We found out a few years ago, by observing the stone around the fire pit, that rocks that are heated for long periods of time and then cooled, will split along natural fault lines within them. With a little help of a sledge hammer after this burning process to break the rock at the fault line, we have manged to remove several unwanted boulders that were far too big to move manually. This information became one of the best tools we have for removing unwanted large rocks. The long heating with an intense fire makes the rocks brittle and susceptible to breaking or fracturing.
First chore is to dig around the rock and slightly under to make an area for the fire. We use a fan as well to keep the heat intense which shortens the process a little, but you can do this without a fan, it just will take longer. Once the area is cleared, set up and light your fire. Keep lots of wood on hand as you need to keep this fire hot! Under the wood panel in the picture is the fan. It was raining most of the weekend so we needed to keep the fan dry. You can see that fire isn't to deeply under the boulder. That is due to the small rocks and gravel just under this particular rock, making it impossible to dig to deep. As long as the flames can lick along the sides and heat the rock it will start the process.
The fire is kept going throughout the day and into the night. Many times when burning rocks we have used this as our fire pit for the night and all sat around the "rock fire" and socialized, cooked marshmallows etc. This rock is directly behind the cottage and we are trying to make room behind there as it tends to get overgrown and damp. We had stared to clear behind there and this big boulder is in our way.
We let the fire die out at the end of the evening and turn the fan off. The next morning shows a crack running along the fault line. Two good hits with the sledge hammer and Voila! A large piece and several smaller pieces are broken off! We had tried to sledge this rock without heating and barely got a chip off. This is extremely hard rock! What a difference after heating.
The process starts again the next morning. The idea is to cook this rock until it is gone! It may take us a few weekends to finish this but well worth it.You can see the fan this time. It is used to keep the fire burning intensely to produce greater heat. We were also able to dig farther under the rock enabling a larger fire more directly under the rock.
You can see the fault line. At this point a ever widening crack is showing on top and down the side. We pour a little water into these cracks occasionally to let steam help separate the stone.
Next weekend we will continue "rock burning" and before you know it, this rock will be gone. Reduced into smaller stone that we have used in our patio, to help to build up the embankment at the front of the cottage and even as seats around the family fire pit.
It's fun, it's effective, and the stone is "recycled". It is definitely "back saving"!
Very clever way to lighten the load.I would love to rocks like that! We're on sand, sand and more sand.
Metaphorically speaking, I think the same process holds true for people. A little too much heat and we fracture along our fault lines. lol
Susan - It works really well and we have a blast doing it!
Barry -So true. We have to watch those fault lines as we grow older.
I would love to have the rocks you are burning..LOL Learned something new today, unique too!
Darsden - LOL a couple of people have said that. Funny how our geographics make us look at things differently.
The patience of a 'natural' process!
Fascinating! Thanks for all the photos showing every stage.. It's incredible how you an unchippable rock can be split after application of extreme heat. Wonderful that the smaller pieces can be reused, too. We live in a kalahari sand area, so not very many rocks around to play with!
Wow, this is truly fascinating. I would never have thought to burn a rock. I like your idea of reusing the rock else where
Violet Sky - Exactly but I must admit it is a lot of fun for my son and I!
Karen - We were really pleased the first time we tried it and it worked so well. Some of the rocks felt like mountains!
Liss - We are really happy with the results!
Hi Lorac
you are clever little rock pixies...and I do like Barry's suggested analogy too...
Happy days