log – Bushcraft Days

March 6, 2019March 6, 2019

How To….. Carve a Giant Log Rocket

Over the last few years I have written a fair bit about carving Finnish Candles or Log Rockets using just the tools I would carry in my bergen (saws, knives, axes etc) so I thought it was time to see what could be done with a chainsaw.

I decided to opt for the Log Rocket as I thought there has been plenty written about using Finnish Candles (referred to sometimes as Swedish Candles/Torches). At the Bushcraft UK Bushmoot last year I asked my friend Rob Nash if he was willing to carve a large log rocket for me using his chainsaw.

For those of you who just like to watch a short video on its construction here it is – for those of you who prefer detailed instructions there are loads of pictorial steps after the video below.

The Log Rocket

The log rocket worked spectacularly and you can get a sense of scale (forgot to measure it) from the picture of Rob standing next to it.

I chose a large piece of piece of what I think was Spruce (hard to tell when there is no bark and it is seasoned). I will be referring to the 3 parts of the log rocket as you can see in the bottom left picture below.

Section 1

Rob took out a slice of the log (approx 1/3 of the log) and stopped the cut about 15 cms from the bottom. Then he cut in from the side at the bottom of the log to remove Section 1.

Section 2

To describe this cut is quite difficult so refer to the picture above in which the pieces are numbered. The aim was to leave Section 3 with a point that could be removed to form the chimney. Again it was a case of cutting down to about 15 cms from the bottom and removing section 2 by cutting in from the side.

Section 3

You can clearly see the point left on Section 3. Rob made an undercut at the bottom first this time and then removed the ‘Point’. This is the area that would form the chimney. The triangular-shaped piece of wood from the centre point was split down further with an axe to form the kindling to get the log rocket going.

The final step here in the bottom right picture shows Rob cutting out a piece of wood at the bottom of Section 3 to slightly enlarge the ‘firebox’ area.

Firebox opening

I have shown the final look of the firebox opening in the top left picture below. Rob created this firstly by re-assembling Sections 1 & 2 with Section 3. The he marked the corners of Sections 1 & 2 that needed cutting to form the firebox opening (that might sound overly complicated, but it’s important if you’re not to cut the wrong corners).

Once he’d cut off the corners he shaved off more wood from the ‘Shoulder’ of the opening so as to enlarge the firebox area.

The Raappanan Tuli cuts

To increase the surface area of the chimney and help the log catch light more quickly I asked Rob to makes some cuts in the flue area. I got this idea from researching different types of log fires – this style of cut comes from the Raappanan Tuli log fire.

These cuts are particularly useful when you have a damp log as the increased surface area greatly increases the chances of the fire taking properly.

Final touches

I used strong wire to hold all the pieces of the reassembled log together – an alternative would have been to make some dovetail joints and join them together with green wood pegs – see here for more details – How To…. Build a Dovetail Log Rocket Stove.

Finally my friend Mark used his drill to give the log rocket a face (which also helped provide a bit more ventilation).

Firing up

I used slivers of the central section Rob had cut out of the log as kindling and lit it all with a lollistick lighter (a firelighter pierced on a sharp stick – have a look here – Lolli Stick Fire).

Party time

The log rocket was a stunning central feature for everyone to sit around in the evening and we even used it as a backdrop in a wedding photo (Magdalena and Phil renewed their vows at the Bushmoot).

We even added a little bit of Cap’n Badger’s magic Rainbow dust to ‘mix the colours up’ a bit.

When I looked at the log rocket the next day (over 14 hours after it was lit) the base was just a mass of burning embers – quite a log rocket, I would say.

Cheers

George

September 4, 2017

‘Space Shuttle’ Log Rocket Stove – With Des Cattys – A Video Post

This year at the Wilderness Gathering my friend Des Cattys was showing his love of Log Rocket stoves to visitors. I decided to drop in on one of his sessions to watch how he constructs one. Like Des I am intrigued by these stoves and I am always looking to improve on their construction so watching someone else at work building one is a chance not to be missed.

If you want more detail on making one of these stoves have a look at my How To…. on building a Log Rocket stove. There are many variations on them and I have included some of them on my Bushcraftdays blog in my How To section.

