|
I have been attempting to repair broken blades using silver solder and a torch. Results have been somewhat uneven. Some blades held up pretty well while others broke again at the joint. I did some net research on blade welders but found they are outside my price range. I did find some used ones on eBay but still rather pricey. While searching I came upon the website below which describes a homemade blade welder. It looks to be a rather challenging project but doable. Has anyone built one of these and if so, what was the result? The author wound his own transformer for the power supply. I doubt a transformer like this is available and winding your own is probably the only alternative. I've rewound transformers in the past but nothing of this type. I find this intriguing but before I forge ahead I thought I'd solicit opinions from the group. I await your response!
http://www.packratworkshop.com/pdf/BandsawBladeWelder2.pdf
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ac9459427, where are you located? Someone in the neighborhood might have a welder.
Ralph
?
I have been attempting to repair broken blades using silver solder and a torch. Results have been somewhat uneven. Some blades held up pretty well while others broke again at the joint. I did some net research on blade welders but found they are outside my price range. I did find some used ones on eBay but still rather pricey. While searching I came upon the website below which describes a homemade blade welder. It looks to be a rather challenging project but doable. Has anyone built one of these and if so, what was the result? The author wound his own transformer for the power supply. I doubt a transformer like this is available and winding your own is probably the only alternative. I've rewound transformers in the past but nothing of this type. I find this intriguing but before I forge ahead I thought I'd solicit opinions from the group. I await your response!
|
An old microwave will provide a transformer that is easy to rewind. The primary an secondary are separated. The core is rated to at least 600W You remove the fine wired secondary winding, cut through the wire, punch the remainder out from the laminations and add a new secondary winding using welding cable.
Make sure you discharge the high voltage capacitor with an insulated screwdriver, as it can still hold several kilovolts.
The transformers also make good spot welders.
Malcolm
I don't suffer from insanity I enjoy it!
Mene, mene, tekel, upharsin
The writing is on the wall.
Ha-ktovet al ha-kir
--------------------------------------------
toggle quoted message
Show quoted text
On Tue, 5/7/19, ac9459427@... [4x6bandsaw] <4x6bandsaw@...> wrote:
Subject: [4x6bandsaw] Homemade Bandsaw Blade Welder
To: 4x6bandsaw@...
Date: Tuesday, May 7, 2019, 2:55 PM
?
I have been attempting to
repair broken blades using silver solder and a torch.
Results have been somewhat uneven. Some blades held up
pretty well while others broke again at the joint. I did
some net research on blade welders but found they are
outside my price range. I did find some used ones on eBay
but still rather pricey. While searching I came upon the
website below which describes a homemade blade welder. It
looks to be a rather challenging project but doable. Has
anyone built one of these and if so, what was the result?
The author wound his own transformer for the power supply. I
doubt a transformer like this is available and winding your
own is probably the only alternative. I've rewound
transformers in the past but nothing of this type. I find
this intriguing but before I forge ahead I thought I'd
solicit opinions from the group. I await your
response!
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They also can be used to make awesome electro magnets for mag-chucks. YouTube has many how to vids showing the various uses of old microwaves. Beware the magnetron!
Best regards and God bless,
Darren McCarley
817-793-8241
On May 7, 2019, at 3:26 PM, "Malcolm Parker-Lisberg mparkerlisberg@... [4x6bandsaw]" < 4x6bandsaw@...> wrote:
?
An old microwave will provide a transformer that is easy to rewind.. The primary an secondary are separated. The core is rated to at least 600W You remove the fine wired secondary winding, cut through the wire, punch the remainder out from the laminations and add a new secondary winding using welding cable.
Make sure you discharge the high voltage capacitor with an insulated screwdriver, as it can still hold several kilovolts.
The transformers also make good spot welders.
Malcolm
I don't suffer from insanity I enjoy it!
Mene, mene, tekel, upharsin
The writing is on the wall.
Ha-ktovet al ha-kir
--------------------------------------------
On Tue, 5/7/19, ac9459427@... [4x6bandsaw] <4x6bandsaw@...> wrote:
Subject: [4x6bandsaw] Homemade Bandsaw Blade Welder
To: 4x6bandsaw@...
