Category Archives: Customized Blades

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 info@roninsgrips.com.


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 info@roninsgrips.com.


20 tips for getting better results with epoxy

I use a ton of epoxy as part of my work plus fixing all kinds of stuff at home, on cars, guns, knives and more.  I’d like to take a few minutes share some lessons learned with you to bear in mind on your next project that involves epoxy:

  1. Buy quality epoxy – not cheap junk.  Epoxy is a generic term and a lot of the no-name blister pack retail stuff is crap.  Go for brand names.  If they list real specs about the formulation then it is probably legit.
  2. I recommend industrial epoxies and not the consumer stuff.  My hands down favorite epoxy is Brownell’s Acra Glas liquid.  It is strong and resists breaking down from repeated impacts very well.  It’s one down side is that it takes a long time to set up so it may not be your best bet if you need something to be fixed and back in service quickly.
  3. Know your application and match the formula to your need – there is no magical formula that does everything.  You may need a putty, a fast cure, a short pot life, higher heat resistance, improved impact resistance, shear strength, etc.  Figure out what you need and then look for the epoxy that will work best for you.  At any given time I probably have 3-4 different formulations on hand.
  4. The longer it takes an epoxy to cure the stronger it is.  All things being equal, an epoxy that cures in 24 hours will be stronger than one that claims to do so in 5, 10 or 30 minutes.
  5. Read the package – setting up vs. curing and reaching full strength are two very different things.
  6. If you want to get epoxy to flow into wood or difficult areas, heat it up.  The liquid thins as it warms up but note this will also speed up how fast it sets up and cures.
  7. As epoxy gets colder, it takes longer and longer to cure.  If you are working outside, use a space heater, flood light or other heat source to keep the epoxy and the work piece area being repaired at least 70F.  I shoot for 80-90F.
  8. Epoxy can get really thick as it gets cold and not want to come out of the containers.  Either keep it inside where it is warm or at least warm it up before you use it,
  9. Epoxy resin can sugar with age just like honey.  What I mean is that will develop a solid mass in the resin bottle – it’s not really sugar!  If you heat up a container of water, take the resin container’s lid off and then set it the container in the water, the resin will warm up and the solid will dissolve back into liquid.  I buy 28oz or larger bottles of Acra-Glas that I don’t always use right away so when it sugars, I do this.
  10. As mentioned above, I buy my epoxy in bulk.  Acra-Glas can be measured by volume and it has a ratio of 1 hardener to 4 resin.  The way I deal with this is very simple – I use 10cc syringes without needles.  I have on syringe in a cup that I use for hardener and one syringe stored in a cup that I use for hardener.  The reason I do this is that the two parts do not react to the air very fast.  I may be able to use one syringe for a several weeks/months before it stops working so I set the syringe in its dedicated cup when done to be used again.  I do not use fresh syringes every time.  A 100 count syringe pack will last me at least a year.
  11. You can definitely color epoxy.  You can buy purpose-made dyes such as So-Strong or add in powdered tempra paint.
  12. You can add fillers for strength or looks.  When filling gaps, I mix 1/32″ milled glass fibers with the epoxy.  The ratio depends on the epoxy you are using, how thick/pasty you want the result to be or how much you want it to still flow into place.
  13. To get rid of bubbles you either need to draw a vacuum, apply pressure or at least use a heat gun to thin the epoxy once it is applied and this allows the trapped air to escape.
  14. When I am gluing big objects together, such as wood panels, forms, or other construction I will use a cartridge based epoxy.  My favorite is Hysol E-20HP.  To use a cartridge, you need the dispensing gun and also the correct mixing tip.  This allows you to squeeze the trigger and properly mixed epoxy comes out of the tip.  When you are done, you just let the tip harden in place sealing the epoxy.  When you are ready to use the gun again, you simply remove the plugged tip with a new one.  This allows for you to deploy a bead of epoxy very quickly but the con is that you throw away a tip every time you stop.  You also can’t color the epoxy first but it is fast and convenient on larger projects.
  15. The surface must be clean for epoxy to work best.  Remove dust, dirt, oil, etc.
  16. A rough surface is always better than a smooth surface.  I always recommend sanding, brushing or blasting a surface to improve adhesion.  Not only do you increase the surface area but you also are creating a texture where the epoxy can get under the base material in thousands of tiny places to really grab hold.
  17. Wear disposable gloves to avoid making a mess.  I buy boxes of the Harbor Freight 5 mil nitrile gloves when they go on sale for $5.99/box of 100.  They really are a good value for a medium-light duty disposable glove.
  18. If you need to clamp parts together, wrap the assemble with wax paper to avoid gluing your clamps to the work piece – yeah, I’ve done that.
  19. Whenever possible, I prefer to clamp work together to get this best bond.
  20. Check, double-check and come back in again later and check your work again to make sure nothing has shifted.

I hope these tips help you with your next project.


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 info@roninsgrips.com.