Cheers

George

January 27, 2016

How To…. Build a Log Rocket Stove – No Axe

One night recently I just could not get to sleep and my thoughts wandered onto the subject of log rocket stoves. Having written on the subject a few times with the Damp Log Rocket and the Fire Face Candles it struck me that I always used large tools such as axes or drills to make them.

This post is about making a Log Rocket Stove with only my knife (a small pruning saw was used to trim the log). I wanted to see if I could easily produce a stove without having to rely on my axe.

Photo 26-01-2016, 22 25 06 — Log Rocket Stove – Without an axe

I like log rocket stoves as they can be made quickly, work well on wet or snowy ground, produce their own kindling and come with a ready made platform for your pot. Once the stove has done its job the collapsing embers make a good start point for a bigger fire.

Set Up

I chose a seasoned piece of spruce wood from my log pile which had a diameter slightly larger than the blade on my Mora knife (do not be tempted to use a log much smaller than this as you will end up with a very small cooking surface) . I also used a larger round of wood as a work surface, carved myself a small wedge to help with splitting the wood and had a offcut of wood ready to batton with.

Photo 26-01-2016, 22 25 07 — Spruce log and a stable work surface

Splitting

I started with my knife first and battoned it into the log (note that the knife blade is at 90 degrees to my body for safety). My aim at first was to create a split as deep as I could with the knife all around the middle of the log to create a weak point in it. The knife was smaller than the log so I could only batton it in a couple of centimetres.

Once I had my point of weakness battoned in all around the log I inserted the wedge into the split at the top and battoned that in as well to try and increase the split some more (upon reflection I think two wedges would have helped). It was at this point my batton decided to snap on me.

Photo 26-01-2016, 22 25 08 — Batton out a split as much as you can with your knife

I went off and got a bigger piece of wood to act as a batton and soon had the log split right down the line off weakness. This line I created with my knife will help you to keep an even split on the log when you have twists and knots in your log as I had with this piece of spruce.

Photo 26-01-2016, 22 25 12 — Use a wedge to split the log

I repeated the process on each split so I ended up with four roughly even sized pieces of wood.

Safety

One thing to be aware is that as you batton down on the wedge is that it will go slightly out of line at times. If this happens just tap the end of the wedge against the work surface until it lines up. This is much safer than trying to drag it back in line with your hands as it is very easy cut yourself on the knife tip.

As the split widens the knife blade will come loose. Let it drop away and only pull it out when it it is completely free. Do not be tempted to force it out as this is another time when injuries happen.

Photo 26-01-2016, 22 25 12 (1) — Quarter the log by battoning with your knife and using the wedge

The Chimney

The stove requires a chimney and it is very easy to carve one out. About a third of the way from what will be the bottom of the stove I battoned my knife into centre ridge of one of the quarters of wood. I then used this a a marker to drive in stop cuts on all the other three pieces of wood.

Then from the what would become the top of the stove I battoned off the centre ridge of wood down to the stop cut. I then used my knife as normal to carve off some more excess wood so that part of the chimney looked fairly even. Once the first was completed I repeated the process on all the other pieces.

Keep all the offcuts and shavings as they will be needed to fire up the stove.

Photo 26-01-2016, 22 25 16 — Batton out the core to form the chimney

From the top, looking down, your stove should look similar to the picture below. I have no idea how wide a chimney should be but I generally tend to take a couple of centimetres off each quarter.

The Firebox

Once the chimney is finished select two of the quarters that fit together and just at the base of the chimney on each quarter carve out a half triangle on each quarter.

I put a stop cut in first and then carved off the excess wood down to the stop cut. The whole just needs to be big enough to let air in and allow you to add slivers of wood into the fire.

Make sure your cuts are opposite each other so that when you fit the two quarters together again you form a triangle.

I used to carve out a square shape with my saw and an axe in the past but a fellow bushcrafter called Takeshi Mizumoto showed me this method by just using a knife – so much easier.

Photo 26-01-2016, 22 25 20 — Carve out a triangular fire box

Raappanan tuli cuts

I like to increase the surface area of the inside of my chimney so as to give the initial flame from my tinder something to grab onto.

