Author Topic: Fixing bandsaw blades  (Read 5673 times)

Bioprof

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Fixing bandsaw blades
« on: November 24, 2009, 08:50:38 PM »
I have several bandsaw blades that need to be braze welded back together.   I found some plans for a jig to hold the ends together while brazing, but have never done anything like this before.  Can I just use regular brass rod to brazse with, or do I need special rod made for brazing?   Would a MAP gas torch be hot enough?   Any suggestions/tips would be appreciated.

Offline John Archer

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Re: Fixing bandsaw blades
« Reply #1 on: November 24, 2009, 08:59:58 PM »
Make/buy a jig...Lee Valley sells a decent one. Silver solder together. MAPP is fine for the job.

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Offline B.Barker

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Re: Fixing bandsaw blades
« Reply #2 on: November 24, 2009, 09:02:36 PM »
I've never tried repairing band saw blades befor but brazing with any kind of brass alloy will take more heat than regular map. If you have oxigen with the map your ok but plain map doesent produse the heat you need.

Offline P.W.Berkuta

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Re: Fixing bandsaw blades
« Reply #3 on: November 24, 2009, 09:28:18 PM »
 Hello Bioprof, I made my own jig out of a scrap 12" long aluminum angle bar. I cut out a 1/2" X 3/4" section in the middle (window if you will). You then scarf the two ends of the band saw blade, flux both ends, overlap the joint, hold in place with "C-clamps", apply heat (DON't over heat or you will burn the flux), apply the braze or silver braze (I prefer this since I got 2 pound of rods)- let it flow out - get the heat off the joint - let cool - grind / sand / file off excess and you should be good to go. MAPP gas will be enough to do the job - your band saw blade most likely is .035 (max) thick X 1/2" wide. The window in the aluminum angle will prevent the jig from heat sinking the joint.
I have several bandsaw blades that need to be braze welded back together.   I found some plans for a jig to hold the ends together while brazing, but have never done anything like this before.  Can I just use regular brass rod to braze with, or do I need special rod made for brazing?   Would a MAP gas torch be hot enough?   Any suggestions/tips would be appreciated.
"The person who says it cannot be done should not interrupt the person who is doing it." - Chinese proverb

oldiemkr

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Re: Fixing bandsaw blades
« Reply #4 on: November 24, 2009, 09:38:02 PM »
I used to use silver solder. Not the low temp kind though , I'm not sure how that would work.

I don't know where you live but if there may be a small machine shop or hobbiest around where you live you might try them. Most vertical bandsaws come with a welder on them for welding blades.

Some are a little tricky to set up and use but a good weld should be possible. This made me think of a guy who used to work for me. 40 years experience and he could not weld a sawblade. He would get so d#### mad when he had to weld one. It really irked him for me to come over and weld it on the first try!!

Offline Acer Saccharum

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Re: Fixing bandsaw blades
« Reply #5 on: November 24, 2009, 09:56:48 PM »
I made a jig, which holds the two blades straight. Grind a Bevel on the joint, as that increases the strength tremendously.

I use low temp silver braze, which melts around 900F. Seems fine. Never had a seam pop unless it wasn't well done to begin with.

Mapp is fine. I use regular propane. Plenty enough heat with propane.

The key is the fixture, which was mentioned above.

I buy my blades now that I ran out of the 100' roll, I found they are almost as cheap as roll stock.

Tom
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Offline Randall Steffy

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Re: Fixing bandsaw blades
« Reply #6 on: November 25, 2009, 06:37:10 AM »
My experience is exactly as Acer related. The bevel I achieve is perhaps 0.100" in width and when clamped properly in the fixture, I insert a piece of ribbon silver solder, cut to the size of the bevel joint. The flux is essential and propane will produce plenty of heat. I rarely need to do much clean-up or grinding, depending on how carefully you aligned the blade ends and bevel joint. And I also find blades welded by the blade shop too inexpensive to justify brazing for myself. It is a good experience though. Good luck.

Bioprof

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Re: Fixing bandsaw blades
« Reply #7 on: November 26, 2009, 06:58:35 PM »
I used to use silver solder. Not the low temp kind though , I'm not sure how that would work.

I don't know where you live but if there may be a small machine shop or hobbiest around where you live you might try them. Most vertical bandsaws come with a welder on them for welding blades.

Some are a little tricky to set up and use but a good weld should be possible. This made me think of a guy who used to work for me. 40 years experience and he could not weld a sawblade. He would get so d#### mad when he had to weld one. It really irked him for me to come over and weld it on the first try!!

I tried a local machine shop and a steel fabrication shop first, but neither of them were interested in helping me out.   I'd like to give it a try first myself just for the experience, but may ask a friend that has a factory that makes wood fixtures.   I'm sure they have a large bandsaw that occasionally needs blades fixed.

Offline Kermit

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Re: Fixing bandsaw blades
« Reply #8 on: November 27, 2009, 01:23:26 AM »
Try a saw shop if there's one handy. I used to have my shop across from a saw guy, so he fixed 'em for me. Look in the phone book. If you're rural at all, that may be out of the question. Worth a shot.
"Anything worth doing is worth doing slowly." Mae West

Bioprof

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Re: Fixing bandsaw blades
« Reply #9 on: November 28, 2009, 03:45:46 AM »
I made a jig, which holds the two blades straight. Grind a Bevel on the joint, as that increases the strength tremendously.

I use low temp silver braze, which melts around 900F. Seems fine. Never had a seam pop unless it wasn't well done to begin with.

Mapp is fine. I use regular propane. Plenty enough heat with propane.

The key is the fixture, which was mentioned above.

I buy my blades now that I ran out of the 100' roll, I found they are almost as cheap as roll stock.

Tom

Tom, where would one find the silver brazing solder?   I've looked in several stores and all I can find is bronze brazing wire or low temp (425 degree) solder.

California Kid

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Re: Fixing bandsaw blades
« Reply #10 on: November 28, 2009, 04:38:04 AM »
Welding supply will carry all types of silver solder and braze.

Bioprof

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Re: Fixing bandsaw blades
« Reply #11 on: November 28, 2009, 05:19:50 AM »
I'll try the A-Ox Welding shop Monday.  It sounds like they should have what I need.