Not being the most desirable, neither a particularly expensive pen to begin with. The 25 could be considered costly to repair if you also have to include in the equation the cost of some one else's labour and trying to source parts that are hard to come by or expensive. In which case it wouldn't be unreasonable to think that many Parker 25's have probably been thrown away or ended up on auction sites for parts. Parker Pen as far as I know either do not repair these any more and more than likely do not stock many spares if at all. They definitely would not be manufacturing any more parts.
Nothing is impossible to make, although you would require time, resources, skill and money. Although I can make many components in my work shop, I can only make low volume parts. I do not have the big machine tools and presses that pumped out tens of thousands of parts every day when Parker was still running at Newhaven, England. Hence to make one component takes many hours. In some cases special tools and fixtures have to be manufactured in order to then make the component.
Some components that were moulded are a lot more difficult to machine from solid plastic and that’s if you could find a plastic manufacturer that could match the colour acrylic you required.
Other components that were deep drawn in presses to produce the caps and barrels would also be much harder and very time consuming to make from solid stainless bar as opposed to sheet metal that was fed into the presses. Below shows the drawn stages of the Frontier BP / MP stainless steel cap. First the sheet metal is fed in to the press. Then it blanks a large disc out. The first punch draws it down a short but wide depth. Automated fingers pick the part up and move it to the next stage where it is drawn even deeper and narrower. It again moves on several stage getting more depth and then contour punches start shaping it. A notch is created for the clip, the stamp is pressed on untill the final shape is aquired. Then it is barrelled to obtain a good finish. Then assembled on an automated line. The finished stainless steel BP Frontier pen can be seen at the end next to a clear demonstrator showing the insides.
Having thought about it, I think the biggest challenge with making reproduction parts for the 25 would be producing a print to recreate the logo consistently on the clip and moulding the plastic inner caps. Plastic parts were made to a very high tolerance. The mould tools were extremely precise.
Below is an Engel injection moulding machine. There were several of these and many more like it at Parker's Newhaven. It gives you a feel for the size of the machinery and the size of the factory to house them all.
That’s not to say 25’s cannot be repaired. Just by acquiring the spares and stripping other maybe damaged pens for parts you can then start to build up some good quality original pen parts. From these an original 25 can be built up with potentially all the correct age related parts. I didn’t say it was quick though, you may be waiting for that one part for weeks, months or even years depending on the rarity!
Caps, barrels and clips can be straightened, have dents removed, as well as scratches. The plastic front ends can be polished to remove light surface marks and stains. Any thing heavier and you may want to consider replacing. Inner caps are probably best sourced from spares or salvage from other scrap pens.
I can carry out various repairs, but I do not sell parts on their own. Please contact me here.
Left: This is a typical run of the sprue that is ejected out of the mould tool and ground up to recycle. Only this sprue still has an actual component attached to it, an Inflection FP front end.... Just like an Airfix model!
Below: Photo from Malcolm Troak's book showing the deep draw process pressing the barrel of a P25.