Best stones for finishing die surface weld repair?

[Rouzer]

Hello, I work in a die maintenance shop. these are not mold dies they are metal stamping dies. My question is about flat surface, contoured surface, radiuses, and draw bead repairs. I am trying to research what would be a good stone or series of stones for when I get my weld ground down close, how can I Stone my weld down and not hurt the parent surface? I understand I must use careful handwork to stay off the parent surface but I also know there are tools that can make this job easier. My company provides stones but not the best of stones. One of our more experienced guys uses a stone with oil on his final touch up. I've been reading about India stones and Arkansas Stones I am interested in Arkansas stones but I do not know if these are the best, I did read where soft stones are good for radiuses because they take the shape of the surface. But then you come to the difference of Arkansas Stones between soft hard and translucent, again this is all new to me I'm just trying to learn.

We mostly have heat-treated tool steel inserts but draw beads are disintegrating on Cheap Cast dies with coated surface after galling forms in a given area. So my question refers to soft surface as opposed to Hard coated tool steels(you know, the kind that crack if you weld them without preheating them and then they might crack anyway if you do not wrap them in a fire blanket for slow cooling)
I am particularly interested in stones for radius and draw beads. But I would also like to hear opinions on flat surface repair as well. I would like to know what's a good stone that will cut my weld down fastest and I would like to hear of a good finishing stone that leaves a really good polished finish. I've only been in the industry for 3 years but I've come a long way and I learned everything from hands on. I have a good set of hands on me and I've been given more difficult repairs lately and I just want to be able to do my best. Thanks in advance for sharing your knowledge.

I've probably posted this in the wrong category but please forgive me as I am new, hopefully experienced eyes will come across this. My shop is old school most work is repaired by Weld and hand work. only Shear die cutter blocks are surface ground and shimmed all other cutting edges are welded and worked back with a piloted burr bit.

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[sfriedberg]

I am fortunate enough to have an old translucent hard white Arkansas stone that my mother bought for $8.89 probably 45 or 50 years ago. Unobtainable today for 10x that price, although you can still get hard black Arkansas stones of a similar character. Lovely for finishing touches when sharpening knives and carving tools. Probably not real productive for mold cleanup, but might be OK for near-mirror finishing touches.

While I have great fondness for the old natural stones, today's synthetic stones are cheaper, more diverse, more consistent, and more readily available. You may already be thoroughly familiar with what Gesswein and Boride offer. If not, have a look here or here.

If you are working down repair welds, you certainly want a range of stones. Coarser grits (and possibly a different abrasive material) to remove material, moving gradually to finer grits for polishing.

 

[Rouzer]

I was on borides website today and I'm interested in a die kit they sell. It's actually very inexpensive I think it was only $12.50. I saw a nice gesswein kit on Amazon for $37 I believe but it came with 12 Stones four different grits three different sizes of each. Yeah a guy could have made a killing if he stocked up on Stones back in the day that are now vintage.

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[boslab]

Geswiein abrasive stones for dies etc, reasonable prices, slip stones and sticks in all grades, think they do stuff for die polishing machines also
Get a magnifier anglepoise! Music helps, slow and boring
Mark

 

[eKretz]

Use some Kapton (polyimide) or similar tape around your weld repair after it cools and is ready to be brought back down flush. Nice thing about Kapton is that it's fairly abrasion resistant. Get some an inch wide and surround the area. That way if you accidentally miss, the parent material won't be touched. Replace as necessary if you have any mishaps. I'd agree with Friedburg on the stones - get some good synthetic stones to do the bulk of the work, then if you want to you can finish with an Ark. Once they wear in, there's not much finer than a translucent or black Arkansas stone.

They're NOT soft though. Arkansas stones are delineated by density, so a Washita or Soft Ark is considerably less dense than a Translucent or Black Ark. Effectively, lower density means the stone acts like it has a softer binder.

 

[rogertoolmaker]

Stoning and polishing die repair after welding

Hello, I work in a die maintenance shop. these are not mold dies they are metal stamping dies. My question is about flat surface, contoured surface, radiuses, and draw bead repairs. I am trying to research what would be a good stone or series of stones for when I get my weld ground down close, how can I Stone my weld down and not hurt the parent surface? I understand I must use careful handwork to stay off the parent surface but I also know there are tools that can make this job easier. My company provides stones but not the best of stones. One of our more experienced guys uses a stone with oil on his final touch up. I've been reading about India stones and Arkansas Stones I am interested in Arkansas stones but I do not know if these are the best, I did read where soft stones are good for radiuses because they take the shape of the surface. But then you come to the difference of Arkansas Stones between soft hard and translucent, again this is all new to me I'm just trying to learn.

We mostly have heat-treated tool steel inserts but draw beads are disintegrating on Cheap Cast dies with coated surface after galling forms in a given area. So my question refers to soft surface as opposed to Hard coated tool steels(you know, the kind that crack if you weld them without preheating them and then they might crack anyway if you do not wrap them in a fire blanket for slow cooling)
I am particularly interested in stones for radius and draw beads. But I would also like to hear opinions on flat surface repair as well. I would like to know what's a good stone that will cut my weld down fastest and I would like to hear of a good finishing stone that leaves a really good polished finish. I've only been in the industry for 3 years but I've come a long way and I learned everything from hands on. I have a good set of hands on me and I've been given more difficult repairs lately and I just want to be able to do my best. Thanks in advance for sharing your knowledge.

