Tag Archives: acid etching

AKBuilds, Blades and Edged Weapons Including Khukuris, Firearms Building and Gunsmithing, Gunsmithing, Sten, Uzi Builds

How to do Home Manganese Parkerizing

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The Following is a Basic Do-it-yourself Manganese Parkerizing Formula

A couple of friends online, Elkaholic and Ding, got me interested in parkerizing years ago and gave me a home brew formula and process steps they use.  I have been tuning that formula for a few years and thought I would share it as I use it both for blades and firearms.  It works great as either the base for a top finish, such as Molyresin or as a finish all by itself.  You may be wondering “why not just buy a premade formula such as the great parkerizing solution from Brownell’s” – the short answer is because tinkering can be fun and more rewarding.  I like to experiment and try different things.   So, with that said, here is the recipe:

Ingredients

– 2 gallons of distilled water  (it gives more consistent results because impurities have been removed – sold at supermarkets and drug stores)
– 2 “biscuits” of clean plain 0000 steel wool (thinner steel wool dissolves faster hence the use of 0000 grade)
– 1 cup of Klean Strip brand Phosphoric Prep & Etch (or other phosphoric acid etching solution around 35-45% concentrate per the Prep & Etch MSDS sheet. Dilute the acid if higher. For example, if 100% pure then go 60 water:40 acid – you can always experiment with the ratio that works for you)
– 6 rounded tablespoons of manganese dioxide (available at pottery supply stores, Amazon or eBay)

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Do this outside – never in your house or shop (unless you have a great vent hood).  If you do it indoors, you will likely make stuff rust fast!

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As you can see, I use a camp stove.  For the first couple of years I just used a Coleman stove but that was always a balancing act with my 48″ long stainless pakerizing tank that I used for barreled actions.  I found the above great Camp Chef stove at Amazon and it is fantastic but any heat source will work. I like propane because its portable and not electric (to avoid any chance of electric shock) and there are tons of propane camp stoves on Amazon.

Also, be sure to use stainless steel for your tanks.  I watch for sales or buy stuff off eBay.  The big cooker above is from Walmart and the rectangular pan shown below is from Amazon and is normally the water pan for buffet lines.

For tongs to move stuff around, use solid stainless.  I tried the plastic ones and they can leave a plastic residue on blasted surfaces and mess up your finish.

Just like baking, if you want more of the solution, take the recipe and multiply it by two, four or however many multiples you want. Just be sure you have a place to store it when done.  I use 5 gallon jugs and label them.

Steps to Follow

  1. Add acid to water in a stainless pan/pot and heat to 190F – don’t boil and waste it.  I use a baking thermometer clipped to the side of the pan.
  2. Spray each wool biscuit with brake cleaner to remove oils and allow each time to dry
  3. As the solution warms shred the steel wool into the liquid and add the manganese dioxide
  4. Let the mix simmer and dissolve the steel wool before adding parts
  5. I always blast my parts before I parkerize them – I’ve heard guys tell about using a wire brush on a buffer or drill press as well but I’ve not tried that.  Blasting removes the oxides and exposes the bare steel.
  6. Make sure your parts are very, very clean and degreased — only handle with rubber gloves after they are cleaned or oils from your skin can mess things up
  7. You can suspend your parts in the liquid with stainless wire.  Leave them until the fizzing stops or about 30-40 minutes.  The time varies.
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  8. Rinse the parts with boiling water thoroughly to remove the acid.
  9. Spray parts with WD40 to get the water away from the steel
  10. Wipe down with oil or apply whatever secondary finish you want – don’t do both 🙂  If you are going to apply a finish on top of the parkerized surface, use acetone or brake cleaner to remove any oils and then follow their instructions.

At the bottom of the post are links to Amazon products including long parkerizing tanks.

Cleaning Up

When you are done, let your mixture cool and strain the liquid through a coffee filter into a plastic can for future use. I use a blue kerosene 5 gallon container because it is a different color from all my other 5 gallon containers plus I label it.  Point being, you do not want to get confused and pour this stuff in when you meant to use a fuel, etc.

