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Post by Roger on Nov 11, 2018 9:32:29 GMT
Hi Dave, Be watching how you get on! Previous exponents have had great results! Wish I had know about it when I needed to remove what was left of the studs in the back head regulator bush...... all 8 of them! Setup an x y vise vertically then using a Dremel with a flex hand piece in the vice a nice thick drilling bush using a new drill all removed with no damage to the bush! Tap run in removed what was left of the studs. New ones made in stainless so shouldn’t have a problem again! Cheers Kerrin I like your idea of stainless studs. There won't be a strength issue will there? Cheers David Hi David, The threads will pull out of the boiler way before the studs break. I buy the longest Stainless Cap Screws I can get from eBay and use the threaded part for studs if I don't need a parallel portion.
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Midland
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Post by Midland on Nov 11, 2018 14:44:35 GMT
Ta Roger. The witches brew is in place!! D
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Post by Roger on Nov 11, 2018 15:45:16 GMT
Ta Roger. The witches brew is in place!! D Just a thought... some paper towels wedged outside of the dam in case it leaks?
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Post by steamer5 on Nov 11, 2018 17:24:18 GMT
Hi David, The studs are 1.5 or 2 mm can’t remember which........ old age, so should be fine. The steel ones had wasted to less than the root diameter , a couple considerably more, so the stainless ones are have got to be stronger. The plan on the next loco is to use stainless for all studs on the back head.
Cheers Kerrin
PS missed the replies....made the studs from stainless welding wire
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Midland
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Post by Midland on Nov 11, 2018 17:53:50 GMT
Good thought Roger but so much has leaked so far that I may end up with half a loco in any case. Seems to be running down the outside of the cladding. My biggest challenge was the colour of the plasticine, IMG_1070 by David Goyder, on Flickr and as well there is the indignity of standing on your nose, IMG_1067 by David Goyder, on Flickr But here was are, IMG_1076 by David Goyder, on Flickr Will check for bubbles later on this evening, Cheers David
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Midland
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Post by Midland on Nov 12, 2018 15:10:39 GMT
Nothing happened. So heated up a small jar of the brew in the microwave and popped one of the broken off studs with its nut into the hot brew and nothing happened. So, checked what I am trying to get out, yes magnetic so it is steel. I have some Aluminium Potassium Sulphate (Alum) Mordant. Some of the articles refer to aluminum ammonium sulfate so I wonder if I have the correct alum?? More research I suppose, getting awfully tempted to drill them out!!!
David
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Post by Roger on Nov 12, 2018 15:31:40 GMT
Hi David, Someone mentioned earlier that it has to be a saturated solution. To me that means you heat it up and keep adding more Alum until no more will dissolve.
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rrmrd66
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Post by rrmrd66 on Nov 12, 2018 16:31:42 GMT
Hi Roger and David
Yes that was me.
You need Aluminum Potassium Sulphate. I think the mordant type is for dying/fixing textiles, but could be wrong there.
I bought mine via the internet. You may need more than you imagine as you need a "stock pot" of it.
It must be as hot as you can make it. I boiled my gunmetal cylinder in a Pyrex bowl for most of the day. If it is going to work you will see bubbles streaming from the steel immediately.
Best of luck
Malcolm.
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Post by simplyloco on Nov 12, 2018 16:32:38 GMT
Hi David, Someone mentioned earlier that it has to be a saturated solution. To me that means you heat it up and keep adding more Alum until no more will dissolve. Hi Roger. We made sure of that with the first attempt. There's something odd going on here! John
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Midland
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Post by Midland on Nov 12, 2018 17:56:51 GMT
Hi Roger and David Yes that was me. You need Aluminum Potassium Sulphate. I think the mordant type is for dying/fixing textiles, but could be wrong there. I bought mine via the internet. You may need more than you imagine as you need a "stock pot" of it. It must be as hot as you can make it. I boiled my gunmetal cylinder in a Pyrex bowl for most of the day. If it is going to work you will see bubbles streaming from the steel immediately. Best of luck Malcolm. Hi Malcolm I think we, and today I, followed the instructions properly. But to start to eliminate factors, I boiled up a new brew, put in a 6 BA screw and a small piece of MS that I parted off and dropped them into the mix. Nothing happened. They just sat there on top of some undissolved crystals looking at me! So have ordered some more crystals from someone else. Later this week we will see what happens. Keeping it hot or warm will be an issue with mine, will raid the wife's hairdryer. Cheers David PS Do you remember where you got yours?
