Unusual Etch on a Moro Blade

[Spunjer]

all the years i've tried etching moro blades i finally honed a certain technique in which i can bring out the lamination; visibly obvious, yet subtle enough so as not to overtake the overall aesthetic of the blade. good examples are these barungs.
i use the usual stuff: dishwashing soap and acetone to strip the oil, then vinegar and baking soda. after achieving the desired etch, i would run hot tap water on the blade to thoroughly was off any chemicals left on the blade.

[Spunjer]

and then this happened...
i was etching this kris as i thought i saw some squiggly lines along the edge. after spending an hour applying vinegar with a stiff nylon toothbrush (my preferred method), i finally started to see some lamination patterns in the usual typographical pattern. vague, but it was there. another hour spent applying vinegar with the toothbrush, but it seemed like this is about as bold as it will get, so i decided to neutralized the acid. after that was done, i ran hot tap water to wash off the baking soda. this is where it got weird. these unusual snake like lamination patterns started appearing all over the blade. the longer i applied hot water, the bolder the patterns got. it even overtook some of the typographical patterns, as in these darker lines were on top of the previous patterns. i've never seen this happen before. anyone ever had this experience? any explanation on what would cause these? one thing that is neat tho, it has this monochromatic scheme going; brass handle and baka-baka, darker brass collar, copper wire handle, and now these brown lines.
p.s.
for the record: i've handled moro blades for years, and i could honestly say that this is the very first time i've been "bitten" by a moro blade. weird.

[spiral]

Nice barung Spunjer!

Ive had the same expierience etching kukri, my conclusian was hot water & air promote an oxidisation that highlight the otherwise low contrast laminations, due to some layers or lamination lines of the bladel oxidising more rapidly than the others.

As a technique I think of it as controled oxidisation highlighting.

Guess it needs a heavy oil soaking afterwards.

Spiral

[ThePepperSkull]

silver kakatua.... *drool*

[Spunjer]

@spiral: thanks! I do have this habit of running a hot water test on these blades to see if they're laminated. When I did it initially, none of those patterns came out.
On your multi, did pattern stayed, or did it eventually fade? Yes, you're right: healthy dose of oil was applied right after...
@dave: It's brass, I'm pretty sure. It's just that it is the lighter shade type, not to mention I went against the grain and decided to clean it up. Of note is the weight of this beast: it's heavy, comparable in heft with kampilans.

[spiral]

Originally Posted by Spunjer

On your multi, did pattern stayed, or did it eventually fade? Yes, you're right: healthy dose of oil was applied right after...
.

It stays, but much cleaning fades it, I guess longer oxidisation leaves a more permant mark, a questian of getting the right balance I think?

Spiral

[Sajen]

Originally Posted by spiral

It stays, but much cleaning fades it, I guess longer oxidisation leaves a more permant mark, a questian of getting the right balance I think?

Spiral

Yes, agree, have similar operating experiences.

Regards,

Detlef

[DaveS]

Spiral: I've had this happen before also after using vinegar to neutralize the
Phosphoric acid that i usually use to etch blades. It seems strange
to me that one acid can be used to neutralize another, but i guess
for some reason it works. Try also heating blades on both sides with
a torch (very carefully). Then apply acid. It seems to emphasize
the high-carbon areas of a blade with some really good results. If
the blade turns out too dark simply repolish, and try again....Dave

[mross]

A weird color but looks like fold patterns to me.

[Spunjer]

Originally Posted by DaveS

Spiral: I've had this happen before also after using vinegar to neutralize the
Phosphoric acid that i usually use to etch blades. It seems strange
to me that one acid can be used to neutralize another, but i guess
for some reason it works. Try also heating blades on both sides with
a torch (very carefully). Then apply acid. It seems to emphasize
the high-carbon areas of a blade with some really good results. If
the blade turns out too dark simply repolish, and try again....Dave

i would normally use a heat gun (use to strip paint) to warm the blade, not hot to touch, before applying my first layer of warm vinegar. you're right, in that it does emphasize certain areas of the blade when etching. never tried phosphoric acid, dave. pretty much stayed with vinegar.

mross: yes it does. but what i don't understand is why is the opposite side has a different pattern? was the core sandwiched together?

[mross]

Originally Posted by Spunjer

mross: yes it does. but what i don't understand is why is the opposite side has a different pattern? was the core sandwiched together?

Sounds reasonable, that would be my guess. Since I'm not sure, if it's ok I can post the photos on one of my bladesmith site's and see what the guys who make this type of stuff think is going on. Or you could just cut it in half and have a look.

[spiral]

Originally Posted by DaveS

Spiral: I've had this happen before also after using vinegar to neutralize the
Phosphoric acid that i usually use to etch blades. It seems strange
to me that one acid can be used to neutralize another, but i guess
for some reason it works. Try also heating blades on both sides with
a torch (very carefully). Then apply acid. It seems to emphasize
the high-carbon areas of a blade with some really good results. If
the blade turns out too dark simply repolish, and try again....Dave

I think vinigar may dilute a stronger concentration of another acid Stan, but to neutralise it, will need an alkali, I think? vinigar still needs washing of or neutralising or will promote further oxidisation.

Lots of water washing & oill often suffices though.

Spiral

[Spunjer]

Originally Posted by mross

Sounds reasonable, that would be my guess. Since I'm not sure, if it's ok I can post the photos on one of my bladesmith site's and see what the guys who make this type of stuff think is going on. Or you could just cut it in half and have a look.

mross, have at it! if you want, i can email you the actual pics. i think i have a good idea on the make up of the blade, but it would be nice to hear from the bladesmith's point of view. the setup seems to be a popular theme among moro weapons (sandwich lamination).