The precipitate, the stuff on the bottom, should be scooped onto a shallow pan, allowed to dry and be disposed of as a hazardous waste.  For example, where ever your community collects old paints, batteries, etc.

Brownells Has Great Parkerizing Solutions and Kits

Brownells sells very well regarded ready-to-use formulations. I have no hesitation at all to recommend the below items to you – they are top notch.

  • Click here for their manganese parkerization supplies. Their formula meets Mil Spec STD171
  • Click here for their zinc parkerization supplies
  • If you have a lot small parts you want to park, they have a bench top kit ready to go that you can buy – click here
  • Click here for their complete parkerizing tank system. This is a complete system for gunsmiths or others who need to park everything from small parts and pistols up to firearms and swords.

In Summary

I hope this helps you out. I’ve used the above many times and the results are solid.

Updated 2/13/24 with new sources and fixed some grammar issues.

Note, I have to buy all of my parts – nothing here was paid for by sponsors, etc. I do make a small amount if you click on an ad and buy something but that is it. You’re getting my real opinion on stuff.

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com. Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.

Tools

Cleaning Up My Grandfather’s 18″ Ridgid Pipe Wrench

Like so many of my stories, this one begins as so “One day I was in my shop and ran across and old rusty tool that was still functional”. Let’s start with a bit of backstory.

My grandfather immigrated from Quebec along with his brother to the Boston area to improve their lot in life. They’d grown up on a farm near Compton, Quebec, and somewhere along the line had picked up the skills necessary to service heavy machinery. He’d tell my dad stories of working on various machines who then relayed some of them to me.

My grandfather had a family, including by dad of course, somewhere near Rockport and eventually bought a farm in Derry, NH, sometime in the late 1930s or early 1940s where he raised dairy cattle, grew hay and what not. Along the way he amassed quite a few tools that then passed on to my dad.

One of these tools was a rusty 18″ pipe wrench that I recall my dad using on a number of occasions and when my dad passed away, I got the tools, including this old wrench.

So, I’m in my shop moving stuff and uncover this big 18″ pipe wrench that I then took a lot closer look at. Interestingly enough, it was made by Ridgid.

Ridgid and the 18″ Pipe Wrench

For years I thought Ridgid was a made-up Home Depot house brand. Actually, it was founded in 1923 in North Ridgeville, Ohio, and moved to Elyria, Ohio, in 1943. What got them started was the invention of the modern pipe wrench. In 1966 it was bought by Emerson Electric and today it sells a lot of different tools including hand tools they make, power tools by Techtronic Industries of Hong Kong and Wet Dry vacs made by Emerson.

This 18″ pipe wrench was rusty but solid. The jaws were still sharp and nothing was cracked or bent.
You’ll notice it does identify the Ridge Tool Company as being in Elyria so that tells us it was made after the move in 1943.
The original patent was 1549164 from August 11, 1925, and was then updated to patent 1552091 dated September 1, 1925. Now the patent tells us a bit more. 1727623 was filed on September 10, 1929. The next pipe wrench patent was 2051755 filed on August 18, 1936. [A big thank you VintageMachinery.0rg having this info online.]

Now if you read the caption of the photo above, the 1727623 patent was in 1929 and 2051755 filed in 1936. That patent was actually split into two and an additional patent 2076830 was filed in 1937. I’m going to go out on a limb and bet that wrench was made somewhere between 1929 and 1937. The compression spring in the wrench is a leaf design and not conical so that does put it prior to 1937 patent.

In reading, guys report the markings as not being very reliable and company records incomplete so the above is really a best guess but it does basically align with when my grandfather would have been buying tools.

So I had a decision to make – leave it alone and let it rust or clean it and apply paint. Well, it’s not like these wrenches are rare collector pieces and this was a tool I would use going forward – seriously, other than being rusty it was good as new.

Removing the Rust

I considered three options – abrasive, electrolytic or acid. The rust was actually pretty light and I opted to go with acid – notably a combination of apple cider and phosphoric acid.

