Chimney Leaking Tar - How Do I Remove it?

[Porcupine]

Hi everyone,

 

My chimney is leaking a bit of tar that has, unfortunately, now run down the side of the boat. Any ideas how best to remove the tarry streak?  

Thanks so much,

Matt 

[howardang]

12 minutes ago, Porcupine said:

Hi everyone,

 

My chimney is leaking a bit of tar that has, unfortunately, now run down the side of the boat. Any ideas how best to remove the tarry streak?  

Thanks so much,

Matt 

This has been discussed before and a number of responses can be found via the search function, accessible above.

 

Howard

[Guest]

4 minutes ago, howardang said:

This has been discussed before and a number of responses can be found via the search function, accessible above.

 

Howard

 

Very helpful.....not

 

 

Same result using just 'removing tar'

 

 

Somebody who can actually answer your question will be along shortly.

 

@Porcupine

[LadyG]

I don't have any tar on my chimney, are you using driftwood rather than seasoned wood or kiln dried?

[matty40s]

Tar down the side of the boat is usually from burning wet wood/ coal and not having sufficient seal round collar/chimbly, or having one of those stoopid coolie hat things on permanently when using stove....allowing the cooling wet tar to fall back onto the boat.

[Higgs]

The staining can be hard to remove, without resorting to cutting back with polishing agents, and sometimes with wet and dry sanding, followed by a polishing. And, as said, coolie hats will drip tar material onto the roof. I find the best way to avoid anything reaching the roof is to fit a smaller flue pipe, just at the top, inside the main flue. This sends all the stuff back down inside. 

 

If you have a 4" bore, you won't find a friction-fit size of pipe to go inside, but the size you'll find leaves a little gap to deal with. It does however stop the pipe from getting stuck in the main flue. I drilled three small holes in smaller pipe, to take rivet pins. The rivet pins will ledge on the main flue circumference. These pins will stop the smaller pipe falling down the inside of the main flue. The small gap between the pipes can be sealed with a flexible sealant. The pipe is obviously detachable, if needed. I don't keep reapplying the sealant each time the small section is removed. The sealant was a rubberised sealant that can be cut with a sharp blade, when set. If cut sufficiently well, and the flue section placed in the same position each time, the sealant would provide a decent gasket effect.

 

 

Edited April 27, 2023 by Higgs

[Jen-in-Wellies]

Other ways of achieving an inner flue to divert tar back down towards the fire, as @Higgs describes. Buy a double skinned chimneys (stainless - ordinary steel will rot through in a single winter of use). This is what I have. Ensure the inner skin is a close fit in the flue pipe. Alternatively, a length of thin stainless steel sheet, rolled in to a springy tube and shoved in to the flue, with the chimney around the outside. This is more of a faff to remove and refit when cruising a canal with low bridges/tunnels/trees.

Rain hats on the top of the chimney, I'm in two minds on. Yes, they can drip tar. They also prevent rain going down the flue when the fire isn't lit. The first winter of owning my boat, when I wasn't living on it, the ash pan in my stove rusted through from this. Without a riveted on hat, you have to remember to cover the hole with something that won't blow away when the fire is out and just as importantly, remember to remove it when lighting the stove again!

As @LadyG says, what you burn is also important. Green wood is especially bad. Having the fire barely ticking over, with the air intakes almost closed for long periods is also bad for tar and general crud production.

[magnetman]

This is a problem of having fires that are too large for the space they are heating. The flue doesn't get hot enough. I've been burning freshly cut ash, apple and hawthorn all winter at the country estate and not had any flue issues because the fire is small (about 3kw output) and I insisted we did it with a 70mm thin wall stainless flue when the fire was fabricated. It is made from 8 inch box section steel 5mm wall thickness. Also has preheated secondary air input which helps. 

It gets hot including the flue which means anything will burn happily in it due to the efficient gas flow but the cabin does not become ridiculously hot and unbearable. 

 

I was surprised (removeable flue for cleaning) to find the flue just has a light layer of dust in it. This is after shifting a lot of green wood through it.  Some of the apple wood was burned within a few hours of being cut. 

 

The whole thing needs to be hot OR you must burn very dry fuel at all times. 

 

 

Wet wood burns hotter than dry wood so if you try to do this on an ordinary fire with a 4 inch flue it is going to get far too hot in the boat which could be quite dangerous depending on the installation. 

