"Plastic Welding" is term people use. Though it tends to mean chemically bonding the mating plastics.

So how should one react to an anecdotal comment like this? The implication is that several vacuum cleaner repair stores have made reports and they reflect badly on Dyson as against results from other manufacturers? So where's the data?

For all I know, 'Dysons' are dreadful machines (not in my experience but who cares? - maybe I've just been lucky) but it's nice to see evidence before making general accusations.

The design is impressive, but the construction is not. I see one being returned every few trips to Costco.

They just feel flimsy. Creaking and rattling make me worry about durability (and indeed I returned my DC41).