Boiled linseed oil & varnish
I have had better results with boiled linseed oil than with varnishes. Varnishes chip off and so on. Uncomfortable on hands. Boiled linseed oil soaks in and seems to prevent substantial water penetration. I’m still using a paddle I made in the mid 80s.
Solution varnishes are easy to make. I’d tend to use seedlac and any somewhat softer resin in alcohol. Although turpentine works with many resins. And I’m always tempted to try acetone as a vehicle.
I make varnish all the time for violins. Easy stuff to do.
I prefer an oil-varnish blend
– Last Updated: Nov-01-04 11:46 AM EST –
I've been using a 1:1:1 solution of varnish (Epifanes, but it doesn't matter much), tung oil and turpentine. I much prefer the resulting softer, satin finish to varnish. This blend is a bit more durable and waterproof than straight oils (I've tried linseed and tung oils alone), but still breathes enough that it doesn't trap water in the wood.
The "solution varnish" you speak of sounds more like shellac than varnish. Can the resulting finish be re-dissolved with alcohol?
shellac
Seedlac = raw shellac.
Solution varnishes are things dissolved in a solvent. Dry by evaporation. Can be dissolved off the surface via a solvent.
Cooked varnishes cure and then cannot be dissolved with the vehicle solvent, if any was used. Polymerization is what I think happens.
Some hybrid varnishes. Will dissolve for a while, but then polymerize and shrink down. Mastic and linseed oil with a turpentine vehicle, for example.
The mix of oil varnish, tung oil, & solvent seems promising. I have some over-age varnish I can cut that way and try.
Steve
Finish properties
– Last Updated: Nov-02-04 8:25 AM EST –
"Seedlac = raw shellac."
I should have know that.
"Solution varnishes are things dissolved in a solvent. Dry by evaporation. Can be dissolved off the surface via a solvent."
Ah, therin lies my confusion. My understanding is that if it can be dissolved by the same solvent that was used to thin it, it's not technically a "varnish". I may well be mistaken about that. In your business, is "varnish" used as a generic term for a transparent finish, rather than denoting one with a specific type of curing process (curing vs. drying)?
"Cooked varnishes cure and then cannot be dissolved with the vehicle solvent, if any was used. Polymerization is what I think happens."
That's correct.
"Some hybrid varnishes. Will dissolve for a while, but then polymerize and shrink down. Mastic and linseed oil with a turpentine vehicle, for example."
What exactly is "mastic"? I'm not familiar with the term, other than in reference to "mastic" used as an adhesive.
"The mix of oil varnish, tung oil, & solvent seems promising. I have some over-age varnish I can cut that way and try."
That sounds like a good use for it. I use turps in my blend simply because I prefer the scent to the odor of mineral spirits. It adds to the sensory experience of finishing a paddle. ;-)
Nomenclature
Not suggesting they are relevant in the USA.
A coating that can be redissolved in its solvent is a “laquer” It does not react with anything to form a film.
Oils like linseed & Tung react with Oxygen to form a crosslinked coating. This drying mechanism is identical to the way varnishes dry.
A mastic is a sealant but could be an adhesive (although not a stong one like an epoxy)
Same here
That’s pretty much my understanding of standard finish terminology.