Thread: Appologies for possible repeat question - shellac mix

The usual starting point for mixing shellac is 250grams of flake to 1 litre of metho / solvent. Depending on the type of shellac flake and where you are up to in the finishing process, you'll then thin that.

If you apply shellac that is too thick, it will almost certainly develop hair line cracks over time, and very likely not harden. It will imprint easily.

It is much much better to use your shellac too thin and have to apply lots of coats than too thick. If however it is too thin, it can excessively raise the grain on some timbers such as hardwoods.

Straining your shellac is essential - particularly if you're using orange, button, garnet or seedlac. Make sure you shake shellac well once it is dissolved to mix through the waxes if they are present. If you're after a cheap source of dewaxed, let a batch sit and decant the clear shellac off the top. It's not completely dewaxed, but certainly useful for producing a bright clear finish coat.

Use dewaxed shellacs under water based urethanes, precats. Non-dewaxed shellacs are fine under oils and oil based polyurethanes.

If the weather is hot and humid, be extra vigilant about how much you are applying. Cold and damp conditions can cause a white bloom to appear as there is water being trapped on the surface - wave a hair drier set to warm over the surface should get rid of the bloom. It would be a good idea to warm the area you are working in if it keeps happening. And don't leave the lid off your solvent/metho - it is extremely hydroscopic and will very quickly during rain become highly contaminated by water.

Putting the shellac on thinly also needs a good brush - the best are from badger's hair (who was the first person to decide to find a badger in order to remove some of its fur for use in a brush is not known to us - presumably because they were killed by the enraged badger...) but you can get away with the soft white mohair brushes from art suppliers in a pinch. Beware - they often moult more than is helpful. Otherwise, use a rubber - the middle which holds the thinned shellac can be old woollen socks, cotton wadding, cotton wool and men's cotton hankies make great covering cloths. Don't use anything that pills or looses fibre.

hey thanks for the info much appreciated will give that a try for sure

Hey, KJ401, is there a shelf life (use by date) on shellac flakes? any info would be good.....Regards......AL

If you store your shellac flakes in a dark, cool but dry space, in an airtight container, they should be good for up to ten years. If they've clumped together or feel sweaty, the storage space wasn't dark, dry or cool enough.

Mixed, its life is 6 months maximum. If you don't use it continuously, rather than make up a litre and then throw some of that out 7 months later, get glass jar, put the flake in the bottom, cover with your solvent by about a third again, let it dissolve (if your flake or buttons are slow to dissolve, the shellac may be past its prime), strain it, and thin it again according to your intended use.

Different flakes have different lives - golden and button are very forgiving, shellac flake or grains that are bleached or dewaxed are a lot less forgiving of not being stored properly.

And keep your flake and made up mixes out of the light.

Thanks KJ...that was very interesting and useful reply, Regards.......AL

Is stocking mesh sufficient to strain shellac? I mixed some shellac recently in accordance with the instructions on the jar and didn't trap anything in the stocking mesh.

Originally Posted by TP1

Is stocking mesh sufficient to strain shellac?

Yes it is, but don't try it while the missus is wearing them... like I foolishly did. The stuff you filtered must have been fairly clean to begin with.

Originally Posted by TP1

Is stocking mesh sufficient to strain shellac?

I have been mainly using coffee filter to strain the shellac. I also used the stocking doubled up then used the coffee filter after that on another batch. The problem is that if you get the wax to filter out as well it just clogs up the filter.

What I have done was mix in one Jar. Wait as per necessary (day or days) then when the wax settles to the bottom I setup another Jar with a coffee filter taped to the lid. You have to pour out very slowly and try not to put the wax part of the mixture until the last bit or at all. I then closed the lid of the filter jar and leave it over night. Little bit of hope in this one but most of it should have filtered to the bottom.

I am not sure if there is a difference between coffee filters as so far I have only been using one brand Harris Filter Paper size 2. It is unbleached natural paper?

I keep the stuff in side the house so to prevent any dust getting onto the filter paper.

As a bit of variation, I use some aquarium plastic air tube to syphon the clear shellac off the wax into another jar after it has settled.

Then I refill the first jar with denatured alcohol to replace what was syphoned, mix it, let it settle and then syphon off again. The mix is a lot weaker but is still usable.

Cheers,

Dan

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Its usual to refer to the stremgth of shellac mix in terms of "pound cut". eg a 1lb cut is 1lb of shellac in 1 gallon of alcohol. I generally french plish with a 1lb cut for sealcoats and then go to 2lb cut for bodying sessions. For glaze sessions Ill cut back to about 1.5lb cut.

As far as flitering goes I just run the fresh mix through a painters funnel...usually available at any paint shop.

Cheers Martin

Great topic ty all picked up my Shellac and mixed 1st batch yesterday.