Hi,

I'm in the process of rebuilding/refinishing my SJ and am hoping to powder coat the case. So far the disassembly has gone off without any problems, till .... I got to the stator, the rotor came out with only minor persuasion, but the stator won't even budge. I've read JohnB's how-to on refinishing and saw that the stator could be removed by heating in a oven @ 200 degrees, is this the only way ? Since I'm refinishing the case I was considering heating it with a propane torch, I'm sure it could hit the 200 degree mark, but I don't want to damage the stator.
I've talked to the powder coating shop I intend to use and he said the lowest temperature he could go would be in the 350 to 400 degree range, would it be possible to leave the stator in place ? Or is there another method to remove it ? Thinking about fabricating a puller but what about getting it back in ? Any suggestions, or ideas would be appreciated.

Thanks,

Leo

After you unscrew everything from the bottom of the grinder you can gently hit the shaft of the motor from the top (through a piece of wood) and the whole assembly will fall out from under the grinder.

It sounds scary but it doesn't even take that much force to get it out

If you do end up needing the heat, a heat gun plus PID would get you 200 degree heat, but you need to be careful of thermocouple placement - if you put the thermocouple on the part, the heat gun will deliver full heat for a while, likely resulting in damage to the grinder.

But if you put the thermocouple in free air in front of the heatgun, you get 200 degree air, but the part won't heat very fast; in fact it would probably cool faster than you could heat it, at a certain point.

But for 200 degrees, one could use the heat gun with pid inside an insulated box to soak the part at that temperature.

Good luck.

Thanks for the replies,

I'll try to heat the case in the oven as JohnB said, as this seems to be the easiest way to do it.
And John, thanks for posting the how-to of your Major refinishing project, it was more than helpful. I did take a lot of pics of the disassembly and made diagrams of the electrical, but your instructions on the doser disassembly were invaluable. I know this isn't rocket science but, it did give me a feel for what I was getting into. Wasn't going to replace the bearings but at this point I might as well. As far as painting, I know I can get good results from spray cans and have no problem going that way but, I was having the frame and shroud of the espresso machine re-powder coated so I figured it would be a one stop deal. I also understand that powder coating is more durable that paint, so there was another reason for going that way. But if I can't get the stator out, I have to decide either to leave the stator in the case when it's powder coated, or paint it. If I leave the stator in, the shop can dial the Temp. down on the oven for the curing process to the 300 to 400 degree range but I don't know if that would hurt the stator. My concern is what appears to be twine and paper insulation on the windings. So I think it's time to fire up the oven. Wish me luck.

Thanks again,

Leo

To all, I would think that a heat gun would do a better job than the oven. You are wanting the aluminum housing to expand and not put any heat into the stator. The oven heats it all and you need to depend on the difference in co-efficients of expansion of the aluminum and steel parts. The heat gun is more controllable than a propane torch. But personally I would blast it with my MAPP gas torch as I need to get all the old powder coat off anyway. Thats how I get the little RPM pump motors apart.Just did three Azkoyen Cappricio grinders and ended up using a weed burner to get all the old powder coat off so the powder coater could do his tricks. It is not uncommon to have to burn old powder coat off as the sand blaster won't touch it, at least not without killling the part. I think that there are chemical strips but I haven't done more than research and bookmark a few sites. I love torching stuff anyway and watching the pretty toxic colors. Yes, I'm from the sixties, I think, At least that's what my drivers license says...Your mileage may vary...
jpboyt

Ok,

The Mrs didn't want me burning the house down so I went outside and used my gas grill, got it to a stable 200 degrees according to the thermometer on the lid, put an old towel on an old baking sheet and about a half hour later the stator came out with a few taps on a thick door mat. Everything went good, just some of the tape shriveled a little, but the insulators on the windings are 100% intact. Now how about going back in ? Should I just reverse the procedure ? Or do I get some dry ice and let the stator sit in it for a while and try to fit it in place that way ? Out for powder coating tomorrow, now I just have to decide on a color. A few more questions, originally the grinder was badged as a Rio, there are two sets of holes in the back of the grinder, I'm assuming one for the Rio badge and one for the Mazzer badge. I plan to badge it a Mazzer, and am wondering if the Mazzer badge will cover the holes made for the Rio badge ? Or should I have the powder coating fill them in and just drill out the ones I need from the inside of the grinder ?
What is the best lubricant to use for the adjustment collar threads ? And is there anything I'm missing here ? First time I've done this, just trying to get it right.

Thanks again for the help and suggestions,

Leo

I've read a post about Duranium burrs, I was just wondering as I'm replacing mine if they would be a worthwhile upgrade. I'm really just starting out and would like some advice on whether it would be better to install new "stock" burrs, or go with the higher priced Duranium burrs ?

I doubt you will need dry ice to re install. Put the stator in the freezer over night, warm the housing as much as you safely can without softening the paint (hot day in the sun really) should pop right in. I do this with press fit bearings and other assemblies all the time....work fast and get it right the first time, be prepared to use persuaders to set it home.