This is a technique from Finland and you can read more about it here in my post on the Raappanan tuli candle. To make the cuts place each quarter on the work surface and gently batton in cuts to the inside of the chimney. Ensure that the cuts are made so that the small split you create is travelling towards the top of the stove.

Finally collect up all the wood shavings you have created and split the larger off cut pieces down to nice small kindling.

Photo 26-01-2016, 22 25 21 — Creating extra surface area and kindling

Firing the stove up

I found some old twine, thoroughly soaked it in water and then used it to tie the quarters together near the bottom.

To light the stove I used a firesteel to light some cotton wool smeared in vaseline. This gives me a burn time off about 5 minutes and as I always carry a supply in my rucksack am happy to use it. A more natural method that I like is to use birchbark and small lumps of spruce resin.

Once the cotton wool was well lit I added a few small pieces of wood in via the top of the chimney. At this stage it is important not to add too much kindling as this may block of the flow of air from the firebox to the top of the chimney. Also make sure your fingertips are not directly over the top of the chimney as you drop in the slivers of wood. Even at this early stage the heat is intense enough to cause injury.

Photo 26-01-2016, 22 25 21 (1) — Firing up

Three pebbles

I popped three flattish pebbles on the rim of the stove to act as a platform for my pot. As this is a small stove you need to keep a close eye on your pot as the water boils or the food cooks so that it does not accidentally fall over. I had this happen once before as I had left the handle of my pot up. The handle snapped back down eventually causing the pot to fall off the log.

All was well with this set up and after about 10 minutes of good heat my water was boiling. if you do not have pebbles to hand I find that 3 pieces of green wood work well instead.

Photo 26-01-2016, 22 25 22 — Three stones and a pot

Afterwards as I was drinking my coffee the stove really came alive with some wonderful flames.

I really enjoyed making this small log rocket stove as it showed me that with a little ingenuity you can make do without an axe. It can be difficult but it is doable and a great way to test your personal skills.

Cheers

George

December 13, 2015December 16, 2015

How To…. Build a Damp Wood Log Rocket Stove

When the weather is inclement and the ground is really wet then the option of making a rocket stove needs to be considered.

This How To…. sets out the steps I took on a wet and windy December morning to make a Damp Wood Log Rocket Stove with only the tools I normally carry in my rucksack.

Photo 11-12-2015, 13 13 59 — The damp wood log rocket

I have dabbled with making different types of Finnish Candles for cooking on and they are excellent for when the ground is wet. Over the years I have also experimented with making Log Rocket stoves but restricted my activities to the workshop as I used drills to make them.

I recently stumbled on an idea on Facebook from the 1st Facebook Scout Group by Paul Hasling. This is the first time I have seen a log rocket stove done without the use of drills so I was instantly taken with the idea. Another Scout instructor José Xavier put Paul’s pictures together into a quick helpcard called the Rocket Stove de Madeira. This is a very simple design where a log is split four ways, a chimney and firetray are carved out and it is all put back together again with string. I will certainly be showing my Sea Cadets how to make one.

First though I wanted to make one when out in the woods with only what was to hand. It being December, there was nothing that was bone dry so I found a dead Birch and cut a section off. It was still damp to the touch, however it had been dead for over a year so it was slightly seasoned.

Splitting

For the job I had my knife, saw, axe and a pen. Using another round of wood I split the log in half by battoning it with my axe (keep the blade of the axe at 90 degrees to your body when you do this).

Photo 11-12-2015, 13 14 05 — Tools and battoning

After splitting the log in half I split each half into three even sections. With very dry wood you only need halve the halves again to make four sections however my wood was damp so I wanted to produce as much surface area as possible which is why I opted for six sections.

Photo 11-12-2015, 13 14 04 (1) — The splits

Stop Cuts

Using a stick and a pen I marked a line on each section about a quarter of the way from the bottom and also numbered each section. These marks were put in so that I could cut in stop cuts so to make it easy for me to cut out the chimney section.

My friend Keith Coleman suggested using tape as a depth gauge for this and it worked a treat, with each stop cut ending up the same depth.

Creating the Chimney

Using the tape as a gauge again I marked a line at the top of each split section and then, using my knife, battoned off the excess wood.

