I know this subject was discussed on the old bb. my searches turned up some info,but I thought a post might bring some fresh info. I found some good used idlers for my rd4, but thought a little manganese overlay should help them wear better. I use my machine enough to warrant the extra work.most info I found says use 7018 as a build up with a manganese overlay in equal amounts. say two passes 7018 then 2 passes overlay for a total of 4 passes.or one pass of each depending on needed buildup.My spoke idlers I assume are cast so since I cant heat the whole thing up to 12oo degrees,I am left with welding 1/2 inch at a time to minimize heat. passes are in short direction, not around the idler.
does this sound about right?
greg

My neighbor said they would use rebar at the dealer ship he worked for.Bending it around the roller & welding it with 7018.You could put hardfacing on top of the rebar.
Joe

I didn't think any of the idlers were cast iron. They are/were routinely built up on with the beads run around the "tire" surface.

KOO is the only one I know of that put the beads crosswise, and he may know something I don't about it. Wasn't it something special about snow building up?

I picked up that info from a lincoln electric manual.I would think that rollin gthe idler as you weld would be the way to do it. a bucket of water to keep the temp down.have the idler in the water as you weld.I have seen machines that weld rollers rotating them as it wire welds them.
are these idlers considered cast steel? then the high temp of welding would not be a issue.I would not want to crack the good idlers I bought. a lot of the lincoln electric discussion centers around the amount of carbon in the parent material. a website that has a hands on discussion would be helpful.
greg

The idlers are cast steel and the tried and true hand weld method seems to be radial around the center rim and zig-sag across the tread like you've been doing.
Although I am familiar with weld buildup of rollers while partially submerged I have not seen that done to idlers. Unless they are extremely thin to begin with I don't think you will have much of a problem with cracking if you alternate around the diameter with your welding. Not to say that they won't crack as it has happened. I too have info on wire feed submerged arc radial welding of the idler and the process was done with the idler rotated in free air without any cooling.

yes in the great white north we zig zag and the snow and ice fills in the rest. it doesn't take long to do on a cold winter's day, LOL

we had the KOMMUNIST KAT out pushing and come across some water, sure did make the tracks snap as the water and snow punched through the holes in the pads.

thansk

NAPA markets and excellant hard facing rod under their brand name. I don't know who makes it for them but I used it for front idlers, sprockets and front idler slides in the front of my roller frames instead of wear strips on my D-8H and they never cracked. I used 3/16 rods and laid two passes on the idlers and sprockets and four or five passes on the slides and never had a stress cracks. I think the smallest size you can get is 3/8 inch rods. - Try e'm you'll like em'....))

And yes, zig zagging the top pass will definately prolong the life of the idler face. Also do it on top idlers and you will eliminete flat spots because the zig zag combined with the dirt will give it traction of sorts to keep the roller moving in wet or muddy or frozen conditions.

Chris

The smallest size is 1/8 rods....sorry

when you were welding , did you worry about how fast the weld was cooling? did the rod require peening to releive stresses?
you idlers are solid, mine are spoked,do you think that changes the amount of heat buildup it can tolerate?
greg

Set both idlers on wooden blocks side by side in front of you holding them off the floor enough to let them turn freely. Lay one pass on one, move the ground to the other idler, lay one pass on that one. keep doing that . It will give the iron time to cool. Also alternate sides of the idler in this system, (Outside of one, then outside of the other, then inside of the first one and then inside of the second, and so on. Set a fan up to the right or leaft of you to keep the air moving across the idlers. It only has to be a 20 inch window fan and it doesn't have to be trying to blow you over. It does two things. Helps cool.(Yes minimally, but it helps) and it blows the noxious gas smoke away from you as you weld. Doing it this way gives the iron time to cool and then you don't need to worry so much about cracking. Cracking may be more the result of the rod than anything. Different rods pull and shrink differently. Check with your welding supplier and tell them you are welding on cast steel that has been case hardened and that the idler has worn through the hard part. The best hard rods I have ever used were called Rainite (I have no idea anymore if it's even made becasue se used that a long time ago) and the NAPA rod I told you about earlier

Hope that helps

Chris