Cracked my Pyroceram from HTT..... : o (

[syvmn]

Working on upgrading my Craftsman 2x42 and was modifying the 2x5" platen with extra supports and a FLAT piece of 2x6 mild steel all welded together. Put my Ceramic liner on last night and took a look this morning to see a crack all the way across about an inch from the bottom. $20 out the window. I think I must have put the clamps on too tight or not really gotten the 2x6 metal backing truly flat. So I'm giving up on ceramic platens.

I have heard that a lot of people use FLAT hardened D2. I am thinking that the disc I used (on the craftsman) for flattening my piece might not have been really "flat".

Is there any kind soul out there that would surface grind a 2x6 piece of D2 for me for a platen? I'd pay whatever cost and shipping. I just don't think I want to try the ceramic glass again.

Thanks for any help or advice.

 

[Matthew Gregory]

Cost of doing business, my friend. Don't give up on it yet!

You need to make certain that the piece of stock you choose is flat - skip using a machine to flatten it and do it the old fashioned way: flat surface and sandpaper. It'll be worth it. Don't go much past 220 grit for the finish, as you want to have some "grip" for the epoxy to grab hold of.

What kind of clamps were you using? shouldn't take much pressure, just enough to hold it in place for the JB Weld to cure. You're using JB Weld for this, right?

 

[insanity]

There is a good chance that it will work just fine with the crack. I would at least try it while you are waiting to get other supplies in.

Wayne Suhrbier

 

[syvmn]

The problem is that the $17 platen costs $13 to ship.

In hindsight I know I made multiple mistakes.
1. I used way too much jb weld. I have a foot welded to the bottom of the platen so I'm sure just a couple of gobs would have been fine. Instead I coated the surface...idiot
2. I used another "flat" 2x6 piece of steel on top of the ceramic liner to apply even pressure with c clamps. I guess I was thinking since things were "flat" I could apply a decent amount of pressure. It was completely unnessisary.
3. I used an untested disk to try and flatten the steel. It seemed flat (no visual gaps dry fitted) but there must have been some small bend.

Now I'm wondering how to get the dang thing off of my platen since it's caked with jb weld...

Back to the drawing board.

 

[Mike Davis]

Don't worry about the crack. If it protrudes, flip a belt, grit in and run it for a second. That should knock off any lip from the crack. As far as the excess jb weld, i wouldn't worry too much about that either...If it is sanded to around 220 it will come off easier than you think, if you need to change it. One bad thing about the ceramic is i get shocked A LOT from the friction it generates...kinda sucks lol.

 

[klammer]

no need to order Pyroceram platens from sites / pay shipping. just head over to any glass / fireplace shop and ask for high temp glass. They should not charge you more than a few bucks...if anything at all.

 

[David Stifle]

I've been using the same piece of pyroceram for about 7 years. Once it's on, it's pretty durable, and I would Not work without one. Any steel you use on a platen will chatter, resulting in uneven grinds. Just my two cents...

Dave

 

[Frank Niro]

Get a can of static spray for clothes and geive the belt a three second spray on the inside as its moving to get rid of shocking. Frank

 

[Brian Ayres]

I went to a glass company to fix their toilet, they cut and gave me 3 pieces of 2"x8" free.... Cut them on the spot. Maybe try calling a couple local glass shops?
Sucks about your crack...

 

[Matthew Gregory]

The problem is that the $17 platen costs $13 to ship.

Yup. Just ordered 4 more a few weeks ago. I cracked mine when I slammed the platen into my work surface. Oh, well... knifemaking isn't a cheap hobby!

In hindsight I know I made multiple mistakes.
1. I used way too much jb weld. I have a foot welded to the bottom of the platen so I'm sure just a couple of gobs would have been fine. Instead I coated the surface...idiot

It's best to coat the surface. When you clamp, the excess will squeeze out. Wipe it off, and let 'er cure!

2. I used another "flat" 2x6 piece of steel on top of the ceramic liner to apply even pressure with c clamps. I guess I was thinking since things were "flat" I could apply a decent amount of pressure. It was completely unnessisary.

I use a couple Pony clamps like these

to hold in place initially, then once the excess is wiped away, I remove the clamps and let it sit flat to cure.

3. I used an untested disk to try and flatten the steel. It seemed flat (no visual gaps dry fitted) but there must have been some small bend.

Now I'm wondering how to get the dang thing off of my platen since it's caked with jb weld...

Back to the drawing board.

Heat the pyroceram up with a torch or a heat gun. The JB Weld will soften, and you can pop the glass off with a putty knife. Cleans up quick!


Don't let it get ya down!!!!!

 

[james terrio]

The JB Weld should fill any non-flat spaces in the existing platen, I think it's good to coat the whole surface. I was afraid to even use spring clamps like Matthew showed, I simply wrapped mine up with masking tape until the JB Weld cured. C-clamps are way too easy to over-tighten. I've been using my ceramic platen for over a year. No slippage or peeling away from the original platen... and I often grind pretty aggressively.

BTW those "pony" clamps are great for lots of other things around the shop too, and they're cheap as dirt.

 

[AltonaHunter]

I recently bought some high temp glass, cost me $73 for 8 peices. I'm going to use mild steel flattened with a fly cutter on my mill and recess the glass in it. Im not keen on glueing it in there as i want it easily replacable, hoping double sided tape will work.

 

[blindhogg]

Matthew has it right , use clamps to get it flat and squeeze out excess JB. Then remove them and let her dry without clamps. You dont need stress in that glass that clamps might induce.
You will have to ensure the glass does not slip/slide out of place is all while drying.
CW

 

[ERIK KNIVES]

I tried JB weld and I hate to buck the accepted practice, but high temp RTV silicone (the red stuff) would have solved any problems here. Get out the excess air, square up the platen and tape the glass, no need for clamps. It will take more work to replace the glass than JB weld because the RTV silicone will not let go. JB weld lets go within a minute on a mapp gas torch. That shelf that everyone tells you to set the platen on is a good idea, but it came about because the JB weld failed in my opinion.

 

[Fred.Rowe]

In the wood working industry its known as a rubbed joint; apply the JB Weld to the platen and use the glass to "rub" or smooth out the adhesive. With a few back and forth rubs the two surfaces will become cohesive; just hold the platen in position until it dries and you are ready to grind. If you use the rubbed joint technique the platen does not need to be flat ground or perfectly flat for that matter; the JB Weld will fill the spaces.

 

[Tait]

I agree that a rubbed joint would pull it together.

Before trying that, you might consider checking whether the two halves are parallel to each other - if it cracked, it seems likely that the two halves aren't in line any more...

 

[syvmn]

I was able to get the glass of by heating the steel. I'll try it again when I get a new piece. I found a guy around here that might have some scraps. Hopefully I can get a piece for under $10. No clamps next time, just tape is what I'm thinking.