@ 08:14 pm (GMT)
Nathan FosterOk, for starters, you need to be absolutely sure you want to show this. You have set the bar very high for yourself by putting your first job online. Sometimes it is better to keep working privately with me and allow yourself to make mistakes without the pressure of a show and tell. Also, I plan on making videos for Tikka users later this year.
As for your questions.
1.) Masking tape, electrical tape, aluminium tape, powdered graphite. What brand/type (if it matters)? Where can I buy it?
Hardware stores- engineers supplies being the best. You may need to purchase graphite from a reloading shop (sold as neck sizing lube).
2.) When I draw around the shape of the action in pencil I then move in a few mm at the tang and draw another line so there will be a reference level left after I've done some dremeling. Will the tang rest on this point at the back when I'm easing the action down into the compound, or is it just a visual reference so I know how much material I've removed during preparation...and this itself gets removed at the end?
The action will rest on this. Yes, it is your height ref point.
3.) In the video the Remington had the bedding to support the barrel because it was a bit of a beast, does the T3 barrel also need this? How far forward of the action should I bed?
Yes, the Tikka can utilize this as a harmonic dampener for this whippy barrel, yours especially. This also acts as a major reinforce for the plastic stocked Tikkas. Bed 1 to 1.5" into the barrel channel.
4.) Is the front of the action supported by the dam up by the barrel, and the rear supported by the reference point I left when removing material around the tang?
Yes. If the stock was plastic, you could also use the pressure point ribs in the barrel channel as height ref points. But in either case, the front dam is critical for height.
5.) The parallel walls of the stock next to the action and very very very close to the action. I need to remove the same 1.5mm+ on each side as I will below the action right?
Yes. I prefer to use a heavy coating of release agent. Another forum member Marty prefers to use electrical tape on these parallel walls for good measure. He has blogged this bedding in the Tikka bedding thread.
6.) In the recoil lug recess I need to remove enough material so there is approx 4mm of space for compound on all sides? This will give the compound enough strength and prevent me bumping the lug as I'm easing the action into the mortice. Is this correct?
Yes, remove as much as you can without compromising stock strength (also remove material underneath) for the exact reasons you mention.