The first step was to spray down the wrench with brake cleaner liberally to get rid of oils. Next, I put a wire brush in my hand drill and removed all of the loose rust and dirt from the wrench body, nut and jaw.

I used brake cleaner to remove the initial oil as well as just before I inserted the wrench into the acid bath.
Getting in a bit closer, note the sole remnant of red paint to the right of the RIDGID logo on the handle of the wrench.

The acid bath was a gallon of grocery store bought apple cider vinegar plus about a quart of Prep-N-Etch phosphoric acid. Apple cider alone would do the job but I was re-using apple cider and I wanted to make sure there was enough acid to do the job.

Now a trick to really get things done is to heat up the apple cider bath and get it warm – you don’t need to boil it. I don’t bother with a thermometer for this – just hot to the touch. The reason why is that heating up a solution speeds up the chemical reaction. If it’s cooler then it just takes longer and if it is boiling off then you are losing liquid needlessly.

This is a full size stainless buffet / chafing pan that I use for acid etching and parkerizing – I clean it after each use of course. Underneath it is my big two-burner Camp Chef Explorer stove that is awesome for heating up tanks with acid or park solution. There are all kinds of different sizes of chafing pans by the way full, half, third, etc. and you can see them first had at restaurant supply stores like Gordon Foods, Sams Club sometimes has them, etc.

Please remember something – do this in a well ventilated area or outdoors or the condensation will cause exposed steel to rust. It’s a very weak acid solution and while the vapors aren’t something you should be breathing, I would be more worried about causing rust if I were you.

Before I put the wrench parts in the warm/hot acid bath, I really hosed them down with brake cleaner one more time while wearing nitrile gloves. The reason for the gloves was mainly to keep oils from my skin from contaminating the otherwise clean surface. Oil will block the acid. The hot bath will remove some oil but it is contaminated at that point and must be discarded.

The bubbles are caused by the chemical reaction between the rust, steel and acid.

I checked it every few minutes and when all the rust was gone, I pulled it out, hosed it down liberally with water and then used WD40 to displace the water and reduce the odds of rusting. This is what WD40 was meant to do – water displacement formula 40.

At this point it was getting dark and I decided to wait until the next day to point the wrench but here’s what it looked like at that point. The next post will be about painting the wrench and the end result.

By the way, I’ve written on using apple cider to remove rust from tools as well as formal manganese parkerizing before this so you can click on one of the links to learn more.

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com. Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.

DIY - Do It Yourself, Tools

Acid Etching With Ferric Chloride and Apple Cider Vinegar – Wicked Results on High Carbon Steel

I recently did two posts about building a new heated tank out of PVC pipe and a digitally controlled heating element that is both effective and affordable. This also marked my first batch of blades where I moved from my traditional hot apple cider etching to using a mix of 70% ferric chloride and 30% apple cider vinegar heated to 90-94F.

The Chemicals

Let me give you a quick overview of the two chemicals I used to make my blade etching solution:

The primary ingredient is liquid ferric chloride from MG Chemicals. It’s available in quarts and gallons and is about 38-42% ferric chloride by volume. The MG Chemicals product is well regarded and that played a big factor in my selecting it. I purchased mine from Amazon and it arrived quickly and well packed.

The second chemical is regular apple cider vinegar from the grocery store. They tend to be normalized around 5% acetic acid by volume. The brand I used was at 5% and there were other brands at 4% that I passed over – go for 5% because you need the acetic acid. I literally bought this at my local grocery store – nothing special.

The solution I made was 70% of the ferric chloride and 30% apple cider vinegar. I wore lab goggles, nitrile gloves, old clothes and am in a well ventilated area when I slowly add the ferric chloride to the relatively weaker apple cider vinegar.

The ratio was based on looking at the end results from other blade smiths and talking about what they learned. In my case, I can tell you that this combination makes for a very nice dark etch.

