agg221

This contains contains the key points You can't meet environmental and ethical standards at the same time as competing with other countries where these are not being met. You can take a conscious decision to abandon these requirements and have a free market, or you can let them keep them and abandon the industry in favour of imports, accepting the social consequences. If you want to retain the industry and the standards then you either subsidise or protect against imports. If you have a non-productive factory you can close it down and redevelop the site for production of something profitable, or more likely housing or an out-of-town shopping warehouse. If you have a non-productive farm you can't do that unless you allow change of use to turn it into housing or an out-of-town shopping warehouse. Non-productive is usually a function of the soil and the microclimate, neither of which can practically be changed. That makes land which is uneconomic to farm useless in commercial terms. Alec

No, this isn't what happens in every other industry. Take the electronics sector in the UK. In the 1990s there were two silicon foundries in the UK, one in Scotland, the other in the North East. They underpinned a substantial electronics industry making devices such as mobile phones. The cost of manufacture in the Far East was so much lower that they couldn't compete and shut down, along with the entire supply chain. It has gone completely for consumer electronics and has largely gone in Europe (Danfoss are moving out too now) and we simply import electronic goods. The same pattern would happen with farming if one way or another it generates a loss rather than a profit. There are things which can be done to make it more profitable - such as treating it like an industry and allowing it to make operational improvements like other production industries do, such as increasing unit areas (ripping out hedges and copses, ploughing right to the edge of roads) to gain an economy of scale on the size of plant, allowing latest developments to be used such as GM and relaxing control on pesticides and the planning and welfare rules to allow construction of intensive battery-type livestock units. That would make agriculture truly competitive, forming a level playing field with the countries from which we import, but I suspect is not palatable for other reasons. Alternatively you could apply protectionism and place high tariffs on imports to allow the market to re-base to a level which was profitable. This might prove tricky in trade deals (what particular product do you think might be making New Zealand so keen to do a trade deal...?) and would also push the cost of living right up, requiring an increase in benefit payments to those who now fell below the bread line. Either that, or we remove subsidies and just let agriculture dwindle, with the land returning to a natural state and accept the demise of the rural economy in many areas (Grade 1 land would probably be economic in its own right but not much else) while relying on imports, probably increasing the amount of greenfield housing development into the bargain since the land would have limited other uses. Or perhaps the subsidy system isn't that bad after all? Alec

I largely agree with you but, leaving aside the economic considerations which mean this will never happen, I think there are two circumstances where involvement of the public purse could be justified. The first would be if it was desirable that works were undertaken. Whilst there is no obligation to maintain a tree, there can be work which is desirable to extend its life or enable its retention, for example reduction to prevent an unstable tree from being blown over or major branches being snapped out after substantial heartwood decay, or haloing of adjacent trees. It would not seem unreasonable to have a system which surveyed TPO'd trees since they represent high amenity value, recommended such works (perhaps still on a voluntary basis), and if taken forward contributed to the costs. I wonder what such a scheme might cost, relative to the calculated amenity value of preservation of TPO'd trees. The second would be if a TPO is placed on a tree. As mentioned, this could represent a reduction in enjoyment of the land, which could be compensated for. The next purchaser would be aware of it and hence not entitled having freely entered into the purchase. That said, this would be an equivalent situation to having your property listed, for which there is no compensation, so I doubt it would happen. It might make councils think carefully about whether to impose a TPO though. Alec

