Is there such a thing as a relatively cheap, electric powered, chipping tool?

Needleguns are normall hydraulic or pneumatic.

Er, that's neither an idea nor a recommendation! :-)

A 2kg SDS is probably lighter than the mains dedicated needle scalers I have seen (often 3 - 4kg), and they are quite large as well.

The small AG with a cup brush would be your best bet I would have thought. Most other options will need an airline.

I was going to write "Sounds like you need a needlegun, but the only cheap ones I'm aware of are pneumatic (and they need a medium sized compressor)"

How about something like this, used in a small electric drill?

OK, it can do most of what I need on the flat areas of the deck etc. (I've already done quite a lot of that), but there are places that need something 'screwdriver shaped' to access them. There's no way an angle grinder with any sort of fitting is going to get near them. For example I've just spotted a rusty channel below a window that's around an inch wide and an inch deep - how can I clear the rust in there?

that maybe the SDS drill with a chisel is the way to go, I've not tried it so it may be more practical than I've imagined.

I have wire brushes like that, while they can get rust out of some awkward places they're far from ideal. Think of a corner (as in a corner inside a box - the box being the cabin) with rust in it, anything round simply can't get near. What's needed is a screwdriver shaped chipping device.

As I said I think I'll try the SDS with a chisel but the ideal would be a sort of mini SDS which could be held in one hand.

No wire brush will remove rust totally. The oxide is harder than steel so all it will do is remove the loose stuff. If you want to get back to bright stuff, you'll need something harder.

Yes, well as the OP that's sort of where I started from, I want a way to clear out rust from tight corners where an angle grinder wheel can't reach.

Two other options spring to mind. One being the ubiquitous get out of jail free card - the multimaster. With a finger rasp style tool on the end it may do what you need.

The other (if you can find one in stock or on ebay etc) is the Bosch scraper vis:

On car stuff - having been caught out before painting after just wire brushing, but not wanting to remove good steel and weaken things more than is necessary as a grinding disc does, I use a diamond burr. That clears out all the rust pits back to bright steel, with minimum damage. But of course rather time consuming on your job. ;-)

I have a Bosch PMF180E (the Bosch copy), I wonder if I can get a suitable tool for that.

Looks perfect! I'll have a hunt around and see if I can find one for sale.

Thanks!

Further to the above does the PSE-180 vibrate 'in and out' as it were as opposed to the PMF180E's sideways/rotary vibrations?

There are a couple of relatively cheap copies of the PSE-180, one from Westfalia and one branded "B / Andrew James". If they do "in and out" vibrations I might try one of those.

Yup, in an out. It comes with some scraper blades, a couple of thin chisels, and some lino cut style gouges. Its sort of like a short travel SDS in action.

Could be worth a punt. ;-)

I've 'punted', on one of these:-

How about the abrasive tipped 300 degree disk of a Fein / Bosch multi tool thingy?