soldering long span bridge

[Flipperlady]

I'd take laser welding of soldering a long span bridge anyday.

 

[JohnWilson]

A brazed joint is stronger than the filler metal, but not as strong as the parent metal.
This info can be readily found on a welding/brazing info site on the intraweb thingy.

Like I said, I'm no physicist but laser welding does not weld the whole joint like tig welding.
Yes you are welding with the same alloy as the framework is made from, but the penetration
is only 'x' deep where as capillary action pulls the filler alloy into the brazed joint filling it completely
giving it a larger surface area to bond to.
It would be interesting to see how two identical frames one laser welded and one brazed/soldered
would compare on an Ingstrom tester.

This is why I like this site, I always like to learn, seeing how none of us have that INGSTROM majig we will just have to just go with what we have.

 

[2thm8kr]

This is why I like this site, I always like to learn, seeing how none of us have that INGSTROM majig we will just have to just go with what we have.

I was hoping you would be inspired to splurge on one.
I'll bring the beer.

 

[JohnWilson]

I was hoping you would be inspired to splurge on one.
I'll bring the beer.

How about we go to IKEA and set it up on the rig that flexes the chair repeatably. Now that's so high tech shinola!

 

[2thm8kr]

How about we go to IKEA and set it up on the rig that flexes the chair repeatably. Now that's so high tech shinola!

Will they let us drink beer while we try it? If so I'm in.

 

[JohnWilson]

Will they let us drink beer while we try it? If so I'm in.

That's what the parking lot is for,

Only problem is I get hungry when I drink and I am afraid of the horsemeat in there meatballs!

 

[Al.]

Strength aside.
For me soldering long span screw retained splints is not accurate enough.
The expansion is enough to make it not passive. These splints are on solid models and with parts and screws that have very little tolerance. Macro movements and the frame will have to flex to screw down fully. May be fine till it is layered and rigid. Then you break the porc.

Laser or TIG welding must be welded from the inside out. Then it is solid.

I dont even bother to cast in one peice. I cast them in sections. That way I control where and what kind of joint I have.
Butt it in the middle of the pontic and V it out on both sides in the wax.

I screw the sections down on the model. Then I take the sprue bar with the sprue stubs attached and weld that in two places on to the top where the sprues were cut off. Now the frame is locked down on the top and bottom. Then I weld the joint in two spots where it butts. One on the gin, the other on the top on the opposite side.

Then I unscrew it to check the fit if the bar is not blocking the screw acess holes.
Then finish welding it up.
Each joint takes me about 15 minutes. I degass each section before I move on to the next section.

John at the Primotec Booth they had this jig that can be used to clamp the frame down on the solid model and welded. So no investing in stone.
The guy helping at the booth works at Drake Dental Lab in NC. He said in their lab they clamp it down and weld with high power and dont have them move.

 

[2oothguy]

Forget about soldering just wax sprue and invest properly and no worries. I haven't had to solder a bridge in a long time. Regardless of the span. But I agree with some in here. Find someone close with a laser welder and let them do it. You can recoup the cost pretty easy.

 

[Tayebdental]

The solder joint is even stronger if the Pontic is sectioned instead .

 

[droberts]

A brazed joint is stronger than the filler metal, but not as strong as the parent metal.
This info can be readily found on a welding/brazing info site on the intraweb thingy.

Like I said, I'm no physicist but laser welding does not weld the whole joint like tig welding.
Yes you are welding with the same alloy as the framework is made from, but the penetration
is only 'x' deep where as capillary action pulls the filler alloy into the brazed joint filling it completely
giving it a larger surface area to bond to.
It would be interesting to see how two identical frames one laser welded and one brazed/soldered
would compare on an Ingstrom tester.

Interesting info. You will see more and more metal fabricating shops using laser than tigs/brazed. You can control the heat source.
This morning, I laser welded a long span bridge welding 3 areas. Not labs casting fault, doctors preps... Anyway, I was able to
change the parameter settings to meet the necessary amount heat and spot size to weld them without destroying any margins, etc.
The bridge was luted together, then invested in stone to allowing me to weld all three. Once finished, divested using shell blaster.
As for penetration of the weld? Use of the parameter settings, controlling the heat and spot size. You can move metal from the side
walls of both copings to get your connection into the center and move outwards with your build up adding wire. Also while adding the
wire "filler", over lapping the welds is a must for a strong joint. Also to add. A doc called the other day to have a milled bar welded
as he possibly made an error in his impression taking. All-on-4, Glidewell bar, #11 was 1mm off with other 3 seated.
He was concerned due to the thickness that it may not be as strong. 4mm bar was cut, properly aligned, luted and invested.
Welded using the same technique as above. My Ingstrom tester " if it doesnt come back, it worked"

 

[desertfox384]

Since we're on the subject of bridges, I've always had issues with implant bridges fitting properly.. I decrease my water powder ratio by 3-4 ML of liquid for bridges, yet almost always have at least a small "tick" on implant bridges, but not regular bridges... any ideas what the difference is? Is it just the fact that its a solid model with no give?

 

[2000markpeters]

Gave up soldering 17 years ago and bought a laser welder. Welding with same alloy gives the strongest weld possible and makes sure their are no galvanic or corrosive reactions. I would have to disagree that a soldered joint is as strong as a welded one, as the solder itself is the weakest link (lower melting point). Once you have mastered the laser weld you have mastered physics.

