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I have some Shellac flakes that have been around for years. When I put some metho in them, the flakes do not seem to dissolve much, but the liquid goes brown. Is this what should happen and I have to filter out the flakes, or should they dissolve completely?
This is not a finish I am familiar with, but thought I would try it seeing I had the flakes.
Is it time to throw them out and buy new?
Thanks:~
G'day Tex - couple of possibilities:
Your shellac is too old and hasn't been stored well.I made a 120 batch of French Polish last week and it took around 1 hour for the flakes to fully dissolve in 100%IMS. Think I'd be throwing your stuff out.
Without going into big discussions, shellac flakes have a long shelf life if stored in a cool dark place. Best result for long term storage is in the fridge. Yours still may dissolve but could take around 3 days and even then I would be throwing it our.You are using cheap supermarket or no name metho.
Best Metho is 100%IMS (industrial methylated spirits) next best 95%IMS. Anything not labelled with 100% or 95% isn't even worth trying as it can legally have up to around 42% water inclided in the mix. The main requirement for metho is that it shoild be OP (over proof alcohol) ie it must be able to burn. Meths will burn with around 42% water added.
Anyway the water prevents the flakes from dissolving.
Test for shellac when mix (fully dissolveded):.Hope this is of some help.
Pour a small amount onto a piece of glass and if it isn't touch dry within 5 minutes it ain't no good. Chuck it out.Test for metho:.
Pore a little metho into a bottle ad few drops of mineral turpentine to it and shake if it stays clear there's little or no water content if it there's any colour change at all there's water present if it goes milky it's rubbish only fit for washing windows with.
Cheers - Neil :U
Neil, As suggested by you, the metho is cheap no name brand. On the label it says 95% v/v ethanol.
I will go out and get some IMS and give them a try, but I think they may be going in the bin. Storage has probably not been the best. At least I will have some good metho for the new batch. I believe the IMS is available from Haymes.
Dallas
That's good information to have. I've read a lot of articles on French polishing lately and none of them have covered that particular subject. Thanks for the education! :)
Quote:
Originally Posted by ubeaut
Thanks for all that information Neil.
One question. Is the downgrading of metho in supermarkets a recent thing?
Thanks again,
Jim
Been going on for a long time, probably almost as long as the manufacturers have been outsourcing it to on-sellers.
Nothing to do with shellac, but......
If you have water in your petrol the best way to get rid of it is to tip a some meths into the tank and it incorporates the water and lets it burn away. Heard of a bloke in Sydney who did this with cheap metho he got from the market and ended up with more water in the fuel because the alcohol content was below the burning point. ie he added another 250 ml of water to the fuel in a 500 ml bottle of crap meths.
Neil :U
Quote:
Originally Posted by ubeaut
Thanks Neil....good tip.
Evan :)
Yes indeed. Bookmarked.
Prob too late to put my two bottles of flakes in the fridge (alongside the ski skins; the missus would love it).
Just picked up a bottle of your Hard Shellac Neil. Time to attack those rotten sticky bowls. How are yours going Evan?
Old shellac is slow to dissolve, and bleached or blonde shellac will usually not dissolve completely, leaving a jelly-like residue at the bottom of the container.
It helps if you stir the shellac for a while when you first add the metho, the surface of the flakes start to dissolve and they won't turn into a big lump stuck together at the bottom of the container. (this applies to animal glue too)
You can dissolve old shellac but you may need to use more flakes, and discard the undissolved portion. The trouble is the mix is likely to be sticky and slow drying, and only usable for flash gilding.
Both should dissolve completely and neither should have a jelly residue. This occurs because the shellac has been badly stored, especially bleached shellac, which is always best purchased in liquid form and with a use by date on the container.Quote:
bleached or blonde shellac will usually not dissolve completely, leaving a jelly-like residue at the bottom of the container
One hot day can ruin or at least degrade the bleached shellac. It should be kept refrigerated at 4C (39F) until it's ready to mix down into liquid. Not many shops or end users do this. Matter of fact I think you'd be hard pressed to even find a shopkeeper or end user who know this. Most of the so called experts don't even know it.
Fresh properly stored bleached shellac will mix down completely with no jelly and so will blond.
Good idea to have an old fridge in the shed to store such things as shellac, superglue, waxes and many other goodies in the finishing line. Along with a few bears and some whine, soft drinks etc for visitors and the after work tipple.
As for dissolving old shellac, don't waste good metho on bad polish. Open the wallet, let the moths out and buy some more flakes...... Preferably from someone who either knows what they're doing or who has a high turnover of the product. Then at least you know you should be getting pretty fresh stuff to start with.
Cheers - Neil :U
Now there's a good tip.
A cold bear is a happy bear ;-}
If you listen closely you can hear then whining. Only pizzpotz keep grog in the shed fridge. :U