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Post by manofkent on Jan 7, 2021 11:19:34 GMT
I want to make a repair to a weeping tube on my copper boiler.
It is only a tiny leak, and I have read some posts on this forum that Loctite sucked into the gap with a hoover on the boiler would do the trick.
But there are a variety of loctite grades suggested, from threadlocking ones (290 etc) to fixing ones (600 series) and many stops in between.
I can see from some of the spec sheets that the Loctite solutions can be stronger and more heat resistant than ordinary plumbers solder.
My question is what grade has anyone used, did it work, and did it satisfy your boiler inspector.
Many thanks in advance
John
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Post by John Baguley on Jan 7, 2021 13:16:33 GMT
I've always used 290 for repairs like that. It's a very thin wicking grade Loctite and will seep into small cracks or pin holes. We had a similar problem to you on my brothers steel boiler which has copper tubes silver soldered in to the front tube plate. Not the best way of fixing them. We cleaned everything up as best we could and put some of the 290 on the areas that leaked and left it to soak in. It works better if you can get a vacuum inside the boiler somehow as that helps to draw the loctite into the joint.
It's worked fine for a few years now and has passed the usual hydraulic tests at our club with no problems.
There have been copper boilers built with threaded and nutted stays where the stays have been sealed with Loctite rather than Comsol and I believe that they were successful.
John
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Post by dhamblin on Jan 7, 2021 14:00:47 GMT
I successfully plugged a couple of leaks like that on my Grandad's Britannia boiler, mostly where soft solder was used to caulk the nutted stays as per LBSC's build notes. I think one of the biggest leaks was on the blower pipe where it passes through the backhead. In that instance David (Midland) generously allowed me to use some of his Loctite 648.
One of our members (my boiler inspector in fact) tried a similar repair to you on the boiler of 'Arthur Hale', a large 5" 2-8-2 locomotive, but after several failed attempts found that the silver solder hadn't properly taken when the boiler was originally built and the small amount there had split after about 15 years service (it was the main loco for use on the portable track, so the most active of our fleet). In that instance it was better to attempt a soldered repair.
Regards,
Dan
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Post by 92220 on Jan 8, 2021 9:27:28 GMT
As John says, Loctite 290 will wick into cracks and up tiny screw threads. That is what it is designed for. I use it a lot as it can also be used for permanent heavy duty locking. I also have Loctite 648 but this is a lot more viscous and wouldn't wick into small cracks.
Bob.
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Post by manofkent on Jan 8, 2021 14:05:52 GMT
Thanks for your replies. It seems that 290 would better suit my needs this time as it is less viscous than 648, although the tensile strength of 648 is immense!
If I had a bigger gap to fill I reckon 648 would be the weapon of choice.
Once again thanks for this information.
John
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Post by 92220 on Jan 9, 2021 9:40:49 GMT
I would agree with that too John.
Bob.
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Post by delaplume on Jan 9, 2021 19:17:41 GMT
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JonL
Elder Statesman
WWSME (Wiltshire)
Posts: 2,976
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Post by JonL on Jan 9, 2021 20:27:29 GMT
As an alternatve, what about waterglass?
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Post by manofkent on Jan 9, 2021 22:39:19 GMT
Hi Nobbysideways.
Presumably waterglass is also known as liquid glass, some sort of silicate mix?
I have heard of this being used a long time ago but I could find out a lot more about loctite.
Has any reader used waterglass?, and if so how is it applied and with what results?
Thanks
John
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Loctite
Jan 10, 2021 8:18:37 GMT
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Post by osiris09 on Jan 10, 2021 8:18:37 GMT
This subject is something that has interested me for a while also as I have a springbok boiler with weeping stays within the firebox. My worry about repair had been that applying heat could cause leaks on other stays. But I had wondered about how the loctite would handle being inside the fire box. When I read the spec sheets for both products it seems the strength of the product decreases with prolonged exposure to heat but I'm wondering if that remaining strength is still stronger than I give it credit for (15% @ 150 degrees on 290 and 26% @ 200 degrees for 648). Or does the firebox not get as hot as I think?
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Post by ettingtonliam on Jan 10, 2021 9:07:05 GMT
Dose the boiler with Radweld?
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44767
Statesman
Posts: 535
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Post by 44767 on Jan 10, 2021 9:22:34 GMT
This subject is something that has interested me for a while also as I have a springbok boiler with weeping stays within the firebox. My worry about repair had been that applying heat could cause leaks on other stays. But I had wondered about how the loctite would handle being inside the fire box. When I read the spec sheets for both products it seems the strength of the product decreases with prolonged exposure to heat but I'm wondering if that remaining strength is still stronger than I give it credit for (15% @ 150 degrees on 290 and 26% @ 200 degrees for 648). Or does the firebox not get as hot as I think? My understanding here would be that, firstly, the Loctite is only filling a gap; the joint is not relying on its strength. Secondly, it is a resin that hardens when oxygen is excluded; it does not melt again when it gets hot. Yes, it may lose its strength but I doubt there is anywhere near enough force to shear it and so make the joint leak again as it is still filling the gap. Loctite 290 certainly would have had my vote. Thirdly, since there is a hole going from the water side of the plate to the fireside, there is a temperature gradient across the plate where the temperature of the water side will be considerably less than the breakdown temperature of the Loctite. Mike
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Post by manofkent on Jan 10, 2021 9:27:24 GMT
Looking at the data sheet it seems that 290 reduces to 15% of its strength after about 800 hours at 150 degrees. I am not sure if this is a constant 800 hours, but in any event my loco will have 30 hours a year at best, so it would take over 25 years to get to this point!
