Broken bandsaw blade repair? - Printable Version

Broken bandsaw blade repair? - Printable Version

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RE: Broken bandsaw blade repair? - mike4244 - 01-22-2020

(12-22-2019, 08:33 AM)Pirate Wrote: Has anyone repaired their own broken bandsaw blade?
I found a nice 3/4 inch blade but it's too long for my 14 inch Delta bandsaw.
I've always wanted to try a 3/4 inch blade.
Without a bandsaw blade welder what's the best way to weld, braze or solder it?
I saw a video of somebody soldering a blade but don't think that would hold up very long. Maybe silver solder?
Any actual experience out there?

I also hard solder ( silver solder) bandsaw blades. You can buy silver solder in tape form and cut a piece to fit. You need flux , where you buy the solder they will have the correct flux. I use a white borax, some people use a black flux. You Tube videos will show you how to make a fixture for
holding the ends in place. Propane is plenty hot , maybe even the small butane torch might get hot enough. The ends have to be scarfed, I use to scarf but now half lap. I recommend scarf because a half lap requires a milling machine.
I buy hard solder from SRA . I do not think they sell small amounts, try Rocklers or another web site that caters more to wood workers.
If you think that this blade is the only blade you will have to solder than see if their is someone that can do this for you for a fee.
I say this because the cost of the tape and flux may be more than it is worth.
I believe that saw sharpening services may do this work.

mike

RE: Broken bandsaw blade repair? - Timberwolf - 01-23-2020

(01-22-2020, 04:15 PM)mike4244 Wrote: I also hard solder ( silver solder) bandsaw blades. You can buy silver solder in tape form and cut a piece to fit. You need flux , where you buy the solder they will have the correct flux. I use a white borax, some people use a black flux. You Tube videos will show you how to make a fixture for
holding the ends in place. Propane is plenty hot , maybe even the small butane torch might get hot enough. The ends have to be scarfed, I use to scarf but now half lap. I recommend scarf because a half lap requires a milling machine.
I buy hard solder from SRA . I do not think they sell small amounts, try Rocklers or another web site that caters more to wood workers.
If you think that this blade is the only blade you will have to solder than see if their is someone that can do this for you for a fee.
I say this because the cost of the tape and flux may be more than it is worth.
I believe that saw sharpening services may do this work.

mike

..................................
You can also buy paste flux that is charged with silver solder...or you can buy ordinary boric acid flux paste and add silver solder filings yourself.

RE: Broken bandsaw blade repair? - daddo - 01-23-2020

I made this thing to join two smaller pieces of metal, rod or wire or whatever I need to solder, braze or weld. I fit it to do blades but I haven't used it but once so far to solder wires together.

I tried fixing a blade last year, but I used 15%- didn't hold after a few cuts. I do have 50% I'll try next time. Doesn't look pretty but the edge of the stop is milled true within .0005".

[Image: BLZjVSb.jpg]

I use a lot of 1/4" blades- those can be more difficult I bet.

[Image: scLG8uc.jpg]

RE: Broken bandsaw blade repair? - mike4244 - 01-23-2020

(01-23-2020, 08:18 PM)daddo Wrote: I made this thing to join two smaller pieces of metal, rod or wire or whatever I need to solder, braze or weld. I fit it to do blades but I haven't used it but once so far to solder wires together.

I tried fixing a blade last year, but I used 15%- didn't hold after a few cuts. I do have 50% I'll try next time. Doesn't look pretty but the edge of the stop is milled true within .0005".

I use a lot of 1/4" blades- those can be more difficult I bet.

Not sure if your solder is actually a hard solder or 50% lead and 50 tin which is soft solder. Silver or hard solders need red heat to flow. If your solder flows at lower temperatures as for copper pipe , than it is not hard solder. Soft solder for plumbing is not the same as hard solder. It is lead free and may have a small amount of silver in it.
If what you have is hard solder , it with proper flux will join the ends of the blade and as strong as the rest of the blade.
Try heating a piece of thin metal or a blade and if the solder flows almost instantly it is not hard solder. If the solder flows only when the blade gets cherry red it probably is hard solder. Your jig looks fine for blades. You can keep the solder from sticking to unwanted areas of the blade by brushing "white out" on each side away from the area to be soldered. White out dries quickly, make sure it's dry before applying heat.
I use tape and white borax flux, apply propane heat under the seam. When the solder flows remove the heat and let cool.
Probably take less than 30 seconds for the solder to flow. Remove excess solder by filing, sanding etc til the joint is flush.

mike

RE: Broken bandsaw blade repair? - daddo - 01-23-2020

I guess I should have been more specific. I use 15% silver brazing sticks (Harris) at work for all refrigeration except for higher stress areas that require the 50% silver.
(Brazing is done at temps above 840 degrees. Soldering is below that temp. )

The 15% liquids at around 1.480 degrees, the 50% about 1,400- both similar but the compounds of 50% allow for a more flexible bonding and fills nice gaps. (Less cracking or failing).

