Shellac finish looks frosty?

[rob.]

I stripped the old polish off an antique chest of drawers by dissolving it in methylated spirit, I used fine wire wool soaked in meths then a cloth to remove. This got most if not all of it off. The drawer faces are mahogany.

I didn't sand the wood to try and retain the colour and patina.

I went over it with a fad and some button polish. The result was a crickled effect that looks like frost in the grain when the light catches it.

I thought ''that's not right'' so thinking there might be contamination I stripped it back again using the same method, this time around I put 4 coats of shellac on with a brush allowing it to dry between coats then let dry for 3 or 4 hours. Ive just cut it back with fine wire wool and rubbered it again with button polish and the frost is back.

It looks like light being reflected from within the grain.

Ive begun to polish the carcass of the chest using the same stripping method and its fine.


Any ideas?

 

[sunnybob]

humidity high?

 

[ED65]

Probably too radical an approach but it might help to fill the grain.

Another workaround might be to oil the wood first if this won't alter the colour too much compared to the rest of the piece, one light application with all the excess wiped away. You can shellac straight away so it won't slow you down much.

Rereading your post the common element appears to be the button polish. Maybe that's the culprit. I presume there was no frosting visible after the initial brushed coats of shellac?

I went over it with a fad and some button polish. The result was a crickled effect that looks like frost in the grain when the light catches it.
...rubbered it again with button polish and the frost is back.

 

[profchris]

I put 4 coats of shellac on with a brush allowing it to dry between coats then let dry for 3 or 4 hours.

That seems far too thick a coat for the timescale. I brush on a maximum of two coats a day, 4-6 hours apart. Even then, if it's humid I might not add any more coats the following day. I've caused myself problems in the past applying shellac in thick coats - as I added more I reached a tipping point where the whole lot rippled and distorted.

I'd guess your button polish is also shellac. I use that, but apply thin and slow.

But it could also be that your button polish has deteriorated with age.

I'd try a test piece with thin coats and more time in between to see if the button polish is still OK.

 

[Grahamemes]

I've never had that issues but from people i have talked about it with it is probably a result of the shellac being applied too thick to quick!

 

[rob.]

Thanks guys, looking at it in better light it seems the grain is open and the polish within the grain is reflecting light differently.
This didn't happen on the rest of the chest because there was no open grain anywhere else except the drawer fronts.

I'm in two minds to use oil as it might darken the drawer fronts too much. Is there any way to get the polish down into the grain? I take it the polish is sitting above the open grain like a cap and this is why its reflecting light in this way?


I am going to wax this after the polish has set, I rub the wax in with very fine wire wool, I guess I'd be taking a gamble to see if that helped the problem?

Would I be wasting my time cutting this back and applying more polish until it was flat? Is this problem with the polish sitting above the open grain?

 

[MIGNAL]

Carefully wet sand it without rubbing through the finish. Do not remove the slurry. Let it dry and then add more shellac, pushing the slurry and shellac into the pores. It might not look pretty but the objective is to fill the pores. Dependent on how open the pores are it may take a number of such applications. Once the pores are filled you can flatten it and start french polishing proper.

 

[rob.]

Carefully wet sand it without rubbing through the finish. Do not remove the slurry. Let it dry and then add more shellac, pushing the slurry and shellac into the pores. It might not look pretty but the objective is to fill the pores. Dependent on how open the pores are it may take a number of such applications. Once the pores are filled you can flatten it and start french polishing proper.

That sounds like an idea, thank you , I'll give that a try.

 

[MIGNAL]

Hard to say going by that picture. If it's open pores then they are really open! It will take a lot of time to fill those with shellac alone. It will happen but you'll have to apply a lot of shellac over a good week or so. The good news is that shellac makes for a very natural looking pore filler. The bad news is the amount of time it takes.

 

[rob.]

They are very open, The original polish looked like it had some kind of water damage,

It was quite rough to the hand and I could feel ridges in places. What I might do is load a small brush with a thick cut of polish then try to get it deeper into the grain that way, but I think you are right, lots of polish , sanding and time is going to be the way this pans out.

 

[ED65]

You're probably set on filling this with shellac at this point but if you filled the grain conventionally (e.g. with plaster) you'd be done in one or two sessions.

 

[rob.]

I think shellac is how this is going to work now that I've started, I've never had to fill grain before when finishing with shellac so wasn't expecting this, but I'll know in the future.
I've put on a few coats using a rubber and cut it back between coats, most of the sparkles have disappeared so I'm well on my way with it. I'm going to let the polish rest now and start again tomorrow.
I did try the slurry thing but wet it down with a little linseed oil then used the charged fad to rubber it into the grain, I think that helped.

 

[rob.]

Any tips guys on a final Polish to remove any lubricating oil. Do I charge a new fad with meths or a very diluted Polish?