Jump to content
I Forge Iron

Galvanic corrosion


Recommended Posts

Found this comment on imgur

Comment: "Careful with the copper pins through a steel tang. I've seen blades fail due to galvanic corrosion causing problems."

Source: http://imgur.com/gallery/hrCUR

I found some explanations on IFI since I had no clue what it was, but was wondering if anyone has any RL experience with this?

What can be done to prevent this? pins in same material as the forged blade? wooden pins for the handle (+ epoxy offcourse) ? Any other ideas?

Link to comment
Share on other sites

Three components to galvanic corrosion: two dissimilar metals + trapped moisture. Salts will speed up the process.

Sealing all the mating surfaces with epoxy or solder will eliminate getting blood/sweat/rain wicking down along the tang or pins. Stabilized wood or micarta slabs do not absorb moisture, unsealed paracord wraps, leather, antler and natural wood do. Plus they add organic acids to the equation.

The ABS forums would have more detailed explanations.

Link to comment
Share on other sites

I was just reading up on this after reading your post, as I am new to this whole blade making process and have yet to come across the term Galvanic Corrosion. 

before reading Johns post ( refreshed the tab before posting to see if anyone more experienced would have a magic answer ) , my thoughts were to make the holes for the pins slightly larger then the actual pin so that epoxy could flow between the pin and the handle, now after reading Johns post I see I was on the right track. 


There is a helpful table at the bottom showing the differences of the different types of metals. 


Link to comment
Share on other sites

"my thoughts were to make the holes for the pins slightly larger then the actual pin so that epoxy could flow between the pin and the handle"


Um, no. Glues are strongest where they are thinnest. You want the fit up on all parts to be as tight as possible, THEN add epoxy or solder. Especially to the handle slabs where they apply to the tang and pins.

Liquids are drawn into the interior by capillary action when two surfaces are only a tiny fraction apart. Drying out again is only at the surface, and takes much longer.

Edited by John McPherson
added quote for clarity
Link to comment
Share on other sites

understandable, I think my wording was a bit off ( it was early and pre coffee posted ) so my brain was only partially engaged. 

In my case, i have 1/8th round brass stock for pins, so drill the hole out to 1/8th, and then take a needle file to it to enlarge the hole only by like a hairs breadth, but by the sounds of it, even that might be too much of a gap from what you are saying.

Link to comment
Share on other sites

Malice: No, filing the hole is NOT a good idea. First it makes the hole larger than it should be. Secondly it roughens the surface of the hole enlarging the surface area speeds chemical reactions.

The epoxy around the pins is a prophylactic (barrier) measure, it keeps the electrolyte (moisture and dissolved chemicals) off of and out of the joint.

If you use marine bronze for your rivets and pins it is FAR less susceptible to galvanic reaction. I'm not sure if marine bronze is a dialectric or dialectric bronze is a different alloy but dialectric couplers are how you hook up the copper plumbing to the boiler, well, etc. in the basement.

IF you can make the holes a couple thousandths smaller than the pins you can still slip them in by chilling in dry ice and warming the knife handle. When the pins warm back up and expand they will form an interference fit and be especially water tight and heck just plain tight. Sealed with a good epoxy, etc. and it'll last generations.

Do NOT get anything between the tang and pins.

Frosty The Lucky.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...