The Process

  1. Heat the etching solution up to 90-94F before I put in the first blade. MG Chemicals recommends the operating range from 94F to 131F and not to exeed 131F. [Click here for their technical data sheet and MSDS]
  2. The blades need to be at least 70F prior to dunking in the solution. The warmer the solution and blade, the better chemical reaction you are going to have.
  3. Clean the blade with brake cleaner throughly
  4. Abrasive blast the blade – I am using Black Beauty these days. It is a coarse coal slag based product. Note, not all guys blast their blades – some just clean them very carefully.
  5. From this point on, wear nitrile gloves when handling the blades to avoid any oils and contaminants from your skin
  6. I again use brake cleaner to do a final cleaning and make sure it fully evaporates. Some guys rub down with acetone – do what works for you but it must not leave a residue
  7. Fully submerged the blade in the heated etching solution for 10 minutes
  8. Remove the blade and wipe off the remaining solution with a paper towel [as a reminder, you must be wearing gloves to not contaminate the blade]
  9. Used clean/bare 0000 steel wool to buff the surface of the blade and remove any loose particles. Note, this 0000 steel wool is bare wool – no cleaners or anything. You find these in woodworking / hardware sections of stores – not in the kitchen area.
  10. Submerge the blade for another 5 minutes and again wiped and rubbed the blade down with steel wool. I think I repeated this process three times per blade but experiment and see what works for you.
  11. Soak the blade in warm water with baking soda to neutralize the acid
  12. Spray the blade down with WD-40 to displace the water
  13. Apply finish – I like to use a 50-50 mix of boiled linseed oil and turpentine to apply severa thin coats. This gives my blades the worn post-apocalypse look. Many guys just coat the acid etched surface with oil to inhibit rust.
Here’s a small 5″ khukuri where all steel surfaces have been blasted.
Here’s the finished khukuri just before I mailed it to its new owner.
Here’s a look at the solution in the tank.
Here is one of the etched damascus blades. The beads on the blade are oil.
Here’s an even closer look at the finished blade.

Summary

I’m definitely very happy with the results and will be using this solution going forward.

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com. Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.

DIY - Do It Yourself, Tools

How to Make An Affordable and Effective Heated Tank For Acid Etching – Part 1

I like to acid etch blades that I build using apple cider and/or ferric chloride. I also manganese park firearms and tools. Assuming the part is prepped properly, there are two common needs in all of the above – the part must be submerged and the solution heated. So you have two options, buy a stainless tank and heat source or build one using PVC pipe. These next couple of posts are going to dive into how you can build an affordable and very effective heated tank to finish you parts plus have some fun doing it.

PVC or CPVC?

We can use rigid PVC pipe as the container to hold the etching solution. It’s cheap, easy to find and easy to work with. I need to explain a few things first about what we can and can’t do with it.

In plumbing, rigid PVC pipe has an operating temperature of 140F degrees. The reason for this is that PVC is a thermoplastic and begins to soften with heat and will burst due to the pressurized water. We don’t have much pressure to worry about other than atmospheric pressure but you don’t want to push plain PVC towards 200F – it really isn’t designed for it.

If you want to do parkerizing at 190F, then you need to use CPVC pipe. CPVC rigid pipe has extra chlorination that allows it to withstand 200F while delivering water under normal household pressures. Fun trivia, CPVC was invented by Genova Products in Michigan.

If you are trying to figure out what you are looking at, if the pipe is white, it is probably PVC. If it is cream colored, it is probably CPVC. It ought to be labeled/printed on the side of the pipe also but be on guard for people putting stuff in the wrong bins at a store or clerks not knowing what is what.

In this post, I am working with regular PVC purchased from my local Ace Hardware because the tank is for acid etching knives and will the liquid will be 90-110F on average. If I ever build one for parkerizing, it would be in CPVC. The reason it’s an “if” is that I already have a big stainless steel parkerizing tank but it’s a headache to drag out and set up whenI need it.

The Parts List

Basically, we are going to build a tube with a cemented permanent cap on the bottom and a threaded cap at the top. You can go with any size you want. For most blades I work with, 3″ is plenty and I wanted it to be portable.