The stop cuts help as the split does not travel all the way to the bottom and so creates a lintel that the fire will sit in.

Photo 11-12-2015, 13 14 03 (1) — Battoning out the chimney

After a little bit of whittling with my knife each segment had the wood removed so that the chimney would be formed when it was all put back together.

It is important to keep all the shavings and little chunks of wood from this process as it can be used as kindling for the stove.

Photo 11-12-2015, 13 14 03 — Trimming the chimney

The Raappanan Tuli style

Now the secret of making damp wood burn is to produce as much surface area as possible for the flame to catch. I learnt this from researching and making the Finnish Raappanan Tuli candle.

On the inside of each segment cut as many burrs as you can so that the flame from your kindling has something to catch onto. I tried out different types of cuts here and some were easier to carve than others – your wood will soon tell you what works well.

Photo 11-12-2015, 13 14 02 — The Raappanan Tuli style

The Firebox

Next up is the opening for the firebox. I selected two segments that fit together (having them numbered really helped here) and marked out with a pen two rectangular areas just above the sill I’d created. I made sure the marking went all the way round to the other side of each segment.

I then used a saw to cut into the wood in the shaded area. Do as many cuts as you can as this makes it easier to remove this waste wood.

Photo 11-12-2015, 13 14 00 (1) — Carving the firebox – stage 1

I then used my saw at an angle to cut out the wood and finished the job off with my knife.

Photo 11-12-2015, 16 11 17 — Carving the firebox – stage 2

When finished the idea is that you want an access point big enough to put your kindling into the firebox area at the bottom of the chimney.

I found some old sisal string tied to a tree and used that to tie everything back together. It was pretty damp anyway and I hoped that would last longer than the copious amounts of paracord I tend to carry around with me. I think some thin wire would be the ideal thing to use though.

Photo 11-12-2015, 13 14 07 — Firebox and all wrapped up

From the top you can see how wide the chimney was. I have no idea what would be the optimal size to have so you may need to experiment for yourself.

Photo 11-12-2015, 13 14 08 — The chimney

Firing Up

As the wood was so damp I decided to go for the sure-fire method of lighting the stove up – good old cotton wool and Vaseline. This worked well however I needed to use 4 Vaseline-coated cotton wool balls to maintain the fire.

I have used shredded birch bark mixed with spruce resin on a number of occasions to light Finnish candles before but I didn’t have the time to collect the resin this time.

Once the fire had started I added tinder/kindling down through the chimney and in through the firebox. The main thing at this stage is to not over-fill the firebox but allow the airflow to be maintained. It means about 10 minutes of work but the damp wood inside the chimney area will dry out and the overall heat of the fire will increase.

Photo 11-12-2015, 13 14 08 (1) — Firing up

Maintaining the Fire

I placed three pebbles on the top of the stove for the kettle to sit on securely.

The gap created by the pebbles also allows you to drop tinder/kindling down the chimney. I like to use strips of birch bark here as it is so pliable and flammable.

If the wind is low or changes direction you may need to get down low and blow directly into the firebox to keep the fire going. Once the wood has dried out a bit you will not need to do this so much.

Photo 11-12-2015, 13 14 12 (1) — Maintaining the heat

I gave the stove about 10 minutes before putting the kettle on and then in about 15 minutes the kettle was boiling. Not as fast as modern stoves but for what is in effect a wet log not bad.

Photo 11-12-2015, 13 14 13 — Waiting for the kettle to boil

I have to thank Jess Edwards for a number of these pictures at the end. Jess is a great photographer and keen bushcrafter so it was great to concentrate for once on the tinkering and leave the photography aspect in someone else’s capable hands.

Observations

Once the coffee was made I was able to have a good look at what was happening with the stove. As I looked closely I could see the moisture in the wood boiling off. If you look in the bottom picture you can see the water boiling away on the surface.

The stove kept going for another hour before I had to put it out as we were leaving.

Overall I was very impressed with this Log Rocket stove with the Raappanan Tuli twist and I will be using it again on my courses.

Photo 11-12-2015, 13 14 12 — A glorious farewell

Thanks again to the Scouts for documenting this stove – I hope you like my little twist on it?

Cheers

George