Chemical cleaning

One for the chemists in our midst:-
    Is there any simple chemical treatment which would dissolve
baked-on carbon from the burner and feed pipe of an oil burning stove? Every six months I service an old stove by removing the burner assembly and small bore oil feed pipe and spend considerable time and effort in mechanically removing the hard, baked-on carbon deposits which have all but stopped the thing from working.
    It would be nice to be able to simply immerse the offending parts, brass elbows and with a steel feed-pipe between, in something relatively innocuous and at least soften the offending material - any suggestions?
     --
Chris Edwards (in deepest Dorset) "There *must* be an easier way!"
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Chris Edwards wrote:

Dissolve carbon, no - but the carbon particles will be stuck together with tars. Methylene chloride or caustic soda might well soften them, depending on thermal history - think oven cleaner.
-- Peter Fairbrother

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Peter Fairbrother wrote:

oops, sorry, didn't read your post thoroughly enough - don't use use caustic soda on brass!
Methylene chloride should be okay though.
-- Peter Fairbrother

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A simple treatment? In a word - no. The brass content rules out the use of any caustic material. You could try solvents or detergents to soften the remaining organic tarry content of the soot, but realistically you will be far better off mechanically removing it.
Is there any way to improve the cleanliness of the flame so that less soot is generated? It sounds as if there is not enough air or it is not mixing well with the oil.
Cliff Coggin.
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I have used Nitromors to shift varnish and carbon in model engines before now, not cheap though.
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Have a look at the products sold for removing carbon deposits from engines. Cylinder blocks are often made of Al alloys, and these also are susceptible to attack by alkalis, and they can't risk vigorous mechanical methods. Google threw up lots of stuff. I must admit I have never tried any of these, I don't really do IC engines.
David
--
David Littlewood

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Take it down to your local engine reconditioner and ask him to let it soak in his decarbonising tank if he has one. Cold soak decarbonisers, which I use myself, are a mixture of methylene chloride, cresylic acid and surfactants (detergent basically) with a few odds and sods thrown in. I did investigate in depth some years to see if I could mix my own rather than pay the extortionate prices the chemical companies charge but found it hard to get some of the ingredients so now I tend to just top the tank up with methylene chloride which is the main constituent that gets used up.
Paint stripper is a similar formulation based on MC and worth a try.
If the carbon has been baked on a very high temperature then it becomes inert and won't dissolve so for inlet and especially exhaust valves I have to resort to mechanical means and you may find the same.
--
Dave Baker



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Hi Chris! Frankly, I would test boiling caustic soda solution on a few brass throw away bits to see precisely how much damage actually occurs. I would agree with not using it on aluminium bits!
I can say with good authority that this caustic boil was the normal treatment for cleaning resin kettles in the paint/plastics industry here.
Meantime, Kind regards
Norman
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On Mon, 22 Nov 2010 04:25:48 -0800 (PST), ravensworth2674

    Thanks Norman and everybody else who has offered advice on shifting baked-on carbon deposits from an old oil-fired cooker.
    I have little or no control over the air supply to the burner inside a sealed combustion chamber and it looks like methylene chloride (paint stripper) is leading by a head from hot biological detergent with caustic soda a possible third but that all these may still need to be supplemented by old fashioned elbow grease.    
    I'll try some of your suggestions when I next service the cooker and I'll report back in a month or so.
    Once again, my thanks     --
Chris Edwards (in deepest Dorset) "There *must* be an easier way!"
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I must just add that Methylene Chloride on its own does not dissolve carbon properly as I found out to my cost when I tried it neat. The carbon softens but turns into the most appalling sticky mess that would then not clean off in my paraffin tank but just moved around the surface of the engine components as I scrubbed them like snotty glue. I had to go back to soaking them in the proper stuff to remove the resulting mess.
The MC in conjunction with cresols (cresylic acid) is what really does the job and the carbon either comes off completely or softens and washes off immediately with a scrub in paraffin.
The people in here have been overly kind to me for many years with help, advice and donations of parts like the ram chips very kindly sent to me FOC which speeded up my antique pc no end and on which I am still posting. I am still indebted to repay much of that so if you want to try soaking your parts in my cold dip chemical tank you are more than welcome and then if that works I can let you have several litres of it (it's old but still works) for your own future use. Buying it new costs about 100 for a 25 litre drum (minimum quantity) so I think you won't want to go that route but I would be delighted to be able to help with a donation of a sample from my tank. In fact I have a couple of 25 litre metal drums of old stuff I never disposed of which you might find is just the job for you. You would actually be helping me by taking them off my hands.
It is safe on all metals including aluminium and brass which caustic soda certainly IS NOT. It works best in a steel tank with a couple of inches of water layer over the top to prevent the MC evaporating. The parts to be soaked MUST be well below the water layer to avoid corrosion. I can advise further if you require.
--
Dave Baker



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Dave.
    Thank you for your kind offer. I echo your sentiment regarding this group. We have both been regular participants here for many years and it has long been a pleasure to note both the knowledgeable maturity and unstinting generosity of the contributors displayed on a regular basis.
    The parts I need to clean are really quite small, mainly the burner chamber and, especially, the fuel supply 'leg' of a very old Aga cooker. I have recently obtained a spare set of parts and next service, in December, I plan to simply swap new for old and take the easy way out. I'll then try cleaning the old bits at leisure in hot washing powder...if it does to the carbon gloop what it does to my underpants, I shall be well pleased! If I have little success with 'Bold', I'll take you up on a cupful of your 'magic mix'
    Once again, many thanks.
--
Chris Edwards (in deepest Dorset) "There *must* be an easier way!"
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Chris It sounds very like a Don oil conversion to a coal-fired Aga. I recall dealing with a similar problem in the late sixties. It was a series of concentric rings each containing a wick. Removing the carbon was a real pain. IIRC the long-term solution was to clean all the Aga's internal passages. Especially hoovering out the T shaped draught tube which was inclined to fill with fine soot/dust.
hth
--
Roland Craven
Nr. Exeter, Devon, UK
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On Tue, 23 Nov 2010 16:51:56 -0000, "Roland Craven"

    Thanks, Roland. You have a good memory, it IS a Don oil conversion!
    I'm told by others that the poorer quality of some oils(ie paraffin/kerosene) plays a major part in the rate of carbon deposit. In recent years there has, apparently, been a significant increase in the import of high-sulphur products, which are said to be major contributors to the problem.
    As my dear old mum used to say - 'worse things happen at sea' :) --
Chris Edwards (in deepest Dorset) "There *must* be an easier way!"
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You're welcome to post them to me and I'll soak them for a few days and see what happens.
--
Dave Baker



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You might also want to consider ultrasonic cleaning if your components are small. I bought four of the ones Aldi sell a few years ago for cleaning car engine fuel injectors and they do a very good job. Only 15 each as I recall. You can't get anything very big in them, maybe something the size of a pair of specs but other manufacturers sell them in any size.
http://en.wikipedia.org/wiki/Ultrasonic_cleaning
They literally blast contaminants off the base material with tiny pockets of very high pressure and temperature shock waves. It's quite good fun watching the particles of carbon lift off the components as the machine works. You can use them for specs, jewellery, coins, cutlery or anything else small and intricate that can't easily be cleaned any other way. Water with a few drops of detergent in to reduce the surface tension works ok on most things.
--
Dave Baker



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