repairing metal brackets in a seneca 8x10

[darinwc]

I have an 'improved' model seneca 8x10 that I am trying to get into workable condition. One major problem is that the front standard is not sturdy. The source of this is the metal brackets that secure the front standard to the rail are cracked. I havent had any luck finding replacement parts. So I am looking into the possibility of getting them repaired. I think it would be fairly easy to weld on some strips of brass over the brackets to reinforce them.

However i have no welding equipment and I dont know anyone is sacramento who could do the work. So my first question is: is there anyone in the APUG community who would be willing to do the work (for a minimal fee) if I mailed the brackets to them?

If not, i've heard people talk about having work done at a machine shop. I would like some advice on how to find a machine shop and if they would be willing to do a small odd job like this.

Thank you.
Darin

 

[Ytlas]

I'm not familiar with the Senica camera but you just can't decide to put brass on something. You have to have an idea what existing metal is, pot metal, steel, magnesium, so on. I would take the front standard to a welding shop and ask their opinion. They might be able to TIG, MIG, braze or gas weld to repair it.

 

[darinwc]

I believe the existing metal is nickel-plated brass.

 

[Ytlas]

You should then be able to have pieces brazed to it.

 

[Donald Miller]

If you are wanting to join brass to brass, you can solder or even silver solder the metal together. Brazing is not the way that I would choose to join the two.

You can solder the two pieces or even silver solder with a Mapp gas torch (available at most hardware stores). The key is to have the metal clean (nickle plating removed from the juncture surface...can be sanded off with emery cloth) apply the suitable flux, heat and apply the fill metal.

If I were doing this, I would use 95-5 soft solder or 45% silver solder. The silver solder has a higher melting temperature (appr 1200-1300 degrees, as I recall). This makes the juncture more stable.

 

[Ytlas]

Whatever you decide, if you heat the brass to a dull red and let it cool slowly, it's called tempering and the metal will get harder. If you heat it and then cool it quickly, that's annealing and it makes the brass softer.

 

[darinwc]

I thought it was the opposite... maybee its different for brass than steel?

 

[c.d.ewen]

Darin:

Welding something that small is not practical - make a new piece. It's just a flat sheet of brass that's been bent into that shape. Yes, a machine shop would be where you'd find somebody with metal-working experience, and they'd be able to make it easily. Have you tried the phone book? Try asking at auto repair shops.

Charley

 

[resummerfield]

Lots of good advice here. I would agree that the best would be to take it to a machine shop and have another part made. But first, look at the old part, and determine why it broke. Maybe you and the machine shop can jointly determine a slight redesign to make it sturdier. You may want the machine shop to send the completed brass part out to be plated.

I would suggest looking for a smaller shop. When you call around, ask if they do prototype work.

 

[Whiteymorange]

Whatever you decide, if you heat the brass to a dull red and let it cool slowly, it's called tempering and the metal will get harder. If you heat it and then cool it quickly, that's annealing and it makes the brass softer.

Slow cooling from red heat is annealing. It is done to make the brass soft and workable. Heating, cooling quickly (quenching) and then reheating to a certain degree is tempering - and I don't believe it is done much with brass. I do know that it is the way that steel is heat treated for strength. Quick cooling makes the metal hard but brittle. Heat treating to the color of straw brings back some flexibility without softening the steel.

Brass is only so hard, period. It's a relatively soft metal and should remain relatively soft and workable to avoid cracking under stress. Try to heat it locally and quickly for the silver soldering and then let it cool. If the appearence is very important you'll have to get rid of the scale that will form from the flux, but it's not that bad. Brazing will fill in the cracks on the brass with a brass alloy- keeping the color clean- but will require a little grinding afterward.

Bottom line? You can fix it with very short money and a little ingenuity, but If appearence is important, bring it to a local silversmith/jeweler. They will do it for you and have things like a pickeling pot for scale removal and the silver solder that will fix the parts cleanly. Metal shops and welders think big. Silversmiths ail do little jobs like you want done.

 

[darinwc]

I'd rather not try to remanufacture new brackets yet.
I will try to solder it first. I found a good article on it here:
http://www.rd.com/content/openContent.do?contentId=18276
Speical note in this article mentions to be patient with brass, that it takes 5-6 times longer to get hot enough to melt the solder.
Also read a tip on soldering parts together. Tin both joints with a very thin layer first, then join the peices together and heat until the solder melts and welds the peices together.

i will try joining some scrap brass together first so I can test the strength.

 

[resummerfield]

One other suggestion..... stop by a welding supply store and show them the part and ask suggestions for a specific solder and flux. There are many different types of solder, even different types of silver solder, and different fluxes to match the base material. The shop may even give you some "tech support". Good luck!

 

[jimgalli]

Been there done this. I had them brazed both sides of the crack then ground clearances back in and a bit more for aesthetics. Worked well. I actually left extra material on the outer side to try to add add'l strength. Sold the Seneca. Solder is less strong than the original brass so a solder repair won't last very long.