14-01-2013, 02:54 PM
Radio cabinets will invariably have originally been sprayed with cellulose lacquer, often on top of toner. These ‘sit on’ the veneer – they don’t penetrate it, so when a cabinet is stripped with Nitromers etc, if Danish oil is then applied, the cabinet will be lighter than original. If the original shade is desired, that can only be achieved by either toner, or by stain, but remember that stain will penetrate the wood and can’t be reversed once applied. If it’s desired to apply oil over stain, the stain should be water based - not spirit based, or the oil will not penetrate the wood.
As an alternative to Danish oil or tung oil, if a high gloss finish close to the original is desired, apart from clear car lacquers such as Tetrosyl, clear, Pre-catalysed solvent based lacquer is a pre-mixed varnish and cellulose mix that’s ready for use straight from an aerosol can is avaiable. As a guide to what the end result is like, nitro cellulose lacquers are widely used for musical instruments such as pianos and guitars, so if that’s the sort of finish you are looking for, that’s the way to go. It's important to appreciate that once Danish Oil is applied to timber, unlike lacquer, the process cannot be reversed. The oil soaks into the timber, and doesn't just 'dry' - it cures. That is a chemical change takes place, which is why each coat must be allowed to cure before the next one is applied.
A little about what Danish oil actually consists of might be of interest
There’s no industry standard ‘recipe’ for the ingredients and formulations for so-called “Danish Oil.” The main ingredients are drying oils such as linseed oil (extracted from the seeds of the flax plant), and tung oil or modified soya oil, blended with solvents (mineral spirits, naphtha, turpentine, citrus oil, etc.), and varnish (alkyd, phenolic, or polyurethane, etc.). However, the actual ingredients may - and probably do - vary widely among manufacturers. But whatever the brand, most makers will state that it dries to a satin sheen – not gloss. The higher the proportion of tung oil as compared to linseed oil, the glossier the finish is likely to be. Some brands (Liberon for example), state that the main ingredient in their Danish oil is tung oil, and state that the finish is ‘satin to gloss’.
For a higher gloss finish, tung oil rather than Danish oil might be a better bet, but as with Danish oil, will need perhaps five or six coats, with each coat being left for a day or so to completely dry and cure before the next is applied. Fine wire wool (0000 grade) is probably the best way to flat it down between coats before finally buffing it with pastewax. Whatever oil is used should be wiped off when applied, and not allowed to lie on the surface or to ‘pond’ as that will prevent the oil from curing before the next coat is applied. Tung oil is extracted from the nuts of the tung tree. Its ability to dry quickly and polymerize into a tough, glossy, waterproof coating has made it an especially valuable ingredient in paints, varnishes, lino, oilcloth and printing inks.
I claim no special knowledge or experience of finishing radio cabinets – my experience is as a woodworker and woodturner. The method of application of wood finishes differs, and there are other considerations for woodturners. EG, for such things as salad bowls, fruit bowls, children’s toys etc, woodturners avoid finishes derived from nuts, as these are not food-safe, due to the risks from nut allergies. This is not a consideration for radios as the only creatures likely to dine off a radio cabinet are the dreaded woodworm!
As an alternative to Danish oil or tung oil, if a high gloss finish close to the original is desired, apart from clear car lacquers such as Tetrosyl, clear, Pre-catalysed solvent based lacquer is a pre-mixed varnish and cellulose mix that’s ready for use straight from an aerosol can is avaiable. As a guide to what the end result is like, nitro cellulose lacquers are widely used for musical instruments such as pianos and guitars, so if that’s the sort of finish you are looking for, that’s the way to go. It's important to appreciate that once Danish Oil is applied to timber, unlike lacquer, the process cannot be reversed. The oil soaks into the timber, and doesn't just 'dry' - it cures. That is a chemical change takes place, which is why each coat must be allowed to cure before the next one is applied.
A little about what Danish oil actually consists of might be of interest
There’s no industry standard ‘recipe’ for the ingredients and formulations for so-called “Danish Oil.” The main ingredients are drying oils such as linseed oil (extracted from the seeds of the flax plant), and tung oil or modified soya oil, blended with solvents (mineral spirits, naphtha, turpentine, citrus oil, etc.), and varnish (alkyd, phenolic, or polyurethane, etc.). However, the actual ingredients may - and probably do - vary widely among manufacturers. But whatever the brand, most makers will state that it dries to a satin sheen – not gloss. The higher the proportion of tung oil as compared to linseed oil, the glossier the finish is likely to be. Some brands (Liberon for example), state that the main ingredient in their Danish oil is tung oil, and state that the finish is ‘satin to gloss’.
For a higher gloss finish, tung oil rather than Danish oil might be a better bet, but as with Danish oil, will need perhaps five or six coats, with each coat being left for a day or so to completely dry and cure before the next is applied. Fine wire wool (0000 grade) is probably the best way to flat it down between coats before finally buffing it with pastewax. Whatever oil is used should be wiped off when applied, and not allowed to lie on the surface or to ‘pond’ as that will prevent the oil from curing before the next coat is applied. Tung oil is extracted from the nuts of the tung tree. Its ability to dry quickly and polymerize into a tough, glossy, waterproof coating has made it an especially valuable ingredient in paints, varnishes, lino, oilcloth and printing inks.
I claim no special knowledge or experience of finishing radio cabinets – my experience is as a woodworker and woodturner. The method of application of wood finishes differs, and there are other considerations for woodturners. EG, for such things as salad bowls, fruit bowls, children’s toys etc, woodturners avoid finishes derived from nuts, as these are not food-safe, due to the risks from nut allergies. This is not a consideration for radios as the only creatures likely to dine off a radio cabinet are the dreaded woodworm!
Regards, David.
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