On the plus side it has a higher "melting " point than solder, and is as strong or stronger.
John
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JonL
Elder Statesman
WWSME (Wiltshire)
Posts: 2,976
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Loctite
Jan 10, 2021 9:44:10 GMT
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Post by JonL on Jan 10, 2021 9:44:10 GMT
The water glass I have seen used in a small boiler but the principle is the same. As I understand it once it's been heated once it resolidifies into a glassy substance which effectively seals any gaps it's crept into. It was effective but should only be used on a bare boiler as it will do the same to every valve! The glassy substance has a very high melting point which you will not reach again
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weary
Part of the e-furniture
Posts: 297
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Post by weary on Jan 10, 2021 10:05:32 GMT
Isn't 'water glass' (sodium/potassium silicate) soluble in water? Hence the name?
Regards, Phil
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Loctite
Jan 10, 2021 10:41:47 GMT
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Post by osiris09 on Jan 10, 2021 10:41:47 GMT
Thanks for answering my question. I also doubt I will run often as I prefer building things to driving but do enjoy getting out from time to time. 👍
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Midland
Elder Statesman
Posts: 1,875
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Post by Midland on Jan 10, 2021 11:37:05 GMT
Dear Manofkent No expert on this but I can relate my experience. My Princess of Wales suffered at the hands of a novice who exclaimed I cannot see the water. The injector was not coping quickly enough so I pulled the fire out on the spot. Really pulled the pin and it dropped. Next was a hydraulic to see what happened and like you there was a weep on one of the top tubes in the firebox. Had a small heart attack over the price of a new boiler, took the advice of the nearest ten model engineers and had twenty solutions. Then a quiet voice suggested I talk with Loctitie to see what they had to say. They suggested 648. The chap said it is quite viscous so it needs to be warmed in a cup of warm water prior to use. Said also it was good up the temperarture of superheated steam so it should work. Try sucking it in. So, made a fitting for the end of my Henry that screwed into the safety valve hole. Laid my little Princess on her side and cleaned up the area with a dremel wire brush. Dabbed a little 648 in the correct spot and whoosh, it disappeared. Left the hoover running and dabbed a bit more and whoose again. So turned the hoover off and dabbed a bit more and left her. About 4 days later went for another hydraulic and the clowns pumped the boiler up to 180lbs when 130-ish was all we needed but she held tight. Got the cert and lived happily ever after. That was all about ten years ago and the Princess lives on. And I might add my bottle of 648, 50ml (a big one) cost about £40 and has been to at least three other boiler owners, cheap when compared to a £2k new boiler. Cheers David
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jem
Elder Statesman
Posts: 1,072
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Post by jem on Jan 10, 2021 16:59:31 GMT
Water glass was used during the war to preserve eggs, I can remember a huge to me pot filled with water glass and eggs in the larder. it worked quite well, though from time to time you got a very bad egg!!
Jem
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Post by delaplume on Jan 10, 2021 17:56:14 GMT
Dear Manofkent No expert on this but I can relate my experience. My Princess of Wales suffered at the hands of a novice who exclaimed I cannot see the water. The injector was not coping quickly enough so I pulled the fire out on the spot. Really pulled the pin and it dropped. Next was a hydraulic to see what happened and like you there was a weep on one of the top tubes in the firebox. Had a small heart attack over the price of a new boiler, took the advice of the nearest ten model engineers and had twenty solutions. Then a quiet voice suggested I talk with Loctitie to see what they had to say. They suggested 648. The chap said it is quite viscous so it needs to be warmed in a cup of warm water prior to use. Said also it was good up the temperarture of superheated steam so it should work. Try sucking it in. So, made a fitting for the end of my Henry that screwed into the safety valve hole. Laid my little Princess on her side and cleaned up the area with a dremel wire brush. Dabbed a little 648 in the correct spot and whoosh, it disappeared. Left the hoover running and dabbed a bit more and whoose again. So turned the hoover off and dabbed a bit more and left her. About 4 days later went for another hydraulic and the clowns pumped the boiler up to 180lbs when 130-ish was all we needed but she held tight. Got the cert and lived happily ever after. That was all about ten years ago and the Princess lives on. And I might add my bottle of 648, 50ml (a big one) cost about £40 and has been to at least three other boiler owners, cheap when compared to a £2k new boiler. Cheers David Hello David, I liked this very much...As a Time-served Marine Engineer I'm a great believer in the saying "The proof of the pudding --etc"........and I'd say that ten years is more than ample to silence even the sternest of critics !! ..... and I used to be one of them it has to be said....but not any more.. Thanks for that recollection--- gives new meaning to the old saying " Suck it and see"...LoL !!
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