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Post by jhaines on May 4, 2007 14:47:39 GMT
I am finding the Loctite product guide a bit of a minefield! Can anybody recommend the correct product to use to when fitting phosphor bronze bolts into a 2” scale copper traction engine boiler. I'm hoping to cure a slight leak without having to overtighten the bolts
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Post by baggo on May 4, 2007 15:40:29 GMT
You might find this of interest. It describes using Loctite 290 for curing leaking boiler tubes but would suggest that this type of Loctite is suitable for use in boilers: home.ca.inter.net/~mguy/a_cure_for_leaking_tubes.htmYou could try using a thread sealant such as Foliac but personally I haven't had a lot of luck with it. John
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Post by havoc on May 4, 2007 16:51:29 GMT
What's wrong with soft solder? I do know it is no use for structural strenght, but this is not the case. Mechanically joined boilers (rivetted) are normally chaulked with soft solder without any problem.
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Post by stantheman on May 5, 2007 6:33:08 GMT
One very obvious reason against using soft solder is because it requires the provision of heat to complete its use. Not any use of course when the boiler is probably complete and assembled. Stan.
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Post by ron on May 5, 2007 8:11:29 GMT
What about PTFE tape? Ron
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Post by chameleonrob on May 5, 2007 8:30:12 GMT
in a boiler loktite will have little strength due to the temperature but still more than enough for sealing puposes, great for stopping pin hole leaks and the like. soft solder will prevent any further silver soldering so it best avoided unless you really really have to. around a bolt or fitting ptfe will be fine as long as you need no additional strength.
rob
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Post by baggo on May 5, 2007 10:09:56 GMT
I've also found PTFE tape to be very effective on threaded fittings etc. I used it to seal the blanking plugs in a recent boiler test and had no problems with leaks at 200psi. The only thing you have to be careful of is when winding the tape around the threads, try not to let it overhang the end of the thread otherwise the excess tends to come off when you screw the bolt/fitting in and you finish up with strands of PTFE floating around in the boiler ready to cause trouble!
John
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Post by Laurie_B on May 5, 2007 12:31:56 GMT
What's wrong with soft solder? I do know it is no use for structural strenght, but this is not the case. Mechanically joined boilers (rivetted) are normally chaulked with soft solder without any problem. And years ago,the generally accepted practice for firebox stays was to make them threaded,with nuts fitted then sealed with soft solder.A localised repair to seal a leak with soft solder should be ok.Loctite could be alright but the temperature rating would need checking against the boiler operating pressure and saturated temperature. For threaded applications such as described,then PTFE tape is probably best.
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Post by Shawki Shlemon on May 7, 2007 9:56:39 GMT
There is loctite thread sealant , I think is no 567 , is white and comes in a tube (like tooth paste ) , it is excellent , I use it on boiler fittings , never leaks .
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Post by spurley on May 7, 2007 11:42:16 GMT
Had a 'wade' through the Loctite website, www.loctite.com some interesting stuff there (I thought anyway!). All products have data sheets available on line, there is a search page www.loctite.com/int_henkel/loctite_uk/index.cfm?&pageid=472&layout=2 where you can select the application and it will give suitable suggestions. Looks like Loctite 564 would be the ideal in this case for thread sealing etc, the data sheet recommends cure times etc. On the same sheet they state that to release fittings or bolts that have been sealed with 564 local application of heat to 250C be applied! I would have thought that would satisfy most of 'our' applications? Even high superheat lines would probably survive, not elements obviously? Cheers Brian
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Post by baggo on May 7, 2007 11:51:53 GMT
Just been having a look myself at sealants and I reckon Red or Green Hermetite will do the job at considerably less cost. Both are suitable for temperatures up to 250° C. The green sets hard and the red semi-hard and both are resistant to steam, oil, etc. I'll get some myself and give them a try.
John
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jackrae
Elder Statesman
Posts: 1,333
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Post by jackrae on May 7, 2007 16:02:18 GMT
And if you don't want to buy anything fancy, just try some old fashioned oil-based paint on the threads before you assemble them. You'll be amazed what good results you can get from old techniques! Hope to see all you happy badge wearers at Harrogate (Friday)- if yours and mine arrive in time jack
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