Thread: Welding Band Saw blades

Heat is important to little and solder wont flow or stick to much and blade melts solder runs off.
What % of silver in the solder is it Pat?? 60% is best.
the clamp could be absorbing some heat Pat the colder the day the colder the steel.

Learn stuff

Hi Pat,
I do my own Blades, but I use 3/8" x 6TPI. I find the 4TPI. to dangerous for me to use as I only cut small stuff, mainly round.
I bought 100 ft. for $81.50, from McDivens Saws in Williamstown, Vic.
Therefore my Blades cost me approx. $7.55 ea. I get 12 Blades from the roll.

I take it when you say Solder, you mean Silver Solder ?.

I was lucky enough to buy some 16 sticks 12" long of Low Heat Silver Solder for $1, at the Castlemaine Swap a few years ago now, & it works a treat.
I hardly ever Break a Blade, they just wear out.

I was also in the right place to buy at Auction a " Yanes w/- Advanced Piezo Blow Torch ". Cost $5.50. Brand New.
I chased another 1 recently, went to $17, & I passed.
It is made in Brasil. It has COD.4450 on it, & I take that to be a Code No.
The Cartridge cost is $3.50, & lasts forever. Has amazing heat, & does those Blades easily.

If you wish I can PM you on how I do it, & if I can do it, anybody can, as I'm almost self taught. I was shown a little on the mistakes I made, but that was all.
Regards,
issatree.



<input id="gwProxy" type="hidden"><!--Session data--><input onclick="jsCall();" id="jsProxy" type="hidden"><input id="gwProxy" type="hidden"><!--Session data--><input onclick="jsCall();" id="jsProxy" type="hidden"><input id="gwProxy" type="hidden"><!--Session data--><input onclick="jsCall();" id="jsProxy" type="hidden"><input id="gwProxy" type="hidden"><!--Session data--><input onclick="jsCall();" id="jsProxy" type="hidden"><input id="gwProxy" type="hidden"><!--Session data--><input onclick="jsCall();" id="jsProxy" type="hidden"><input id="gwProxy" type="hidden"><!--Session data--><input onclick="jsCall();" id="jsProxy" type="hidden">

Hi Issatree,

Me and I'm sure others to would like to know how you braze your blades.
Why don't you show and explain it here?

Thanks in advance,

John

What He Said.
Cheers Tony.

You need more heat and you did you mention flux? I may have read it too fast. I use a MAPP gas torch for silver soldering. The solder will flow where it's hottest and you have to get it fairly even to get it to flow to all the areas of the joint. This takes a fairly broad flame and/or more volume. I've done really small things with propane but for anything with any size or thickness it takes my MAPP gas torch.
If the metal is dirty it won't solder or won't solder evenly. Clean it first. Usually just the grinding or sanding will work but if I let it sit too long I clean it with Naptha.
I'm not an expert on this. Only done it a few times but it's a pretty simple process. I have done a fair amount of silver solder while trying to learn jewelry making so I'm starting to get a handle on that end.
I don't have photos of the process but there are jigs sold on the market to help you keep the blade parts aligned. Grind down the blades so they overlap in a Scarf joint kind of way. Apply flux to the joint and if you have ribbon solder put that in there. Then just heat it up until the solder flows to all parts of the joint.

One of the secrets to silver soldering is also neat joints. Silver solder has a great capillary action and is strongest with fine capillary type joints. So pay strict attention to making the scarf as neat as you can.

The higher the silver content the more forgiving it will be and less temp is required. But the down side is more silver, less strength and higher cost.

Its a balance between getting a strong joint and ease of use. Check with your local welding supplier as to what is recommended for joining band saw blades and go with that.

As John has mentioned keep it clean, as clean as possible. When cleaned do not even rub your finger across the joint area as this will effect the way the solder runs and sticks.

Heat, take your time, don't be in a hurry as it may not get up to the right temp and that will only add to the problems.

Flux is usually wet, do not allow it to dry out as its not resurrect-able and use sparingly. Just coat both sides of the joint with a thin covering,putting heaps on only makes the excess bubble out its hard to see whats going on.

How strong is silver solder? Well I have seen it tested to 2500lb per sq inch and pass with flying colours.

Once you have mastered it, it will be come second nature.

Hi to all,
I had sent Pat a PM, but have now been asked to put the reply for all to read. This is most likely not the correct way of Brazing Blades, but is the way I do it, & it works for me.

