Never heard of boiling the nylon bolts to make them stronger. You can heat treat steel (I an Engineer by education and profession - can you tell? <GRIN>). Heating a material up to a prescribed temperature and then allowing to cool slowly, as opposed to quenching, will aneal the material, though not all materials can be heat treated, i.e. nylon.

I have found that the black nylon bolts, as well as the black DuBro LG are brittle. If you really think about it, in order to get the black color you have to add the max. amount of pigment (as opposed to the other colors). This pigment obviously makes these components more brittle.

Needless to say, I haven't seen you damage to the bottom on your Ecstasy from the ashfault, but I sure as heck would not prefer to take out the LGB (landing gear block). though like I said I haven't seen the damage and I was not there (though l love to see this one fly! - I'd love to see all of them fly!<GRIN>)

I would think that the 18x5 would do better on your engine. Let us know how you make out!
Kevin