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The Craftmans Shop => New from Old => Topic started by: awemawson on April 03, 2017, 06:47:23 AM

Title: In-Sink-Erator resurrection
Post by: awemawson on April 03, 2017, 06:47:23 AM
When we had the recent water main burst and the ensuing high pressure surge when they fixed it, one of the many things that failed was our 'Magic Tap' at the kitchen sink that delivers boiling water ready for a cup of tea or coffee - a WONDERFUL device  :ddb:

Now the failure timing may have been co-incidental as these work by having a small well insulated tank whose output is always vented to the tap spout, and when you operate the lever cold water enters and displaces the hot. So in theory the tank is never under mains water pressure.

I pulled it apart, found that the tank is two stainless pressings bolted together, with a special odd shaped seal between them retained in a groove. This had failed, and I was able to replace it with one I made up from 'O ring' cord. The repair was a complete success in that the leak was fixed, but in either dismantling or re-assembly the centre of the temperature setting potentiometer disintegrated leaving it fixed at 90 deg C. OK for coffee but very marginal for tea. No markings on the pot and measuring it in circuit was inconclusive  :bang:

No pictures taken at the time as  things were a bit fraught however a few days later one popped up on eBay "Spares or Repairs" and declared leaking and limescaled up - all for 9.99 plus postage. I thought even if it's not repairable it's worth getting to be able to positively identify the value of the pot, or maybe use the pcb.

Well it duly arrived and the following dismantling, repairing and reassembly pictures are all of this second device.

But first, to set the scene, here is the original and it's tap:


Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 03, 2017, 06:54:43 AM
It was immediately apparent to me that the faulty In-Sink-erator had been opened up, as normally there is a small rivet holding the two halves of the case together - this had been replaced by a self tapping screw.
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 03, 2017, 07:01:03 AM
Now a quick 'blow test' on this one implied that the main tank was OK but the plastic balance tank on top was leaking at it's seam - but I needed to open up the main tank anyway to de-fur it with citric acid (marvellous stuff!)
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 03, 2017, 07:06:20 AM
Now the furring was not the usual hard scale that I'm used to, but quite soft and could be wiped away. I do wonder if it had been used in a house equipped with a 'magnetic de-scaler' as I understand that these keep the lime stone suspended rather than let it deposit - just a theory - no proof  :scratch:

However with citric acid it came off beautifully, leaving the tank and heating element sparkling  :thumbup:
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 03, 2017, 07:14:24 AM
So next make a new gasket - well I'd done this previously and developed a technique so that presented no real concerns  :thumbup:

The main problem is accurately measuring the O ring cord to have the same length as the original squarish gasket, and keeping it in place as the two flanges were bolted back together.

.... but I had a cunning plan ....  :ddb:

It turns out that cable mounting 'P-Clips' are just the job  :lol:
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 03, 2017, 07:19:11 AM
So now to turn my attention to the plastic pressure balance chamber.

Again this has been made in two halves - but instead of being bolted it is glued. As there is an aperture though the tank for the inlet and outlet pipes, there are two glue lines. The inner one had survived and was still strong, but the outer had failed leaving a big leak.
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 03, 2017, 07:24:10 AM
At first I didn't think that it was going to be much of a problem, just gluing it back together, so I started by opening it up all round, and pegging it open to allow me to scrape off the old glue.

OK what glue to use. Well the obvious thing I initially thought would be the solvent weld glue used on plastic plumbing - it's ok for drinking water, and ok for boiling water so that's what I used.

 . . . . . . . silly boy  :bang:
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 03, 2017, 07:34:58 AM
Leaving it to dry / evaporate / set or whatever for a good 24 hours it was immediately obvious that it hadn't worked - this plastic isn't soluble in this glue  :bang:

A lot of opening up, re-pegging, scrapping and cleaning ensued - this also pulled off the remnants of the original glue, which (ok with a bit of force) just peeled off the plastic.

Time to do some testing. I had several glues to hand, including Normal Araldite, Rapid Araldite, a speciality 'hard plastics' glue and various silicone squeezy tubes of sealant.

On the flat, smooth upper surface of the tank (which I cleaned scrupulously with acetone) I put dabs of each of the glues and left them for 24 hours before trying to dislodge them with a sharp blade.