 

 

 

 

 

 

 

[mrsmelly]

I used to get this on my first boat until a seasoned boater told me to bin the coolie hat. Never had any again. How to get it off will depend on how precious you are about your paint finish?

[rusty69]

White vinegar works. 

 

What it does to the paintwork though, I am far from certain. 

 

Like smelly, we binned the coolie hat years ago. 

[peterboat]

14 minutes ago, magnetman said:

This is a problem of having fires that are too large for the space they are heating. The flue doesn't get hot enough. I've been burning freshly cut ash, apple and hawthorn all winter at the country estate and not had any flue issues because the fire is small (about 3kw output) and I insisted we did it with a 70mm thin wall stainless flue when the fire was fabricated. It is made from 8 inch box section steel 5mm wall thickness. Also has preheated secondary air input which helps. 

It gets hot including the flue which means anything will burn happily in it due to the efficient gas flow but the cabin does not become ridiculously hot and unbearable. 

 

I was surprised (removeable flue for cleaning) to find the flue just has a light layer of dust in it. This is after shifting a lot of green wood through it.  Some of the apple wood was burned within a few hours of being cut. 

 

The whole thing needs to be hot OR you must burn very dry fuel at all times. 

 

 

Wet wood burns hotter than dry wood so if you try to do this on an ordinary fire with a 4 inch flue it is going to get far too hot in the boat which could be quite dangerous depending on the installation. 

 

 

 

 

 

 

 

Are you using one of James fires Andrew?

[rusty69]

Just now, peterboat said:

Are you using one of James fires Andrew?

I bet if you ask nicely he will post a picture of it (again). 

Edited April 27, 2023 by rusty69

[magnetman]

Just now, peterboat said:

Are you using one of James fires Andrew?

Yes he did the fabrication I had some input to the design including insisting on the small diameter flue. I also had him fit a blowtorch hole above the grate (1 inch BSP pipe at an angle with a screw on cap). Always wanted a blowtorch hole for a fire ! Not needed to use it so far. 

[bizzard]

I always use a coolie hat, I make my own and never have any tar dripping from it onto the roof. The diameter needs to be quite small, just big enough to stop rain pouring down. Too bigger diameter and tar will drip off the edges like drips off the end of your nose when you come in to the warm out of the cold, similar principal.

Edited April 27, 2023 by bizzard

[Col_T]

We have an Morso Squirrel on the boat, and always use a coolie hat whenever the stove is lit, with no tar problems over 8-ish years.
 

We burn a variety of woods sourced from a variety of places (garden, canal, towpath and occasional kiln dried) always with a few ovoids. We never try and keep the fire in overnight, preferring to close all air controls when we go to bed.

 

HTH

[Puffling]

I seem to recall a thread here last year about using a double skinned chimney and packing the space between inner and outer tubes with insulation.

The reasoning was that smoke escaping from the inner tube in contact with the flue is prevented from travelling into the outer tube, condensing, and trickling back as tar.

 

There was some debate about whether to use glass wool as insulation packing or whether spray foam from a can would be sufficiently fireproof to serve as an insulator.

[Silent Flight]

I saw a weather vane style spinning setup on a chimney the other day. 

It was a CNC metal flame that caught the wind so the smoke always went away from the wind.

 

I thought it looked really good, and seemed super practical.

 

Does anyone know where it was from? Or did the owner make it himself?

[David Mack]

Something like this?

https://smokiejoes.co.uk/

[Silent Flight]

Thankyou @David Mack precisely something like that! 

[rusty69]

We had one of them. The squirrel ate it.

[Porcupine]

Thanks so much for all your advice. Lots to ponder. 
 

Matt x 

[jacko264]

I don’t know  if it helps  but you can buy tar remover to remove road tar off car paint 

[BEngo]

 

49 minutes ago, jacko264 said:

I don’t know  if it helps  but you can buy tar remover to remove road tar off car paint 

Chimney tar is in a different league to road tar.  Petrol will shift road tar.   Chimney tar eats its way into the paint and usually needs polishing out, or neutralising  and then painting over.

 

N

[Waterway2go]

A working boatman once showed me how to deal with this.  Break off a suitable small branch of an overhanging tree and shove it up and down the chimney a few times (whilst continuing to steer the boat with your other hand).    The result is two-fold: a cleaner chimney, and one less overhanging branch that can knock your water can off the roof.