Band saw blade welder idea

[yf]

Has anyone built a band saw blade welder?

I have a small portable spotwelder that I tried welding blades with. I just clamped the blades to the sides of the electrodes and was only able to get it to weld one time.
When I handeled the blade the weld cracked.
(didn't realize it had to be annealed)

Being that real blade welders are going for more than I can afford on Ebay. I want to build a jig of sorts to connect to the spotwelder for making band blades. I'll have to experiment with annealing time.

Has anyone made something like that?
Any ideas that would make it simpler or better?
I would like to be able to weld blades up to 3/4" wide.
The spotwelder outputs a maximum of about 2200 amps at about 1.5 volts.

Thanks in advance

BTW when I need to forge just one item I can sometimes use the sotwelder to heat it in seconds to red yellow or white heat, depending on the thickness. The largest I tried was a 1/2" nut (3/4" AF) to weld it to a piece of threaded rod. Heat it and hit it on all flats on the anvil. Then arc weld on the end and grind smooth. Takes less time to do it than to describe it.

[Treven Baker]

Sorry I cant help with your questions. From what I have heard the sivlver solder and jig method works well. You can buy those on Ebay for about $30.

[Rich Carlstedt]

A couple of hints:
Your clamp should be spring loaded to maintain a force of the weld.
You should pre-wash the blade in solvent, as oil preservatives will screw up the weld.
To anneal, you could use a propane torch. just get the blade red hot, then slowly draw the torch away till it is black , about 10 to 15 seconds usually. But watch heating the whole blade, only the weld portion should be done. you might want to put a sheet metal deflector in a "V" form to protect the rest of the blade.
hope this helps you

[Ed ke6bnl]

check this site out for some ideas maybe someone can help in making a home made unit of this sort. Ed ke6bnl So. Calif.

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Ed ke6bnl
Agua Dulce, Ca.
70 mi. S.E. of Los Angeles

[Ed ke6bnl]

check this site out for some ideas maybe someone can help in making a home made unit of this sort. Ed ke6bnl So. Calif.

http://www.advancecarmover.thomasreg...ver/welder.htm

sorry left out site.

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Ed ke6bnl
Agua Dulce, Ca.
70 mi. S.E. of Los Angeles

[Thrud]

yf:
You have more than enough jam to melt the blades - as a fuse!

Make a insulated jig that aligns the blade and upsets it at least one or two teeth. Screw clamps of some sort will be needed as a fair amount of force is require to upset the weld and hold the blade stationary. You then reduce the amperage and anneal it, grind it, go for lunch. You will need to experiment a little with amperage for welding, and for consistant results the spotwelder contactor should be wired to a adjustable seconds timer.

Your unit might already have that, if it does not, it is a good idea, because it make for extremely consistant welds. And you should have enough amps to spot light aluminum with a timer.

[yf]

Thanks for the replies.

Thrud,
This is not a conventional spotwelder it is the small handheld unit with a trigger switch. I think its a previous model of whats on this link.
http://www.mscdirect.com/ProductImages/6233812-11.jpg

There is no adjustment, except for how long you hold the trigger and pressure of the tongs.

Seems my memory is failing, (BTW I am not an old fart I just act and sound that way )looks like this things got more amps than I remember.
It does heat a 9/16" dia. tire iron to white heat really fast. They make great chisels and punches BTW.
Is there a way to get pictures here without having them first on the web?
I would make a quick drawing just to see if we're thinking the same.
Some of the instructions for blade welders say to "hold the weld button in for decreasing amounts of time to anneal"
I guess I could do that by triggering it too.
I just don't want to waste time making a special jig that won't work.

At a previous job I came across a "Cold Welder" that was used to fuse copper wire end to end for wire drawing. It was so simple I couldn't believe it would work, so I spliced a bunch of pieces of 12 AWG wire with it and it worked very well. It requires a different die for every size though. It basically just mashes the ends together very precisely and the crystal structure of the metal somehow twines together. The joint is very strong and if dressed looks like one piece. It requires no power except for a hand operated lever. There are two clamp dies that hold each piece, that are forced against each other to make the weld. I guess its a bit similar to friction welding, but without heat.
Someone needs to know that

[This message has been edited by yf (edited 12-12-2002).]

[yf]

Seems the amperage varies with the length of tongs because of conduction losses. Longer tongs less amps.
almost 6000 amps at 1.6 V with 6" long tongs!
You can defibrilate a whole town.
Simultaneously.

If you see one for sale used, consider it, its a very useful piece of equipment.
New ones are a fortune.

[docsteve66]

Made a "tranformer" for welding blades from an old microwave (1500 watt i think) and a loop of braided flat battery lead. Cut the high voltage winding off, pass a single turn of cable around the core of the tranformer to get 1 volt, two turn for 2 volts (the ones I have counted are alway one turn per volt out for 100 volts in. so actually you get 1.2 volts for one turn. The amps are very high- pegged my clamp on ampmeter on highest scale. Keep the leads short and make as few joints as possible. We had an old bandsaw with a defective transformer so I did not make the blade holders.
Annealing with most bandsaws is just press the buton a few times and let it cool. The holder (even on commerceial machines) some times acts as a heat sink and cools the blade too fast for annealing on the first try. Some witchcraft is involved.

I have had good luck silver soldering. you can buy a kit, but the main thing yu get with the kit is some thin slips of silver solder- not worth the price, use some filings of solder, or tiny pieces instaed, flux well. grind the blades at an angle and overlap them. I suggest not only grinding the side of the blade flat but also make a tiny depression on therear where the weld is. a scrap of angle iron, with a hole for the flame works pretty well for a holder. Just be sure the blade ends press aginst each other, I used C clamps to hold, the pressure of the clamps "bows" the blade. differnt pressures on the blade makes one bow more than the other. Still some witch craft but not as much as welding IMHO
Steve

[yf]

I made a jig and tried silver soldering some years back. Didn't work out for me.
I'm not a witch so maybe that has something to do with it
Mybe I should try a better flux. I was having trouble getting the solder to adhere, even when the blade was cleaned thoroughly.