Fixing Rust pitting on Air rifle, Diana 52

[MagnumPI45]

I guess I'll try posting again since the last one didn't post.

We have a Diana 52 that is over 25 years old, a long, a long time ago it was put in storage from a military move where the facility was exposed to flooding/moisture.  Even though the gun was in a case and wrapped it still received some surface pitting/rust on the outer exposed areas, no pitting where the stock covers the metal.

I tried re bluing another rifle that was damaged and the results were just okay, not good enough to me for a higher end gun like a Diana.

I want to try re bluing it now.  From my research some say cold bluing is not great for a entire rifle, it is better for spot bluing so I was thinking it may be better just to sand the pitted areas down and just re blue them instead of the whole rifle.  Hot bluing is probably not a DIY option especially for a air rifle with seals and a spring.  Also read where different blue's give different results on different metals so I may need to try more then one.

Has anyone tried re bluing a Diana Air rifle or any air rifle, if so how were the results, was there a blue that stands out, how has it held up, do you recommend just spot bluing from the pics or doing the whole thing.  I want to do it myself.  The metal side lever cocking bar looks to be a different metal/finish then the rest of the rifle.

[longhunter]

Take it to a pro. Hot bluing won't harm an aririfle.
I had one done, that had some terrible pitting, looked almost better than new, when I got it back. Didn't cost much, either. I think it was around40, or 50 bucks.
Just make sure to degrease it, re oil it, when you get it back, because some of the bluing salts may still be leaching out from around the area where the barrel fits into the receiver.

[happymecanic]

^^^ Best advice ^^^

I've had mixed results with cold bluing, mostly good but sometimes inexplicably bad, considering I always prep my parts the same way. It seems it depends on the steel itself, I find it does a better job on 4140 steel than on C12L14 for example. It can yield good results on a complete rifle, I entirely re-blued my Slavia 624 that had some rust pitting on. It must be kept well oiled, but the finish is holding up fine up to now, not much wear marks on the barrel after about 400 shots or so. I've always used Outer's gun blue:

[MagnumPI45]

Thanks for the replies. 

I am not going to send it off somewhere, there is no place near me that does it, prices are well over $100 at the minimum to do it from some research/calling, some are over $400 and that does not include shipping.  I already had the seals, piston/springs replaced by/at Umarex recently so I am getting into it would be around the same price or cheaper just to buy a new one then also getting a place to re blue it.

I will really start researching soon and figure what the best plan of attack is for DIY or if I should even bother, just wanted to see about experiences from people here.  Anyone know what kind of steel Diana uses for the 52, it may help with what kind of blue to choose.