New Moro kris

[kai]

Hello Apolaki,

What are some signs of corrosion to the blade for leaving it in too long in 5% vinegar acidity?
I noticed the tip of blade has some split in the center. It may have already had that condition however. I did not notice til now.

I believe I can see the forging flaw already in the pic you posted originally.

Hairline cracks and pitting are not cleaned by surface grinding/polishing (unless removing heaps of metal). That's the pro side of vinegar - it helps to really clean a blade thoroughly!

If any pitting or cracks are deep, it will take time and repeated picking of stubborn areas to really clean them out. Depending on the extent of corrosion, the blade may look quite bad (not expected with this kris); however, a thorough cleaning will do much for long-term conservation (if stored properly) and remaining craters/cracks can be filled with hard wax to seal them off.

The surface will get somewhat dull from vinegar or other acids (or even porous if you over-clean). The more you invest in careful manual removal during the initial cleaning/etching, the easier is the polishing afterwards which will get the metal shiny again.

Regards,
Kai

[apolaki]

I have left the blade in a vertical bath of 5% vinegar for a couple days and tried to clean it a couple times by running water over it and scrubbing.

The dark smudge develops really fast after resubmerging in the vinegar. It develops thick again at both sides, and when I take it out of the bath to rinse it off with water and scrub it smells REALLY RANCID AND PUNGENT!!!! (Is it a toxin or hazardous to inhale)? My mind may be going overboard, but I wonder if it's arsneic or something? Any way, I was scrubbing it with a plastic brush very hard with citric dish soap thinking it will scrub the black smudge away, but it didnt seem to do much.

Then I realised that the black smudge actually fades away when the blade dries. The last photo shows what it looks like when it is almost completely dry. Is the rust not being removed or am I making some progress?

Thanks!

[Battara]

Uh..........maybe a little over etched. You may want to repolish and etch with a little distilled water, or don't leave the blade in that long.

[Sajen]

Originally Posted by Battara

Uh..........maybe a little over etched.

Hello Jose,
I think that we don't see an intended etch, it will be the result of the bath in 5% vinegar solution to loosen the rust.
That's what I said before, the blade need to get polished anyway after the bath. The blade wasn't corroded so much that the bath was required.

Regards,
Detlef

[Ian]

I agree Detlef. This blade needs some sand papering and polishing, then a final etch. The red area in the bottom picture is active oxidation that needs rubbing off also.
Ian

[Battara]

Oh.........I misunderstood.

[apolaki]

Hello all,

Is sand papering the only solution to this?

I thought vinegear will losen rust and it can just be scrubed with a hard brush and then dried with hair dryer and fonally oiled down.


But many are stating sand papering woth dofferent grades. What are some alternate solutions?

[kai]

Hello Detlef,

The blade wasn't corroded so much that the bath was required.

I beg to differ: There are several deep cracks which surely were filled with rust. There is no way that a gentle polish of the surface would have removed these pockets of residual rust. Thus, for long-term preservation a limited acid soak was not a wrong strategy; with good planning, the process could have been shortened though.

Hardly any harm done in this case - we all have seen much worse restoration attempts, I believe!

Regards,
Kai

[kai]

Hello Apolaki,

Please try to answer those questions raised in post #18.

Regards,
Kai

[Sajen]

Originally Posted by kai

I beg to differ: There are several deep cracks which surely were filled with rust. There is no way that a gentle polish of the surface would have removed these pockets of residual rust. Thus, for long-term preservation a limited acid soak was not a wrong strategy; with good planning, the process could have been shortened though.

Hello Kai,
I have polished several moro blades with a much harder grade of corrosion without a bath in a vinegar or citric acid solution before, not one of this blades show until now new active corrosion.
But in general I agree, it can't hurt! I only want to state that it wasn't really required. And a more easy way would have been a direct polish.

Originally Posted by kai

any harm done in this case - we all have seen much worse restoration attempts, I believe!

For sure! So please don't push Apolaki to remove the hilt. Who get a small shock when he realize that he need to polish a blade (sorry Apolaki ) will have a great problem to fix the hilt later again proper. All my Moro kris blades I have restored by self never I have dismantled the hilt, the result is in many cases visible at this place, just search a little bit.
Yes, it's a little bit circuitous to polish a kris blade with attached hilt but for sure more easy as to dismantle a hilt and more to reattach it proper again IMVHO.

Regards,
Detlef

[Sajen]

By this pictures (taken from Gustav) you can see, how a kris hilt is constructed in many cases and I think Apolakis kris hilt as well. When the brass bands get broken when you want to dismantle the hilt you need to open the binding and you have a difficult restore object. It can be done but only for experienced persons.

Regards,
Detlef

[Ian]

Originally Posted by apolaki

... when I take it out of the bath to rinse it off with water and scrub it smells REALLY RANCID AND PUNGENT!!!! (Is it a toxin or hazardous to inhale)? My mind may be going overboard, but I wonder if it's arsneic or something? ...

Foul smelling liquids are often contaminated with bacteria and molds. Vinegar contains plenty of nutrients for microorganisms to grow in an aqueous medium. When you say it smells "rancid," I think you are referring to products resulting from microbial contaminants rather than a toxic gas being emitted from acid contacting the metal of the blade.

One possibility might be hydrogen sulfide ("rotten egg gas") if there is any sulfur in the metal. I've not heard of this being a problem with acid etching of steel/iron. Perhaps others have some more information on that possibility. Otherwise, I think your term "rancid" probably covers what is happening here.

Ian