Archive for the ‘Tips and Techniques’ Category

Making a trommel – Part 2

Sunday, June 19th, 2011

All bolted together the working end of my newest toy looks like thumb 1. By this time I had decided a secondary panel inside the drum to keep things working away was not necessary, and instead I split a length of 100x100x2mm steel to make two large pieces of angle. I used these to both joint the drum ends and the screen together as well as provide agitation in the drum as the material tumbles around. Thumb 2 shows where all the rock eventually tumbles out of the drum. Last pic shows how I attach most materials that are welded end on. Tacked into position first and then a piece of angle iron on at least 2 sides is fully welded to provide extra rigidity.

Since belts stretch and need constant tensioning I added in a simple system to achieve this as seen in the next thumb. To tension the belt all that needs to be done is the 100mm bolt is screwed further into the assembly, pushing the entire engine up. The opposite end is bolted through 2 pieces of angle to act as the pivot point. Last thumb shows how the angle of the drum can be adjusted should it need to be set up on sloping ground, a few cranks on the turnbuckle can raise or lower it quickly and easily.

Making a trommel – Part 1

Sunday, June 12th, 2011

The earth sift I made works as it was intended. BUT…. it is time consuming and it does take a toll on the body having to bang the sieve screen to get dirt to fall through it. At this time of the year the clays in the soil are also activated and you end up with a “sloppy” rock wobbling around on top of the screen.

Trommels are an industrial machine that are basically a perforated rotating drum on a slight angle. The material to be sifted is dumped in the higher end, the drum rotates with anything smaller than the screen passing through it as it tumbles with the larger particles passing through the lower end and into a spoil pile (or as in mining into a crusher).

So here is the simple outline of how I made a trommel to make my job of sifting soil for the walls easier.

First job was to secure a cement mixer, a quick tour through eBay and their localised subsidiary Gumtree found a suitable cement mixer for sale for $180. I used this as a base since a trommel needs a slow and controlled spin and a cement mixer already has the gearing in place to achieve this. Important note is that mixer had a bowl that was bolted to the gearing. The first thumb below is the mixer I bought. Second thumbs shows bolts cracked and the bowl removed to expose the gearing.

I picked up an ex food 44 gallon drum for $15 and an elcheapo 5.5HP honda knock off engine for $177 from Paramount Browns. The drum I sat in a square frame on casters and used the momentum of the grinder to cut a 100mm lip into the lid and then separate the drum into hoops, roughly a third of the drum per section as in the third thumb.

Also in the third thumb is the most difficult part by far – getting the 25mm galvanised wire sheet ($42 from Senturion Steel) to roll. That took several ratchet straps and a lot of swearing to roll it back on itself. I’ll leave that strapped up until the frame of the drum is complete and then I will unleash it and trim the excess.

Last thumb in this group shows the new axle for the trommel, it’s a very large 1&1/8 x 10 inch high tensile bolt which also happened to be very expensive at $38.

First thumb in this group shows how the gearing works in the mixer. Second thumb shows the axle and gearing in place. The bolt was welded to a 5mm plate with a hole drilled into each corner of it. The most thinking of the job involved working out how to centre the axle in the base of the drum.

I did this by subtracting the diameter of the gear ring from the diameter of the drum, halved the result then used a ruler to mark that measurement in as many places as possible around the rim of the drum. From there I positioned the gearing ring and marked the bolt holes. Once the holes were drilled I scratched a line between opposing sides and that gave me the centre of the drum. Since there are six holes and the bolt head is hexagonal, simply lining up the “corners” of the bolt head with the scratched lines centred the axle assembly perfectly. Holes were drilled, bolts welded to the plate and internally the bolts were secured using a small piece of angle to spread some of the load as shown in thumb 3.

All up this gadget will come in under $500 and since the mixer bowl will be able to be restored I’ll be able to sell it once the project is finished as either a mixer, a trommel or both.

Almost ready for building consents application

Sunday, November 29th, 2009

We have the engineering back finally. I had to send it back and insist that some of the terminology used throughout the paperwork was inconsistent with what we were actually doing. A big thankyou to RCI for understanding my concerns and getting all the words in order.

