Least amnt of heat per unit volume metal deposited...

Awl--
In my shaft-repairing contortions, the above question has arisen amongst brazing, tigging, and stick. Also sumpn I've wondered about for a while.
I maintain that brazing involves the most heat, cuz you gotta get the base metal perty red (at least I do!), which is difficult to localize w/ O/A--esp. going around a shaft.
TIGing the next, cuz of the heat involved in puddling. Proly O/A welding is about the same as tigging, mebbe a little more?
Finally, stick welding the least, mainly cuz it's so fast. Some have said higher amps will ultimately deposit more metal with less heat.
Are these assessments correct? Partially correct? Appreciate all opinions. ---------------------------- Mr. P.V.'d formerly Droll Troll
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Seeking the east amount of heat can give you problems. A localized heat will increase shrinkage stresses while something like torch brazing which produces large amount of heat produces less heat differential across the body of the shaft. I would favour stick and judicious balancing of weld locations. That said I would not hesitate to preheat the entire shaft up to around 200 F. to reduce hard spots. Randy

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 06 Apr 2005 13:34:01 GMT, "Randy Zimmerman"

Agreed though in my opinion if he wants the least amount of warpage brazing it likely to be the best choice in my experience. I do this type work a lot and wouldn't have any problems with it using any method. In truth I would probably MIG it just because it's faster but if I'm really concerned with warpage I will sometimes braze to help minimize it.
He's never stated what the shaft is actually used for that I've seen but if it's not to highly loaded he might well get by using something like JB Weld to build it up and then turning it back down. I've done that a few time when I couldn't get the shaft hot without messing something else up.

Wayne Cook Shamrock, TX http://members.dslextreme.com/users/waynecook
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I spent my last year of my apprenticeship in a small machine/fab shop. We had lots of farm repairs come in through the door. Whatever the machinist ( owner) wanted I did. Occasionally he wanted the shaft built up with torch brazing, but most of the time he wanted me to build up with stick rather than hard wire. The only bad experience I had was when we attempted to repair a shaft that had been built up with metal spray. It was the wierdest stuff to try to weld to. We ended up machining it off completely and then buiiding it up with weld. Randy

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 07 Apr 2005 02:25:18 GMT, "Randy Zimmerman"

I've used a lot of stick in the past but I've found that if I work fast enough with the mig to get the piece good and hot then it machines ok. If I don't let it heat up then mig tends to make hard spots that make for lousy machining.
I hear you on the spray metal. I cringe every time I see someone suggest it myself. I've seen to many of them fail and when they do it just a big mess to fix. The absolute worst application I've seen was on a vane type vacuum pump that the oil companies use to fill there tanker trucks. Someone had spray metal built up the inside instead of fitting a liner and when it started coming loose it made a big mess. I was able to use a screwdriver and pry it all out except for a few places around openings where I had to use a hammer and chisel.
Wayne Cook Shamrock, TX http://members.dslextreme.com/users/waynecook
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
| Awl-- | | In my shaft-repairing contortions, the above question has arisen amongst | brazing, tigging, and stick. Also sumpn I've wondered about for a while. | | I maintain that brazing involves the most heat, cuz you gotta get the base | metal perty red (at least I do!), which is difficult to localize w/ | O/A--esp. going around a shaft. | | TIGing the next, cuz of the heat involved in puddling. Proly O/A welding is | about the same as tigging, mebbe a little more? | | Finally, stick welding the least, mainly cuz it's so fast. | Some have said higher amps will ultimately deposit more metal with less | heat. | | Are these assessments correct? Partially correct? | Appreciate all opinions. | ---------------------------- | Mr. P.V.'d | formerly Droll Troll
It just dawned on me that perhaps a product like Labmetal would build up your shaft just fine. It's used for building up worn shafts, filling weld pitting and casting pores, and all other kinds of stuff. I used it to fix a dent on my engine block face and inside the water pump. Haven't run the engine yet, but I've heard glorious things so far. Do a search for Lab Metal and you'll get all the good stuff.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.