Navitron Renewable Energy and Sustainability Forum

WIND TURBINES => Direct Heating Systems => Topic started by: biff on May 02, 2012, 01:59:59 PM

Title: chemical metal patch.
Post by: biff on May 02, 2012, 01:59:59 PM
I am sitting here waiting for herself to come back with another tube of liquid metal,
            In the general run of things,checking boss measurements and pulling on pipes etc,one has to expect some little complaint from a system which has been untouched for almost 10 yrs,so yesterday she noticed some little drips under the tank in the hot press and after a lot of looking I finally found that the top seam on the tank was perforated and tender,,uuups,,I had exerted quite a bit of force undoing the immersion bung a few weeks ago but it only began leaking yesterday,,
    So  new tank is required,preferably a stainless steel one,The present one is an albion 1050 x 450 twin,quick recovery coils and it has done fine up intill now.It did have the heavy duty bottom which i was told would resist the peaty water much better but i suspect the inside is probely well eaten by now so stainless steel from now on.
  This morning i bought a large tube of "chemical metal",fired it all out on a piece of cardboard,,fired all the hardner into it,gave it a good stir and was about to slap it on the offending area when i noticed it had suddenly gone rock hard.So i guess i will use less hardner on the next tube..The tank has to be changed but i need time to choose the right one and this patch effort will keep the place dry untill i am ready.

Title: Re: chemical metal patch.
Post by: Billy on May 02, 2012, 02:15:55 PM
I remember having a seam leak after some tweaking.  I used an egg cup to collect the drips but the heat meant it never overflowed.  Eventually the hard water made a magnificent stalactite and I never had a problem again.   :ballspin  No doubt someone has had to sort it out in the intervening years.


Title: Re: chemical metal patch.
Post by: biff on May 02, 2012, 11:00:58 PM
System refilled and working,
                           Got the second lot mixed with enough hardner to allow me a few minutes to slap it on.Then i decided to expand operations and continued around the rim with a further 2 more tubes of the same.A horrible messy job but once the 2L2 wrap goes back on will look fine.
        I had my camera down inside and right round the places out of normal sight and it seems that it is just that one area that was the problem,directly opposit the immersion heater bung,
       The bung required extra effort to tighten in order to seal the gasket,so scrapped the gasket and intended to tape up the threads but could not find my normal supply of plumbers tape so cut nice long pieces out of the white freezer bags,rolled the bung 6 times and inserted with very little pressure.this makes it easy to remove for when the new immersion is fitted shortly and puts an end to distorting the tank with needless pressure.
  Was not a nice job for inside because outside was a day for the garden,beautifull and sunny,There was a slight spit of rain around dinnertime but dried up immediatly it hit the ground.Working up the stepladder with the heat coming off the tank and the sun streaming in through the window was warm in the extreme.. but its done now and looks like it will keep together for a while longer. :crossed

Title: Re: chemical metal patch.
Post by: wookey on May 02, 2012, 11:37:10 PM
I've found this stuff good for sealing leaks in tanks:
I used the la-co stick, but I guess the cheaper putty is good too. With the stick you heat up the area with blowtorch, scribble over the area with the stick end and let it cool. Sorted in seconds. My tank has stayed fixed for 3 years now. The only catch is that you have to drain it enough to heat up the area in question.

Title: Re: chemical metal patch.
Post by: biff on May 03, 2012, 12:14:35 AM
Cheers Wookey,
                    There is also a little motorised valve in that link which i could use in the new water heater.

Title: Re: chemical metal patch.
Post by: biff on May 14, 2012, 05:23:10 PM
Ahhhhhh Lordy,
              Liquid metal,!!,,Let me see,,Have i a good word to say about Liquid metal,,?? NO No  NO..Frankly its xxxxx,,pure xxxxx.
      Having done my best to cure a leak on our copper hot water cylinder,endured the sauna effect on the top of the step ladder,I was of the opinion that i had done a fantastic job,,like i deserved a medal for it,or something along those lines.
  The first thing wrong is the smell,It takes a good 10 days at least to get rid of the pong,something between petrol and rotten meat,very unpleasent.
 Second,Its hard to judge the hardner,either too much or too little,
 Thirdly,,It can decide out of the blue that it is not intrested in working any more and let the liquid you are trying to contain escape.I suspect that it cannot cope with the expansion and contraction of the copper cylinder and cracks. So today when i went to organise the hotwater cylinder for the new immersion i discovered a leak coming from the same place as before,Not a bad leak but a leak nevertheless.So i am quite disgusted with my liquid metal efforts,I should have known better.So on the blower to the folks in heatmerchants  and ordered a replacement,310.00euros,which is not too bad,the s/s version is twice the price.
  So there you have it folks,,liquid metal is not really suitable for hot water cylinders,,,sob,, :'( :'(

Title: Re: chemical metal patch.
Post by: Heinz on May 14, 2012, 05:55:52 PM
Why not solder a patch on the thin bit? That's what I did with my previous tank, wee leak at the bottom seam, bit of copper tube unrolled for a patch, tin the area and the patch, solder into place and Bob's yer auntie  ;D did the same when I accidentally shot the copper gas meter pipe with an arrow when I was a teenager !!


Title: Re: chemical metal patch.
Post by: biff on May 14, 2012, 07:20:42 PM
Hi Heinz,
        The leak is in a very difficult spot to reach and to do a proper job it will have to come out alltogether.So if i am going to drain down the system and go to all that trouble,i may as well invest in a decent cylinder that will last either another 10yrs in copper or indefinatly in S/s.The cylinder reaches very high temps because the stat is set higher than normal and i think that is what broke the seal on the liquid metal.
     We have already begun clearing out cupboards and removing everything to make access to the tank easier,so tomorrow morning work will start in earnest.