Depends on who is doing the sandblasting - and what you are getting blasted.
And even what sand they are using ! Silica sand is a no no (for the operator), garnet sand (the red stuff) is good. There are also a variety of other sand types. Large stuff is not good, high pressure is not good. I saw a (car) bonnet blasted with high pressure, it expanded the bonnet at least 2 inches sideways - not good.
The place that gets my business has a rotary type compressor - no air tank - the sand comes out in large bucketfulls almost, and the sheer volume does a great job of removing all the old paint rust gunge etc. The steel surface (and it must be steel, never alloy) comes out a looking almost like its been lightly polished. You can't see any indents with the naked eye , but paint gets a great key onto it. It has to be thoroughly dusted off, several times, and I usually wipe it over with dilute phosphoric acid, to keep future rust at bay, before any painting.
You can of course get stuff bead blasted, and this is possibly gentler. But it tends to be slower, and possibly much more expensive - because of the extra time Probably in a smallish cabinet ?
Someone recently quoted someplace they were quoted 3 hours to do a Commando frame. That is rather slow (bead blasting ?), I've had a frame , engine plates mudguards and a few bits and bobs and dodads done in ~20 mins (?) with said rotary compressor, cost about $50. Done in a steel container type blastroom.
Its also worth commenting that Nortons at least had their own sandblasting facilities, so we know for sure that Nortons were sandblasted in a past life (pre commando, not sure what happened with those). Most shops that do powder coating will have sand blasting facilities of some sort - but will mostly then want to powder coat it also. !
In answer to the question "Is there any other way?": Paint CAN be removed with a chemical stripper; I've done this a couple of times. I like the water-soluble kind, as you can flush it with a hose. Even the original dipped-and-baked enamel on my '67 A65 came off this way, although it took three or four applications.
A painter may want to blast anyway, to give the metal a "tooth", but it's a lot less work if the paint has been removed.
Note that blasting is not required for powder coating, if you decide to go that way. In fact, powder coating can go on over old paint, as long as the old paint is firmly bonded to the frame. The last frame I did was powder coated, and all I did was sand the frame by hand to remove any rust or loose paint, and take the gloss off any remaining paint. The powder coater then dipped it in solvent to remove any dirt or grease, which is SOP.
I'm impressed you got paint stripper to remove baked enamel, I've not had much success with that. Paint stripper (methylene chloride type) is about the only way to remove old powdercoat, apart from melting/burning it off with a propane torch.
I've had good success with removing some types of paint off tinware parts using hot caustic. Boil it up, and slosh it on. (below) Took the paint neatly off a pair of Commando steel sidecovers, the old paint just drops off like a skin. Beware, it will do this to human flesh too, so take all necessary precautions. Also works well cleaning old paint and gunge off iron cylinders and iron cylinder heads. It is water based of course, so watch it isn't left for long, could promote rusting. Beware also, it also eats alloy, so keep well away.
I have taken a fairly uncommon and scrappy old petrol tank, and sanded it back (using sandpaper) by hand. No unexpected damage or surprises doing it this way - although it can take a while - some of those old paint types were tough. And old tanks can sometimes show many old layers and colors = many previous lives.... ?
Sand blasting is the way to go, as Rohan describes it, but only on steel parts. That's the way I do it, but if you are cleaning sheet metal, it should be blasted at LOW PRESSURE, and with fine grit blast media.
As for paint stripper: If there are seams , rolled edges, or two parts welded together or spot-welded, the stripper will creep into the seams, only to re-emerge after you have applied new paint, to ruin the paint job in the area of the seam.
This is my reason for using low-pressure blasting on sheet metal parts,
+1 for soda blasting. Then remove obstinate bits with a scraper. I do these processes myself--therefore no external contractors to liaise with/delay the work/f**k up the work etc. Also gets you close to the parts--you see things that you otherwise wouldn't. Gets you to bond with the bike. Sounds crazy?---that is just what my wife says!-----but it works for me. Just my two centsworth of course.
Is sandblasting the best way of stripping paint, rust etc or is there a better way? Less severe maybe with same result
I guess the main question is what type of part you need stripping and what the subsequent finish is intended.
For frame and other body parts which you are going to paint yourself then an easy less severe but slow method is to use paint stripper as suggested. This usually requires multiple applications followed in between with pressure washing and/or use of a wire wheel on a drill to remove stubborn bits, make sure you use skin/eye protection. Following removal of all paint you might want to use a rust remover or suitable anti rust primer.
For engine parts such as crankcases, I would avoid sandblasting & bead blasting, A better alternative is Vapor blasting which uses a slurry of hot water, de-greasants, corrosion inhibitors and blast media. This process closes the pores of aluminum and leaves a semi polished wipe clean finish.
Additionally you can simply sand parts with wet & dry paper, starting with coarse and ending up with fine. Clearly this is very labor intensive but you can achieve a mirror finish on most metal surfaces depending on your requirements.
1968 A65 Firebird 1967 B44 Shooting Star 1972 Norton Commando
Thanks all, need frame, tanks, wheels done. Not much paint left but lots of rust to be removed so sandblasting still sounds like the best solution just need them to go easy on tanks etc to not cause any damage