Oh, bother! Loose rear sight base on a Finn '27

[jmoore]

Was doing a pre-"range trip" check on the Finn and noticed the rear sight base was quite "wiggly". Pulled the barrel bands and handguard off for further inspection and the whole rear sight assembly slid completely off it's dovetail. Never was a good fit, as the old solder only stuck where it was blobbed up.

Resolder due to the poor fit is likely to be a disaster. Also don't want to refinish the whole thing.

Am leaning towards "steel bed" epoxy compound to re-attach it, but before proceeding, does anyone have any other suggestions?

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[vintage hunter]

Why would re-soldering it be a disaster? Soft solder works at low temps compared to silver solder so finish damage will likely be minimal if any. Epoxy would likely be a short term repair due to vibrations and expansion/ contraction as the barrel heats up during firing then cools off afterwards. Just my .02CW.

[jmoore]

I should think that soft solder would perform as poorly or worse than steel filled epoxy in this case, as it's not intended to fill large gaps. Solder does best in tight fit situations. Mind you, it did seem to do OK from 1934 until sometime recently on this particular rifle, but the job was poorly done- by the Finns it appears! Photos coming.

[jmoore]

Slow, but finally! Photos.







Believe it or don't, those lumps of solder are between 0.010" and 0.015" highter than the parent metal. Good solder joints ought to max out around 0.003". Also not much actual contact between the base and barrel, although both were very well tinned. The fit was just poor!

So, to avoid another poor soldering job, and probable bluing problems due to fluxing and such, Devcon "Plastic Steel" Putty (A) 10110, was chosen as filler and adhesive. Surrounding surfaces were coated with release agent, and the epoxy was carefully mixed and applied in generous quantities to both mating surfaces. Then assembly and lots of clean up! By the time for a range exercise, the epoxy should be well cured.




Focus didn't work out too well, but it's all that's available so far.

One bonus to this epoxy is that it is a dark metallic grey color. So ant that shows around the edges looks very much like old solder. As extended rapid fire sessions aren't likely, I don't think heat will be an issue, either, but if it fails, you'll get to see a part II.