I do use the white flux (Also Harris) for ferrous and non ferrous metals for removing the oxides during brazing (no good for; aluminum, titanium and magnesium). It works between 1,000 and 1,600 degrees F.

I prefer to use the oxy/acet torch with a small tip and a clean carburizing flame since it heats much faster than the propane torch- a better "in and out" instead of heating everything around the area, though you have to be careful. I work the heat to draw the braze into the connection then back off a few degrees to create a small build so there's no recesses.

*I have an old roll of soft solder in the shop somewhere that is so old I'm sure it has lead in it. I just keep it for looking at. Have little use for the stuff.

I use that gel stuff I use when welding that keeps the mig tip clear. Not sure of the name, but it seems hold up well and keeps stuff from sticking where you don't want it to.

What I am not sure of, is what affect on the temper of the blade the heating has- How to regain the temper and the best way to anneal it to keep it from cracking. It's so thin, it is hard to control the temps or see the colors. I was thinking perhaps I had allowed it to cool too quickly without annealing the blade and that led to it cracking. ?

RE: Broken bandsaw blade repair? - Cooler - 01-24-2020

(12-22-2019, 08:33 AM)Pirate Wrote: Has anyone repaired their own broken bandsaw blade?
I found a nice 3/4 inch blade but it's too long for my 14 inch Delta bandsaw.
I've always wanted to try a 3/4 inch blade.
Without a bandsaw blade welder what's the best way to weld, braze or solder it?
I saw a video of somebody soldering a blade but don't think that would hold up very long. Maybe silver solder?
Any actual experience out there?

Our industrial Do-All saw has a welder built into the saw. We buy blades by the 100 foot or 250 foot coil. There is a grinder included for prepping the blade and for cleaning up the welds. I believe it has a tempering cycle (lower heat) to keep it from becoming brittle.

Do-All sells a stand alone welder for about $4,000.00. Grainger has one (with the grinder) for $1,250.00.

https://www.grainger.com/product/DAYTON-Welder-6A489

It is probably logical to simply buy a new blade. If you know a machine shop with a Do-All saw they might weld it for you.

RE: Broken bandsaw blade repair? - Timberwolf - 01-26-2020

(01-23-2020, 09:00 PM)mike4244 Wrote: Not sure if your solder is actually a hard solder or 50% lead and 50 tin which is soft solder. Silver or hard solders need red heat to flow. If your solder flows at lower temperatures as for copper pipe , than it is not hard solder. Soft solder for plumbing is not the same as hard solder. It is lead free and may have a small amount of silver in it.
If what you have is hard solder , it with proper flux will join the ends of the blade and as strong as the rest of the blade.
Try heating a piece of thin metal or a blade and if the solder flows almost instantly it is not hard solder. If the solder flows only when the blade gets cherry red it probably is hard solder. Your jig looks fine for blades. You can keep the solder from sticking to unwanted areas of the blade by brushing "white out" on each side away from the area to be soldered. White out dries quickly, make sure it's dry before applying heat.
I use tape and white borax flux, apply propane heat under the seam. When the solder flows remove the heat and let cool.
Probably take less than 30 seconds for the solder to flow. Remove excess solder by filing, sanding etc til the joint is flush.

mike

.................................
You can keep the solder from sticking to unwanted areas of the blade by brushing "white out" on each side away from the area to be soldered

I just use an ordinary lead pencil for that purpose...coat the area that you dont want the molten solder to go, with the pencil.. molten Solder will not migrate across the line of graphite..

When I make these luthier planes, I use three different hard solders that melt at different temps..starting with the solder that melts at the highest heat, then using the next lower etc...Not doing that can cause some joints to "unsolder" themselves due to the heat migrating.

My heat source is a Smith Little Torch oxy/acet. outfit that I have had for 40yrs.

RE: Broken bandsaw blade repair? - daddo - 01-27-2020

(01-26-2020, 07:06 PM)Timberwolf Wrote: .................................
You can keep the solder from sticking to unwanted areas of the blade by brushing "white out" on each side away from the area to be soldered

I just use an ordinary lead pencil for that purpose...coat the area that you dont want the molten solder to go, with the pencil.. molten Solder will not migrate across the line of graphite..

When I make these luthier planes, I use three different hard solders that melt at different temps..starting with the solder that melts at the highest heat, then using the next lower etc...Not doing that can cause some joints to "unsolder" themselves due to the heat migrating.

My heat source is a Smith Little Torch oxy/acet. outfit that I have had for 40yrs.

Where did you find that giant pen?
Laugh

RE: Broken bandsaw blade repair? - Timberwolf - 01-27-2020

(01-27-2020, 12:36 PM)daddo Wrote: Where did you find that giant pen?

...........................
Amazon is your friend..............
Rolleyes

RE: Broken bandsaw blade repair? - John Mihich - 01-27-2020

I tried SS and just couldn't get it to stay. I watched a video on using a tig welder. I will try that next.