In the previous post we mentioned the standard yellowing of solvent-based polys.
We’ve had a small interesting number of occurrences of yellowing prematurely, just to confuse the issue somewhat.
It’s a timely reminder that floor sanding contractors have to be doubly careful about knowing their work environment. That is, who else is doing work on the site- painters? Plumbers? Sparkies? How much does it affect your preparation?
Quite a lot, in some cases. One incident recently involved a warehouse-sized job coated with a high-build polyurethane. The coating went yellow rather quickly, with prominent roller marks. It turns out that, while the coating was curing, the large concrete walls were spray-painted with a two-pack epoxy concrete colouring. Spray fumes filled the entire area, and the coating reacted to the hardener in the concrete paint, since the fine spray was settling all over the floor.
It brings us back to those old golden stories where the floor is coated and the freshly-painted walls turn yellow. The poor innocent floor sander gets all the blame, yet if only someone had told him that the painter has only just been in, and he didn’t use the correct undercoat. Or the one where the painter painted too soon after the plasterer had finished- the plaster hadn’t cured, and when the floor sander slapped the first coat down, the plaster bubbled (underneath the paint!). Again, the floor sander gets the blame.
It probably isn’t advisable to sit your customer down in a dimly lit room, shine a bright light into their face and interrogate them until they confess to what other trades have been desecrating your floor sanding site (as much as we’d love to). However, it is definitely important to determine what other jobs have been, or will be, done on the site. No detail should be considered too silly.