cornish wood burner

I think your first job tomorrow should be a sharpening lesson, give him a saw then keeping it sharp is his responsibility. Practice makes perfect as the saying goes. Sounds like he will get plenty of practice.

Hi John We have some experience using contract chippers and the heizos you mention are a bit small. I am not sure what power you have but I would have thought a minimum of 300hp to be remotely competitive. You will be competing with outfits that can chip 25mc wood for £8 a ton. As a guide we use machines driven by 360 to 780 hp. Why only G30, that has to be the slowest and the most power hungry. Moisture content has a big influence on price and desirability. I cannot say what you would get per tonne but possibly if you could air dry the wood then sell direct you might have a sideline market. The sun takes some beating for cost of drying.

3MW wood burner sprung a leak, stone went through a telehandler tyre, puncture in my car tyre and my lad broke my last jigsaw blade. Average sort of day. Time for a beer I think!!!

Assume 4 KWh/kg so a 8kw stove should use about 2.5kg/h allowing for some inefficiency So burning 10hours a day then 25kg/ day Hard or soft little difference in weight used just need to feed it more often with softwood as less dense.

How about an ad in Gumtree or local free ads etc. There must be a lot of people in your area that will process and burn softwood if it is cheap enough / free.

One thing that I havn't seen mentioned here is how good the seals are on our storage cans. I would think unmixed petrol does not deteriate in a jerry can with a perfect seal but keeping fuel in a plastic container with a less than perfect seal would allow deteriation.

20% sub 3mm for G30 spec chip. Heizo is a good chipper and I would be very suprised if you are producing more fines than this. Might be time for a blade sharpen if you are.

I agree that wet wood is easier to chip than dry but if you hire a chipper it will almost certainly be a decent machine so it will not be bothered by dry wood. Normally we get a few hundred tonnes before the blades need sharpening. Certainly if you try and chip with blunt blades then you will get excess fines.

Why don't you air dry your wood first and then chip it. Presumably you do this with firewood

That sounds about right. It varies obviously but in rainy Cornwall an average day is around 80% by day going to 100% at night. I expect inland should be a bit drier but I still would expect several nights near 100% RH.

If you consider a winter night with 100% RH which most are then from the graph it looks like wood will dry down to just under 30%

The winter days will be fine its the nights that are the problem. Part of my day job requires RH control of glass houses. We have very accurate monitoring and it is amazing to see the jump in RH as the sun goes down. Air movement is what you need when the RH is at a level to take the moisture but look at the graph and you will see the result of 100% RH. By having a open tunnel in the winter you are feeding moisture into the logs exactly opposite to the summer good work. Condensation and moisture laden air will increase the MC of your wood at night in winter.

Hi Mikeyne Your poly tunnel sounds good. Have you put in vents either end to get some air flow through. Probably closed in winter open in summer. One point in winter we have more night than day so I expect that is mainly at night when the moisture is reabsorbed. Lower night temps and the RH will go to 100%. Certainly does in Cornwall, 98 % by day as well ATM. If you could get a stack of wood to its expected minimum mc at the end of summer it might be an advantage to cover the logs with polythene /insulation to restrict the moisture being reabsorbed. Not tried it but it might be an interesting experiment.

I think we are all agreed that education is the key so I would like to add to the Spacemans post. The theroretical energy loss due to moisture is far different to the actual one. Apart from the energy needed to evaporate the water, the flue needs to be of sufficient temperature to prevent creosote forming so as he says the fire needs to run hot resulting in a lot of heat going up the chimney. A modern efficient wood burner running on 30% MC wood burning hot with an insulated flue should be able to achieve high enough temperatures. The problems come with uninsulated flues, stoves that are shut down, inefficient appliances or worse still open fires. Dry wood is definitely desirable for the less than perfect burning conditions and equipment.

Do you not think that if you can educate customers and give them honest accurate information then they might realise the difference between wood ''seasoned'' to 35% at the bottom of a Cornish valley and wood from a merchant who has seasoned his timber on high ground to 20%, stores it undercover in a warm dry barn and delivers the advertised quantity and quality. Both may have been cut for the same length of time but a reading of the moisture content would demonstrate why some logs are better than others before going in the fire. From this follows that advice from their local supplier about the suitability of his/her product be it hard or soft wood will more likely to be trusted rather than believing the hype of a foreign importer.

We have just started to look at the possibility of a drier. What would you consider to be the right machine.

Especially at night. As the temperature drops the air cannot hold so much water vapour. RH gets to 100% and the water is dumped. Condensation on your car in the morning is an obvious sign.

Try F R Jones

How about a small plate under the rear of the tipper body with captive nuts then the vice can be easily bolted down when needed.

Logsnstuff what I am saying is meters can be inaccurate and also will vary with how hard the spikes are pushed into the wood. We sometimes buy chip in for our biomass boiler so we need to know accurately what the MC is. The meter I use for chip reads right between 25 and 35%. Above and below this band it reads drier than the wood actually is. I have checked it with microwave and scales many times so I know what to allow to obtain a fairly accurate MC. Round wood is a different ball game. We use about 3000 tons of soft wood a year and after a couple of years stacked on a windy site at the end of the summer it gets down to about 25%, slab wood goes down to about 18% . Winter both rise about 5%. However I can get several % difference depending how far and where the spikes are pushed into the wood. Therefore I am suggesting we calibrate our meters and operating method. I can see all here try to sell a quality product and it must be frustrating to be undercut by the beer money brigade but if you demonstrate to your customer that the MC of your logs is better than the completion then you should be confident in the accuracy of your meter and method.

I would agree with this to a certain extent depending on the definition of warm. What surprises me is the comments about misleading people and then talking about MC in single figures or very low teens, presumably not kiln dried but going from a meter. If you suggest these sort of figures to your customers without verification are you not as guilty as the OP's importer?

I presume we all know that moisture meters are only a guide and even if accurate vary with how they are used. Does anyone check with scales and drying by oven or microwave?

I can see your point but picture this. You are not a farmer but have a small strip of land beside a road, you have spent a dogs age clearing up the results of flytipping, put a locked gate on the field to prevent the repeat dumping of bricks, blocks, tree stumps, asbestos sheets and considerable amounts of garden clearance type material, then put stone down to make a clean and tidy entrance. Two days later you find a heap of green waste dumped on the freshly laid stone entrance.

So that's where that rubbish came from!!!! Over the hedge is bad enough but keep away from the gateway please. Have had both.

Agreed. I've bought several machines for home and work. 3 off 185mm circular saws, 355 metal chop saw 355 disc cutter and a cheap 355 chop saw that I cut firewood up with at home. All have been fine cutting metal and wood. One small problem with a trigger which evolution sorted. After a three years I would rate the saws higher than the makita ones for build quality and ease of use. Makita is still operational but no one likes to use it.y