Old french polish... uses?

[rafezetter]

Are there any uses for old french polish of indeterminate age; I know it normally has only a useable shelf life of 6 months or so but I thought if I did a drop test and it hardened - could it still have some basic use?? My buildermate has brought back several cans of the stuff and wondered if it might be used as a basic sanding sealer - possibly as a grain filler mixed with pumice?

 

[Austinisgreat]

Well, as french polish is basically shellac dissolved in alcohol, I'd assume if anything over time the alcohol would evaporate away leaving a more "concentrated" shellac solution.

Perhaps add a little more spirit to the old polish and it would be as good as new.

But certainly to use as a sanding sealer if its going to be sanded back anyway, can't see the problem.

Others will no doubt have more to offer.....

Cheers

Andrew

 

[mickthetree]

I got all my french polish out recently and had a couple of old mixes in plastic bottles. I guess about two years old. I mixed up a new fresh batch in some new bottles but thought I'd do some experiments with the old stuff.

Its my understanding from a David Savage French Polishing DVD that as the alcohol in the old stuff evaporates it leaves behind any moisture it contained, therefore the more alcohol you add, and leave to evaporate, the more watery the solution will become over time which leads to drying problems.

All that aside I planed up some scraps of oak I had lying round and applied as a sanding sealer coat. This dried over night and seemed fine the next day. I have increased my application and have even "dolloped" some on and it has dried.

I wouldn't like to use it on a project I have lavished time over, but I see no reason not to use it up where it doesnt really matter.

I did notice that in one of my bottles the lid had popped open and all of the moisture and spirit had evaporated leaving dry shellac flakes behind. Next experiment is to add some fresh spirit and see if it mixes then dries.

HTH

 

[Sawyer]

I have various bottles of French polish which have been around for 3-4 years. I use them from time to time on projects and have had no problems. If the bottle is reasonably full and tightly sealed, shelf life appears to me much longer than 6 months.

 

[marcros]

i tend to mix up enough for a project when I need it. I have used older stuff as a sanding sealer by adding a bit more alcohol, but I think that commercial spirit sanding sealers have some other ingredients in the mix.

It probably does last for longer than 6 months, but like glues, I dont think it is worth the risk of pushing the boundaries, at least without testing it before use.

 

[Eric The Viking]

Use it up as knotting solution?

I've just done 60m of boards (yesterday), and for various reasons had to get some knotting from our local ironmongers - good people but pricey. Hugely expensive.

It's now in the same jamjar I usually use for shellac, and looks and smells much the same - dries almost as quick, too.

 

[Grumpygn0me]

make sure you are using pure alcohol not rubbing alcohol, I have some mixed and still useable that I made up 6 years ago, must be airtight seal to stop the spirit evaporating though

 

[rafezetter]

Thanks everyone for the replies - most of the containers are pretty tightly sealed, a couple look unopened so I'll give them a try as sanding sealer.

I was under the impression knotting solution as just basic dark shellac anyway - as you say, I cannot tell the difference either.

You may have noticed Erik I'm also from Bristol, would you care to share the name of this ironmongers please?

 

[Eric The Viking]

Mogfords in Westbury-on-Trym.

They're a great, traditional, general ironmongers if a bit pricey. they know their stuff, and they're also local to me, so I'll use them if I'm going into the village, in preference to Toolstation/Screwfix.

Are you this side of town?

 

[rafezetter]

Mogfords in Westbury-on-Trym.

They're a great, traditional, general ironmongers if a bit pricey. they know their stuff, and they're also local to me, so I'll use them if I'm going into the village, in preference to Toolstation/Screwfix.

Are you this side of town?

Yes I'm in filton, just a few minutes walk from the college - I've walked past Mogfords a few times, but never went in, I should have a gander sometime soon.

For the prices it's much the same as Bishopston hardware, or Pearces on Glos Road - much higher than a diy outlet, but as you say better service too, although I think Pearces selling 60 grit sandpaper on a loose roll for £3.99 a meter is more than a bit pricy.

