soldering long span bridge

[Principefly]

I would like to know what are the investment materials that you used to get precise soldering in long span bridge, both made of precious metal, palladium and even alloy base
. Even if you use tools like 'Solder stand GC' and 'Spider Line' and have your impressions if they help to have more precision-
Thanks

 

[2thm8kr]

I use Hi Heat from Whip-mix. Attach sectioned bridge work with pattern resin and
plop it in a patty of investment. Right before it sets trim away excess and solder.
Perfect 99.9% of the time.

 

[technician]

Dr Kuns

I would like to know what are the investment materials that you used to get precise soldering in long span bridge, both made of precious metal, palladium and even alloy base
. Even if you use tools like 'Solder stand GC' and 'Spider Line' and have your impressions if they help to have more precision-
Thanks

 

[Principefly]

??Sorry,but I don't understand..

Dr Kuns

 

[martintay]

I use Hi Heat from Whip-mix. Attach sectioned bridge work with pattern resin and
plop it in a patty of investment. Right before it sets trim away excess and solder.
Perfect 99.9% of the time.

Also attach investment sections if separate ( to keep heat absorbtion to a mimimum ) with alumina bars/rods and pre heat in burn-out furnace before soldering. I always use alumina bar for strenght as well even if investment is one piece.

 

[Principefly]

Where can I buy bars of alumina? I'd already looking for another purpose, but I was not able to find them ..

 

[2thm8kr]

Also attach investment sections if separate ( to keep heat absorbtion to a mimimum ) with alumina bars/rods and pre heat in burn-out furnace before soldering. I always use alumina bar for strenght as well even if investment is one piece.

I wax out the areas around pontics to keep heat absorbtion out of the equation and burn it out in the furnace before soldering.

 

[martintay]

Where can I buy bars of alumina? I'd already looking for another purpose, but I was not able to find them ..

Not sure , ours are about 30 years old lol. Think they may have come from Vita . Guess you could get someone to mill you some in Zr..... in different lenghts with a few retention slots . Should last forever

 

[Principefly]

good idea

 

[martintay]

Make sure they are a flatish oval shape for anti-rotation with a few retention slots.

 

[doug]

Find a local lab with a Laser welder and let them do it.

 

[cheadlemick]

Solder all my bridges! Non precious as well, piece of cake, just heat everything up thoroughly!

 

[Principefly]

No one else wants to share his secret technique?

 

[pjd cdt]

Secret technique ?
Well I wax or glue together bridge.use a old fg bur for a splint and spruce wax tissue side for a channel for the flame to go thru.
use high heat soldering investment or phosphate investment with water only.
Fill abutments with investment than paper towel dry some of the remaining investment to make a patty place bridge occlusal side up in patty.
Set one hour , steam off wax and flux with pre solder flux
Put in cold oven to first 300c than to 850c
Hold solder with hemostats and flux solder
Use single orifice tip and set oxygen very low 1 or 2 lbs? Flame should be very quiet and blue part less than a half inch
Remove bridge from oven and heat uniformly remember more mass more heat less mass less heat.
Heat to cherry red and apply solder 180 degrees from flame it will flow to heat.
Once you think the solder has filled the joint you can turn off the oxygen and the flame will illuminate the bridge for easier inspection

Pete




Sent from my iPad using Tapatalk

 

[Principefly]

'Secret technique' was a phrase joking ..
Anyway, thanks for the detailed description you provided.
My main curiosity was whether with long span bridge, the greater part of you used a particular system, such as 'Solder stand GC' to avoid distortions of the casting

 

[2thm8kr]

'Secret technique' was a phrase joking ..
Anyway, thanks for the detailed description you provided.
My main curiosity was whether with long span bridge, the greater part of you used a particular system, such as 'Solder stand GC' to avoid distortions of the casting

I have the GC solder stand and the 'spider' from some other manufacturer, but I find the patty
technique to be faster and more fool proof. By the time you set up the stand or pegs on a tray, the investment patty is almost set, then trim away the excess investment while it is partially set.
PJD's technique is almost the same as mine. I let mine bench set 20 mins then throw into a hot
burnout furnace for 20 mins. If it's a really long span I put it back in the furnace and turn off to cool to room
temperature. Don't know if slow cooling does anything for the framework. Maybe I'm just superstitious.

 

[cheadlemick]

Dont forget to throw the bones on the casting room floor and dance three times round them! Apart from that i do it exactly the same way as 2thm8kr!

 

[2thm8kr]

Dont forget to throw the bones on the casting room floor and dance three times round them! Apart from that i do it exactly the same way as 2thm8kr!

I'll have to try the bones.

 

[JohnWilson]

I used to be in awe watching an old Cuban master tech solder like this that worked for me. Its a fine line between a perfect joint and a rolled margins. the laser welder made my life so much more predictable with out any bone dances.

This old school way in the hands of a skilled tech is awesome unfortunately the strength of the joint isn't anywhere near the strength of the parent alloy. This is another reason why a laser is far superior in every way.

 

[cheadlemick]

Sorry John physics proves you wrong! a correctly soldered joint is as strong as the original!