Date: Tuesday, May 7, 2019, 2:55 PM
?
I have been attempting to
repair broken blades using silver solder and a torch.
Results have been somewhat uneven. Some blades held up
pretty well while others broke again at the joint. I did
some net research on blade welders but found they are
outside my price range. I did find some used ones on eBay
but still rather pricey. While searching I came upon the
website below which describes a homemade blade welder. It
looks to be a rather challenging project but doable. Has
anyone built one of these and if so, what was the result?
The author wound his own transformer for the power supply. I
doubt a transformer like this is available and winding your
own is probably the only alternative. I've rewound
transformers in the past but nothing of this type. I find
this intriguing but before I forge ahead I thought I'd
solicit opinions from the group. I await your
response!
http://www.packratworkshop.com/pdf/BandsawBladeWelder2.pdf
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I have found that a tapered (scarf) joint of about 3/16" long and silver solder is stronger than the original weld.? I take either a ribbon of 55% silver solder or a round piece hammered flat and I place it between the two pieces of blade (held under a little tension) in a home made fixture along with SS flux between the clean blade surfaces.? Then I heat it up with a propane torch until I just see it melt.? Then I remove the heat.? I get much better results than if I try to add silver solder to the joint.? When I added silver solder to the joint, the flux sometimes burned and interfered with the SS.? After, I anneal the blade with a propane torch.??
|
Bruce why anneal after? Where does any hardness come from unless you are quenching the joint after welding?
I like your method, that is how I will do it when I get around to doing it.
You can do the same with brazing rod.
Ralph
?
I have found that a tapered (scarf) joint of about 3/16" long and silver solder is stronger than the original weld.? I take either a ribbon of 55% silver solder or a round piece hammered flat and I place it between the two pieces of blade (held under a little tension) in a home made fixture along with SS flux between the clean blade surfaces.? Then I heat it up with a propane torch until I just see it melt.? Then I remove the heat.? I get much better results than if I try to add silver solder to the joint.? When I added silver solder to the joint, the flux sometimes burned and interfered with the SS.? After, I anneal the blade with a propane torch.??
|
Ralph,
The challenge with both welding and brazing blades is that the blade cools down very quickly, becoming brittle. After some frustration with brazing, due mostly to mistakes already pointed out by others (e.g. using a brazing rod instead of a ribbon, not controlling properly the thickness of the braze, etc.), I cave-in once I found a blade welder for a decent price.
With that one I indeed learned that my main mistake was that I didn't anneal the blades properly. After learning how to anneal them properly, my blades work much better.
Paolo
toggle quoted message
Show quoted text
On 5/8/2019 08:44, Ralph Hulslander rhulslander@... [4x6bandsaw] wrote: Bruce why anneal after? Where does any hardness come from unless you are quenching the joint after welding?
I like your method, that is how I will do it when I get around to doing it.
You can do the same with brazing rod.
Ralph
|
Thanks, luckily I have a friend with a welder and he has been machinest for fifty so knows what he is doing.
Ralph ?
?
Ralph,
The challenge with both welding and brazing blades is that the blade
cools down very quickly, becoming brittle. After some frustration with
brazing, due mostly to mistakes already pointed out by others (e.g.
using a brazing rod instead of a ribbon, not controlling properly the
thickness of the braze, etc.), I cave-in once I found a blade welder for
a decent price.
With that one I indeed learned that my main mistake was that I didn't
anneal the blades properly. After learning how to anneal them properly,
my blades work much better.
Paolo
On 5/8/2019 08:44, Ralph Hulslander rhulslander@... [4x6bandsaw]
wrote:
> Bruce why anneal after? Where does any hardness come from unless you
> are quenching the joint after welding?
>
> I like your method, that is how I will do it when I get around to
> doing it.
>
> You can do the same with brazing rod.
