La Cimbali M20 Eleva rebuild - Page 3

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
OldNuc

Postby OldNuc » Jun 15, 2018, 8:36 am

Starter/starting fluid is light oil and ether. It is just about the last thing I would be using on anything I wanted to put water into. It also can become anhydrous and at that point it becomes a contact explosive. Not a good gasket remover. Good clean acetone will work as a solvent and it will not leave any residue to anguish over, likewise MEK. Petroleum based products are to be highly discouraged. Brake cleaner is a mix of mostly 100% isopropyl alcohol but it does leave a light deposit. That fiber gasket is likely asbestos and cotton. Fresh high strength paint remover works but is not good for you either.

The bottom line is just about anything that is going to aid in easy removal is not good for you, the environment, or banned.
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grog

Postby grog » Jun 15, 2018, 10:37 am

Hmm, although the gasket is certainly original, I don't know if it contains asbestos. The machine is a 1988 so that would be late. I guess it's possible at the tail end of asbestos use. I'll be sure to use a mask from here on out, as I'm getting to the dusty stage of removal.

Rich, so you would say acetone is my best bet? I really don't want to take the risk of more dry sanding / chipping with the possibility that it's asbestos, but I do need to get a bit more off of there. An element seal feels like one where you really want to make sure to have absolutely clean surfaces for the new seal.
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grog

Postby grog » Jun 15, 2018, 11:46 am

I looked up when Italy stopped using asbestos and it wasn't until 1992 (!) so Rich is likely correct that these original fiber gaskets contain asbestos. That would also explain why the torch wasn't doing anything to it!

I wiped the work section down with a damp cloth and I'm actually at bare metal in virtually all of it, so rather than risk more exposure to environmental hazards, I'll see where this gets me in terms of pressure testing.
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grog

Postby grog » Jun 22, 2018, 10:55 pm

Through sheer luck, found the Serto fitting I needed for just a coupla bucks on the Bay. So no soldering needed (so far). There aren't that many of these on Fleabay in general, and they are spendy when purchased from a distributor, so I feel super lucky to find the exact compression fitting that just happens to fit the tubing size I need. The old install had PTFE tape so I did so as well. I'm a little worried I may have over-tightened it, although I stopped once it didn't turn with 'reasonable effort' on the wrench. I'm also a bit reluctant to unscrew the other fitting to check and see...I guess I'll know if I damaged it by over tightening, the first time the solenoid kicks on.

Picking up the media blasted group components (main bronze bore and aluminum spring surrounds) from the machine shop on Tuesday. So this weekend is compression jig building time so I can get the groups rebuilt and then we're on to pressure testing.

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grog

Postby grog » Jun 26, 2018, 3:41 pm

Got the group components back from the machine shop. They cleaned up really well, and as others have noted, glass bead blasting gives a matte finish. I really like it, and it makes me wish I could have had the pistons blasted as well.

The pitting on one of the spring surrounds is quite bad...but since these are unobtanium, I'll just have to make it work. The area you can see where the bolt hole is just gone in one section, is not of consequence as those are only for attaching the plastic spring covers, which I never intended on installing anyway (I prefer the exposed spring look). One of the piston rods is also more pitted than the other, so I'll likely rebuild the more pitted components together and just consider that the 'backup group' and minimize use.

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The bronze group bores cleaned up amazingly well. They taped off the bore itself since those were already cleaned up nicely and they didn't want to inadvertently strip the finish off inside it.

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Anyone have any thoughts on a clear coat I could put on the spring surrounds to at least prevent further degradation? Now it will be running on Seattle water (which is very soft), and I'll have a filter system between the water supply and the boiler. Still, it seems prudent to try to contain/seal the corroded areas against further damage.
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grog

Postby grog » Jun 27, 2018, 12:34 pm

Commencing group reassembly:
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OldNuc

Postby OldNuc » Jun 27, 2018, 1:08 pm

Aluminum corrodes in acidic water and lasts best in a slightly alkaline Ph water. You can clear coat with MAG wheel clear coat. If you use this after coating bake in a ~150F oven until fully cured-dried.

For the cosmetics you can fill with the regular JBWeld epoxy. This will be multiple steps as it will sag until cured so positioning is critical. Speed cure in an oven. There are other metal fillers but they are industrial products and rather expensive. Once a filled in just spray with the color of aluminum you like.
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grog

Postby grog » Jun 27, 2018, 2:31 pm

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OldNuc

Postby OldNuc » Jun 27, 2018, 2:36 pm

Yes as this must be baked at high temperature to cure properly and likely has a rather noxious solvent. This works well and actually looks like freshly bead blasted aluminum. https://www.por15.com/POR-15-Detail-Paint_p_103.html Convenient spray can application and it does set up as a hard coating.
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grog

Postby grog » Jun 28, 2018, 10:27 am

Ok, POR15 Detail paint on the way. Will report back on how it works out.

Anyone know what this indicator is for? I assume it's on when the pStat is on, but it wasn't connected to anything when I got the machine and there's no random wire where this would obviously connect. There is a power indicator light down next to the power switch, so that's not what this is. Maybe it's a low water warning light, since it's next to the sight glass? Manuals and schematics for this machine are practically impossible to come by (I've contacted La Cimbali directly and no joy there).

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