Some random thoughts that might help you (or not).
Use chemicals to do the stripping. My experience is of the old nitromors stuff, people do not rate it as much now. If peelaway indeed peels the varnish away fine ... if not you may need a scraper like this
https://www.toolstation.com/shop/Painti ... ook/p58907 (there is also a useful just triangular shape of the same thing). I also quite like this one
https://www.toolstation.com/shop/Painti ... ool/p44507 which is heavy at the handle end (like a small hammer), and you can use to hit your head every time you gouge the wood.
The above tools/ideas are to be used in combination with chemical strippers.
Then you will have the varnish in the more ornamental bits where a scraper is no good (but the point bits of the "hooks" I pointed out may be useful. If it peels fine, if not you will need a stripper (down Tom) and woodworking wire/steel wool (a medium to fine grade, eg. 0) see:
http://www.thefurnitureconnoisseur.com/ ... finishing/. You finish with sanding as necessary but if you have to sand go with the grain of the wood. You could use finer steel wool instead of sand paper (00 or 0000) but as the wood will be obliterated by your choice of coating you might as well save the elbow grease.
Finally, varnish. If you must make it as dark as you want (I would rather drown myself in the lager crap I am having than do that) you have two things to consider.
a. If you use wire wool there will be bits left behind that will simply rust with a water based varnish.
b. As Dewalt said, a varnish with colour suspends the colour above the wood, so it kind of obliterates the grain. A water based varnish obliterates more than a solvent based varnish. Given you are trying to paint the poor thing black with some grain showing through a solvent based varnish (drying in 16+ hours would be a better choice). Remember, the more coats the darker and more obliterated the result. You don't have to worry about solvent based materials yellowing over time. Yours would not yellow.
c. Protect the hearth as much as is possible ... chemicals can work wonders on it.
d. If you opt for wire wool have rubber gloves as you will have to use it with the chemicals, and have spare pairs as your fingers will go through.
e. In an ideal world, if it was all down to bare wood you could use dyes to achieve the colour you wanted and then clear varnish as a top coat. Dye is not an option whilst the ornamental bits or the grain are not free of any previous varnish.
Am I too detailed?
I have been where you are going with a very simple surround (home made) that I wanted to bring back to natural colour. And mine was a "simple" surround. I ficked the hearth (did not really mind), removed the surround and did it all over again and got a new fireplace installed (not by me) and I refitted the surround. Thoroughly enjoyable but painful on my elbows. Polishing wood with steel wool is not fun
I hope it helps a little. Just keep the decorator's multi tool gadget with the heavy end handy at all times
