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Etching Damasteel


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As some of you know I make a bit of pattern welded steel and over the years I have got the etching of carbon steels down to an art or how I want it to be.

 

So now I find myself trying to etch a piece of Damasteel that I have turned into a finger ring. A friend said use muriatic acid, as I didn't then know what it was, it was suggested I use nitric acid. So I mix up a solution of about 30% nitric with water. Cleaned the ring,hung the ring in the solution expecting to see the pattern materialize. The ring sat in the acid for 2 hours and had no effect what so ever

 

Then I find out what muriatic acid is and make up a 30% solution of hydrochloric acid and water. Put the ring in this and a faint glimmer of a pattern appears. Thats all that happened in about 2 hours of being in the acid mix.

 

This morning I checked the Damasteel website and one of their etching solutions is with sulphuric acid. I mix up a 30-40% solution and try again. You guessed it, nothing happened.

All of these solutions have been strong enough to burn my concrete floor when I have dripped some on it. The hydrochloric and sulphuric acids are from new un opened containers, that have been kept in the dark. They are about 10 years old though.

The steel was finished to an 800 grit.

 

So the question is, does anyone know whats going on or have any suggestions as to why I am having so much grieve with this.

Carbon steels and ferric is just so much easier. To be honest acids scare the c**p out of me.

 

 

Mick.

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Hi Mick, Jake makes a good point re: heat treating the ring first.

Other possibilities could be the way your mixing your acid solutions. Are you stirring them after you've mixed them? And are you using them at room temperature? Don't know about you, but my place is starting to get a bit nippy!

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The steel is Damasteel grade 95x.y Austenitic stainless damascus, soft, non magnetic. Its their grade specifically for jewelery, knives and forks etc.

 

When I mix the solution up it is stirred and the heat generated from adding the acid to the water is quite high. I have also resorted to standing the glass with the etchant in, in a saucepan of very hot, just of the boil water.

 

Is the 800 finish to high for the acid to get a bite on ?. All the acids are Technical grade. Unless I get any other suggestions, I think I will just dip the ring in the neat sulphuric acid and see what happens.

 

Mick.

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Mick, I'd take it down to no more than a 400 grit finish and try again. Using acids neat is generally not a good idea for what we want. If the solution is very strong it can leave streak marks and pitting on the work. At least it does for me.

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i have no experience with the stuff but... i saw this

 

http://www.cartech.com/techarticles.aspx?id=1450

 

Stainless Steels

 

When etching austenitic stainless steels, DIC illumination will better show the grain structure and help find cold-work deformation, when such exists. Waterless Kalling’s reagent can be used to show the general structure of many austenitic stainless alloys. Other agents such as Glyceregia or Acetic Glyceregia may be required to retain ferrite, carbide precipitation.

 

If the only interest is grain structure in an austenitic stainless, start etching with a more aggressive etchant. However, start etching with Glyceregia for a shorter time if interested in features other than grain boundaries, such as carbides, ferrite stringers, second phases and duplex structure.

 

Ralph’s reagent normally provides a good etch for general structures in ferritic stainless steels. Waterless Kalling’s and Glyceregia also can yield good results. Even after a good polish, scratches may still be visible. They may or may not be a problem.

 

Ralph’s is usually best for the precipitation hardenable stainless steels; however, Vilella’s reagent will work fine if a light etch is preferred. Etching time will vary because the alloy in the aged condition will react quicker to the etchant. The higher the aging temperature, the quicker the response. An alloy aged at 1100°F (590°C) will etch darker and quicker than one aged at 900°F (480°C).

 

The annealed structure in PH stainless steels requires either an aggressive etchant for a short time or a less aggressive etchant for a longer time. Here, Ralph’s reagent could be used for a few seconds, or Vilella’s, which is less aggressive, for a longer time.

 

Vilella’s reagent is preferred for martensitic stainless steels. Etching time and response will vary depending on whether the alloy has been annealed, hardened or tempered. Annealed samples usually require the longest etching time because everything is in solution, with not much to be seen. It is best to stop etching while the specimen is still on the light side. Etching has gone too long when the sample starts going black. A little experience will help the examiner to stop etching at the right time. Hardened and tempered samples usually require less etching time than annealed

 

 

it does mention that aging with make the etch darker.. ? ... i've read this several times in other areas concerning " Macro etches "

 

 

i do have friend that uses alot of damasteel for his knives... i'll try giving him a call and see what he says...

 

good luck on the etch

 

Greg

 

 

 

ps .... almost forgot...becareful with sulphuric ..its very exothermic when diluted...

 

-also a weak sulphuric dilution can act more like a strong acid if boiling hot.. which is interesting

 

pss... becareful if you do the h202 mix with HCl... its fizzy bubbly and mix in the right proper order

Edited by Greg Thomas Obach
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Thanks for that Greg but I think that is for the study of metallurgical properties/grain structure. I would be very interested in what you friend has to say.

 

The exothermic properties of mixing sulphuric acid with water was quite surprising. It all gets very hot.

 

Mick.

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I found that using muriatic / hydrochloric from the hardware store, and heated in a jar with a lid (for fume control,) and set in a pyrex container with water on a hot plate did the trick, but I was never happy with the level of detail in the Damasteel, as the areas of finer pattern got eaten away without differentiation. I tried a bunch of their recipes, and stopped when I was admonished by some chemists for even thinking about using the recipe with perchloric acid. I was using the same austenitic material as you.