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rrmrd66
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Post by rrmrd66 on Nov 12, 2018 19:11:03 GMT
Hello David Yes try this supplier: www.ebay.co.uk/itm/100g-ALUM-Aluminium-Potassium-Sulphate-Mordant-Reagent-Sulfate-Aluminum-/181333885525I was wrong about the mordant use!! The customer review could have been written by me ( but wasn't). This was totally my experience. I think you need something like 1 gram of alum to every 1 cc of water to make the saturated solution plus high temperature (just boiling). I was surprised how quickly the reaction began. There is a YouTube clip somewhere of a guy in New York doing this. That is what made me try. Oh! I found it first attempt: www.youtube.com/watch?v=JCADI0YSt8MIf sll else fails I suggest you revert to the Cotes du Rhone to calm yourself and then "Dremel" it out. Best wishes Malcolm
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Midland
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Post by Midland on Nov 12, 2018 21:54:57 GMT
Malcolm Much thanks for your guidance. I expect Simplyloco and I will experiment once the magic potion arrives probably by a witch on her broom stick. Must not say too much more as SHMBO has her's parked outside!!!! Perhaps the way to get the solution saturated is to boil it up on the stove first of all and then pour it on my poor little engine. Will report for your assessment shortly. And will be away for a couple of days, going to the Palace of Westminster to sort out Brexit!!! Cheers David
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Post by Jim Scott on Nov 12, 2018 22:09:06 GMT
Hi David There is no doubt that this process is effective and you should be able to see the action immediately on a piece of steel placed in a hot saturated solution of potassium alum sulphate. However, you might also have noticed that practically all of the references refer to removing broken taps. This is because the solution penetrates to the bottom of the tap via the flutes and so the process works on the length of the tap from top to bottom. Moreover, because of the flutes it works at the thread interface at both cutting and trailing edges. Often the tap is just partially dissolved before it becomes slack in the hole allowing the remains to be poked out. Consider a broken stud, broken off level with the surface. The only bit exposed to the alum solution is the end of the stud, therefore although the process will work it is only acting on a small area. You might find that it takes a considerable time to dissolve the whole stud this way. Drilling the largest hole possible through each stud without damaging the threads will help speed things up considerably, but at some risk of accidentally damaging said threads. If you need to save the original threads this combination of drilling and dissolving may be the only satisfactory way forward, finally cleaning up afterwards with a plug tap. I hesitate to present the 'best way' but personally I would opt for a drilling jig and if space permits drilling and re-tapping to a larger size then fitting dual diameter studs. Others will no doubt suggest more/better ways. Jim S
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Post by Roger on Nov 13, 2018 0:18:21 GMT
Malcolm Much thanks for your guidance. I expect Simplyloco and I will experiment once the magic potion arrives probably by a witch on her broom stick. Must not say too much more as SHMBO has her's parked outside!!!! Perhaps the way to get the solution saturated is to boil it up on the stove first of all and then pour it on my poor little engine. Will report for your assessment shortly. And will be away for a couple of days, going to the Palace of Westminster to sort out Brexit!!! Cheers David Hi David, With all the will in the world, I can't see you getting the boiler hot the way you describe. You may have to strip it bare and then warm it all up very slowly with a blow torch and then cover it with fire blankets to get it hot enough for this to work. My gut feeling is that this is going to take forever to dissolve unless you do what Jim Scott suggests.
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Midland
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Post by Midland on Nov 13, 2018 11:05:00 GMT
Hi All First of all Malcolm, I must have used your previous email to source the crystals and indeed have seen the experiment in action. I got mine from your source. My mixing is suspect as the two samples I put in have not moved. I must find a pyrex pot or try an aluminum one just to see if I can get a reaction. Once there I may try it again on the studs. But Jim, I think drilling out and making the studs a little bigger may have to be the answer. There is plenty of meat on the two bits so if I was very careful I might get away with it. 'SL' has warned me away from drilling as the drill will wander and not go down straight. I have had the boiler off this thing once and do not want to strip it down again so need to ponder over the next move. Perhaps some Muscadet tonight might help! Cheers David
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Post by Roger on Nov 13, 2018 14:59:15 GMT
Hi All First of all Malcolm, I must have used your previous email to source the crystals and indeed have seen the experiment in action. I got mine from your source. My mixing is suspect as the two samples I put in have not moved. I must find a pyrex pot or try an aluminum one just to see if I can get a reaction. Once there I may try it again on the studs. But Jim, I think drilling out and making the studs a little bigger may have to be the answer. There is plenty of meat on the two bits so if I was very careful I might get away with it. 'SL' has warned me away from drilling as the drill will wander and not go down straight. I have had the boiler off this thing once and do not want to strip it down again so need to ponder over the next move. Perhaps some Muscadet tonight might help! Cheers David Hi David, Just a few thoughts if dissolving the screws doesn't work. Drilling out the studs without a guide is not something I would ever do. Drilling them out with a hardened drill guide is not a problem in my opinion though. You can go 0.2mm under size if it's done well and get them out. Maybe you could spot through the piece that bolts on to this and drill some undersize holes in a piece of 10mm thick Gauge plate and harden it. If some studs came out, those can be drilled to be a snug fit and hold the drill jig in place.
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jma1009
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Post by jma1009 on Nov 13, 2018 22:12:14 GMT
Hi David,
I have used Alum off ebay and at first no effect then I whacked up the strength of the solution and left it in sunlight on a hot Summer's day and poked about at it a bit from time to time and got an excellent result dissolving a broken tap in one of Stepney's side tanks, but it does take awhile.
Jim's approach makes sense to me. With a 1/32" dental burr in a dremel and a steady hand and a good light you ought to remove quite a bit of the studs to allow the Alum to penetrate deeper, otherwise it is just a long wait and refreshing the solution from time to time and doing something else in the workshop.
I did note that your lower right hand water gauge bush has a lot of accumulated scale showing inside the boiler, and you might want to consider a thorough clean of the boiler innards below the water line.
Cheers,
Julian
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Midland
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Post by Midland on Nov 14, 2018 19:35:30 GMT
Julian/ Roger
Many thanks for your wise words. I am doing a go slow on this as I ought to be able to get the chemical erosion system working. So I will persevere here and try a few experiments. When I can get ordinary nuts and bolts to bubble then I might have a chance with these studs. If it takes a week to erode them, we know it will take a week. I am not in a big hurry. In the meantime I have a Princess Royal backhead cover to beat to bits and some lovely small fittings to make so I am happy to all that I can to avoid damaging the 990 boiler by drilling willy nilly. Yes Roger if we get there some sort of jig will have to be used. Julian yes a good clean out will be on the agenda! Cheers David
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Midland
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Post by Midland on Nov 15, 2018 22:33:52 GMT
A new thought. A friend has suggested spark erosion. Any thoughts?? D
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Post by Roger on Nov 15, 2018 23:22:04 GMT
A new thought. A friend has suggested spark erosion. Any thoughts?? D Spark erosion certainly works, but you have to line it up as accurately as if you were drilling it out because out will spark away anything.
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