Solvent or cleaner for exhaust elbow?

[john_morris_uk]

Can someone remind me what an appropriate solvent/cleaner for an exhaust water injection elbow might be? Can I use central heating cleaning solution? Should I try and get hold of some acid to de-coke it with? Just the normal carbon build up and deposits from the exhaust and its a cast iron high rise elbow off a Volvo 2040 but that won't make any difference I imagine.

 

[mattnj]

remove it and scrape it out manually, thats what i did....
dont think many chemicals would have removed the 6mm thick layer that was on there...

 

[john_morris_uk]

remove it and scrape it out manually, thats what i did....
dont think many chemicals would have removed the 6mm thick layer that was on there...

It is removed - and I have taken the plugs out (its a high rise one as mentioned and its impossible to scrape out all the inside - some places are inaccessible.

It looks very like this:

 

[Heckler]

It is removed - and I have taken the plugs out (its a high rise one as mentioned and its impossible to scrape out all the inside - some places are inaccessible.

It looks very like this:

On my previous 2030 ordinary, i took it off and started digging, what with that and soaking in fresh water, the whole lot crumbled inside.
I bought a new one!
Stu

 

[Sammy Lou]

Caustic Soda

Hi,

I've just done my one this week for a VP2002 - I used caustic soda & it removed all carbon/calcium deposits. I first tried ferinox? central heating cleaner but it didn't touch it. 4 days soaking in a bucket of caustic soda (changed solution twice) removed everything & left the steel clean. Did not touch the steel or the paint - only removed carbon & calcium type deposits. Unfortunately for me there was too much corrosion on the elbow & once the caustic soda had done its job the corrosion was through the wall of the elbow in two places. Still better to find out now than have a failure at sea - well that is what I'm telling myself to ease the blow of having to buy a new elbow!

I hope this helps

PH

 

[john_morris_uk]

Hi,

I've just done my one this week for a VP2002 - I used caustic soda & it removed all carbon/calcium deposits. I first tried ferinox? central heating cleaner but it didn't touch it. 4 days soaking in a bucket of caustic soda (changed solution twice) removed everything & left the steel clean. Did not touch the steel or the paint - only removed carbon & calcium type deposits. Unfortunately for me there was too much corrosion on the elbow & once the caustic soda had done its job the corrosion was through the wall of the elbow in two places. Still better to find out now than have a failure at sea - well that is what I'm telling myself to ease the blow of having to buy a new elbow!

I hope this helps

PH

Thanks - caustic soda it is then. Its not too badly clogged up - I fitted it new myself four or five years ago, so I hope that a soak in caustic soda will sort it out. I've even got the Volvo green paint to make it look like new again!

 

[Impaler]

We used to use Redex on machine guns if that's any help.

 

[oGaryo]

4 to 5 years ago would lean me towards replacing it not treating the deposits.. the cost saving isn't worth the risk of hydrolock imo

 

[john_morris_uk]

4 to 5 years ago would lean me towards replacing it not treating the deposits.. the cost saving isn't worth the risk of hydrolock imo

I haven't checked the price, but I think they are £400 odd.

 

[john_morris_uk]

Thanks - caustic soda it is then. Its not too badly clogged up - I fitted it new myself four or five years ago, so I hope that a soak in caustic soda will sort it out. I've even got the Volvo green paint to make it look like new again!

Two days of caustic soda and the paint has softened, but the carbon deposits have barely shifted. I think some Hydrochloric Acid might be needed? I know you can buy it in France - how do I get hold of some in the UK? Or is there another solution? (if you'll pardon the pun!)

 

[john_morris_uk]

Don't know if anyone is still interested in my exhaust - but here is the latest installment:

Bought some patio cleaner as it says on the container 'contains Hydrochloric Acid'.

I heated the exhaust up (kettles of boiling water) and drained it off and put the whole thing in the patio cleaner agent. The result was some immediate pretty impressive fizzing and removal of black gunge.

