KvdW Mirage Complete Overhaul

Equipment, technique, or just drinking the stuff

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Postby CakeBoy » Mon Jul 25, 2011 9:29 am

Nice. Looks like it's going well.
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Postby JankSolid » Tue Aug 02, 2011 4:11 pm

Sorry for the break in transmission folks.

I can't believe how long it's taking to descale the HXs! It seem that no matter how much acid I put in there it and how much I rinse it out between-times, it still foams up indicating a reaction taking place inside.

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One of them came clean after 2 days. The other? I'm well in to day 3 on that one.

I've been passing the time cleaning and polishing the pipes, solenoids, flow meters, valves and fittings.

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Last edited by JankSolid on Thu Jun 14, 2012 9:58 pm, edited 3 times in total.
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Postby JankSolid » Tue Aug 02, 2011 4:25 pm

As soon as the boiler and HXs are fully descaled I can start putting it all back together. It's fun pulling a machine apart, tedious but rewarding to clean it up then fun again to reassemble it.

This one is up there with the worst. Hard to believe there was anything coming out of it at all. I'd bet that it's never seen a water filter!

Looks like someone's had a go at some kind of "repairs" on it in the past. Some of the joints were heavily bound in teflon tape (the mark of botch - you don't need any kind of sealant on a compression joint - the clue's in the name).

Also, the rubber washer in one of the steam taps had been replaced by a few (it was hard to tell how many) of those self-adhesive rubber feet that you stick on things to stop them sliding around :roll: . Needless to say these had turned into squidgy goo.



Here's some more pics...


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Last edited by JankSolid on Thu Jun 14, 2012 9:59 pm, edited 2 times in total.
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Postby GreenBean » Thu Aug 04, 2011 4:36 pm

Very impressive work Jank. :shock:
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Postby Skippy » Thu Aug 04, 2011 6:39 pm

Nice, i like the polished copper.
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Postby JankSolid » Thu Aug 04, 2011 10:56 pm

Incredibly, one of the heat exchangers is still slowly bubbling away in a vat of acid. Down to one "bloop" every 60 seconds or so.

I'm really hoping that it will be done by tomorrow as literally everything is ready to go back on the machine (bar a couple of bits that Kees has sent me which will arrive tomorrow).

- All pipework and brass fittings cleaned and polished
- Groups cleaned and polished (new dividers, gaskets and screens waiting to go on)
- All 5 solenoids stripped, cleaned and rebuilt.
- Steam and water taps and arms stripped, cleaned and rebuilt with new gaskets and seals
- Stainless steel bodywork washed and polished
- New RPM motor and Fluid-O-Tech pump

All waiting to go back on to the pressure washed frame.

So I spent the day building up a La Scala Butterfly and got a call-out to fix a Super J that had glass in it. Glass in it!
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Postby wacchimacchiato » Fri Aug 05, 2011 1:28 am

Hi JankSolid,

What is the strength of the acid solution you're using please? I'm going to be descaling a stripped down visacrem vx shortly (pretty skanky) which I will post on a new thread - plus wound up with a sheared boiler bolt and am hoping it can be drilled out (fingers crossed - new problem on me!)

Many thanks

Craig
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Postby JankSolid » Fri Aug 05, 2011 9:51 am

Hi Craig.

The stuff I use is 20% Hydrochloric Acid. I use it in any strength from neat, for small tough areas of scale through to mixing it 1:5 with boiling water for a general dip. Be careful! Follow the H&S. It burns if you get in on your skin and you don't want it near your eyes.

As for the sheared bolt. You may be able to use a method I devised when working on carburettor jets. Drill a small hole down the centre of the bolt. Hammer in a small Torx bit til it's nice and tight in there and then reverse it out with an electric drill on low speed/high torque.

If that doesn't work you will have to drill out the whole thing. If it's brass it should be pretty easy. Try to centre-punch first the part you need to drill. Then start with the smallest drill bit you've got - say 2mm- and drill a pilot hole. Be careful not to snap it. Then, using incrementally larger bits, keep going until you are almost touching the thread. It's, more accurately, milling rather than drilling I suppose. It helps if you have one of the other bolts so you can match up your drill bits and see when you're nearly there. When the thread is nearly exposed you should be able to start picking it out with a dental pick or similar. I would then clean up the thread with an appropriate sized tap.

I have to get a male plug out of this boiler and the cap is rounded off. I may well end up drilling it out if the WD40/blowtorch attack doesn't work. If i do, I will post some pics.

Good Luck!
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Postby wacchimacchiato » Fri Aug 05, 2011 11:25 am

Thanks for that, much appreciated! I'll be having a go at that bolt over the weekend!
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Postby JankSolid » Wed Aug 10, 2011 3:30 pm

Boiler all clean now

Image
Last edited by JankSolid on Thu Jun 14, 2012 10:00 pm, edited 2 times in total.
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Postby JankSolid » Wed Aug 10, 2011 3:39 pm

Weekend over.
Riots over (I think - still hearing sirens every 5 minutes, but that's normal for round here).
Offspring back to his mum.
SO.....

Rounded-off cap centre-punched...


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...and drilled


Image

I didn't take photos as I went up through the drill bit sizes. I went up to 10mm.
Last edited by JankSolid on Thu Jun 14, 2012 10:01 pm, edited 3 times in total.
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Postby JankSolid » Wed Aug 10, 2011 3:46 pm

I was going to go to 11mm and pick out the thread but then I remembered something :idea:.

I've got a spindle from a bench grinder that has a conical reverse thread...


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Job's a good un!

Just need to polish the boiler and all's set for the rebuild.
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Postby Aadje » Fri Aug 12, 2011 6:08 pm

Welcome! And good to see all the work you've put in is paying off. Great to see such a machine handled by such a skilled man :)

On this machine the top section and middle chamber are blocked off from each other. A water feed is taken from the upper thermosyphon pipe, through a solenoid and in to the back of the central chamber.

Kees indeed lets the water flow through the E61 at the top and gets the actual water for the coffee from a separate tube. It provides better temperature stability.
Bits 'n' pieces . . .

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Postby JankSolid » Sat Aug 13, 2011 12:40 pm

Thanks to Aadje and everyone else who has complimented my work!

This project nears completion and I was hoping to bench test over the weekend. However, a couple of small probs have arisen.

The male threaded bit of the expansion valve snapped as I was screwing it in to the manifold. It's a standard part and I have ordered a new one which will arrive on Monday.

Also, as I was tightening up the pipe union to the steam connection of the pressure gauge, the back of the nut was pulled right off. I've never seen that before! The back of the nut was really thin (like a washer) and it wasn't even tight when it gave in.

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The jury's out at the moment on whether to just replace the whole pipe or get lsjms round here with his Rothenberger and remove the nipple, replace the nut and braze the nipple back on.

This is the 4th part that has snapped under the spanner on this machine. I like to think I'm not a heavy-handed worker. Brittle brass :?:

Meanwhile, here's some more pics...


Image


Image
Last edited by JankSolid on Thu Jun 14, 2012 10:08 pm, edited 5 times in total.
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Postby JankSolid » Sat Aug 13, 2011 12:43 pm

Image


Image


Image
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