Let me give you a piece of advice – it’s aways better to be a little bigger than you think you need than to find that out later. When in doubt, make it wider and taller — within reason of course. Note, I knew a 3″ diameter and about 16″ tall would meet most of my needs but not all and I was fine with that. I’ll pull out my four foot stainless tank when I need to do something huge like a cleaver.

In terms of parts, you need the following:

  • A length of pipe of the diameter that is needed
  • A coupling for that size
  • A threaded adapter for that size – you cement it onto the end of the pipe and it gives you a national pipe thread on the other end
  • A threaded plug that fits into the adapter
  • An end cap of one type or another. If you use 3″ or 4″ pipe, you can use a toilet flange adapter to actually both plug the end and allow you to connect it to the wood if you aren’t making it very tall. I would be worried about torque on a tank with an overall length of 24″ or more. In those cases I would cement on a normal end cap and build up a crade around the pipe to support it.
  • You may want a drain for a big tank – I didn’t need one for this little unit because I can easily lift it even when it is full of the acid etching solution.
  • PVC cleaner and cement (note, PVC and CPVC use different cement)
  • Wood to form a base to keep the pipe from tipping over so it needs to be both wide and heavy enough. Really it’s up to you as to how you secure it to be vertical. I like a mobile base but you could tie it to something, etc.
  • A heating source and controller – we’ll get into more detail in the next post.

Weight Considerations and a Drain

Bear in mind that this tank can get pretty heavy if you plan on using really big piple (6″ or bigger). Water weighs 8.34 pounds per gallon. You will find that other liquids can weigh more. Apple cider vinegar may be around 8.6 pounds and ferric chloride might weigh 10-12 pounds per gallon depending on the concentration.

I bring the weight up because if you are thinking of building a big tank, the weight is going to add up and you may want to install a drain near the base. There are two big reasons you need to think about this – you may want to move the unit around plus you will need to change the solution as it ages and breaks down from use.

This is my 3″ tank I just built. The toilet flange us availab;e for 3″ and 4″ pipe and is handy for smaller tanks. I’d build a cradle/surrounding frame to support a bigger tank.

The pictured tank is about 16″ tall with 3″ pipe and has about a gallon of 70% ferric chloride and 30% apple cider vinegar in it. I can move it around very easily and portability was one of my design goals.

Assembling The Pipe

PVC is really easy to work with. You cut the pipe to the length you want or have the store do it for you. I use a big miter saw for stuff like this to get nice square ends and use an airline to blow all the loose plastic out (wear safety glasses).

To “glue” the pipe together, you first prime the surfaces and then apply the cement. Note, PVC and CPVC use the same primer but different cement. In this case,I use Oatey’s purple primer and clear cement. Read the directions on their box just to make sure. Bear in mind the solvent is really thin and is going to run everywhere – especially in cold weather.

I’m a creature of habit. I’ve had very good luck with Oatey products so I stick with them. There are other brands out there such as Ace’s own private labled stuff, but I stick with Oatey to avoid surprises. When following their directions and using their products, I’ve not had a joint fail/leak yet,

The Base

To make the tank stable, you need a big enough base both in terms of area and weight. I had some old 1×12 stock that I chopped into squares and stacked if four deep for weight. You can do whatever you want and your goal is stability, however you get it.

I centered the flange on the first board and screwed it in. I’m not sure I would trust the flange to handle the potential torque of a long pipe. For me, once I get around 24″ overall, I am going to build a cradle and not subject that flange to a ton of stress.
I then applied epoxy and clamped the layers together. I was kind of experimenting as I went. Just one piece of wood wasn’t heavy enough so I then added the additional layers after. I could have glued the base and then used longer screws to secure the flange had I known more up front. I wound up with four layers of wood in the end.

I have another tank that is full of a boiled linseed oil an turpentine mix that I use for hydrating wood handles in khukuris and cleavers that I restore. It has a rounded end bap on the bottom and the base is more like a heavy cradle made up fo 2×4 lumber that gives it weight and then goes up the sides to provide support.