I topped it up some more and left it for a while - on return I discover that there is a nice electrolytic action going on and the copper/bronze pipe that the raw water rubber pipe from the heat exchanger clips onto and which is a press fit into the exhaust injection high rise elbow is gently being depleted of copper molecules and the cast iron of the elbow is being coated with a sheen of copper in a very pretty fashion wherever there isn't any paint.

I removed some of the liquid to leave the copper pipe above the surface and stop the electrolytic action and its now soaking outside and gently frothing at its various mouths.

 

[LadyInBed]

Mine is cast in Aluminium and cost an elbow and leg to replace.
A thought struck me that I could coat the inside in something like chemical metal to help stop the rot.
Any thoughts?

 

[jack_tar]

See article in august edition of sailing today expect i will be barred from the forum now!!!

 

[TradewindSailor]

Two days of caustic soda and the paint has softened, but the carbon deposits have barely shifted. I think some Hydrochloric Acid might be needed? I know you can buy it in France - how do I get hold of some in the UK? Or is there another solution? (if you'll pardon the pun!)

Try phosphoric acid .... it will probably do less damage than hydrochloric. I have never soaked the elbow in long enough to get it 'spotless', but it generally lasts 400 odd hrs before needing a clean again.

Phosphoric acid can be obtained in different concentrations. I use Metalprep 79 by Henkel (bought in Mexico). It contains Phosphoric Acid, Glycol Ether, and a proprietory Alkylphenol Ethoxylate ...... the latter ingredients are probably for desolving any grease etc. Unfortunately the bottle doesn't show the strength of the acid .... but I would guess 20%.

I soaked the elbow for 2 hrs in a 1 part Metalprep to two parts water.... but suggest you monitor the progress. Always add the acid to the water .... and follow the products instructions.

By the way I am not a chemist ..... so read on in case someone has corrected me.

 

[RobBrown]

Brick cleaner?

I think that much of the stuff sold in the UK as brick cleaner is essentially HCL. Contents list on the tin would confirm.

 

[john_morris_uk]

For those who read my plea for guidance on cleaning an exhaust elbow here is the final installment. Thank you to all who offered encouragement and advice

Patio and brick cleaner did the job on the whole. I tried caustic soda and phosphoric acid based cleaner as well. The phosphoric acid is very good for treating rust, but it didn't touch the carbon and other build up in the exhaust.

Lesson: use the right cleaner and don't allow bronze bits or copper bits of the elbow to be in the solution at the same time as the cast iron.

I removed the exhaust manifold and cleaned it all up, put it back on with a new gasket and some black sticky gasket compound from volvo (small tin with built in brush £8.00) I also removed the drain plugs in the heat exchanger and cleaned them and refitted them with gasket compound as there were traces of rust around them where they may have been seeping very slowly..

While I was at it I fitted all new rubber pipes and some new hose clips on rest of the cooling system of the engine and a new rubber end cover on the hear exchanger and all rust treated and painted.

On first start up, I realised I forgotten to tighten the exhaust hose clamp as it was spraying water, so quick turn off and sort it out.

Once that was tightened I ran the engine on load (in reverse - pulling the boats in the trot against the tide on their moorings) for over half an hour and until the whole thing was nice and hot.

NO SIGN of any leak anywhere. I'll post a picture of it all when I get a chance. Hurrah I have a boat again...

I then spent two hours cleaning the bilge and sponging out all the spaces where the engine had sprayed water when it developed its leak.

Now we have a clean bilge, a clean and working engine, and I just have to sort out the radio fit and the faulty aft shower pump and stern light. None of these stops us going sailing though!

 

[lsjaboardceltic]

Exhaust elbow clogged & cleaner

To de-clogg it I used hydrochloric acic (muriatic acid in Italy). It soaked for 36 hrs & I changed the 50/50 solution evry hr or so. The solution available was 30% to buy. The patio & brick cleaner may well be similar. First I tried caustic soda which also worked but removed the Volvo paint as well!. Its clean now & will last another few years.

 

[coliholic]

If you're after Hydrochloric acid a swimming pool shop should stock it, it's used for cleaning the calcium (?) deposits off the titanium plates in salt convertor thingys. Leastways they stock it in France