>
> Ralph
|
I think the plans are from a Popular Mechanics book my father had 60 yrs ago, so it's pretty old technology. Recently I got given a relatively new stand alone band saw blade welder that had some faults and got it fixed by electricians at a welder-service shop, but, alas, haven't had much luck in getting good welds, mostly from my inability to control the annealing.? I am assured the welder is as its maker intended. It's not the first instance of blade butt welders being difficult to get good results from, that?I've heard of. My point is that you're maybe going to build an old design welder that will be difficult to get all the right pieces for, and then probably just as difficult to get working properly.?? I think you'd be better off spending a bit more time jigging the blade for brazing, and then using the right braze (I'd be using 630*C melting point silver solder). There are some neat grinding jigs on YouTube to get the scarf right - jv
|
My suggestion for mastering the annealing is to try it in dim
light and get a feel of how long and how frequently you need to
push the button to get the blade to start to turn dark red: when
you get the weld at that temperature, you start decreasing the
time/frequency of your pushing the anneal button for at least
twice the time you feel is necessary.
Start with a chunk of an old blade (even if it is not circular,
it does not matter, unless in real life you're trying to weld
20-30" long blades - i.e. even shorter than what is used by a
portaband): anneal a portion and try to bend it. If it doesn't
break, bingo! Try to remember what you did and repeat it.
Paolo
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I think the plans are from a Popular Mechanics book my father
had 60 yrs ago, so it's pretty old technology.
Recently I got given a relatively new stand alone band saw
blade welder that had some faults and got it fixed by
electricians at a welder-service shop, but, alas, haven't had
much luck in getting good welds, mostly from my inability to
control the annealing.? I am assured the welder is as its maker
intended. It's not the first instance of blade butt welders
being difficult to get good results from, that?I've heard of.
My point is that you're maybe going to build an old design
welder that will be difficult to get all the right pieces for,
and then probably just as difficult to get working properly.??
I think you'd be better off spending a bit more time jigging
the blade for brazing, and then using the right braze (I'd be
using 630*C melting point silver solder). There are some neat
grinding jigs on YouTube to get the scarf right - jv
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How about repurposing a microwave transformer instead of making your own.? There is a ton of information on the wed about cutting the secondary windings off a salvaged microwave transformer for home brew EDM machines, spot welders, arc welders, etc.? Seems like a no brainer to do the same for a blade welder.? Some designers are even using several transformers together for increased power.
A simple google search turned up hundreds of pages about repurposing and rewinding the secondary of microwave transformers.
James
?
I have been attempting to repair broken blades using silver solder and a torch. Results have been somewhat uneven. Some blades held up pretty well while others broke again at the joint. I did some net research on blade welders but found they are outside my price range. I did find some used ones on eBay but still rather pricey. While searching I came upon the website below which describes a homemade blade welder. It looks to be a rather challenging project but doable. Has anyone built one of these and if so, what was the result? The author wound his own transformer for the power supply. I doubt a transformer like this is available and winding your own is probably the only alternative. I've rewound transformers in the past but nothing of this type. I find this intriguing but before I forge ahead I thought I'd solicit opinions from the group. I await your response!
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Thanks Paolo.? The thing didn't come with any instructions so that's a good start - jv
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I am on the lookout for a discarded microwave oven and have viewed YouTube videos on rewinding them. I didn't learn anything I didn't already know but it was encouraging to see the current level of activity. I have also viewed videos on silver soldering blades and have tried just about every technique described. I have made fixtures for grinding the scarf joint, holding the blade ends for soldering and using both wire solder and strip solder of several different brands. The best results were with low melting point, (430 deg F) solder which would not affect the hardness of the blade. I even rigged a test fixture for measuring the strength of the joint of test pieces. All withstood a tension of 400 lbs and some up to 675 lb.,( the maximum I could measure). I spent a lot of time on this and I've pretty much given up on it. If I can find a microwave oven transformer that will be my next move. I'll post results.?
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Craigslist, Facebook, nextdoor, etc. Post up a request looking to up cycle old microwaves. I had 10 in less than a week. If you're I. The DFW are, I'll happily give you one.
Best regards and God bless,
Darren McCarley
817-793-8241
On May 16, 2019, at 9:13 AM, "ac9459427@... [4x6bandsaw]" < 4x6bandsaw@...> wrote:
?