This is a 4″ pipe with a wood scaffold base. It’s very stable. This is a tankI use for moisturizing and treating long wood hanndles.

Summary

That’s it for now. In the next post we are going to talk about heating the tank. This is where I did the most experimenting and can share some ideas with you.

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com. Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.

DIY - Do It Yourself, Gunsmithing, Tools

How to Make An Affordable and Effective Heated Tank For Acid Etching – Part 2

In the last post, I covered the basic construction of the tank. In this post I want to talk about heating the tank. Thanks to mass production of digital temperature switches, you can build a digitally controlled heated tank for a very reasonable price.

Why Does Heat Matter?

In case you are wondering, heating the solution does matter. Years ago, in 1889, a chemist by the name of Svante Arrhenius proposed an equation that would later bear his name. Basically, a chemical reaction increases as the level of activation energy increases. The reason temperature enters in as that you are raising the energy in the liquid, more energetic particles are bouncing around and increasing the volume of reactions which means that more successful reactions will occur as well. We can use a rule of thumb that for each 10C increase in temperature, the reaction rate will double and for each 10C drop, it will be cut in half. To sum it up, cold=bad for chemical reactions. As a side note, this is also why marginal batteries fail when cold weather hits.

So what this means to acid etching is that in my cold unheated shop in the Winter, reactions are going to be real, real slow. Thus, I must have a way to heat the chemical and the submerged part to improve the reaction.

The Heating Element For The Tank

The first thing I wanted to do was to keep the cost down and the second was that I didn’t want something that would get so hot that it would melt the PVC. I had a 30 foot length of roof heating tape from when we cleaned out my dad’s garage that I had been thinking about for a while. It always makes me feel good when I use something that was my dad’s. (There are tons of options on Amazon – click here.)

These roof heating cables use AC voltage to warm up and melt ice are readily availble and are designed not to get so hot that they melt the shingles but also are designed to be spread out and not right next to each other so I was going to need to test the design. I planned to wrap the tape from the bottom of the tank until I ran out cable with each coil right against the previous. I was counting on convection of move warmer fluid up and cooler fluid down but I wasn’t really sure how it would sort out.

Another nice things about these heating cables, or heating tapes, is that they do not use a lot of electricity. The 30 foot model my dad had was spec’d to draw only 150 watts at 12 volts. That makes for a nice portable unit that you can run off just about any extension cord.

So, step one, I applied the tape to the empty tank and secured it just with 3M 3340 aluminum HVAC tape. This is the tape made for higher temperatures with an aluminum foil backing – it’s not dcut tape. I then watched the temperature with my Fluke 62 Max IR thermometer. You need an accurate thermometer and the Fluke has served me very well – it’s proved itself to be accurate, reliable and durable – it’s been bounched around a lot in my shop.

So, the temperature slowly climbed but made it all the way up to 170F before I shut it down. The PVC still felt pretty good but it was way hotter than what I wanted. Just plugging the tape in and calling it done was not the answer. Sure it would heat the liquid up fast but I couldn’t safey leave it unattended. I needed something to control the temperature but use the heat tape.

Please note that there are pipe heaters that are a different creature. Some of them need to be submerged in water or wrapped around a steel pipe. Do not use those types of heaters. There are a ton of different names buy you are looking for the cable or tape that is put on roofs to melt ice dams, etc.

Solution – Use A Digital Temperature Controller

I thought I knew the switch I was going to buy until I did some further research. Some controllers are very easy to set up and others seem a bit more confusing. I opted for the WILLHI WH1436A Temperature Controller 110V Digital Thermostat Switch. All you do set set the temperature for ON and the temperature for OFF. That’s it. If you want them, there are some more advanced settings that you can explore if you want but this seemed like just what I needed.

I undid the top few coils of the heat tape and rewound them with the temperature probe wrapped in them. I then used aluminum HVAC tape to secure the top. I set ON to 90F and Off at 95F and plugged the roofing tape into the controller.

