that resin to warp the outer shell.

[Tom Dulski]

Hot summer?

 It’s been over 95 degrees all week 

[flatpack]

Got a mate and this happened to his elephants.

[Rick]

Yep - that looks awfully familiar to me. The surface cracking and pulling away from the rest of the model opening up the cavity. Mine were thinner walled so it took months rather than years but it does seem to be an issue with these hollow cast models. Someone suggested a uv torch to help with hardening up the model after clean-up which is a good idea (I usually just put them on a windowsill) then trying to glue them back together after that. First step, though, will be to get rid of the resin gunk - isopropyl alcohol if you've got it, water if you don't (but it will take longer that way). Good luck with the salvage work.

[Cait Sidhe]

As other folk have said, the model has been hollowed but without drainage holes (or insufficient holes) to flush trapped liquid resin out during the cleaning and curing process. The resin inside continues to produce gases and such so the pressure builds until the model inevitably cracks or explodes open. In this case there seems to be pretty big drainage holes so the model hasn't been washed properly and the unwashed resin has been trapped inside once it's glued, I'm surprised the resin wasn't oozing out during painting. Probably worth mentioning that uncured resin is nasty toxic stuff, wear gloves if handling it.

I'm kind of shocked this is the second thread here in a couple of days about professional printing services selling models that are exploding/cracking.

[Tom Dulski]

 
This was not from a professional printer or anything. I purchased it from an eBay seller a few years back. Oddly I purchased and painted 2 of these tanks and the other is still fine.

[fred]

What is odd with this one, is those two large holes in the base of the turret - do they go through to the void that has split open?

[Tom Dulski]

What is odd with this one, is those two large holes in the base of the turret - do they go through to the void that has split open?

Yes, they open up into the hollowed out turret.

[Harry Faversham]

Got a mate and this happened to his elephants.

Bet that made his eyes water!


 

[Rick]

Bet that made his eyes water!


 

The first four might just be ok, but the next one will be bad - you've really got to watch out for the fifth elephant! 

Right, I'll get me coat.

[Waffles_vs_Tacos]

I have seen and heard of this happening with a lot of thicker resin pieces. I think as FDM gets better and better, less and less resin prints will be used.