Size is impossible to say since, as you have identified, it depends on what you are going to use them for. However, the Alaskan is not a good tool for making thin boards - it will do it of course but the ratio of boards to sawdust becomes very unfavourable. 1.5" is a good minimum but generally 2" is a good thickness to aim for if you have no other ideas. The cherry is most likely to be useful for something decorative, so 2" slabs, waney on both sides, with a 4" thickness as the first and last slab (less dimensionally stable out there and it's good for legs). The oak could end up structural for something, so some 3" is a good idea as well as 2". With both of them, cut as long as you can, except if that will leave a wasteful length as the last bit. Say for example the log is 16' long and the maximum cut you can make is 12' long - I would go for 2x8' lengths but if it's 18' long I would take a 12' from the base and a 6' from the top, unless there is significant taper in the base but parallel above, in which case I would reverse this. Drying - stack in the shade but where the air will get through, well stickered with something on top to shed the rain. If stacking in the woods (which is fine and does make them a lot lighter to shift later) I would use some blocks to get them right up off the ground away from the weeds. Wherever you stack, I wouldn't bother with sealing the ends as the losses will be negligible - unless you are extremely tight on length for a project and need every last inch. Alec

The principle is that you receive a payment based on the area of agricultural land which you hold. To do so, you have to have a minimum holding of 5 hectares and any land you are claiming for must have an 'entitlement' - these can be bought and sold in their own right, so you need the land and the entitlement together to receive a payment. To receive the payment, you also have to comply with various other rules such as the type of crops you grow as a rotation, certain areas being left uncultivated, retention of hedges etc. These have a negative impact on the return you can make on the land so offset this reduction in income. This is a relatively recent thing - following common agricultural policy reforms, which also introduced the 5ha threshold. Before the CAP reforms we used to get a payment against our 1.8ha field. This was a few hundred pounds. Without it, we are pretty much condemned to making a loss so the land is only farmed because I am stubborn enough to want to do so. It would pay a lot better to rent it out to someone for horses. The only revenue which will offset the losses in the long term is the cricket bat willows we grow along the edge. Alec

I use an 090 but only for preference over about 30" width. From there down to 15-18" the 076 is faster (below that, the 066 is faster although I usually just stick with the 076). Chain speed wins over displacement at about those break points. In theory I could file the rakers down further to take advantage of the torque from the 090 but going non-standard would mean having multiple chains for different widths/hardnesses of timber so the chain remains standard and the 090 is a bit slower. It really comes into its own above about 4'. Alec

Whichever they find most comfortable in hand. All decent makes will split well and hold a suitable edge. Wooden vs fibreglass handles are a matter of personal preference. I like my Gransfors large splitting axe. Alec

Yes, they can. Traditional Swedish tar production effectively burned the wood in a retort but rather than burning the gas it was piped off and everything condensed in turn, allowing the collection of tar, turpentine and methanol (wood alcohol). A retort running at the correct temperature will release tars etc. along with the gas. If you pipe them straight back around they all get burned but if you were to pipe the gas through a heat exchanger (such as a copper coil in a big tub of water) they would condense out and could be collected, allowing the gas to go back in and sustain combustion. Alec Alec

I suspect this may be a blanket statement (appearing as it does alongside the comment relating to retaining all timber on site) designed to stop the log fairies, which would be a more genuine issue if the beetles start emerging near other trees. Alec

£2 to £8/Hoppus depending on demand, supply, location etc. More than that would only apply for something very special. Alec

Generally the best idea, but sometimes the timber supply and the design stage don't line up nicely. We were two years in the planning stage for our extension, during which I cut slabs to get them drying. I knew I needed 'something x 3" ' or 'something x 2" ' and had a good idea of length, so cut slightly over anticipated length and left them drying. It gave me something I could get on with and I could then rip them down to width once I knew the dimensions. It also meant the timber was closer to dry when I installed it and any defects which showed up could be cut around. Alec

I think a lot depends on how soon you want it milled and what sizes you want it milled into. Cutting it asap would minimise surface cracks - milling over the summer is most likely to result in damage. If you know the dimensions you want then cutting straight to size is the best option, however if you are less sure then cutting it into 2" and 3" slabs (maybe a couple of 4" if you are using a construction with sole plates) will let it start drying. You can then cut these to width as required when you know the dimensions, using a large hand-held circular saw. Not sure if you can get a Lucas through a 1.2m gap but if you can and you know the dimensions you need, I agree with John. If you can't, or you don't know the dimensions, or the longest sections you need exceed the capacity of a Lucas, you are pretty much left with an Alaskan chainsaw mill as the only option. This is also a good option if you need fairly large beams. An Alaskan will take a wider kerf and is not as fast but it would get the job done, particularly with a double-ended set up (which would be my preference for 4ft diameter). I can assist with the Alaskan milling option if that turns out to be the best route. One other thing though - do you know what sort of oak it was? If it's Turkey oak it may be best avoided. Alec