 

[MIGNAL]

Over time alcohol absorbs water but it's nowhere near enough to effect ready mixed shellac that has been stored in bottles.
Shellac does go through a change, a form of degradation known as esterification. It also does this in it's dry state, although the refined grades are much more susceptible to this than the less refined types. In fact I have example of Seedlac that are more than 25 years old and still work perfectly. I can't say the same for bleached varieties.
The worst offender is the dry form of White shellac, sometimes known as Bone shellac, which may have a shelf life of only 3 months. That also explains why you hardly ever see this form of shellac in it's dry state.
Ready mixed shellac is often given as being 6 months (some say 3 months) shelf life. You may well get a longer shelf life than this but there is no doubt that it is degrading the longer that you keep it. It takes longer to dry, makes French polishing much more difficult and eventually it will start to clog any abrasive paper that may be used. The 'rule' is to buy dry shellac types and mix enough to finish the current project.
Those of you who have very old shellac in bottles that seems to work are probably missing the difference between freshly mixed shellac and shellac that is effectively out of date.

 

[mickthetree]

Hi Mignal, thanks for the info. Seems sound and from experience.

I think what some of us were questioning is not if we could use old mixes for french polishing, but what to do with them. My experience has been that as a sanding sealer it has worked just fine. It has a use, but if french polishing then a new mix every time.

 

[MIGNAL]

Perhaps but just be careful that the sealer isn't too thick and sitting on the surface of the wood. Put a harder finish on top of that and it might lead to crazing. Hard on top of soft doesn't usually work out too well. Soft finishes like wax won't be a problem of course.

 

[AndyT]

In my ignorance I didn't know that it was supposed to go off in storage.

The last thing I used some on was a utilitarian plywood box to organise some loose tools on a shelf. It was perfectly OK, although the polish is probably over 20 years old.

Maybe now I know, I'll buy new for the next important project...

And on a side issue re local hardware shops versus the big sheds, I've always found ours to be very competitive on price, often charging quite a bit less cash. And by the time you factor in the saving in time, fuel and aggro, FAR better value!

 

[custard]

I always use a mixed "cut" of shellac within a month or two or chuck it out. Why take a risk with a project?

Flakes (and I pretty much only use de-waxed, blonde flakes) are a different story. I used to date it and chuck the batch after a few years if it hadn't been used. But good shellac flakes are getting more and more expensive so I looked into it a little more.

https://www.toolsforworkingwood.com/sto ... c%20Flakes

This article fits well with my experience. Use good, fresh alcohol; agitate vigorously; chuck out the shellac "dust" but retain the larger "flakes"; and it pretty much lasts indefinitely.

Good luck.

 

[rafezetter]

I always use a mixed "cut" of shellac within a month or two or chuck it out. Why take a risk with a project?

Flakes (and I pretty much only use de-waxed, blonde flakes) are a different story. I used to date it and chuck the batch after a few years if it hadn't been used. But good shellac flakes are getting more and more expensive so I looked into it a little more.

https://www.toolsforworkingwood.com/sto ... c%20Flakes

This article fits well with my experience. Use good, fresh alcohol; agitate vigorously; chuck out the shellac "dust" but retain the larger "flakes"; and it pretty much lasts indefinitely.

Good luck.

That's a good article, thanks Custard

 

[MIGNAL]

Not a good article at all. It's flawed and lacks the scientific understanding relating to Shellac, which is well understood.
They later admitted that they were receiving shellac samples that they could not dissolve, irrespective of time, alcohol and the amount of agitation. Their later advice was to store shellac flakes whilst excluding as much oxygen as possible.
Refined/processed shellac types have a shelf life. You cannot stop it's degradation in relation to it's solubility in alcohol but you can retard it's degradation. Shellac, over many decades, can become impervious to it's 'natural' solvent alcohol. Restorers have spoken of having great difficulty in solving French Polished surfaces that are decades old. Your dry flakes may keep for 10 years or a little longer if you follow the advice for excluding oxygen. I've had some that has become slow to dissolve after just a few years, with a gelatinous mass in the bottom of the jar that simply refuses to solve.
Here is an update:

https://www.toolsforworkingwood.com/sto ... 16/Shellac

'From a retail standpoint shellac flakes are a fussy product. First of all it's a great finish and sticks to everything. But how fast shellac dissolves is a function of the age of shellac, how it was stored, the quality of the alcohol used, the size of the flakes, and agitation.