All of them came off, but by far the hardest to dislodge was Normal Araldite - it would come off but clung on reasonably well. Where the halves of the tank go together there is a moulded shape that increases the surface area, and I reasoned that if I gave this a rough finish it would give the glue a better chance - so Normal Araldite it was to be  :clap:
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 03, 2017, 07:42:13 AM
Now I was fairly certain that the Araldite was going to make the tank waterproof, but I wasn't too happy with the fact that in tension, as the two halves are pressed apart, it would take the strain over many years  :scratch:

... time for another cunning plan  :lol:

I reasoned that, if I formed a channel that effectively clamped the two halves together, the Araldite would no longer be taking the tension and I might sleep easier  :ddb:

A quick measure up found me some lengths of brass channel, 1/4" external, with 1/8" legs that just nicely fitted the flange. Only problem was it was only available in 1 foot lengths  :bang:

OK two of them ordered, and when they arrived I set to to make them one
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 03, 2017, 07:46:45 AM
Now forming this channel round the tank flange was going to involve heat and hammering - not sensible to do it on the tank itself - so time to make up a template out of steel plate.

To the rescue came my CNC Plasma Table that kindly turned an Autocad DXF into tangible form - did I ever tell you - I love my CNC Plasma Table  :ddb: :ddb:
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 03, 2017, 07:50:10 AM
So after a bit more fettling and furtling it was just a case of filling the channel with more Araldite fitting it, tightening it up and then getting the mess off my hands  :clap:
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 03, 2017, 07:54:12 AM
I then left it for another 24 hours before re-assembling the unit.

I'll give it another while before trying it, just to make sure that the Araldite has fully cured.

.Now the big question - can Araldite take the heat. The packet say it's good for 80 deg C this will get close to (but not) 100 deg C - time only will tell  :bugeye:
Title: Re: In-Sink-Erator resurrection
Post by: AdeV on April 03, 2017, 08:11:44 AM
So... a couple of questions...

a) Is this the original one, or the ebay-dud that you've resurrected? I presume you gave it a bit of a test before dismantling? After all, sellers have been known to tell the odd porkie, maybe the heating element is shot...?

b) That brass band (no, not the one playing in the bandstand, the one around the tank...), is that compressing the two halves of the tank together? I'm just wondering if, rather than Araldite, you could have used a high-temperature mastick/rubber-type seal instead, thus no worries about the Araldite giving up due to temperature. Of course, if the brass channel is just there to hold the glue in place, then fair enuff, glue it must be.

Anyway... until today I thought an "In-sink-erator" was one of those mincing machines, ala an American "Garbage disposal" unit, so you just lobbed any old stuff down the sink - meal left-overs, unwanted rats, children... - and it minced them up & sent them off to the sewage company for them to scratch their heads over...

I've used an over-sink boiler before now (Heatrae Sadia Streamline machines - very nice, but heavy on the juice), and my old workshop I fitted an over-sink handwash unit - not the "instant" ones (which are rubbish and consume more gigawatts of electricity than Doc Brown's time machine), but a tanked variety. Mind you, that ate a few gigawatts as well...
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 03, 2017, 08:29:40 AM
Ade,

I resurrected the original, and as mentioned in the first post took no pictures - this details the re-build of the eBay one. The woman I bought it from assured me that it heats up but leaks - I've no reason to doubt her honesty as she declared the other faults, but you are right, I should have at least put a meter on the heating element - but I didn't !

The brass clamp is a tight fit on the flange, and the Araldite packed into it was just to ensure it bedded down firmly.
Title: Re: In-Sink-Erator resurrection
Post by: howsitwork? on April 03, 2017, 06:11:50 PM
Andrew

care with the araldite. At higher temps it can denature. If you ever need to get it off something heat to about 200-300C and it turns to toffee and can be scraped off. Once heated it is much easier to remove.

As a sealant the high temp rubber type stuff you use on over doors works but has little physical strength ( not tested that statement as it's just sealing the glass in the door but sure grips glass well and that's upto 300C ).

Whats the tea like???

Ian
Title: In-Sink-Erator resurrection
Post by: RichardDepetris on April 04, 2017, 01:02:58 AM
Wow!  When I saw the photos, I thought you were going to turn it into some exotic coolant system.  I am trying to build a mini mill from scrap parts so every machine looks like a scavenge worthy prey. LOL!
Title: Re: In-Sink-Erator resurrection
Post by: SwarfnStuff on April 04, 2017, 03:05:01 AM
Andrew and all,
                Just so you know (I looked it up) the tea making mobs say 180 - 195F for brewing tea, so your 90C is just at the top end of their recommendations. Plus it will cool somewhat as soon as it hits the cup or mug.
              I always enjoy your adventures / misadventures with your humour and great write-up style.   

    Enjoy a cuppa,    :coffee:
John B
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 04, 2017, 03:18:06 AM
Thanks John et al  :thumbup:

Hopefully the repaired one will be able to be set to full temperature, marginally under boiling point. If it works and does so for a few days, then I'll pull the original one apart and replace the twiddle pot (which is sitting on the kitchen window cill next to me as I type!)

