Will resoldering front sight damage bluing?

[NikA]

Picked up a rifle this weekend, got it home and noticed the front sight was loose. Turns out, original solder job was less than excellent and only flowed at the front and back of the base. Significant corrosion between the soldered areas probably detached the solder at one end.

I assume that thorough fluxing of the area to resolder the sight will damage the bluing, which I'm hoping to avoid. There are still soldered areas on both the base and the barrel. Anyone successfully resoldered a sight without needing to reblue? Is it possible to clean the solder area without fluxing, e.g., by thoroughly sanding the area to be soldered?

[cwtebay]

Can't speak to bluing, but on a nickeed 1892 SRC I sanded / buffed the area and packed the surrounding areas with cold Play-Doh. Fluxed and used silver solder on it. Looks good and works awesome.

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[Der Gebirgsjager]

It would be tough to do. If the sight is still attached but loose, maybe you can pry it up enough to get some J-B Weld under it? Just a thought.
Many fluxes will instantly remove bluing.

[Uncle Grinch]

If you have, as you say, significant corrosion, under the sight, it needs to be removed and buffed out. Then you can resolver it and apply cold blueing to touch it up. Anything else and the corrosion is going to get worse.

[country gent]

The solder wont take to the corroded metal sight or barrel, even the old solder may give a problem. Clean both parts to good metal. Lightly flux For this type gob I like the flat silver solder sheet about .005 thick, Cut a piece of this to match the joint and lay in place then flux the sight base and clamp on location. Heat till solder melts and flows. Clean up and touch up bluing

[NikA]

Thanks for all the suggestions guys; I won't get to dealing with this until later in the week or possibly the weekend, so please keep them coming.

To clarify, the sight has been removed from the rifle, both sides have been soaked in Kroil, scraped with a penny and scrubbed with a bronze brush. At this point, I do not believe any more cleaning is going to occur without chemicals that will damage the bluing.

I had considered epoxying the sight to the barrel, but if it comes off in the field due to disparate rates of thermal expansion, it's liable to disappear in several inches of snow and/or mud and never be seen again.

My previous experience with hard soldering was on stainless and involved very acidic flux that was a PITA to clean afterwards. As mentioned in the OP, I am specifically trying to avoid a crappy bluing touch-up job. The sight isn't strictly speaking needed (rifle is scoped), but I think a fair amount of polishing would be necessary to removing traces of pitting from where the sight was previously attached.

I'm thinking I may just substitute regular plumber's flux and try tinning the underside of the sight to see how that goes in terms of staining and adhesion. If that works, I'll try sanding the area of the barrel where the sight was attached and reflowing the solder to attach the sight.

Thoughts on that approach? I have some silver bearing solder around, thoughts on using regular LF versus that to keep the temperature down? Rifle is a small varmint caliber without much recoil.

[ulav8r]

Hi-Force 44 https://www.brownells.com/gunsmith-tools-supplies/general-gunsmith-tools/solders-flux/hi-force-44-solder-prod709.aspx

Carefully clean the bottom of the ramp and the barrel, removing all traces of solder and corrosion. Mixing unknown solder alloy with new solder may or may not be successful so it is best to remove all that is there now. Ask Brownells for their recommendation for the best mask to keep flux from damaging the bluing. I have read that graphite pencil lead rubbed on the bluing will protect it but there may be something better. After cleaning clamp the ramp in place and apply the mask to the barrel and ramp, remove the ramp and apply flux, then reclamp and solder.

Good luck.

[BigEyeBob]

Apply soot to the areas where you dont want the solder to go after cleaning the areas to be soldered . A kerosine burner or acetylene torch will do it.

[Outpost75]

I ran into this exact problem with a Cimarron-Pietta Pistolero 4-3/4" in .45 Colt on which the sight was crooked. Gun shot way off!

Smacked front sight with a 2 oz. brass hammer to straighten up, and snapped the front sight off. Poor factory silver-solder job with only a wee bit of silver solder about the size of a no.6 shot in the sight cut. Cleaned out the sight slot and filed sight down to bare metal, first tried red Loctite. Sight came off again. Then cleaned again and tried Permatex Steel Weld, also failed to stay put.

Finally cleaned again and pounded sight firmly down into barrel slot and used my M1911 .45 ACP grip screw bushing staking tool and whacked the sight fore and aft and again twice on the left side only to forcefully erect the front sight straight-up at 12:00 and so far it has stayed tight for 100 rounds of factory full charge loads for several iterations of filing and trying front sight to correct zero.

Blue was NOT disturbed! So far have filed 0.080" off front sight to correct elevation!

[Ragnarok]

I went shooting with a surplus Colt Police Positive Special .38 years ago.....was sitting at the kitchen table wiping the old revolver down and heard a 'tink'?....It was the front sight hitting the floor!!! I was flustered for sure

Anyhow...a little research and some high silver content silver solder/flux plus a good butane torch I stuck it back on and it has stayed on fine.

The old Colt had quite a bit of finish wear on the sight and barrel...had to get things hot to braze it back on. Cold blue covered it up and it looks better than when I bought it

[MostlyLeverGuns]

There are a few YouTube videos on techniques to keep solder where you want and protect the rest, the jewelry guys worry about this.

[Geezer in NH]

Yes it will damage the bluing. It will take much skill for it not to [impossible in my opinion] You do not have that skill. Asking the question shows you do not. I am not dissing you as it was a question.

I blued barrels and everything that can be blued in the last shop I was a partner in.

Solder the sight back on and get the rest re-blued. Done right no one will know.

[John Taylor]

I get about one a month to replace/repair the front sight. You don't need silver solder if the sight is set into the barrel, low temp solder will work. A lot of early pistols had the sight staked in but I still like to solder them. The flux will take blue off. I use the High force 44 solder from Brownells and plumber flux. Sometimes both parts need to be tinned first. Also use this solder for front sight ramps on rifle.