Home Built Bandsaw Blade Welder? Any around?

often on sale for $139. What do you consider awfully expensive?

Joel. phx

Thanks for the tip, Joel. Guess I will have to pay more attention to the HF flyers! I just bought one of their carbide grinders for $119 and that is a winner. Of course you still have to buy decent grinding wheels for it, but the basic machine is good.

John L

Not me {drool} I'm trying to cut back...hhhharrrrbooorrrrFffrrreeiiiggghhhttttttt. Bad enough they send me a flier every week, now they've opened a store a couple minutes away.

Found another machine that's been mentioned on the group:

deja search on 'bandsaw blade welder group:rec.crafts.metalworking' turns up quite the few hits,...

Joel. phx

I've got several magazines with plans in them. There does seem to be a current shortage of the 200 amp, 5 volt, war-surplus, magnetron filament transformers that they call for, though. Price out one of those before you decide if the commercial product is too expensive. Silver brazing is always an option and much cheaper, you can make a jig out of a chunk of angle iron and a couple of bulldog clips.

Stan

Loads of ex computer (min / mainframe) switcher power supplies will give you

5v DC at 200 amps and are relatively cheap

Andrew Mawson

A good source for custom transformers is to use the winding and core from a variable transformer such as a "Variac". You can often find on ebay a used variac with cosmetic defects, missing a knob, or some such for a good price. All you need for a transformer is an intact winding and a VA rating that meets or exceeds your needs.

Remove the core from the frame of the unit. Tape up(2 layers) the exposed winding conductors so that you end up with a big iron donut with two wires protruding from under the tape. Obtain some flexible insulated wire rated for the secondary current you need and wrap several turns (in the same manner as the original winding)around core. The new winding does not have to be distributed evenly around the core, just wind it on in a single layer. Apply 120VAC to the primary (original winding) winding and measure the voltage on the secondary. It will be some small value that can be increased by adding more secondary turns or decreased by removing turns. Once you reach the proper voltage, tape up the secondary winding to hold everything in place. It will be up to you to fabricate some mounts for the assembly to secure it with out damaging the tape. The secondary current available is the rated primary current times the voltage ratio.

Example: Assume the original unit was rated for 120V, 10A. If the desired secondary voltage is 5V, then rated sec. current is 10( 120/5) = 240A. The unit rating is 10A x 120V = 1200VA.(also 5V x 240A = 1200VA)

You may have to add a turn or two to allow for winding resistance to maintain the desired value of secondary voltage under full load.

Randy