Sydney rain and shellac

[Bodgy]

I was finishing a new table. The rails used to hold the lower shelf are hoop pine. When applying shellac to these, a cloudy, milky or chalky white stain appeared in several places as the shellac dried. Multiple coats later, same thing.

Would this be due to the damp weather? The timber has been stored inside and didn't appear damp. I guess hoop pine is relatively hygroscopic, so maybe it absorbed some moisture?

I'm assuming damp as I have done a fair bit of shellacing and never seen this before. Incidentally, this is the Shellac out of Bumlings, usually use the Sponsors, but thought I'd try this - the immediate gratification got me (again). Does have lots of foreign matter, but otherwise no probs so far.

Am I on the right track with suspecting damp timber?

How should I redo the stuff up? Please don't say strip back to timber!

[ozwinner]

Am I on the right track with suspecting damp timber?

Yep..

How should I redo the stuff up? Please don't say strip back to timber!

Guess what..??

Al

[Auld Bassoon]

Yep..





Guess what..??

Al

Wipe it thoroughly with Meths, and you'll get it off fairly easily.

[RETIRED]

Yep..





Guess what..??

Al

Sadist!!!

[Termite]

You didn't happen to buy your metho at Bunnies too did you......it's only 95% and will add to your problem.

[ozwinner]

Sadist!!!

Its the final twist of the knife which makes it all the worth while..

Al

[redwood]

You didn't happen to buy your metho at Bunnies too did you......it's only 95% and will add to your problem.

bloody hell another thing we are in agreance on:eek: bunnies meths will do that. get a hair drier on warm setting and give the area (only if it is fully dried/cured) a good buff. its more than likley moisture is still trapped in from the meths, most of the time the white mark will dissapear

[Bodgy]

Thanks all, nothing like watching another's suffering.

The metho came from K Mart, but before you laugh, I've used it before and no probs.

When we go back to the drought, I'll wipe off and re do - once its dried out. One does get used to drying times etc., whilst its hot. I suspect I've been a little impatient.

So many things to make, so many tools to play with, so little time (and timber)

[ozwinner]

"Diggers" metho doesnt do the cloud trick.
It will in damp weather, but then any metho will.

Al

[Tex B]

Bodg,

The same thing happened to me last week with some jarrah knobs, using Ubeaut hard shellac. I thought I had put it on too thick or something. Ended up sanding down pretty drastic (starting with 40g, working up to 800) and wiping on instead of brushing, and it came up fine. I never thought to suspect damp timber. Since I'm only about a three wood from you, we may have been working in the same conditions.

Tex

[Gumby]

Since I'm only about a three wood from you,

You mean you live about 220m away, around the corner way off to the right, in the next street.

[Bodgy]

Tex

My shed is in a valley, next to a creek, hence damp is always a problem. I think damp is the undoubted culprit. We seem to have a concensus, which is unique.

Gumby, if I hit a 3 wood 220 metres, I wouldn't worry about a slice. I don't have a slice, I have a boomerang, often ducking as the ball swings around and starts to head back to point of origin.

[durwood]

The white marks are called "blushing", its caused by the moisture in the humid air landing on the surface ( same as getting dew on the lawn in the morning ) as the metho extracts the heat out of the air the water can't stay in suspension as steam and cools down.

Can also happen in cold weather. Spray painters use heating lamps to help prevent this from happening. If you have to coat shellac when its humid put a heater near the job but only close enough to warm the air not directly on the coatong as it will blister. Extra heat will keep the water in the air.

It only happens in fast drying materials like shellac and lacquer, it has to be just about snowing for it to happen in enamels.

As it does it with each coat as it dries stop and fix the problem, if you do a further coat the white colouring will be trapped under the shellac. If you keep going not only will it be hard to remove the discolouring but you can also get blister as the moisture expands and bubbles up the coating. Especially in lacquer as its more likely to be put in the sun than shellac.