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Message: <blockquote data-quote="Stephen Howard" data-source="post: 627834" data-attributes="member: 41">Got a job on the go - a mid '60s Selmer MkVI tenor. It's in for a general shakedown and as part of the job I'm resoldering the crook clamp. This is a very common job, particularly for Selmers - which seem to suffer quite badly from selective galvanic corrosion on this part.I couldn't even begin to count how many times I've done this job down the years. It's always the same process; unsolder the clamp, clean all the mating surfaces, smear with flux then fit to the receiver - taking care to align the break in the clamp with the slot in the the receiver. Clamp it up and have at it with the solder. Clean up and lube the screws. Job's done.And that's exactly the procedure I followed on this horn. And it failed. Got halfway through the cleanup process and noticed that the clamp had come away near the slot.Must have been bad prep. No big deal - just annoying. Take it off, clean it up, do it again. Which I did.It failed again!***???Took it off again and had a closer look at the clamp - and noticed that there was hardly any solder sticking to it...just a dark grey film.Cleaned it all up and decided to 'wet' the clamp with solder before refitting it - and that's when I discovered that the solder was simply balling up and rolling off the clamp. It just wouldn't stick.I've never seen anything like it on a horn - ever.At this point I started to think that the clamp might be made out of something exotic. Usually it's nickel silver or brass - but I've seen red brass and bronze used for decorative effect. All of these metals will soft solder just fine. This had to be aluminium bronze.I've never seen it used on a horn before, so haven't got the right products handy to effect a good soldering joint - but what I did have was some solder for aluminium. I figured I could use this as a base layer if I could get it to stick to the clamp - and thereafter use leaded solder to blend in and secure the part. It's worked in the past with aluminium, should be worth a go - right? [ATTACH=full]34384[/ATTACH]So here it is, all primed up. Looks a mess, I know, but that solder just doesn't flow. I scraped it down a little to allow the clamp to fit on the receiver, bunged some heat on and teased the clamp down into place as the solder melted. Topped it up with leaded solder and bingo! Job's a good un.Took the clamp screw out, popped a wedge in the slot and gave it a twist. The joint held - and then I thought I'd give it a bit of a bigger twist...y'know, just to make sure. And crack...there goes the joint.I've got a pot of special active flux on order - which ought to solve the problems. It had better do or the customer's going to be a bit miffed!Thing is though, why on earth was this horn fitted with an aluminium bronze crook clamp? I mean, why?? It's a pig of a material to work with in the first place - and if it was a standard fitment I'd have seen hundreds of them by now. A factory special option perhaps? Even then I think I'd have seen at least a handful over the years.It just doesn't make any sense at all.</blockquote>

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