Assuming no more lambs born in the next hour, I'll put the repaired one in for test, with a bowl under it just in case  :ddb:
Title: Re: In-Sink-Erator resurrection
Post by: JerryNotts on April 04, 2017, 04:27:52 AM
John B,
Where did you find the tea making temperature, might I suggest, cos it's in deg F that it was a US source.

Following many years of personal expereince I, and almost every colleague I have known over >65 years always specify a 'rolling boil' for the water immediately before (0-5 seconds) adding the water to the pot.  If mashng the tea using a teabag in a mug more or less the same spec. is mandatory. In years gone by where I have been able to measure the conditions, and depending on the height above sea  level 'rolling boil' means 99-100deg centigrade ( Celcius, whatever that is). And don't let the water boil too long as otherwise you will drive out all the dissolved gases (mainly oxygen) which add to the flavour.

I'm hestant to suggest tha using water at 195 deg F (90.55 deg C) to make tea may be the reason why many US citizens prefer to drink coffee.

My six pennorth for what it's worth.

Andrew, yet another excellent 'new from old' project from you.

Jerry
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 04, 2017, 05:44:43 AM
Thanks Jerry  :thumbup:

Well so far so good. I've installed the repaired unit:

Tried for leaks cold - none  :ddb:

Then set it's control 2/3rds up its uncalibrated scale and let it heat up, and proved that the controller turns off at set point - which it does  :ddb:

Then measured it's output temperature - 92.5 deg C  :ddb:

Then turned it up to pretty well maximum on the scale, let it get to set point and measured again - 97.6 deg C  :ddb:

Now I need to give it a good flush and check that the water tastes ok.

I suspect any glue issues if any will be revealed over the next few days  :bugeye:
Title: Re: In-Sink-Erator resurrection
Post by: russ57 on April 04, 2017, 06:26:52 AM
Not that I wish calamity on you, but I do love when you have broken stuff to repair - always entertaining and educational..

-russ

Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 04, 2017, 06:29:52 AM
Thanks Russ  :thumbup:

Don't worry there's always something breaking round here to keep you amused :bugeye:
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 04, 2017, 10:10:19 AM
So it seems to be working fine so far - had a few GOOD cups of tea - no taint in the water flavour and it seems to be controlling it's temperature OK, so I decided to try and change the adjustment pot in the original unit.

Opened it up, exposed the PCB, decided as the mounts for the new pot are slightly different, to cut the legs that are the ends of the track and leave them in the PCB for possible use to solder the new one to. Then I un-soldered the third connection that is the wiper - this is in fact two common connections presumably to give better mechanical strength  :scratch:

Having got the Pot off the PCB I measured it's resistance - 28.3 kOhm . Argh - the replacement is 50k (well 47k being a standard value) BUT THE ORIGINAL SAYS 50K on it's body  :bang:

Now as the wiper mechanism had collapsed I thought that part of it might be shorting out the track and giving the low reading. A careful bit of dissection with a scalpel exposed the bare track releasing the remains of the wiper - it measures 28.3 kOhms  :bang:

So I'm in a bit of a quandary now - do I put the 47k pot in, or try and get a 28k - well 27k is the nearest preferred value - or has the original track gone low resistance. If it has I've never come across such a failure mode before, they always go high resistance  :scratch:


 
Title: Re: In-Sink-Erator resurrection
Post by: RussellT on April 04, 2017, 05:03:22 PM
I'd be inclined to go with the 47K.  I can't believe they fitted pots marked 50 believing they were 28K, so they must have thought it was a 50K.  Also unless it's more complicated than the PCB looks the 47K will give you all the values you could get from a 28K.

Russell
Title: Re: In-Sink-Erator resurrection
Post by: howsitwork? on April 04, 2017, 05:04:31 PM
Andrew

what does the rebuilt one have as it's value if you can access it?
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 04, 2017, 05:40:58 PM
It also says 50K on it as I photographed it to source the replacement, but never measured it  :palm: Nor do I seem to have kept the picture, however it was exactly the same as the one here except the marking was printed not pressed in.
Title: Re: In-Sink-Erator resurrection
Post by: russ57 on April 04, 2017, 09:03:09 PM
I'd give it a go as well. At worst, the useful adjustment range will be 'compressed' so the calibration may change but it should work fine.

