So far this crack fix has held up extremely well for us even on dirt roads. Below are the basic instructions for this repair. We have tried 3 other methods. All have done the job, but have not lasted. One method looked horribly messy and didn’t last. So for now this has been the best and most stable method we have found to solve the ELF body crack problem.
Now after 3 years, I can definitely recommend the following.
A sheet of ABS plastic cut and heat molded to fit the bend in the body.
An electronics heat gun or even a powerful hair blower dryer might do it to help mold the new piece of ABS to fit the ELF body. This is a slow time consuming process.
Don’t be in a hurry
Do not burn or melt the new piece of ABS or the ELF.
Do not heat or mold the new strip of ABS plastic while it’s on or next to the ELF. You’ll melt the ELF. Take it carefully this is a slow process!
Clean all parts with denatured alcohol.
The Glue ( All ABS glues come with health warnings)
From here there are 2 methods that you can follow. You need glue. Plastic manufacturers sell ABS glue. It’s a milky white in color. In my area it comes in a container that is too large and too much glue for my needs.
Recently we went to the plastics factory to purchase a small flat piece of ABS to fix another small crack. We noticed that there are now smaller bottles of glue available. Yay!
We still opted to make our own concoction which seems to work fine for us. But that bottle of store bought glue is definitely easier.
Combine small amounts of
Acetone
ABS shavings
Mix the acetone and shavings in a glass container much like a baby food jar.
It will take time for this to melt and dissolve to become a glue.
Spread the mixture in and on the crack. Apply pressure to hold the crack closed for 24 hours. Be sure to leave a fairly flat surface when done. In 24 hours you’ll need that flat surface to lay your the molded piece on.
Next day
Apply the mixture on the body and placed the molded piece. Again apply pressure for 24 hours.
On the inside we still have a repair from our earlier trial and error attempts to fix ELF cracks. We lived and learned. It did not hold up well on the outside. But it’s held fine on the inside so far. This repair has aluminum flashing that’s cut to fit. It’s gorilla glued to the body for extra support.
We prefer the ABS /Trylon glue method now that we’ve done both.
So far the ABS/Trylon repair method has held solid for years, even while traveling on dirt roads. If you have questions just contacts us, we will try to help out.
Since the original post our mango ELF had a crack in a very odd place. I can only assume it was damaged by a spectator while I was in the store. We again used the glue method on the back side to mend the crack.
When it comes to fixing our ELFs this is our method, it may or may not work for you.
The crack
We used a small straight piece of black ABS that was much like a solid straw in shape. We found that this was easier to fit into the rounded ELF body bends. We also glued a small white piece of ABS to the rounded piece and the ELF for even more stability. 
The finished repair