I have been meaning to do a quick wright-up about using vinegar to clean up rust, so here it is eventually!
Here are some before pics:
Even the wooden handle looks worse for ware:
My first challenge was finding a container big enough to put the plane in, I eventually settled on a paint tray. The vinegar was diluted to about 50/50 with normal tap water, however I didn't measure this actually, it was more of an eye ball measurement. I started off with brushing the solution on with an old toothbrush and that actually worked pretty well right off the bat, however that is still a lot of work, so I wanted to soak the plane and see what would happen.
The plane soaked for about 3 days (I probably should have taken it out a little sooner, but things were just too busy to get round to it).
As you can see I still didn't manage to submerge the whole plane, I did however manage to soak the parts. The solution was very dark and there was some foam on top showing me a chemical reaction as definitely taking place.
After taking it out of the solution it did still require a lot of brushing though...
But with some brushing the change was very apparent!
I then started with "tool-in-a-can" and some fine water paper to clean up the residue and remaining rust. It did also seem necessary as the plane started to rust up again within minutes.
Here you can see the difference between the 2 blades, one cleaned with tool-in-a-can and sanding only (in the plane) and one first cleaned with the vinegar method and finished with tool-in-a-can (in my hand). It did however for some reason leave the change in colour as can be seen just below the slot, I suspect this might be where the blade was hardened. It did seem to remove the outer finish of the blade as well, so I'm not sure if it will retain an edge as well as before.
Here is the final side by side comparison, the small plane was cleaned with tool-in-a-can only while the larger plane was done with vinegar.
The results look similar but I would say the vinegar plane is more uniformly clean.
So in conclusion I'm a little in two minds here, the vinegar method does work, but it has a couple of drawbacks:
1) Finding a large enough tray/container to soak the rusty item in (not always a problem, but will be in many cases)
2) The item has to soak for a bit.
3) It seems to remove the finishing from some metal parts, so I guess you will have to be careful on what exactly you use it on.
4) You still have to brush the item, so some elbow grease involved.
5) You still have to sand a bit and apply machine oil of some sort to protect the metal.
This may be a good method for heavily rusted items or items that prohibit sanding down (lots of small details etc.), but for simple items I think just sanding down with a fine water paper and machine oil is quicker and just as effective.
I hope someone finds this useful, thanks for looking!