I put about a 1mm. bevel on both ends of the Blade, & using my White Wheel. I then run the Blade Bevels lightly, over my Wire Wheel.

I put my jig to 1 side in my vice & keep it away from conbustable materials.
My friend made up my jig out of 25 x 25mm.angle iron with a hole cut out in the centre.
This jig has 4 small hex. bolts with 10mm washers, to put the Blade under.
He also milled out a section for the Blade to sit in under the washers, & to keep the back of the Blade straight.
I then secure the Blade with 1 Bevel over the other.

I take the Silver Solder, & belt it with a hammer so it is flat, & cut a small piece off about 1 1/2mm. & holding it with Needle Nose Pliers as it will fly. With another pair I lift 1 side of the Blade, & put the S/S between the Bevels. You also need some White Out Correction Stuff.
About 1/2mm.from the join, put 1 stroke of this on either side of the join.
Believe it or not, this stops the S/S from running away.

Apply some flux & not to much, put the flame to the Blade, & bingo it is done. It needs to be Red Hot so the S/S will run. Just before you remove the flame, squeeze the join with a pair of pliers. give it time to cool.

2 things, my S/S is Low Heat S/S, & my Blow Torch is Brasilian made with a Cartridge & a Peizio Starter.

After the Blade has cooled off, I use a 10in. - 250mm. round wood in the vice, to put the Blade over & file the excess off on either side, but be careful that you don't file to much, & file the back straight. I think 1 of the tricks is not to use to much S/S.

This works for me, & most of my Brazed Blades wear out & do not break. Yes,
sometimes they go bump, bump, but not as often now that I have the hang of it.
Also, I will do 3 - 4 Blades at 1 time, just makes it easier.

I may have stated earlier, that I buy Skip Tooth of 100ft. x 3/8in. x 6 teeth per inch, for $81.50, from McDivens Saws, In Kororiot Creek Road, Williamstown, Vic.

So my Blades cost me approx. $7.55 ea. & I get 12 blades from the roll.
Hoping this all makes sense, & if you need to know more, just ask.

Another small trick I learnt, was to take a bluntish blade, turn it inside out, so the teeth are facing up, when you put it back in the saw, & with a file at about 1 - 2 Deg. & sitting on the table, lightly file the teeth, while it is going. OK, so, yes the set is gone, but it will still cut for quite some time, & doesn't do a bad job.

Regards,
issatree.

Good advice Issatree. A jig is well worth the effort of making for both grinding and soldering.
Richard Raffan re-cycles his blades by touching the up on the grinder. If you have a steady hand its worth a try.

I us a ribbon type silver solder 1/4" wide x 1/32" thick. The flux is a paste type.
Procedure I use: Made my own jig but that is irelevant. Bevel the blade ends, install in jig, apply flux on beveled faces, cut a SMALL piece of solder and place it in the joint, heat with propane torch until cherry red and the solder flows well. (with a propane torch this will take 4 - 5 secs. max. IMMEDIATELY remove the heat and DO NOT try to "improve it" Re-heating the solder will ruin it.
Remove excess solder and make smooth on a drum sander or something like that.
Works well for me.
If you have not already done so, check on gas flame shapes and see where the hot point is for various flames, It is usually near the tip where the flame can often not be seen. This knowledge can effest your soldering quality.
Lotsa luck.

Originally Posted by hughie

Good advice Issatree. A jig is well worth the effort of making for both grinding and soldering.
Richard Raffan re-cycles his blades by touching the up on the grinder. If you have a steady hand its worth a try.

I have heard a story of Richard asking at a club demo for a sharpening stone when he found the BS blade to be dull when he got it turned the BS on and used the stone to touch up the blade. No he wasn't taking the back edge away

Just a comment from someone who has spent the last 25 years in the welding game..... make sure the silver brazing alloy (correct name) is a MIN of 45%
most commercial saw makers and repairers use a silver brazing alloy of 50% with 3% nickle to give the joint or tooth that extra toughness this should be avaiable from any decent welding house for you Victorians ther is a company in Thomas town Melbourne callled SBA Australia they make the stuff and will be able to tell you who stocks their product (no conection just one of my old suppliers)
Regards
Bowl-Basher

I could be wrong but I thought most commercial bandsaw blades were resistance welded with a machine similar to this?

Band Saw Blade Welder - Grob Inc.

Nice Fred, but a little out side of the cheap price range at US$1800+