I've probably posted this in the wrong category but please forgive me as I am new, hopefully experienced eyes will come across this. My shop is old school most work is repaired by Weld and hand work. only Shear die cutter blocks are surface ground and shimmed all other cutting edges are welded and worked back with a piloted burr bit.

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I assume your polishing draw die radii to a high polish so it looks like it is bright chrome plated. Welding on harden tool steel is a concern that the correct welding process is used. And even then is to be avoided as a last resort. Sometime it is better to make a new die. If your draw radii are being washed out. Consider using D2 and heat treat to 62-64Rc Use India stones to polish your dies. First surface grind the die section and then polish. Arkansas stones are strictly for high finish polish. I think where over concerned about the stones selection. I have thoughts of only marginal required results. This is a job you just have to put in your time to obtain the required results. I wish there was a picture of the job.

Roger

 

[eKretz]

Erm... He did specifically mention this:

So my question refers to soft surface as opposed to Hard coated tool steels

 

[Rouzer]

I was able to achieve a fairly high polish through a series of stones and die grinder polishing pad, I found a soft Stone and it was great for my first stone as the surface in front of the draw bead on the lower was galled, and contoured, and causing scratches on the part. I got my draw bead repair in the upper pretty shiny too. It failed to run, this was my second visit to the repair.

With the shiny draw bead, after hitting a test part, I was able to see a small area with a heavy mark which told me it was tight. I aggressively polished it(red wheel for die grinder actually removes steel/weld). It was a success. This was a cast surface with soft coating. The draw bead basically diminished from wear caused by galling that was ripping the part. I saw a repair done by an engineer and his surface was mirror finish, I want to be able to do that.

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[eKretz]

If you want a mirror, you need to go up through the grits, making sure that you remove the scratches from each previous grit - if you switch the orientation of the scratches each time this is easier to see - so first orient the scratches left to right. Next stone go 90° to that until all the scratches are gone. Next stone go 90° back to the first orientation, and so on, removing all the scratches each time until you're done. You need to go up to a fairly high level to get a mirror finish. At least 8000 grit, then polish with something like Mother's Mag and Aluminum polish (works fine on steel also) or a leather pad or cotton buff with some chromium oxide compound or something similar. Here's what it will look like when you're done:

 

[Rouzer]

If you want a mirror, you need to go up through the grits, making sure that you remove the scratches from each previous grit - if you switch the orientation of the scratches each time this is easier to see - so first orient the scratches left to right. Next stone go 90° to that until all the scratches are gone. Next stone go 90° back to the first orientation, and so on, removing all the scratches each time until you're done. You need to go up to a fairly high level to get a mirror finish. At least 8000 grit, then polish with something like Mother's Mag and Aluminum polish (works fine on steel also) or a leather pad or cotton buff with some chromium oxide compound or something similar. Here's what it will look like when you're done:

Thank you that is helpful info.

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[Erstwhile]

The DME edm stones work really good, especially if you have a stunning gun, if your shooting for mirror I'd probably work my way up from 200 -600 in stones and then switch to diamond lapping compound with a buffing pad.

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[Rouzer]

The DME edm stones work really good, especially if you have a stunning gun, if your shooting for mirror I'd probably work my way up from 200 -600 in stones and then switch to diamond lapping compound with a buffing pad.

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Thank you we have Diamond compound but I don't know if I use it properly. We use a felt-like material attachment for a straight die grinder. I rub the diamond compound into the felt. This is like a cylinder only Coned on the end. It's not a pad. I would like to get some pads that that I can screw into my collet attachment for my angled die grinder which is what we use for green and red polishing pads. I don't think those are the type of pads you would use for Diamond compound, they are intended to polish as-is. Also we have light medium and heavy/hard Diamond compound and I do not know what's the difference or in what applications they are applied best. Then we also have another Diamond compound that is not specified as light medium or hard. I know the medium is brown and the hard is red. I honestly think my diamond polishings have been useless since I did not work my way up through the grits on stones prior to it. Up until now I've Stoned with a pink 80 grit stone that we use to deburr Cutting Edge repairs. I will work my way up to a high Grit next time before I Diamond polish. we have a bunch of Norton stones made in mexico but the grit is not specified on the boxes so I will have to look up the part numbers on the internet and hopefully find out the grit but I do think some of them are a high Grit. So up until now I've not been stoning or Diamond polishing properly.

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[eKretz]

Yeah, it would make things tough to jump through the range too fast. Once you get to a very fine grit you don't want to have ANY scratches from the coarser grits left or they will stick out like a sore thumb.

If you need a mirror finish I'd recommend something around tripling the grit every jump. So if you're starting with 80, go to 240 next, then 800, 2500, 8000, then polishing compound. When you step through like this each step takes a pretty short amount of time - especially up in the higher grits because the scratches get shallower and shallower. Also double check what grit your diamond compounds are or you could end up going backwards. For small repair areas you might want to just buy some automotive wet/dry paper in the grits you need and use them with a block that you could shape to whatever contour you want.