More yellow stuff and crowded worksites

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.

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– Rumour quashed

Coldplay had a hit song once, about an old solvent based coated floor which copped too much natural light. The chorus went

“…and it was all yellow”

However, contrary to some rumours which have been doing the rounds, Synteko Classic does not yellow.

We’re not having a crack at solvent-based polys.  We sell ’em. Everything has it’s place. But the fact is, they do go yellow/ orange over time and more so with sunlight. Synteko comes out of the container with a slightly amber colour. That’s how it is. Once you put it on the floor, it does not discolour through exposure to light. Perhaps, when referring to “yellowing”,  some people are getting confused between ongoing discolouration and the coatings’ natural shelf colour.

The timber itself can also discolour with the light. Synteko may darken slightly, but not yellow. It really does bring out the natural colour of the timber.

Another important point about Synteko Classic is that it is not a conventional solvent based poly. It’s an acid-curing alkyd resin (not to be confused with an “Al-Kyda” resin which is made by terrorists). It’s otherwise known as a “conversion varnish”. Here’s the basic difference: Solvent polys are able to be “reactivated”. Even a fully cured coating can be converted back to a liquid state if you douse it with enough strong solvents. You know when you’re re-coating an old floor, that it’s sometimes neccessary to make it a little tacky, so that the subsequent coating can bond.

Synteko cures permanently. You can’t reactivate it with any assault from the strongest solvents. It’s for this reason that Synteko can be the cure for many coating ills, such as adhesion issues or rejection problems.

Comment with your experiences or ideas.

– Coating icky contaminated floors

Here’s a sneak peek of our forthcoming useful tip in our December newsletter HUMMINGS- (Issue 17).

We do harp on a bit about some topics but they’re worth repeating. In this case,  the oily timber problem seems to be making an epic comeback.

Now, before anyone writes in to complain that we are saying nasty things about nice products which they happen to sell, like Brush Box, or Spotted Gum, let’s be clear: We love timbers like Brush Box and Spotted Gum. They are beautiful timbers and we love to see them on floors.

And this, folks,  is exactly why we like to help our contractor customers face the cold, hard reality that certain species are chock full of natural oils and saps which wreak havoc with conventional and popular coatings such as single pack, solvent-based polyurethane.

We like to know that they are being finished to the best standard in order to promote their beauty in the homes of the consumer. Because they are beautiful timbers, did we mention?

The fact is, modern exotics are chopped down younger than in previous generations and they retain more immature saps as a result. These oils and saps like to reject solvent-based, single pack polyurethanes as well as some two-packs .

When the contractor’s customer (builder or home-owner) announces they have installed Queensland Spotted Gum (or whatever)  you have two choices. You can either run away screaming, or be prepared.

Firstly, DON’T finish on too fine a grit.  A 120g screen is as fine as you’d want to go. No 150 or 180 paper. Finishing too fine literally draws the oils to the surface with all the heat and activity. It “burnishes” the oil across the face of the timber, spreading it around like a glaze. Also, the more closed the grain, the less adhesion the coating will have. Will all those contaminants around, the last thing you should be doing is limiting the scope for adhesion.

The conventional wisdom of washing the floor with solvents, thinners or metho seems to be less effective these days. Firstly, on bare timber, you have the same problem as above; drawing the oils to the surface. This is fine if you can then disperse them. But solvent/thinners/metho wipes on a first coat will be just as disastrous. The key here is to a) disperse whatever contaminants are on the surface and b) make sure the first coat is nicely cured to lock in whatever contaminants are under the surface. Too much solvent will reactivate the coating.

Which means the floor will be better off with a hot soapy bath (who isn’t?). A quick warm mop with a water-based floor cleaning solution specifically for timber floors (such as Arboritec Floor Clean). Then a wash with cold water is needed.

The soapy wash gets rid of the contaminants. The cold water wash “snaps” the moisture curing coating and ensures a clean, powdery cut back. The last thing you want is a tacky, reactivated coating which will fail to prevent the rise of more contaminants.

We these tips in mind you should be able to approach both the pre-coating phase and each coating phase with enough preparedness to avoid a disaster. There is never too much preparation for this.

Don’t forget to compliment the homeowner on such a fine choice of timber :).

Comment with your experiences or ideas.

– THE RINGS OF SATIN

Some folks have been ringing lately about a seasonal problem which is coming back into, well… season.

Applying the solvent-based subdued glosses (i.e. semi-gloss, satin, matt) is an acquired skill which can still catch out even experienced players.

The most common problem is finding glossy patches on an otherwise good finish. The reason for this is simple. All the subdued glosses contain a matting agent, like a powder. As the solvents are rising to cure the finish, so are the matting agents. If any catalyst occurs to speed up the curing, the matting will not rise sufficiently and you’ll end up with a plain old gloss. Catalysts can be things like direct sunlight or a slight draft near a window or doorway.

With this in mind, no preparation is too thorough. Mask off doorways or sticky window jams. Pull down outdoor blinds to prevent direct sunlight.  Don’t park your Piper Comanche near the front door with both propellers running full bore. That kind of thing.

Also, these subdued glosses need to “keep moving”. The roller should be moving well constantly to avoid lap marks. Lap marks are more of a concern with subdued glosses because the matting agent can make them more prominent.