I can see the value, but I don't know of anyone doing it. Most bars are fatter in the belly than at the ends so it would be possible to re-grind the groove and get extra life. Say an extra 2mm deeper would give a lot of life and not make any real difference to the profile, although it wouldn't work so well on parallel sided bars. I can see possible issues as they do also tend to wear wider in the groove, particularly where the chain feeds in from the drive sprocket, which is not possible to address with a re-grind. Alec

I think that is stunning, and in the right place you could probably sell it for enough to buy an entire kitchen! Alec

A good idea to build the prototype in mild steel - you really don't want to be using expensive materials to test the theory and make design changes in. Yes, you've got it on the ferritic stainless steels. They will suffer less because of the reduced expansion, but also because they conduct the heat better so the outside surface won't actually get as hot. They are also a lot cheaper than the austenitic grades (300 series) as they don't contain nickel. I would look at grade 410 (technically martensitic rather than ferritic but you really don't want to know....), otherwise known as EN 1.4006. It does exist as sheet but not sure where you would get it - Outokompu would be a good starting point. Alec

The materials part of this thread has got rather 'in depth'... Essentially yes, boiler plate would be a good starting point. Boilers are made of quite a few different grades of steel (or indeed cast iron) and all are generally the right sort of thing. The steel grade ASTM A515 I mentioned above is a form of boiler plate. There are other boiler plate grades which won't survive so well so it would be useful to know which one it was, but all will be better than mild steel. The main difficulty with boiler plate is that it is usually rather thick. The aim is to make a small retort, which generally means you want thinner, lighter walls but if you weren't looking to make it portable and had a good source of boiler plate it would be an excellent option. Alec

But that's based on corrosion properties and the stripping of the Cr oxide? The rate of loss of section in retorts does not appear to be particularly high, and in a reducing atmosphere this would be expected. The limiting factor appears to be high temperature strength, manifested in creep resistance. Figure 1 in the link below indicates the relative strength vs. temperature of low carbon steels (e.g. mild steel) vs. the ferritic and austenitic grades: SSINA: Stainless Steel: Composition/Properties You can see that at around 650degC the ferritic stainless grades have twice the strength of mild steel. Austenitic grades such as A2 (304) and A4 (316) have far higher strength but they also have much lower thermal conductivity and high coefficents of thermal expansion (CTE). High CTE is an issue if heating is not uniform and/or the shape is constrained at points as some parts will expand more than others and the differential stresses may result in distortion. It's these bulk properties which make stainless attractive. If you look at the power industry where the standard grade for steam pipes is P91 this also uses chromium and molybdenum to achieve its high temperature strength - it is in effect very close to the ferritic stainless grades. In theory, grades such as ASTM A515 would be a better choice as it has excellent high temperature strength (typical uses include fireboxes in boilers) but they are pretty much unobtainable in the right thickness so stainless is probably the best practical option. Based on the relative properties of the ferritic and austenitic grades, I think it would be tricky to design a horizontal retort with even enough thermal stresses to make it in an austentic grade so would go for a ferritic. For a vertical retort, 304 would probably be my first choice based on availability, price and properties. Alec

You can weld stainless with MMA down to about 3mm thickness without too many problems and it would be the cheapest option by far, but trying to fabricate a tube to plate joint as you first project would not be an easy way to learn! The fitting you are looking for is a stub end. These are often welded in, but if you have access to a power drill, ideally a pillar drill, you can add the bolt holes as required. Googling 'stainless stub end UK' shows up plenty of options, for example: Stub End Along with many others. Alec

