Exhaust Elbow - cleaning?

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andf

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I've taken my (cast iron) exhaust elbow off to inspect. Corrosion wise, it is in good shape, but was partialy blocked with sooty, calcified deposit. Much of this I have removed by chipping it away but there is much more in the parts that I can't reach.

Is there anything that I can 'pickle' the elbow in that will disolve the deposits?

Courier
 
You could try this...

Hydrochloric acid, AKA: muriatic acid, spirits of salt, agua fuerte.

This stuff really shifts calcium deposits, but keep it away from aluminium!
 
If it is a carbonate deposit then yes hydrochloric acid will make short work of it but if it is oily caustic soda solution may be more effective.

Some brands of brick/masonry.patio cleaner are HCl based. Some or not though. B&Q stock 6 different ones:-

Swarfega Brick and Masonry Cleaner is hydrochloric acid based
BUT
Swarfega "Tough Clean" is based on citric and phosphoric acids.

No Nonsense contains hydrochloric acid

Extreme Green is based on aluminium chloride

Cementone Brick and Patio Cleaner is hydrochloric acid based

Geocel Ecochem Brick and Mortar Cleaner is aluminium chloride based.

Therefore check the label and data available on line before buying.
 
Be careful! I had this problem on a cast iron elbow and when I started tackling it with a screwdriver the iron was so corroded that the screwdriver wnt straight though it!! I actually replaced the Perkins Perama fitting with the Volvo Penta equivalent - which was cheaper, which must be a first!
 
Doh!

Well I suppose it was inevitable really. The HCL worked so well in cleaning all the crud from the inside of the elbow that it revealed the hole in the casting!!

Still better at home than under way I suppose. Time to raid the piggy bank.


Courier
 
Re T.K.'s comment, has ANYONE got a good story to tell about exhaust elbows?
The last two boats I've owned have "remote" elbows - ie there's a metre or two of flexible iron before the water gets added via heavyweight cast-iron fittings.
Both have lasted for 30-odd years and are still fine.
Maybe there's a bonus in the gas temperature dropping a little before the mix takes place?
 
Cast iron exhaust elbow

I had a problem with an exhaust elbow about 21 years ago on a return trip from Holland. Really bad weather and Bridlington reported F9 off the land as I was approaching under sail (no engine because of hole in elbow) around midnight.

A few stories here:
1) Homing in on fixed green light for harbour. Heard breakers and saw light go to red (traffic lights). Eventually found the harbour with a white light (green replaced 2 weeks earlier). No GPS in those days.

2) Sailed into harbour with scrap of sail and rounded up onto a fishing boat. Immediately told by "Harbourmaster" that I needed to move to wall opposite. Did that only to be pinned by wind and then told by real Harbourmaster there was a ledge & couldn't stay. Got help onboard and ashore, pulled with line at stern and pushed off with 2 boathooks. Went outside harbour put up scrap of sail and repeated the exercise.Once back on fishing boat it was easy to pass a line forward and move to head of the harbour.

3) Problems getting a part for the BUKH DV20 at short notice. Made up a replacement from cast iron plumbing bits. Basically a piece of pipe with 2 elbows and T piece to inject water. Worked a treat for trick back to Scotland & I kept it for years as an emergency spare.

Learned to keep a spare, to epoxy paint inside of new elbow before fitting it and remove to clean every couple of years. They seemed OK for 5-6 years use after that and I had the same boat for 23 years with no other engine problems.
 
Cast Iron Elbow

A blister usually appears on outside first. I keep a couple of car exhaust bandages in the tool box just in case of a total failure. They set with heat and water.
 
Fizz

andf said:
The HCL worked so well in cleaning all the crud from the inside of the elbow that it revealed the hole in the casting!!Courier
Click to expand...

HCl dissolves calcium carbonate evolving CO2. It also dissolves Iron evolving Hydrogen.

I guess (and it IS a guess!) it will go for the calcium first so you should check the fizz, maybe with a match??
 
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