Friday, October 13, 2017

The magic of muriatic acid


      I was working on a new coat hook design and working through what screws to include with the hook when I realized that there is no perfect screw that will work for every application.  This is sad. What follows is my attempt to help rectify this for the average person. Or perhaps the person with no fear and time on their hands.  

The coat hooks I'm working on.  These are made from scrap square bar. Slotted screws not hammered.  





Hammered Phillips head screws.  You can see how rough the slots are.



Hammered Phillips head screw. 
   


     I think if you are reading this you probably have a fantastically funky home and amazingly wonderful taste.  It follows that somewhere along the line you bought some forged hardware because ...hey...it's beautiful.  You may have gotten it online from one of the big players (or a small shop like mine) or at a festival or even from the local hardware store, but when you tried to install it you discovered that the screws aka mounting hardware didn't work for your situation.  They might have been the wrong length or the wrong type or maybe there wasn't any mounting hardware.  The supplier of the beautiful forged  hardware was no help, mostly because they are not me, so you went to the local hardware store and got some screws that would work.  Those new screws were perfect except they were bright silver and not the wonderful color of forged iron.  Rather than live with that you either returned the forged hardware in frustration or maybe you painted the screws, or if you are like me, you colored the screws with a Sharpie.  (This is not a paid endorsement.  I'm not opposed to paid endorsements so if you want to pay me to endorse something, drop me a note.)    I admit to using a Sharpie on occasion to fix a color issue on my hardware.  I'm helpful, not perfect.


     There are, however, a couple of other probably better solutions to the bright silver screw or bolt problem.  For this muriatic acid solution the screw has to be zinc plated.  I think it's also called hydrochloric acid.  It can't be stainless steel or nickel plated although you can darken both of those too.  I'll get to that later.  The easiest at home solution to darkening zinc plated screws is muriatic acid.  If you have a pool, you already have some.  If not, it's pretty cheap, comes by the gallon, and can definitely hurt you and possibly kill you if you aren't careful.  Also it's available at all the usual home improvement stores.  The important thing for this application is that it dissolves zinc. 

A really bad picture of zinc plated screws
      In order to get the zinc off the screws they need to be immersed in the muriatic acid.  The guy I learned this from used a piece of steel wire to dip the screws in the bottle of acid.  It only takes a couple of seconds.  I like the acid to remain fresh and I do this a lot so I usually pour a little acid in a plastic cup and drop the screws in.  For the samples in the pictures, I just put a little acid in the lid. 
 
On the left is the plated screw.  On the right is the screw with the plating removed by the acid.
     Once the plating is gone, rinse the acid off the screws and let them dry.  They will probably be a little rusty, but they will be the dull grey color of steel.  After that you can hold the head in the flame of your stove while holding the screw with a pair of pliers until the head turns black.  I would then dip the head in wax.  You can also oil it with kitchen oil.  Like seasoning a cast iron pan.  I had a buddy who seasoned his cast iron pans with Crisco ( Again, not a paid endorsement, for the buddy or Crisco). You can probably use that too.
 
     I think this is a fairly easy way to get a better look for forged hardware.  It doesn't give you a hammered look, but at least it's not bright silver on black.  
 
The plated screw.  The screw with the plating removed.  The screw heated in the stove and waxed.  My dirty hand.

     I'm trying to make hammered screws for my hooks.  I tried to find slotted screws at the big box home improvement stores.  They only have Phillips head.  Phillips head doesn't work that well when I hammer the head so when I have a big enough hardware order, I will add a box of slotted screws to supply with my hooks. I can clean up the slot after hammering much better than I can clean up a Phillips head.  Once I have the screws, I can list the hooks for sale.

    I should mention that there are a couple of caveats with this process.  You do not want to touch muriatic acid.  It's acid.  You also do not want to breath the fumes.  Do this process outside and don't stand over it.  I'm pretty sure breathing the fumes will mess you up.  Once you have removed the plating, the screws will rust. If you want to look at a list of safety tips, click here

    If you need blackened screws or bolts for a bathroom, you could try just holding a stainless steel head in the stove fire. This would also work for nickel plated screws.  Neither of those will rust as readily, but they are also more money.  Natural gas heat on the stove would probably be enough heat to make the head turn black.  It may take a bit longer. I don't know because I have a propane torch, and a forge and an oxy-acetylene rig. (google spell check wants to change this to foxy-acetylene.  What is foxy-acetylene?  Please tell me if you know unless it's going to scare me.)  I don't actually use the stove.  

   The best looking decor is consistent.  You want the mounting hardware to match the rest of the hardware.  This is a little step in that direction. 

    I hope this works for you without pain.  

    Now I need to get back to work.  Until next time

    j

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