Powder Spray Weld...

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Every once in awhile someone asks about Powder Spray Welding..Quick build up method..Here is a great example why it sucks..Two rollers..Each 90" long...8.75 dia.They were sent here to have the O.D.'S cylindrical ground...and then the last 2 1/4" tapered by 1 degree so the ends cannot touch..These are glue laminator rolls and the glue has to have a "way out" before it gets to the end of the roller on each side so the hot glue stays in the tank..My boss ground the O.D. ...Gave them to me and said "Just turn the taper on the ends".."Sure no problem"..Big problem..We had no idea these were powder sprayed..Powder spray and tool bits = disasterHere is a good example of that..See the grooves in the tube body?They are there so the powder has something to grab onto..Note how its "flaking off"..You end up with these "Cat whiskers" as we callem'Get out the toolpost grinder now... This is what grinding the taper does..The stuff sucks..Plain and simple..I get all the fun jobs.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Zap:Can you go into a little more depth about what powder spray welding is and the practice by which it is done? Is it some sort of inductive spray welding method? You're saying the piece is first grooved and then spray welded to build up its surface?
Reply:http://www.eutectic.com/wCastolin_com/index.phpEutectic has lots of info on their web site.
Reply:You basically thread the OD..Get a big torch out and heat the area red hot..The powder spray unit has a torch head on it..usually runs on acct/oxy..The powder comes in a plastic bottle much like the ones that "bubbles" come in..You screw the bottle onto the torchhead..The Torch is gravity fed the powder and then you hit the trigger all 3 mix and you "spray" hot powder onto the surface and hope it holds...It must be ground to finish it..as we can all see...I hate the stuff myself.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:why would they do that on a new item?I could see doing it to add size to something to a worn part... But new?Me!
Reply:Originally Posted by Me!why would they do that on a new item?I could see doing it to add size to something to a worn part... But new?
Reply:Originally Posted by zapsterIt was done awhile ago..The rollers have been in use for a year and just sent here for truing up end to end..After awhile they taper all by themselves..And if its only .005 end to end?You have .005 too much glue on one side of whatever its doing.....zap!
Reply:Originally Posted by Me!I was referring to the Powder Spray Welding.
Reply:That looks like a whole ton of fun zap.  You must be the luckiest sob ever.    I would hate to have to mess with that stuff.How do you smooth it out?  Or do you just call it good as it is in the last pic?
Reply:Or do you just call it good as it is in the last pic?
Reply:I've used thermal spray a few times on cast iron jobs...As a last resort.  I have mixed fealings about the stuff.  I think variations of NiRod do a better job without cracking in either cold welding or preheated repairs.  I have read up on where they use it for build up, but dont have any experience on the machining end of things.  I'm still kinda clueless as to why they would pick that process over MIG, Duelshield or TIG. I do know one thing... A couple ounce bottle will set you back quite a few bucks for cast iron welding.Common sense in an uncommon degree is what the world calls wisdom.