 

[2thm8kr]

Gave up soldering 17 years ago and bought a laser welder. Welding with same alloy gives the strongest weld possible and makes sure their are no galvanic or corrosive reactions. I would have to disagree that a soldered joint is as strong as a welded one, as the solder itself is the weakest link (lower melting point). Once you have mastered the laser weld you have mastered physics.

I don't believe anyone has claimed a brazed joint IS stronger, but I would like to see some data from studies done on the difference in strength between a brazed and a laser welded, not a TIG welded. There is a lot of physics involved in getting a properly brazed joint as well. With good techniques it's possible to have an extremely high success rate. So much so, I couldn't justify the expense of a piece of equipment, I'm just not going to use that often. Setting up to solder a bridge only takes a few minutes plus the time the investment takes to set up and burn off the pattern resin and it's pretty cheap. I'd rather spend the dough on something more fun.

 

[2thm8kr]

Since we're on the subject of bridges, I've always had issues with implant bridges fitting properly.. I decrease my water powder ratio by 3-4 ML of liquid for bridges, yet almost always have at least a small "tick" on implant bridges, but not regular bridges... any ideas what the difference is? Is it just the fact that its a solid model with no give?

On full arch cases have you tried attaching a 'runner bar' from the distal of both free ends.
This helps to keep an even expansion in the investment.

 

[2thm8kr]

Interesting info. You will see more and more metal fabricating shops using laser than tigs/brazed. You can control the heat source.
This morning, I laser welded a long span bridge welding 3 areas. Not labs casting fault, doctors preps... Anyway, I was able to
change the parameter settings to meet the necessary amount heat and spot size to weld them without destroying any margins, etc.
The bridge was luted together, then invested in stone to allowing me to weld all three. Once finished, divested using shell blaster.
As for penetration of the weld? Use of the parameter settings, controlling the heat and spot size. You can move metal from the side
walls of both copings to get your connection into the center and move outwards with your build up adding wire. Also while adding the
wire "filler", over lapping the welds is a must for a strong joint. Also to add. A doc called the other day to have a milled bar welded
as he possibly made an error in his impression taking. All-on-4, Glidewell bar, #11 was 1mm off with other 3 seated.
He was concerned due to the thickness that it may not be as strong. 4mm bar was cut, properly aligned, luted and invested.
Welded using the same technique as above. My Ingstrom tester " if it doesnt come back, it worked"

Are you filling the entire joint or overlapping surface perimeter tack welds?

I like your Ingstrom tester as well, I have the same one.

 

[droberts]

Are you filling the entire joint or overlapping surface perimeter tack welds?

I like your Ingstrom tester as well, I have the same one.

Only tacks welds are the first 4 that are rotated 180 degrees to prevent distortion or warping.
Once that is completed, a full bead weld can be placed on both sides of the work piece. After that
full bead welds are placed adding wire "filler". You do not want to try and pool your weld with the filler wire just to
fill the void. They must be overlapped for strength in a full complete pass. Following those instructions
will give you a strong, void free weld. My website (www.hawkeyedentalstudio),has a video of a laser welding.
Not adding wire, two pieces butted together, with actually a wide gap. Using the parameter settings of the welder, I can control the spot
size, amount of heat, and speed to properly weld the pieces together. Even without a filler wire, it would take a vice and a pair
of pliers to bend and try to break it.

 

[adamb4321]

the only thing you really have watch with laser welding is the composition of the alloy you are welding. precious alloys containing zinc should be avoided as the joint will be brittle upon cooling.

 

[soohan]

I have a phazer welder from Primotec. I tack a spot on the buccal and lingual to hold the sections together then solder the connector with my torch. This takes about 2 minutes literally. I have tried welding the whole connector but no matter how careful and slow I try it still rocks when finished It takes a long time to weld a connector even if it does work compared to the technique I described above.

My name is Han and I'm running dental lab in chicago.
I'm trying to buy phazer welder from Primotec .
anyway I'm very interrested in your soldering method.
I you don't mind can I talk to with you about welder and how you use it
630-530-5217
[email protected]

 

[soohan]

I have a phazer welder from Primotec. I tack a spot on the buccal and lingual to hold the sections together then solder the connector with my torch. This takes about 2 minutes literally. I have tried welding the whole connector but no matter how careful and slow I try it still rocks when finished It takes a long time to weld a connector even if it does work compared to the technique I described above.

My name is Han.
I'm trying to buy phazer welder from Primotec .
anyway I'm very interrested in your soldering method.
I you don't mind can I talk to with you about welder and how you use it
630-530-5217
[email protected]

 

[2oothguy]

No one else wants to share his secret technique?

I if i need to but it is rare that i need to s

No one else wants to share his secret technique?

Well if i need to solder a bridge. Most of the time i will cut the joint with a very thin disk. Then i will cut hash marks in the connections. Next I take a rubber wheel and polish the connections. Now comes the part that will blow your mind. Well maybe not, I use a solid model. Make sure it fits your working dies individually. The solid model has to be very dry but by the time it is in metal it is. Put your bridge on the model and get the flame small but very hot. Should sound like your whistling between your teeth. Hit the connection and it only. Don't or try not to put to much heat on the model. I put the tip close as i can to the connection, just past the blue tip. When it gets hot enough I hit it with the solder. Done, Check the fit on a new solid and the working model, Good to go 98% of the time. For this to work you gotta be quick, Takes me about 10-15 sec once the flame hits the metal. That should give you a idea on how fast and how hot your flame needs to be. I will try to get a video next time. Hopefully not to soon thou. lol