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Need recommendations on brazing basics...

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middle.road

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#1
If this is already covered in another thread please pass that info on. I've searched for an hour and have tossed in the towel.

Over the years I have gotten rid of most everything I had in regards to welding/brazing/ETC. So I'm starting over.
I've never done and proper 'welding' or 'Brazing' in my life. Been around but never enough hands-on.
And then I scored a set of tanks from and HVAC gent's estate sale and now I've got a need to braze some things and have absolutely no idea where to start.
I've installed new hoses, still have to install the safety valves and then hope there's enough gas to do what I want to do.

Glasses/Goggles? Need 'em to fit over prescription glasses. I have no idea what to go with.
Rod/Filler material? right now I want to do steel to steel and the like - nothing fancy. Currently I want to braze a 5/8" rod to 3/16 plate for and idea I have for a hand scraper so that I can repair the lathe and get going again.
(should just get a TIG but there is no way with the current budget...)
I will be trying to braze carbide later if I succeed in learning.

And any and all insights for a complete noob would be appreciated.
As always the budget has taken some serious damage the last couple of months from those d*mned unplanned expenses. Nothing major but things are rather tight.

Thanks,
_Dan
 

Cadillac

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#2
Check those tanks you just got. They made be out of date and need recertifications to get filled.
Brazing you’ll need brazing rod,some flux, and a torch. Flux parts get red hot and let the filler rod flow. Make sure your parts are clean,get hi temp flux.
 

machPete99

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#3
See Keith Fenner on youtube, he does a lot of torch brazing repair work, typically on cast iron castings.

I have done a bit of TIG brazing with silicon bronze filler. Its generally easier than welding, no flux required. Need to keep heat below welding temperatures (until things just start to glow red).
 

4ssss

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#4
Also, you'll need silver solder for carbide.
 

benmychree

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#5
For carbide, a silver solder sandwich with copper in the middle is used, the steel that is used for the shank should have a machined pocket to fit the carbide blank, clean the parts with a solvent such as acetone or a non flammable safety solvent that dries quickly, coat the braze area and blank with silver solder flux and assemble the parts, with the silver sandwich in the middle; heat the assembled parts from the bottom with the torch until red, and when the silver flows, press down on the top of the blank with something pointed until the silver solidifies, then place the tool in a place where it can cool slowly.
 

john.k

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#6
If you are on a tight budget........I suggest the following money savers.....never use actylene,use liquid gas in a BBQ cylinder and refill at the hardware.Flux is expensive,but its just borax...so get some borax at the supermarket.Brazing rod is expensive,and dont use silicon bronze meant for copper pipe(unless its free).....Use plain old 70/30 brass........and for odd jobs,you can use plain brass wire....The secret of brazing is enough heat.....when the heat is sufficient the brass will flow all over ,and not just sit in blobs......For eyes,I just use green plastic safety glasses,the disposable kind.....if you need a correction,you may be able to use a combo sunglasses /indoor glasses.....The white flux is the bad part ,the steel is only at red heat,but the flux glows white in the flame...............Finally,you can braze using any heat supply,such as a forge,that gets the work hot enough.
 

middle.road

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#7
We're overly blessed with acetylene. two tanks. (All chained up and capped properly.)
The first torch kit ensemble that I bought four years ago at RV dealer/repair shop auction, I went and took the O2 tank back to the vendor for re-cert and fill.
And they shafted me on it, 'leased tank' is all they said and took it. Wouldn't give a discount or anything on a new tank, nada nothing.
I was a bit dumbfounded. I asked this dude about the acetylene tank and he got this vacant look and just said bring it by, I laughed and left.

This current set from the HVAC auction is current. I replaced the hoses, and I've got safety fittings ready to install.
I figured I'd just use it for heating up iron until I used up the O2 and then sell off what I can, unless I can get the O2 refilled.

And now I've got the bug to braze...
 

john.k

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#8
I havent used acetylene for 50 years due to the cost,exorbitant in 1970,who knows what now.?.....Its nice to be able to do sheet steel and exhaust pipes with acetylene,but thats all. My gas supplier recently unilaterally increased cylinder rentals by $50 a year ($250+),in mid lease,very cunning ,as most would have part full cylinders and need to keep on.,or not notice the increase..............Iv tried TIG welding braze,but the zinc seems to vaporize,so i must be doing something wrong.
 
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