I am on the lookout for a discarded microwave oven and have viewed YouTube videos on rewinding them. I didn't learn anything I didn't already know but it was encouraging to see the current level of activity. I have also viewed videos on silver soldering blades and have tried just about every technique described. I have made fixtures for grinding the scarf joint, holding the blade ends for soldering and using both wire solder and strip solder of several different brands. The best results were with low melting point, (430 deg F) solder which would not affect the hardness of the blade. I even rigged a test fixture for measuring the strength of the joint of test pieces. All withstood a tension of 400 lbs and some up to 675 lb.,( the maximum I could measure). I spent a lot of time on this and I've pretty much given up on it. If I can find a microwave oven transformer that will be my next move. I'll post results.?
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Hello, and sorry for revamping this way old thread.
I'm in search of some welder plans but it seems the one at ?is not more reachable.
Is there any chance that someone has saved the pdf and would like to share ?
I'm not at all good in electronic, so the one from harold strand ( the one is easy tofind in internet ) is not good for me ( is for 115V and I'm in a 220V country ).
Thanks
Pierluigi
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Most I have seen the internet used a transformer from microwave.??
They remove the high voltage windings then replace with just over one turn of very heavy copper sold wire .?
Will gives very high amperage at low voltage.??
Dave?
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I have use high strength silver solder it work every time better than blade welder I had.?
Dave?
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I've never had good results with silver solder, I can never get it to wet the joint thoroughly. I'd be interested in learning what flux people are using to get good results.
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On 12/19/2023 5:57 PM, davesmith1800 wrote: I have use high strength silver solder it work every time better than blade welder I had.
Dave
--
---------------------------------------------------------------------
Jim Frame jhframe@... 530.756.8584
Frame Surveying & Mapping 609 A Street Davis, CA 95616
-----------------------< Davis Community Network >-------------------
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Cleanliness next to Godliness. Especially if you're using silver solder! You want the cleanest joint you can get. Very high proof alcohol, or acetone to degrease the ends, then scrub with a clean SS wire brush, and clean again! Then use a good flux. Borax (from the Boraxo company) is what my dad taught me to use. I've also done some jewelry work, and they use some fluxes with a bit of fluoride in the flux. It's more expensive... but it works well on precious metals, which are sometimes difficult. Borax is cheaper. You can also use Boric Acid. If you can use an oxy-acetylene torch with a fairly large tip. You need it heated to at least red heat as fast as possible. Dip the hot end in your flux. Repeat for the other end. Then align them, butt them together, and and heat both ends red hot again, while pressing them together and adding more flux! While they're still red hot add your solder after warming it and dipping it in the flux, too. Press them together some more, while heating. Then leave the joint alone until it's stone cold!?
You can dissolve borax in distilled water or alcohol, and IIRC, you can dissolve boric acid in alcohol, too. Been a really long time since I last used it. Though I've got about 3 pounds of boric acid sitting here. Borax is quite a bit cheaper, and works just as well in my experience. You can usually find a 4 or 5 pound box in the laundry detergent aisle of almost any grocery store for around $5 or $6...
Works for brazing a lot of other stuff, too.?
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY!
Expect in one hand, expectorate in the other. See which one gets full first.
On Tuesday, December 19, 2023 at 08:04:34 PM CST, Jim Frame via groups.io <jhframe@...> wrote:
I've never had good results with silver solder, I can never get it to
wet the joint thoroughly.? I'd be interested in learning what flux
people are using to get good results.
On 12/19/2023 5:57 PM, davesmith1800 wrote: > I have use high strength silver solder it work every time better than > blade welder I had. > > Dave > -- --------------------------------------------------------------------- Jim Frame? ? ? ? ? ? ? ? jhframe@...? ? ? ? ? ? ? ? 530.756.8584 Frame Surveying & Mapping? ? ? ? 609 A Street? ? ? ? Davis, CA 95616 -----------------------< Davis Community Network >-------------------
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You have put a angle to solder joint. Like gluing leather belts.?
Then take a high strength silver solder.?
Butt type soldering does not work.
Dave?
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James Rice
davesmith1800
Jim Frame
Bill in OKC too