Without wishing to throw a spanner in the works, I've not had much success with water-based varnishes, which most seem to be these days due to the commitment to reduce high 'VOCs' (Volatile Organic Compounds). Hence, when I buy any form of varnish or lacquer for brush application, the first thing I look for is the brush cleaning instructions. If it says 'wash brushes in warm soapy water' I steer well clear, and look for something which on the can, says 'High VOCs' or 'clean brushes with white spirit'.
That said, if someone has used a varnish and achieved good results on radio cabinets that they can recommend, that takes the mystery out of the equation.
For radio cabinets, I've tended to use either Danish oil, or clear gloss aerosol lacquer.
Danish oil needs no skill to apply using a lint free cloth and gives a nice sheen - not too high a gloss. It doesn't just 'dry' - it goes through a chemical change and hardens. additional coats can be applied as desired after say 24 hours at room temperature. I've attached a pic of a Ferranti set which was a skip find, that I stripped and applied Danish oil to, which came up very nicely.
Alternatively, I've used both acrylic clear gloss lacquer, used extensively by woodturners these days. Being water-based, it's less hazardous. I can recommend GTPRO 'Redline Pro Wet Look Clear Lacquer', which is acrylic and is actually intended as the lacquer top coat of alloy wheel paint, designed to be weatherproof and scratchproof. It typically costs £6.99 for a 400ml aerosol plus post.
Two other brands of lacquer which are well thought of are U-Pol Clearcoat' power cans and 'Tetroysl Trade Spray' clear lacquer. The downside is that they're more akin to nitro-cellulose so can be hazardous if sensible precautions aren't taken.
U-Pol contains:
Acetone (CAS-No.) 67-64-1 5 - 23 Flam. Liq. 2, H225
ethyl methyl ketone
4-methylpentan-2-one, isobutyl methyl ketone
Ethylbenzene
the U-Pol Safety Datasheet is here:
http://www.u-pol.com/files/12719/up0804-SDS-EN
Typically, it costs £12.99 for two 500ml cans post free.
Tetrosyl Trade Spray contains acetone, butyl acetate and iso-butanol, so likewise, there are safety considerations.
The Datasheet is here:
https://www.tetconnect.com/images/st...ATS019_SDS.pdf
To quote the maker's blurb:
The trade spray series from Tetrosyl is the professional solution to topcoat finishing. Ideal for use on rigid plastics, wheels and wheel trims, and compatible with cellulose finish paint. The adjustable spray nozzle provides a ‘spray gun’ finish straight from an aerosol and the quick drying formula ensures a smooth and quality finish.
Unquote.
Radio cabinets will have originally been sprayed with nitrocellulose. The only one I've re-sprayed of late was a Unitra Figaro Special which was rather like the high gloss Grundigs etc. It was the worse for wear, but didn't need to be totally stripped. I tested Tetrosyl on an inconspicuous part to check compatibility, and it was fine, so I applied several coats, flatting it down between coats till I was happy with it.
I've attached a pic of the Figaro.
Not wishing to take the thread off topic into irrelevancies, and for no other reason than to illustrate the finish attained using Tetrosyl Trade Spray clear lacquer, I've attach a couple of pics of a not very exciting little bowl I turned (from a scrap of scavenged Iroko when Hull dock gates were being repaired) and finished with Tetrosyl spray.
One last point or stripping cabinets, do bear in mind that the veneer will at best be 1mm thick - most likely 0.6mm. Hence, it's desperately easy - especially on the top front curved edge of Bush and other sets, to sand right through to the underlying timber. Much better to use a cabinet scraper (NOT a paintscraper). About the coarsest paper I'd use on veneer is 220g, sparingly, and always with the grain.
Hope that's of interest.
Every good wish with the restoration John.