Help with a silver solder problem

[deadin]

I have a cracked frame that I need to braze/silver solder. See the pictures below.
The crack is ~.017 wide, .200 long and .060 thick. The hole shown is .450.
My problem is that I need a way to hold the solder from running out the backside.
I was thinking of turning an aluminum "plug" (that the solder wouldn't stick to) that would just fit in the .450 hole, but how much will the aluminum expand under heat? I don't want to expand the crack any.
Any other suggestions??

 

[ttrikalin]

turn and bore a cored Ali plug an slit it. will stay put and will not distort the piece any.

do wou have access to welding?

 

[Jasonb]

The alloy will possibly melt or even distort, thats what I have found when using similar methods, a lot will depend on the overall size of teh part and the amount of heat you need to get into it for the solder to flow.

I'd be tempted to run a saw/fine file through the crack until you can insert a thin strip of similar metal into teh crack and then solder it all together, that way the solder will wet the infil and have something for the capillary action to suck it to.

As said a sacrifical block on the outside would be the better way to retain the solder.

There are solders that form a better fillet and have more gap filling capacity than others, its the 40% silver at the bottom of this page
http://www.cupalloys.co.uk/popular-silver-solders-leads-to-prices-c26.html

J

 

[Mainer]

The melting point of pure aluminum is about 1220 degrees F, which is about the melting point of a lot of silver solders and significantly below brass brazing, so I'd be concerned that an aluminum plug might melt. The melting point of some of the aluminum alloys may be higher, might be worth checking to see if you could could come up with a high melting point aluminum and a low melting point silver solder that would be workable. You could always use a brass plug, let it get soldered in place, then bore it out afterwards.

I think the flat strap on the outside, as proposed by a couple of others, may be your best bet though. If you can arrange it so at least part of the strap can be left in place as reinforcement,, so much the better.

 

[Herbiev]

Could you use plaster of paris to plug the hole then drill it out when done?

 

[steamer]

Make a backer out of steel and coat with oil

Heat it up and burn the oil off leaving the carbon soot in place.

Now use the uncleaned steel piece as a backer....the silver solder "Probably" won't stick to it...I'd try it anyway.

Dave

 

[Jasonb]

Correction fluid is another good item to make parts nonstick.

J

 

[deadin]

I like the idea of using something to make the backer "non-stick". (When you say "correction fluid", is that the same as "white-out"?)
Question--- how to get the backer in place without scraping off the coating as it has to go down on a hole?
The brass plug and then bore it out has possibilities also.
The shape of the exterior surface doesn't lend itself to backing from the outside.
Unfortunately the only access I have to a welder is a shop that repairs logging equipment. I don't think they could handle anything this small........

Thanks guys... I'll have to just jump in and try something soon..........

Dean

 

[steamer]

I like the idea of using something to make the backer "non-stick". (When you say "correction fluid", is that the same as "white-out"?)
Question--- how to get the backer in place without scraping off the coating as it has to go down on a hole?
The brass plug and then bore it out has possibilities also.
The shape of the exterior surface doesn't lend itself to backing from the outside.
Unfortunately the only access I have to a welder is a shop that repairs logging equipment. I don't think they could handle anything this small........

Thanks guys... I'll have to just jump in and try something soon..........

Dean

Hi Dean,

Can you show us a bigger picture of the part....can't work around limitations if we can't see them...

Dave

 

[deadin]

I will get some more pictures from different angles tonight.......
(Got to go manage a "garage sale" today..)

 

[krv3000]

two things to av a go at have you got a broken fire brick chop a lump out of it and shape to the hole it will help with holding the temp while soldering or fire cement

 

[Paswest]

Where I use to work , I was the only machinist and every time the welders had to fix a probleme like this I machine them a graphite plug.
Work every time.

 

[Maryak]

I don't wish to be a party pooper, but what is the metal that is cracked? Knowing this could help a lot in deciding on a suitable repair.

Best Regards
Bob

 

[steamer]

Excellent point Bob....what is the base metal?

Dave

 

[mike os]

and what does it hold...

 

[deadin]

Good questions......
The base metal is forged/milled steel (as in .22 pistol frame). Ideally it should be TIG welded but I don't have access to one. It is not a repair that I plan to actually shoot although it should hold under low powered loads. (It's just that having a crack in the frame bothers me. :-[ And, besides, I have several other examples of this model that I can shoot.)
Here are some more pictures:
The first shows it isn't feasible to put the backer on the exterior because of the milled rail. I will have to do a little milling/filing to remove any overslop from the braze.
The second is a better overall area, and the third is of what the whole assembly looks like.
(I should mention that the stud is what receives the recoil of the slide and spring.)

 

[Jasonb]

I'd stand by what I first said clean up the crack to say 1/16" wide , insert a bit of steel, solder and then file flush.

J

 

[Maryak]

Maybe Oxy/Acetylene weld if no TIG. ???

Perhaps it's just me but weld or braze seems preferable to silver solder.

Best Regards
Bob

 

[Ed T]

2nd JasonB 's suggestion. With a bit of effort the same filler piece could repalce the material that's missing at the top of the slot that the retaining pin rides in. That said, is there actually material missing where the crack is or is the butt end of the gun bent which has opened up the space. That is, is the hole still round, or is it stretched?

 

[Groomengineering]

Ideally it should be TIG welded but I don't have access to one. It is not a repair that I plan to actually shoot although it should hold under low powered loads. (It's just that having a crack in the frame bothers me. And, besides, I have several other examples of this model that I can shoot.)


Hmmm.... If it were me I'd farm out the TIG repair, then heat treat and remachine -OR- solder, braze, JB Weld, whatever, and remove the firing pin to make it a perm display model. I think that any repair done on a firearm should make it safe for anyone down the road. Not trying to shoot down your idea or to sound too harsh, but even with a .22 the butt end of that frame snapping off and smacking you in the forehead would be somewhat less than pleasant.

Just my .02c

Cheers

Jeff