[G. McCormack]

my impression is that silica type impurities took that golden hue from the etch, revealing a normal folded and welded structure. Was your etchant brand new and clean, or had it been used before?

[Spunjer]

Originally Posted by G. McCormack

Was your etchant brand new and clean, or had it been used before?

it's brand new and clean.. always been a habit of mine to never reuse the same etchant on a different blade. besides, vinegar's pretty cheap as a matter of fact, the kris that i etched right after this came out "normal" (shown both sides). again, notice the different lamination structure variation on each side.. (sorry about the lighting.. took it under less optimal condition. the brownish tint was due to the artificial overhead light. actually it came out similar to the barungs above..)

[mross]

Originally Posted by Spunjer

mross, have at it! if you want, i can email you the actual pics. i think i have a good idea on the make up of the blade, but it would be nice to hear from the bladesmith's point of view. the setup seems to be a popular theme among moro weapons (sandwich lamination).

The smith's are in agreement with you on the construction.

Here is the link.

http://forums.dfoggknives.com/index.php?showtopic=23350

[Spunjer]

thanks for the update, mross!
somehow i'm beginning to think the pandays of old had these pre-made blank billets lying around so when it's time to make a kris, he picks up a couple to sandwich a core.

[delor]

I agree with mross. The "random" pattern is the proof of a laminated construction.
If there is no sign of lamination between the edge and the first brown line, this could possibly be a sandwich construction with central single steel (not sure, according to your two last photos which seem to show uniform lamination on the whole blade).
A good reason for sandwich construction is that a combination of non "quench-able" materials (ie : low carbon steel and nickel) was often used for lamination, in order to get good etching contrast (steel goes dark grey and nickel remains bright). If the laminated material canot be correctly hardened, this leads to sandwich construction which allows to have some good steel at the edges. Also good steel was much more expensive in the old days than common iron, so the less steel used the better it was for economical issues.
I cannot say what are the materials used for the construction of your blade. Might be iron + steel...

[Spunjer]

thank you, delor, for a thorough explanation in the lamination process! would you say that the core is a solid piece, or would it resemble a tuning for (with the edges as tines)? ,

(not sure, according to your two last photos which seem to show uniform lamination on the whole blade)

.

the last two photos are actually from a different kris i etched on the same day. i added the additional photos as a comparison to the original kris that was posted

[delor]

When a blacksmith didn't want to use rare good steel for the whole blade, he had to choose between two kind of construction :
- sandwich : 3 welded layers, with central good steel layer (first photo)
- welded edges : 3 welded bars, with good steel at the edges only (second photo)

Sandwich is much stronger because the welded surfaces are wider. Weld lines are quite irregular because of the strong hammering for the welding of the whole surface. I believe this is the construction of your blade.
(Welded edges are easy to detect because they show very regular and straight weld line because of the light hammering).

Of course, each of the separate parts can either be homogeneous or composite material (laminated & twisted core being the most traditional structures).

[Spunjer]

delor,
thank you for the excellent illustrations! it's basically how i pictured the lamination in my mind, and was going to use the google sketchup, but the illustrations you provided are perfect. thanks once again.

Sandwich is much stronger because the welded surfaces are wider. Weld lines are quite irregular because of the strong hammering for the welding of the whole surface. I believe this is the construction of your blade.

i think you are spot on on this one. my respect to the pandays of oldjust went up another notch..

[delor]

Originally Posted by Spunjer

my respect to the pandays of old just went up another notch..

Yes, blacksmith of the ancient times, especially Merovingians and Hindu ones (but not only) did prodigious works we hardly can reproduce nowadays, although we now have machines and deep understanding of chemical and physical issues about steels...

[Spunjer]

incidentally i was watching "Weapon Masters" last night and the episode was "Katana". it showed how the japanese made their famous sword. very fascinating, to say the least!

[ThePepperSkull]

Is the second configuration the type of welded edge we see on twisctore blades?

[delor]

Twisted and forge welded bars can be used in any kind of blade construction. Nevertheless, the second type of construction is more likely to be used for twisted core, because it allows the removal of a lot of material from each side of the blade without impinging the construction itself.

By the way, to obtain a twisted "stars" pattern (by example like the turkish ribbon), one will have to :
- forge weld a laminated bar,
- twist the bar
- reforge it to square section
- forge weld it within the whole blade construction (there may be more than only one twisted bar...)
- grind to remove approximatively 1/3 of the material from each side of the blade in order to reach the twisted stars pattern which lays inside the bar.

So, you are right, the most usual construction will be made of the welding of a single bar or multi-bars core with separate edges.

[MichaelZWilliamson]

I realize this is a very old thread.

Mild acid followed by boiling water is one of the techniques for cold rust bluing, typically used for double shotguns. Acid, boiling water, wire brushing, repeat 8-10 times will give you a deep, blue-black finish.

So the vinegar followed by hot water came close to almost performing the first step.

[Battara]

The only thing is that the original blades that survived with their original etch were not blue but brownish. In fact, Moros used this old formula:

1. cover the cleaned blade with citrus juice (like calamansee, a type of lime)

2. place in the hot sunlight

3. wait

4. wash off with water

The result was a grey to brownish color on the laminations of the blade. Sounds similar.

[kino]

Originally Posted by Battara

In fact, Moros used this old formula:

1. cover the cleaned blade with citrus juice (like calamansee, a type of lime)

I had the impression that Iba / balimbi /kamias or carambola was used for etching.

[Battara]

Originally Posted by kino

I had the impression that Iba / balimbi /kamias or carambola was used for etching.

I was told once that calamansi was also used, but the others make sense too.