I inserted the temperature probe a few coils down and secured the top with 3M Aluminum HVACtape. Note the small cable clamp screwed into the wood base securing the bottom of the heater tape and preventing it from unwinding.

I started watching with the Fluke meter and since the temperature based on the probe was 40.2F, the controller turned on power to the switch and the tape heated. It did cut power around 95F but the tape continued to warm up even so by about 10F so the peak temperature was between 103-105F according to the Fluke. This was actually within my acceptable range. I was just ballparking 90F but even 105F was fine by me.

The digital controller works well. I’m going to leave it loose some I can move it around depending on what I am working on and were.

There was one minor hitch I noticed during experiments – the controlled heat took over an hour to warm up the fluid. If I unplugged the tape from the controller and plugged the tape straight into AC power, the fluid heated way faster and the pipe never felt soft – probably because the tape was heating part of it and the acid was cooling it. This was the fastest way but risky because if you forget, it’s going to get quite hot. I let the fluid get up to 160F during one run and decided that I would only do this if I was in a big rush and going to be there working the whole time. If I wanted to play it safe, letting the controller keep things safe was a better bet. I could have also sped things up by setting the OFF temperature higher, say at 110F and that’s something I will experiment more with.

The temperature controlled tank worked out great on these high carbon steel damascus blades.

Operating Temperature Range

Do not heat ferric chloride past 131F. Remember that the heating element will still heat the chemical another 10 degrees or so past the upper limit you set as OFF.

The operating temperature range from MG Chemical is 95-131F. Based on my results, I don’t see a need to push the upper limit.

Click here both for their technical sheet and MSDS sheet,

Conclusion

I had about $30 in the PVC and fresh glue, nothing for the base, the controller was $29.99 and the roof heat tape was free but if you bought it, the price would be around $30. This definitely falls in the affordable category plus I turned out some really cool etched damasus blades using the controlled tank. If you want to know a bit more about the chemicals and my process, click here.

When I was done, I let the tank cool down, screwed on the lid, cleaned things up, coiled the cords up and stored the tank for the next use.

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com. Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.

Blades and Edged Weapons Including Khukuris, Gunsmithing, Tools

Acid Etching Steel With Apple Cider Vinegar

2 Comments

Some folks have asked how I get the dull grey look on khukuris that I used to work on.  The answer is simple – apple cider vinegar straight from the grocery.  I’ve also experimented with various ratios of Prep-and-Etch, which contains Phosphoric Acid, and gotten a darker color but apple cider works remarkably well.  Apple cider vinegar contains 5-10% acetic acid (CH3COOH) depending on how it is made.  For example, I read that Heinz is about 5%.  My local store carries Spartan brand, which is their store brand, and it works just fine – again, this is apple cider vinegar from the grocery store.  

This process only works with steels that can rust.  For example a mild steel or high carbon.  It will not work on stainless, aluminum, etc.

Safety Notes:

I would recommend doing this outside or some place very well ventilated or else if the acetic acid condenses on metal surfaces in your shop/garage, it will cause rust.

Wear safety glasses and don’t goof around with the stuff.  I’ve never had a problem but probably need to say some kind of warning here.

Process:

  1. Clean the part and remove all oil and grease.  Either hose it down really well with brake cleaner or soak it in acetone.  Any oil, even from your skin, will mess you up.  
  2. Abrasive blast the part – I use “The Original Black Beauty” media that I get at my local farm supply store.  It’s made from coal slag and is fairly environmentally friendly.  It does break down quick so if you use your blast cabinet a lot, be prepared to clean it out and add new media when performance starts to suffer.  Blasting will get you a really nice uniform surface color.  I suppose you could try sanding or wire brushing but blasting has worked the best for me and is all I do now.  My only recommendation is not to use sand because as it breaks down it creates a fine dust that will never come out of your lungs – read that as “bad”.  I do use a blast cabinet with a vacuum to get rid of dust, you could do this outside with a hand blaster or tank blaster and dust mask if you needed to.  I wear a hood when blasting outside as the media goes everywhere.  Just protect yourself is the bottom line.
  3. Wear rubber gloves and clean the part again – the gloves are to keep oils from your skin from contaminating the part and preventing etching.  Cleanliness is critical.
  4. Put the part in cider that is at least 70 degrees.  I like 100-150.  If it is too cold the reaction slows waaaaay down.  I don’t like to get it super hot or boil it as you lose a ton of cider with no real benefit.  I have done this in everything from stainless steel containers to plastic containers and even plastic trays used for wallpaper with halogen lights warming it up.  In general the colder the cider the slower the etching and the hotter the cider the faster the etching bearing in mind you will have the cider evaporating faster.
    Note:  If you do not see bubbles coming off the part then either the solution is too cold (especially on cold days under 70F), the part is not clean or ready (so clean and blast it) or the cider too weak.  I’ve never had an issue with weak cider – always the first two.
  5. Submerge the part in the acid and let it sit for 15-30 minutes.  It’s not a strong acid so there’s no rush.  Just check the part and stop at the color you want. The warmer the water and the part, the faster the reaction and vice versa.
  6. Rinse with hot water
  7. Rub down with WD40 and steel wool to get the loose particles off
  8. Then I like to seal it with boiled linseed oil (BLO).  Some of you may know BLO for woodworking but it is an old school rust inhibitor.  If you don’t want BLO, then thoroughly oil your part.

I like the results.  No real harmful chemicals are used, it’s cheap and looks great.

3/4/2020 Update: I recently did some blog posts on building a cost effective digitally controlled heat tank from PVC pipe that is perfect for acid etching – click here for that one. I’m also using a ferric chloride and apple cider etching solution now – click here for that one.

Photos:

The light brown solution is just apple cider.  If it is darker, it was 25-50% Prep-and-Etch + the vinegar.

Use whatever container works. These were from a bunch of zip ties I bought once.
You can see the abraded surface from the abrasive blaster. You can acid etch without this step but I find doing this first really makes for a good finish plus all the tiny nooks and crannies really let the BLO grab hold.
This one is getting ready to go it. I use WD40 when done to remove the water – it literally means “Water Displacement” forumula 40 and excels at that.
You will see lots of little bubbles. I go by the color of the etched steel more than I do the degree of fizzing or time.
These two have already gone through the process.
I like the post apocalyptic look it gives.
This giant cleaver was acid etched and then sealed with BLO.
Another angle of the big “splitter”. The blade is over a 1/2″ thick!
Another cleaver.

Abrasive Blasting

You can usually get a coal slag blast media very, very cheap from farm stores.  Check there first because off Amazon you are paying a pretty penny for shipping whether they bury it in the item’s price or call it out separate.  I think I pay $7-9 per 25# bag at Family Farm and Home.

This is the actual product I use:  http://www.blackbeautyabrasives.com/products/black-beauty-original-abrasives.php

Now for the blasting, you have tons of options – hand blaster for small work, siphon blaster, pressurized tank or cabinets.  It all depends on how much blasting you plan to do.  I started out with a siphon blaster – dirt cheap but very slow.  I then got a tank and it was very fast and portable but media went everywhere.  I still have that for working on cars and big parts.  However, for my grips, gun parts and knives, I use my blast cabinet.  I have a Cyclone brand large bench unit and am relatively happy.  If I had it to do over, I would have gotten a free standing unit with a bigger and deeper hopper so I’m not constantly hitting the side or moving media around by hand.  I have a foot control pedal and that really helps plus it gets a the pneumatics out of the cabinet where they would normally be subject to abrasive dust and wear.

Cyclone Manufacturing
http://www.cycloneblasters.com/

My pressurized tank blaster is a Harbor Freight unit.  It’s held up relatively fine other than my constantly wearing out valves and tips.  The tank itself is just fine.
http://www.harborfreight.com/40-lb-pressurized-abrasive-blaster-68992.html

Summary

Acid etching is easy and rewarding. I like using BLO to seal things partly because of the color it imparts.

I hope this gives you some ideas!

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