I think I screwed up badly

B

blueline1226

Joined
Feb 3, 2017
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12
Ok so I made 2 big errors i think, and im looking for some help....

I got some D2 steel, which I've never worked with before, I'm also a noob in general with this so.... I was trying to flatten the metal using a belt sander laying flat. it was hard to hold and then I was getting bad static shocks. I then held with a magnet and shocks went away but... I couldn't feel the heat of the metal... I think I work hardend the metal because It wouldnt get any flatter... does it really happen that fast with D2? Can this be undone easily or is that cut of metal screwed now?


Also big mistake which might cost me some time and $$... I just put on some new ceramic glass on my platen with JB weld (original) and let it set for 15 hours before using it. Well the heat seemed to have totally screwed up the glue, it looks like it has stopped touching the glass half way as you can see in the picture below... Is that whats happening or is it drying more? Ugh I feel like an idiot today

Screen%20Shot%202017-03-07%20at%2012.14.17%20PM_zps3dl2lykk.png



What should I do?
 
Was your platen truly flat before you installed the pyroceramic? That looks to be about the area where knives are ground. If you didn't flatten your platen, there would be a dip there. That will probably crack soon.
As far as the D2 is concerned, will a file bite into it? You may have just glazed the belt over or wore it out.
 
Put on a new 50 grit belt and it will cut again.

Sounds like you are using a worn belt
 
I agree with Adam. D-2 is rough on belts. Use a new coarse grit Blaze belt( or other good ceramic) for best cutting.
 
Josh Rider said:
Was your platen truly flat before you installed the pyroceramic? That looks to be about the area where knives are ground. If you didn't flatten your platen, there would be a dip there. That will probably crack soon.
As far as the D2 is concerned, will a file bite into it? You may have just glazed the belt over or wore it out.
Click to expand...



To be honest not sure if it was truly flat simply because of how the JB weld was on, I just aligned it and clamped it. It was that darker gray the whole way through before I started the grinder. It was pretty hot after using it for a little while. the odd thing was that I was grinding near the top area which is still the darker gray, so im not really sure what happened. Maybe pressure up top and heat lifted the glass on the bottom...

Should I try to remove the glass now and re-apply?
 
Well the problem is, it may crack while it is on there or crack when you're trying to get it off. And unless you have a surface grinder or another flat platen, you're going to have the same problem.
Is it supported at all by a metal shelf or lip?
 
Josh Rider said:
Well the problem is, it may crack while it is on there or crack when you're trying to get it off. And unless you have a surface grinder or another flat platen, you're going to have the same problem.
Is it supported at all by a metal shelf or lip?
Click to expand...

the platen itself was new and flat, the glass was assumed flat as well. I have another glass I can put on. It is supported by a full metal shelf built into the platen. I might just live with it on there like that, and if it cracks then I'll remove it, or do you think this could explode and be a bigger problem?

Also could my belt tension be too much and thats why its causing the extra heat build up? I didn't lessen the spring tension, so the belt is on tighter than it was before... Thanks for all the help and replies by the way!

I believe what happened was that the JB weld wasnt fully cured yet, I used it after 15 hours because I thought how long it takes but it says its actually 24 hours to set on the box... so I'm thinking the heat build up screwed up the JB weld and thats what happened.
 
If it's supported I would just continue to use it.
If your platen is too proud of your idler wheels it could be why you have so much heat.
I usually use a level straight up and down and put a piece of sandpaper between my wheels and the level but allow the platen to touch the level so it's just barely proud. If this doesn't make sense I can take a picture.
Grinding flat stock is going to build up a lot of heat anyway. I was tapering a tang the other day, I had just recently removed my pyroceramic and the platen was HOT!
 
When flattening a steel bar on a coarse belt and flat platen, the steel can get very hot. I regularly get it to glow dull red when doing the distal taper and hogging the bevels.
I use a big grinding magnet with the contact plates lapped flat so it will not pull the steel in a warp when grinding. When moving the magnet or turning over the blade, I let the steel cool a minute in the air before dunking the steel in the slack bucket so I don't get any cooling warp from the very hot steel.
 
I would have waited longer before using that platen. JB weld can take up to 24 hrs to cure.

I agree to try a new belt on your grinder. What kind of.belt were you using in the first place? Was it aluminum oxide?
 
Josh Rider said:
If it's supported I would just continue to use it.
If your platen is too proud of your idler wheels it could be why you have so much heat.
I usually use a level straight up and down and put a piece of sandpaper between my wheels and the level but allow the platen to touch the level so it's just barely proud. If this doesn't make sense I can take a picture.
Grinding flat stock is going to build up a lot of heat anyway. I was tapering a tang the other day, I had just recently removed my pyroceramic and the platen was HOT!
Click to expand...

Thanks, yeah my platen sits proud on that machine, but unfortunately its how its designed, so I can't really do much about it. I've decided to mill my stock flat instead. It worked much better and with less stress to me, and no heat.

Stacy E. Apelt - Bladesmith said:
When flattening a steel bar on a coarse belt and flat platen, the steel can get very hot. I regularly get it to glow dull red when doing the distal taper and hogging the bevels.
I use a big grinding magnet with the contact plates lapped flat so it will not pull the steel in a warp when grinding. When moving the magnet or turning over the blade, I let the steel cool a minute in the air before dunking the steel in the slack bucket so I don't get any cooling warp from the very hot steel.
Click to expand...

Quick question, how fast and at what temperature does D2 actually work harden at? I googled it but didnt find any answers... It's not like titanium where it heats quick right?


S.Alexander said:
I would have waited longer before using that platen. JB weld can take up to 24 hrs to cure.

I agree to try a new belt on your grinder. What kind of.belt were you using in the first place? Was it aluminum oxide?
Click to expand...

Yeah I think that was my ultimate problem. I read too quickly and thought 15 hours was good, but its totally not ready for the heat I put on it at 15 hours. It wore the belt out super quick, which is why I thought I was doing something wrong to the metal. I was using Norton Blue Fire belts in 36grit, and 60grit: http://www.nortonabrasives.com/site.../Flyer-Belts-Bluefire-R840P-8348.pdf?t=730795

That stuff.
 
Take a pic of your idler wheels and platen, all the designs I know of allow for it to be adjusted. You can easily take your platen assembly apart and slot it. The platen adds thickness and you will start to grind the edges of the platen down. Not to mention prematureally wear all your builds down.
 
Don't clamp your platen if you're using JB weld. It will cure under stress/tension and end up cracking sooner than later.

Slather it on both your platen and backer, stick it together, and just let it sit flat. A little tape to keep it from shifting probably wouldn't hurt, but I wouldn't use clamps.

As for the D2, try a new belt, and dip into a water bucket when it starts to get warm.
 
Do not clamp the glass itwill cause it to flex. I coattbe platten with JB weld and then coat the glass with jb weld. I then push them togather and move the glass back and forth so it settles and gets full contact. I then just let it set for a few days.
 
Don't worry about work hardening the D2 from grinding.

You can grind a fully harden and temper D2 with a new fresh 50 grit belt
 
JTknives said:
Do not clamp the glass itwill cause it to flex. I coattbe platten with JB weld and then coat the glass with jb weld. I then push them togather and move the glass back and forth so it settles and gets full contact. I then just let it set for a few days.
Click to expand...

Yep, like bedding an action or scope base.
 
Steel doesn't work harden because it gets hot. It work hardens from the friction shearing grain boundaries on the surface. This isn't a significant issue with a steel like D2.
 
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