-russ

Title: Re: In-Sink-Erator resurrection
Post by: SwarfnStuff on April 05, 2017, 02:22:33 AM
Jerry,
       I searched again today and cannot find the actual page but the "T2" people here, https://www.t2tea.com/en/ca/features/how-to-brew/how-to-brew-fundamentals.htm
At the top there is a list of the various types and their recommendations. I do recall that the figures I quoted were for the Oolong tea. All up, I reckon it's totally up to your choice which temp you choose. My mum for example made sure the kettle was boiling furiously before making a cuppa.
You make it you drink it I guess.
If you search for  'ideal temperature for tea brewing' you will get heaps of stuff to confuse you.
So, that sorted, back to Andrew's adventures.
John B
Title: Re: In-Sink-Erator resurrection
Post by: JerryNotts on April 05, 2017, 04:01:45 AM
John,

I'd go with your mum's method.

I only have so much detailed info from working 50odd years in chemical labs where the making of the tea was a critical operation, subject to much observation and experimentation, and occasionally using words, as Churchill said 'from the earlier letters in the dictionary' to descibe the results. The Operator was the biggest variable.
Employers would not go to the expense of specific teas, nor tea bags. In any case once brought up on Ceylon Teas, BrookeBond etc and the use of a tannin encrusted teapot you just got used to it. Strength and flavour being the main critererion. Some of the pots and their owners had gone through the war.

As you say back to Andrew's thread now.

Jerry
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 05, 2017, 06:56:09 AM
So I decided to install the 50K pot. This entailed creating a Frankenstein Monster of a pot comprising the new body with the base incorporating the different mounting pins from the old pot.

Initial tests seem OK. I set the pot mid way, plumbed and powered it up, and got 95 deg C. Then wound the pot up to maximum and got 97.2 deg C which is just about right

Then I brush painted some conformal coating over where I've soldered to re-make the vapour protection that was there before.

Still very puzzling about the 28K / 50K conundrum  :scratch:
Title: Re: In-Sink-Erator resurrection
Post by: AdeV on April 05, 2017, 07:57:42 AM
As you say back to Andrew's thread now.

Just one last diversion if I may....

I only have so much detailed info from working 50odd years in chemical labs where the making of the tea was a critical operation

Critical as in - everyone knows the world stops unless lubricated with sufficient cups of tea? Or critical as in, you were actually blending/refining teas?

Curious minds....

Andrew: Presumably, the low end of the resistor was providing the maximum temperature (i.e. tending to zero ohms). With your old pot failing "high resistance", it could no longer tell the machine to go to maximum temperature. Normally if a pot fails at high resistance the issue is with the wiper; often the wiper & "output leg" are wired together, which I assume was the case in, er, this case.

So... that given... it wouldn't matter if it was a 28k pot, a 50k pot or even a 147k pot... the low resistance end would give the maximum temperature.


However... I'm sure you've thought of all that stuff (cos I knows you are good with electrickery), so if I'm talking out of my Chinese hat, just say so...
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 05, 2017, 08:31:27 AM
Ade, the original pot wiper had been knocked off in the dis-assembling of the original device - my own clumsiness not removing the shaft before laying it on the bench. The actual track was undamaged  :scratch:

Any road up it's working and making me tea and coffee, and the fixed 'spares or repairs' one tucked away for the next failure  :lol:
Title: Re: In-Sink-Erator resurrection
Post by: Pete W. on April 05, 2017, 12:32:43 PM
Hi there, all,

Sorry if this is  :offtopic:  :offtopic:  :offtopic: 

But please can someone tell me how you get two (or more) quotes in the same reply? 
Title: Re: In-Sink-Erator resurrection
Post by: mattinker on April 05, 2017, 02:01:37 PM
Cut and paste the quote from another reply!

Matthew
Title: Re: In-Sink-Erator resurrection
Post by: DMIOM on April 05, 2017, 03:15:05 PM
...... Any road up it's working and making me tea and coffee, and the fixed 'spares or repairs' one tucked away for the next failure

or perchance two in readiness to fuel the class in December?  :coffee:

Dave
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 05, 2017, 03:32:32 PM
Got a big Urn for that  :lol:
Title: Re: In-Sink-Erator resurrection
Post by: charadam on April 05, 2017, 05:28:36 PM
Is Big Urn available for Bar Mitzvahs as well?
Title: Re: In-Sink-Erator resurrection
Post by: awemawson on April 06, 2017, 02:14:52 AM
No, that's Big Earn  :lol:
Title: Re: In-Sink-Erator resurrection
Post by: JerryNotts on April 06, 2017, 03:38:57 AM
jOHN,

Perhaps my last word on the tea topic.  I suppose it depends what is meant by critical, the OED has at least 5 separate definitions. My use of the word was to describe the effect of poor quality on the staff. On occasion the effect was to distract to the extent that the lunchtime cribbage, bridge and chess schools (other games are available) lost their joyous and sometimes raucous edge.

Jerry