Resistance Welding Bandsaw Blades?

randyjaco

Active User
H-M Supporter Gold Member
Joined
Oct 5, 2010
Messages
1,041
I used to be able to resistance welding bandsaw blades. But I am having problems now. I am now only successful @10 per cent of the time. I am not having problems with annealing or tempering. My welds are burning through.
I have cleaned the clamps, checked for their movement and everything the manual says. The blades are cleaned, they're cut square and I have tried all the compression settings.
Each time I try, it will get red at the back, IMG_20160208_100245.jpg IMG_20160208_100401.jpg then the heat starts moving toward the teeth. By the time that area is hot and compression starts, things start burning.
Any suggestions?

Randy
 
I silver solder all mine no problem, paste flux and sheet silver solder, a simple fixture to hold the blade, grind to opposite angles about 30 degrees, just that simple.
 
Looks like you need to clean and align the clamps. Look a bit dirty, not getting a good connection.

Also, try setting the power down a bit (narrower blade setting if you have it)

EDIT: Another thought is a bad connection internally. Might be worth taking it apart and looking at the wiring.
 
Last edited:
Are you sure that the takeup is working okay? They look like they aren't absorbing the material that is heated.
 
I have checked out the wiring and don't see anything obvious.
There is no means of dialing the heat. This particular welder heats until the movable clamp moves a specific distance and a micro switch cuts the current.
I will give the clamps another look.
The take up appears OK, but I have no idea of the amount of compression required. I did try adding manual compression to the process and didn't see any improvement.

Thanks
Randy
 
This particular welder heats until the movable clamp moves a specific distance and a micro switch cuts the current.

That being the case, maybe try adjusting the micro switch so it cuts off the power a fraction sooner. Not sure if this will help, but the welds look like that are still being heated when the clamps have reached the end of travel. The other possibility that comes to mind is that the movable clamp is not opening far enough to start with or is not moving through it's full travel.

I have seen the same issue with a blade welder that I use sometimes, but I have never torn it apart to see what the problem is.
.
.
 
I used to be able to resistance welding bandsaw blades. But I am having problems now. I am now only successful @10 per cent of the time. I am not having problems with annealing or tempering. My welds are burning through.
I have cleaned the clamps, checked for their movement and everything the manual says. The blades are cleaned, they're cut square and I have tried all the compression settings.
Each time I try, it will get red at the back, View attachment 121758 View attachment 121759 then the heat starts moving toward the teeth. By the time that area is hot and compression starts, things start burning.
Any suggestions?

Randy
Are you releasing one side when they are cherry so cooling does not pull the weld apert?
 
Judging from the photos alone, it looks too hot or over cooked. I would look closely at the MS thats cuts off heat.
 
Back
Top