Do I need to re-heat treat?

S

syvmn

Joined
Apr 5, 2009
Messages
169
I just heat treated my knife and was sanding off some crap on it before putting it in the toaster over and I think I over did it a bit. There is a bit of the "rainbow" color right by the edge. Do I have to re-heat treat this?

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I would say that you got it to hot while sanding, if this was done after the temper cycle, yes you would need to heat treat again, but since it was done before, I am not sure, I would think yes. Also not all steels allow you a second chance at heat treat, so it will depend alot on the steel used, wheather you just reheat and quench or start all over on a new blade. Hope this helps.
 
It was 1080 steel and I already threw it in the oven for tempering. Can I still re-heat treat?
 
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I'm sort of a new-be but i do it this way.
when in doubt, do it anyway to make it as right as possible.
vern
 
I agree with you, I'm a huge noob as well. I'm just curious if I can re-heat treat it. I don't want to go through the trouble if it wont help. Its kinda sad too, this is the first knife I've made where it actually looks pretty good with strait bevels and all.
 
yes you can re heat treat it. If you already hardened it you will need to re-harden. keep a coffee can full of water beside your grinder. and dont use gloves. that way your constantly dunking it. It's tedious but not nearly as aggravating as having to re harden your steel. normalize the steel 2x then on the third time quench. "*Normalizing is a critical step in a high performance blade. Once forging to shape is complete, and using a magnet to determine critical temp, heat the blade to just critical, and allow it to COMPLETELY cool in still air. This has the effect of relaxing all the internal stresses that have been built up during the forging process, and will eliminate 90% of warpage problems. Multiple cycles are of great benefit, and should be experimented with to achieve optimum results in your shop."

*=taken directly from Ed Caffrey's website

Jason
 
Thanks jason!

I've read that the last time your normalize though you should be dunking the blade in vermiculite or pearlite. Is this necessary?

So I should be normalizing with every knife?
 
thats annealing, or softening the steel, not normalizing normalizing is like a good massage on a tight muscles. Annealing is like not excersizing and letting it go to flab...
Yess every knife should have atleast 4 normalization cycles. 2 before annealing and 2 before quench.
Jason
 
I've never annealed. Is the only benefit to it just to make the steel softer and easier to work with?
 
yes I'm sure the steel came annealed... unless you recycled something to make it like a leaf spring, lawnmower blade, or something...

Jason
 
Just an idea, but it may be a good idea to go ahead and anneal the piece, drill any pin holes you might want and/or holes to lighten up the handle, then normalize and heat-treat the knife again. I made that mistake a couple of times, and drilling hardened steel is rough on your bits if they make it through.

When you quench the knife again, check multiple times for straight-ness. It can warp easier after you've thinned the edge.
 
JasonSCarter said:
Yess every knife should have atleast 4 normalization cycles. 2 before annealing and 2 before quench.
Jason
Click to expand...

I could be wrong but I thought annealing puts the steel in a homogenous state, regardless of previous HT, so wouldn't that make normalizing before annealing moot?
 
I apologise for sounding like an smart @$$ but, Yes I suppose it would if all the steel was homogenous to begin with... Normalizing before annealling kinda just sets it up for better spherical grain refinement prior to annealling other wise you get a lamellar anneal which will still eat a drill bit but file work and bend easily.

Jason
 
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