Friday, November 25, 2016

I'm not sure what his point is...

No doubt it's purely coincidental, but twice this past week I've gotten emails from people asking technical questions. Now I'm quite happy to share my limited knowledge with anyone who asked, in the interests of growth and improvement.
But this one has me wondering;

Are your kits made of resin?

If so, what do you recommend other than the cyanoacralates for assembly as cyanoacralates are highly hydrophylic and can, therefore, be wedged apart by wedging from accumulated moisture as well as having a very high coefficient of thermal expansion, which also can result in their joints debonding (place a joint in a freezer overnight).

Cyanoacralates are **not** a true adhesive as they merely displace the air in a joint and rely on the partial vacuum they thusly create with respect to atmospheric pressure -- there is no no adhesive ionic or covalent bonding when using cyanoacralates.  Such is why they have a greater tensile strength and a much lower sheer strength.  Consequently, US Navy and NASA forbid using cyanoacralates for ocean, rocketry, and orbital engineering.

Model sailing ships in museums, even those in enclosed cases, have had the knots in rigging, fixed with cyanoacralates, fracture from repeated slight temperature variations resulting in cyclic fatigue (much like repeated bending of a wire coat hanger until it fractures).
Now I'm in no position to argue the science in this fellows assertions, but I don't know that I care. CA works just fine for me and I have 30 year old resin kits that are holding up just fine.
I'm more curious as to why this fellow felt the need to present this data to me in this manner. Is he just showing off? Does he somehow feel better having demonstrated a superior knowledge about some arcane subject. Or is he fishing for an obscure reason not to purchase kits from me?
For some reason, this feels a bit like on line trolling to me. Sadly having 2 websites and a blog leaves me open to this kind of email and I knew it going in, but really? 


Stephen Hester said...

Sounds like a frustrated polymer chemist to me.

Karl A. said...

That was an odd email. CA glue has bonded plenty of kits well for me (as well as my fingers a few times) and that was no 'partial vacuum", it was good old fashioned sticky.

Ted Culotta said...

I often encounter this problem when I place my models in the freezer overnight, he said with tongue planted in cheek.

Simon Dunkley said...

If he knows so much about CA, then how is it that he doesn't know of an alternative?