Grain filling before varnishing - can I use shellac seal?

[Tetsuaiga]

Hello. I'd like to ask a quick question about grain filling. I've previously used shellac finishes and used a 1 pound cut as a seal coat prior to applying grain filler then sanding off.

Can I do the same steps before applying varnish? I'm entirely new to using varnishes so don't know if it would be okay. I intend to try using an oil varnish diluted with alcohol which I can wipe on.


Thanks

 

[MIGNAL]

Firstly Oil varnish will not dilute in alcohol.
You can grain fill before applying any type of finish. The filler should be in the pores and not sitting on the surface of the wood.

 

[Tetsuaiga]

Ah I must be getting a bit confused. I was intending to try and make something like a Danish Oil or Wiping Varnish.

I thought Danish oil was a mixture of Oil Varnish, Tung Oil and some kind of mineral spirit?

I was reading this article for example http://www.popularwoodworking.com/artic ... what-is-it

Can you point of where i'm getting confused as I thought this is suggesting I can mix a oil varnish with mineral thinner. Thx

 

[MIGNAL]

Yes, mineral turps will more than likely dilute your oil varnish. . . . but that's not what you wrote in your original query, which stated 'alcohol'.

 

[Sgian Dubh]

Ah I must be getting a bit confused. I was intending to try and make something like a Danish Oil or Wiping Varnish.

I thought Danish oil was a mixture of Oil Varnish, Tung Oil and some kind of mineral spirit?

I was reading this article for example http://www.popularwoodworking.com/artic ... what-is-it

Can you point of where i'm getting confused as I thought this is suggesting I can mix a oil varnish with mineral thinner. Thx

I think you are getting confused because you are getting information from American sources. I can tell because North Americans talk about pound cuts of shellac, and the British don't. And by mineral thinner I think you are referring to what North Americans call mineral spirits, which is known in the UK as white spirits. Danish oil formulations are essentially white spirits with either tung oil or boiled linseed oil, plus some resins, and maybe some heavy metal driers and other elements.

You can make a wiping varnish by simply taking an oil based varnish and adding enough white spirits to make the liquid workable with a cloth-- start by adding about 25- 30% white spirits to the full strength varnish. You know you're buying an oil based varnish when it says on the tin to clean brushes with white spirits or brush cleaner. If the can says clean tools with soap and water you're buying water based varnish, which is the wrong type of varnish for this kind of mix.

You can grain fill either before or after applying a coat or two of varnish, or for that matter shellac, lacquer, or any other type of film forming finish-- it depends what effect you're after. Slainte.

 

[Tetsuaiga]

Thanks thats really helpful. I generally get most of my information from the net but I do have a few books though they don't go into nearly as much detail as i'd like.

For some reason I thought I could just use any of the spirits i've used before in woodworking finishes, I assumed it was just the alcohol nature which performs the mechanism for thinning. Obviously it must not that simple though, I have quite a bit to learn.

 

[MIGNAL]

There are many types of solvents (thinners). Two of the most common, in terms of wood finishing, are Alcohol and Turpentine (Turps, Turps subs, White Spirit).
Shellac (French Polish) dissolves or thins in Alcohol but not in turps.
Oil Varnish dissolves or thins in turpentine but not in alcohol.

 

[Tetsuaiga]

Is Turpentine/White Spirit not a type of alcohol then? With the name Spirit it makes me think it would have something to do with alcohol.

Also is White Spirit fine to use, I know its a sustitute for Turpentine so presumable doesn't function entirely the same in all applications.

 

[MIGNAL]

Ah, I see where the confusion comes in. White spirit is a derivative of the petro chemical industry, not fermented and distilled as in alcohol. Completely different solvent. Don't know why they call it white spirit, probably because it looks like a clear distilled alcohol.

 

[Tetsuaiga]

Maybe its called spirit just because its a distilation of crude oil. At least i've got that straigthened out now so thanks.