What dimensions (and do you have facilities for welding?) Alec

Yes, we're touching on similar things. The idea is that the teeth make a cut wider than the body of the blade (same on a chainsaw). On green wood this typically needs to be wider than on dry wood. In theory, the body of the blade should not even touch the wood, although in practice it usually does a little. The fact that you were seeing marks on the blade suggested it was worth a look, although if the teeth are dull they may be pushing fibres out of the way rather than cutting them cleanly which means they spring back and rub more easily. It isn't too hard to touch up a dull carbide blade with a diamond file. You file off the top rather than the face. That circular saw I brought over made a fair few 3.5" deep cuts rip cuts around 7' long without struggling, despite having half the teeth missing! That had been sharpened with a a diamond file the night before - prior to that it would have struggled with a half inch deep cut. Not sure whether I am coming over or Andy is - depends on whether his wife lets him switch his working days (he is part time and doesn't generally work Fridays). Alec

Have you checked the effective set on the teeth? Some tipped blades have true set, others it's the width of the carbide but sticking a straight edge across should show up whether there is still adequate set. Alec

I agree that a clay soil will not benefit greatly from it, certainly with regard to nutrient management. However, clay can be difficult to work with in a garden, being sticky and heavy in winter and then drying out like a rock in summer, so breaking up the structure will make it more pleasant to dig and it would help to stop a pan developing on the surface in summer so any flash summer storms soak in rather than running away. However, it is a lot easier and cheaper to get a good load of chippings in, stack them for a year and then spread them as a thick mulch on the surface to get essentially the same benefit, topping up as needed. The only point where it would be useful is if the soil is in fact silt rather than clay. Fine silt can look superficially similar but will benefit a lot more. Alec

I took the 066 out milling yesterday. Main use was for the mini-mill but also for bucking the log to lengths. It had a 25" 3/8" lo-pro bar on so rather than carry a second bar, I took both ripping and cross cut chains. It was very, very quick. Alec

Stainless steel will typically be 304 unless it is stated otherwise. 316 has more nickel and some molybdenum which pushes up its wet corrosion (seawater) and creep resistance, but it has the same maximum recommended service temperature. See table in the same link. There are two issues - one is corrosion (loss of section) and the other is deformation under thermal cycling, due to a combination of creep and non-uniform expansion. Loss of section does not appear to be an issue with the Exeter but deformation certainly has been. TVI's retort has just had a second adaptation to raise the retort chamber as it sagged where the legs rest on the chamber. Given free choice, starting from sheet material I would probably go for a ferritic stainless as they are cheaper and should perform well enough. This is the sort of steel that diesel exhausts are made from. If I had the option of a pre-made vessel, such as a stainless drum, I would go for that instead though as the mass production method for making this would drop the costs far lower than I could fabricate it for. In an ideal world if I just wanted to avoid distortion I would go for bolted cast iron plates, which would last an extremely long time but the cost of casting moulds would be the limiting factor. This would be a lot heavier and probably not at all portable. I can't see any reason to go for the ultra-high temperature steels or nickel alloys - durable as they would be, the costs would be prohibitive. Alec

I haven't spotted any polar bears turning up yet, but if I do I'll put a picture up As per openspaceman's comment, there is no difference except typically size of the bits. With biochar, because you are not burning it, you can also get away with less thoroughly charred material (brown ends) as the bacteria consume the tars and oils. What it does, is have a very high surface area which is active to trap various molecules passing by, but able to give them up again to a plant. The most interesting one for me is water, as it takes up excess to stop waterlogging and then keeps more water available to alleviate drought, reducing the need for irrigation. Other very useful ones are water soluble fertilizers such as nitrates, phosphates etc. where trapping them stops them from leaching, increasing soil fertility and reducing the risk of leaching into watercourses (we are right by a river from which drinking water is abstracted). It does also happen to trap carbon from forming CO2 but the impact of that is likely to be negligible compared with the effects of other gases such as methane. Alec