Recommend a rod for overhead please...

[dntfxr]

I need to do some welding on my newly acquired d20 dozer. It's on the c frame that supports the blade and it has some old repairs on it. I'm thinking I'll grind a vee in the cracks but not sure which rod is best for this app. Some will be overhead and it's a little rusty. Thanks for the help

 

[Shield Arc]

On the whole, the position has nothing to do with it. It's a matter of the base material.

 

[dntfxr]

Yeah sorry I hit send before I was ready

 

[Shield Arc]

To be safe I would contact the manufacture for recommendation of a weld procedure. My gut says 70 maybe even 8018, with preheat for sure, and maybe some post heat, or wrap with insulation for a slow cool down.

 

[Iplayfarmer]

I don't worry about position. I just move my work to make every weld a flat level weld. I even flipped my 16' double axle trailer so I could weld new spring brackets onto it.

That's probably not an option with a dozer. If you do decide to flip your dozer to weld it, please take pictures.

 

[Shield Arc]

I don't worry about position. I just move my work to make every weld a flat level weld. I even flipped my 16' double axle trailer so I could weld new spring brackets onto it.

That's probably not an option with a dozer. If you do decide to flip your dozer to weld it, please take pictures.

I do that all the time, here is my next project soon as the tide goes out. :laughing:

 

[jake98]

I do that all the time, here is my next project soon as the tide goes out. :laughing:

That is WAY too funny!

 

[grsthegreat]

I do that all the time, here is my next project soon as the tide goes out. :laughing:

yup... high price scrap metal. What i dont get....aside from a ships captain that abandons the ship before the passengers, is why they needed to be air lifted off the ship...when its 50' from shore? What am i missing.

 

[dntfxr]

Lol thanks for the replies fellers! I just got off the dozer, its amazing what even a little dozer can accomplish!
I considered taking the c frame off and turning it over to weld and that may be the best option- or as you say, I could drive it up a big oak tree and at least it would be an easy vertical then! I heard from my Komatsu dealer today and they said it is a common repair and to just use "heavy rod and weld it hot". All I have right now is 10# of 7018 so if that will work I'll go that route. I don't have power at the future homestead where the dozer is, but I can rent a miller bobcat for 60$ a day. I'll probably go that route and fab up a heavy angle iron patch to reinforce it.
I have a decent amount of experience welding but very little overhead experience. The little I did years ago I do remember being a challenge. Any tips on technique or suggestions?
Thanks guys!

 

[Shield Arc]

I have a decent amount of experience welding but very little overhead experience. The little I did years ago I do remember being a challenge. Any tips on technique or suggestions?

Things to remember when welding overhead:

First it really isn't any different than flat, in some ways you can even see better when welding overhead.

Get as comfortable as you can, if you can keep your elbows tucked into your rib cage. If you have to extend your arms out to far fatigue will set in pretty quick, then you'll start to shake.

Cover up best you can, but it is a matter of time until you get burned, so get use to it!

If using 7018, place it in your kitchen oven at 300-degrees a couple hours before you need it. Try to keep a short arc length. A long arc length will give you a wet puddle, a wet puddle is harder to control.
If the weld is running left to right in front of you it really doesn't mater which direction you go. But if the weld is running towards and away from you, I think you'll find it is easier to weld away from you, than towards you. When welding away from you it is real easy to judge your travel speed. When welding towards you, you have to look through the arc to see the amount of fill, that takes a little more practice to know what you're looking at.

 

[easygo]

I suggest that you try to position a piece of scrap on a couple of saw-horses or whatever gives a similar position, to the troubled spot on the dozer. Try to weld on that piece of scrap overhead before starting the actual repair. I did that and was amazed that I actually produced a good weld.

 

[dntfxr]

Thanks for the tips Shieldarc that'll get me going. Bad thing is it's gonna take half a day to clean it up between the mud, rust and crappy welds it came with!

 

[dntfxr]

I suggest that you try to position a piece of scrap on a couple of saw-horses or whatever gives a similar position, to the troubled spot on the dozer. Try to weld on that piece of scrap overhead before starting the actual repair. I did that and was amazed that I actually produced a good weld.

Very good idea! Will do!

 

[dntfxr]

Actually I just remembered a spot with a small hill that is pretty steep that I can drive the dozer up to get it closer to vertical, almost upside down! If I can park it there with the blade lifted and the brake locked it should help. At least I won't have to lay down quite so low...
Thanks for the suggestions guys, they all have been a big help!

 

[Tractor Seabee]

I assume that is a pretty thick member. If you can get to the opposite side it would be good to vee both sides rather than one side. If the cracks go all the way through; can you block the two pieces so they wll not move? If not you may have to put on a temporary splice to hold it in place. Make sure you cut out all cracked/flawed material. If you don't, you may build the same flaw into your new work. Be sure to grind out all bad materials. If it is say 1" thick material grindig the vees(s) can be tedious. I would burn out with a scarfing tip on the O/A cutting head and then grind it bright. On the vees(s) leave as much thickness in the bottom as the diameter of the rod. I would use 6010 for the first pass or 2 passes if it is over 1/2" base material. and finish up with the 7018. 6010 is easier to control in the bottom of the groove and get unflawed full penetration. As shieldarc said; keep a short arc for good puddle control. It never fails that if you have a minor flaw in the root pass it will carry through on every subsequent pass. That is why pipe welders always are meticulous on the root pass (always use 6010 unless the approved procedures different) and even grind it well before starting the next pass. A leak in a 24" pipeline can get you sent back to the hall.

Ron (old UA pipefitter)

 

[k0ua]

On that oven heating of the rods I would suggest an electric oven, as a gas oven makes water from the combustion of propane and oxygen in the air.
and your goal is to drive out the water in the rods and to heat them up too.

James K0UA

 

[Haywire]

SA suggested sticking the 7018 to the work for a few seconds to get it good and hot too. Not sure if it was in this thread or not. They tend to blur together a bit.

Ian

 

[jake98]

They tend to blur together a bit.

Ian

Oh Boy, You've got it bad... :laughing:

 

[Gary Fowler]

What ever rod you decide to use, prep the metal first. Get all the rust, scale, dirt, old weld, etc. ground out before you strike an arc. It is hard enough for beginners to weld overhead but leaving some contaminants on the base metal makes it 5 times harder to weld than welding on good clean metal. If you take the extra time to properly clean the weld area it will make the actual welding go much easier. My Rule of thumb is to clean at least 1/2" back on both sides of the weld area for equipment repairs. My company rule is 1" for pressure welds but I think 1/2 is fine for your application. Make double sure that you get any existing porosity and slag from old weld out. Welding over porosity will make it at least double in size and make for a very weak weld.
Your idea of parking on a slope might just help. Anything to get the weld from flat overhead to a slight vertical incline will help keep the slag away from the puddle especially with 7018. As for direction to travel, I always like to weld toward me. This makes it easy to see the weld puddle and as the rod gets shorter, you dont have to reach further away from your body, but it is a lot of personal preference in positioning, whatever is comfortable for you is the best way.

 

[Iplayfarmer]

... I considered taking the c frame off and turning it over to weld and that may be the best option-

Seriously, this may be the best option. It will take time, but may result in a better repair when you're done.

You may also consider gussets or added plates accross the crack to re-inforce the repair. The fact that it has been repaired once before and re-broke highlights the possibility that this spot is a trouble area.