 

Between the poor etching qualities and the absolute headaches encountered simply even procuring the stuff I decided it was easier to get a press and figure out how to make my own stainless damascus. Further, though Damasteel says that their austenitic material is 316L and 304L, my own stainless material, definitively made from the same materials, etches WAY faster and cleaner in simple heated muriatic acid.

 

I still have a bunch of Damasteel I won't even touch.

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J, Thanks for the reply. I am rapidly coming to the same conclusion as you. After many attempts with all the different acids and no repolishing/finishing in between, just a rinse in fresh water. The finish is about the same as dipping carbon steels in ferric when the pattern appears after a few seconds. This piece has sat in different strengths of various acids for a total of around 5-6 hours and you can't even feel the pattern with your finger nail.

 

Mick.

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Heating the muriatic acid did really make a big difference, if you haven't tried that. Good luck! I feel your pain!

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Hi

 

ok.. just had a long talk with my friend and he says that he uses straight muriatic acid with no dilution... i imagine just technical grade from hardware store..

- and leaves it for 30 to 45 min ... outside in fresh air

- but that is the damasteel for knives.. after heat treat

 

he also said that his mike norris damascus he etched in straight ferric

 

sorry... can't help much... only other thing that comes to mind is to do with HF acids and thats too dangerous... hmm.. what about that gell that welders use to clean stainless welds..... it could be an experiment if you have a small test sample

 

didn't Ric post that he was making some layered stainless stuff... what does he use...

 

 

G

 

 

 

 

 

 

 

 

 

 

Thanks for that Greg but I think that is for the study of metallurgical properties/grain structure. I would be very interested in what you friend has to say.

 

The exothermic properties of mixing sulphuric acid with water was quite surprising. It all gets very hot.

 

Mick.

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Interesting thread! I recently welded up a billet of 303 & 316 and it hasnt even looked like etching in sulphuric :angry: I had forgotten about it untill now, but will get some brick cleaner and heat that up and give it another go!

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After being told that ferric has no effect on Damasteel all I could think off was using acids, which didn't work very well. One sugestion was to warm up the acid or I was going to try and dip the ring in the undiluted acid.

Greg's post mentioned his friend that etches Mike Norris damascus in straight ferric. So thats what I tried today only I heated it up to around 80C/180F. As soon as the ring was in the ferric a pattern started to appear. I decided to etch the ring for about 20 minutes, just checking every 5 minutes to see the level of etch.

The biggest problem with this stuff is that there is hardly any difference between the steels. 316L has 17% chromium and 12% nickel. 304L has 18% chromium and 9% nickel. So it all seems to etch at about the same rate with the 304 just a bit quicker.

 

When the ring came out of the etch it looked pretty scabby, with light grey areas and lighter grey areas. The high parts were sanded back and polished on a small buffing wheel.

 

The two rings below have had a resist painted on the inside to stop any etching as they have no liners. If "the other half's" finger drops of due to nickelitus or whatever its called, I shall let you know.

 

stainless-rings.jpg

 

 

Thanks for the help,

Mick.

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I have been watching this thread as well thanks for the info everyone. Mick i think they turned out nice.

 

Bob

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I don't have a lot of experience etching stainless steel. However recently I made some fitting that are 304/316 pattern weld.

I etched in fresh 34 percent hydrochloric at room temp for about 6 hours.

SSmokumeset-00368.jpg

The 316 layers showed no sign of etching at all, but the 304 layers reacted with a slow and even bite.

This is Door County Forge material.

Patrick :)

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  • 2 weeks later...

I had similar problems with this

Damasteel themselves said to use aqua regia

 

trouble with this acid is its very dangerous,extremely strong and toxic as hell

 

you can't get it outside an atmosphere controlled lab where I'm from

 

So I used 50/50 ferric chloride

and I kept etching for 6 hours

the downside is it can cause pitting and uneven etching

especially around the tiny bubbles that form

 

I kept removing and cleaning

 

It seemed that after 2 hrs or so that the acid started to bite in quite well

especially after raising the temp to about 60-70 c

 

the end result was a very good deep etch

 

pic attached

 

RIMG0691.jpg

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  • 2 weeks later...

I had some reasonable results today with my 304 / 316 billet using brick cleaner (?muraic?), and standing the glass jar in a bucket of warm water. Not a deep etch after a couple of hours but encouraging enough, I think if the water was hotter, and I did something to keep the water warm it might have been a bit more effective. I ground the etch off one side of the billet and have left it in cold brick cleaner (it will be there a couple of days now!), Ill update when im back in work monday and see what it looks like !

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This is my first try at stainless P.welding, Im actually quite proud of this little scrap of metal ^_^

 

Brick cleaner did the trick, I left it in 3 days in cold acid, and it had about the same effect as 2 hours in warm acid. Nice clean looking, if shallow etch.

 

sd1.jpg

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  • 3 weeks later...

i use ferric on the innitial etch... buff and the re-etch with muriatic to get contrast

1/2 hour in ferric... buff... 15 min in warm muriatic

 

Andy Ring Concave.jpg

Andy Ring Concave Side.jpg

Edited by a.priddy
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