Now we have all this, it’s time to send Darren at Wise Drafting Pty Ltd the engineering so he can complete the technical side of our drawings.

Once we have these back it is then off to a certifier. The certifier is the third party who checks all the drawings and engineering and signs off on them as complying with all relevant codes. We could have Council do this as part of the application, but by going the private route we remove any potential objections the council may have. Simply put – if the certifier says it’s all proper Council must send us an approval notice within 5 days of us lodging for this part of the application.

Once we have all this paperwork and it’s stamped and approved it’s again to Council for the third-last application we need to make on this journey. We still need to apply to Council to have them approve the waste water installation and issue a certificate of occupancy.

This phase has been long and drawn out with a lot of “traps for new players” we have come across despite researching as thoroughly as we did.

Would we do it again?- Yeah, I think we would. This process has cost us a around $4000 from the first chat we had with Darren and including the (yet to be done) certifier’s work. This is around $1500 more than if we had left it all to Council to make the decisions on. I feel we got more of “our way” with the end result since we have paid the professionals we used to deliver what we wanted. Council on the other hand are only obliged to approve what they feel is fitting with the development plan for the area, and I feel we would have been forced to heavily compromise the end result to satisfy that plan.

If you’re thinking of going the owner builder route and want to discuss with us just what we had ready at each stage of this process (and what we missed), or just want some general advice I’m always happy to offer what I can. Contact me via the information contained in the About section of this site.

Ebay and buying “stuff”

Saturday, August 15th, 2009

Having spent most of yesterday with hire companies looking at what stuff costs to hire for the period of time we are likely to need it (which means doubling the estimated time), last night I turned to Ebay to check out some prices.

A word of warning – most of the cheap tools on Ebay are no name and cheap Chinese imports, but if some of these things can last us for the build before they fall apart, that will do us just fine. Last night we picked up a brand new whipper-snipper styled concrete vibrator with 1 years warranty for less than it would cost for 1 weeks hire. We had figured on needing one of these for 8 weeks, so this was a bargain. If it makes it out the other side of the build we can flog it via ebay with any recoup on the original price a nice bonus.

I’ve got some bids in on 3kW sine wave inverter generators right now, again cheap Chinese imports but again with a 12 month warranty. These have been selling for 20% of the price of brand name generators, and I can’t find a bad word about them in google other than “they are Chinese imports”.

A panel lift for ceiling plasterboard is going for less than half of the price I can buy one for locally, and this is an IDENTICAL item. It’s actually less than the cost of hiring one for 48 hours, so again we’ll use it then flog it and any money back is a nice bonus.

Finally some words of wisdom when purchasing anything via Ebay:

1. Know what the product is worth, and how much it is worth to you.

2. Understand how much postage will cost you.

3. Set your price limit taking into account cost + postage vs buying the product from a local shop.

4. Check the seller’s reputation and if there are any negative comments read why and decide if you are prepared to risk the same issue yourself.

5. Enter your set price limit as your MAXIMUM automatic bid. For those not aware of how the automatic bids work lets take a simple example.

The tool you want you are prepared to pay $100 for. You enter $100. Your first bid appears as the minimum required for you to lead the bidding, lets say it was the first bid and it is set at $0.99 (as many auctions start). 3 days later with 3 minutes to go and 15 bids made in total you are leading with a bid of $42.50

Along comes Joe Schmuk who waits until the last minute to enter a bid. He enters $50 and your auto bid counters with $52.50. Joe can play the game right up to $100 and not beat your auto bid, so you secure the tool as the earliest maximum bid will win the auction if there is a tie. If he gives up at $72.50 the tool is yours for only $75.

To explain how there would be a “tie” – unlikely yes, but lets say you both enter a max bid of $100 but are beaten by a bid of $105 that is later retracted. You would win since you placed the first maximum bid of $100.

I have learnt to always enter what I would be prepared to pay. The auto bid system is there to help you win the item at the lowest price without giving away what you are prepared to pay.

6. Pay promptly after winning the auction, and use Paypal where possible as it offers you some security with buyer protection.

7. Don’t forget to leave feedback about your experience. If the experience sucked, rate it poorly and explain why to warn other buyers. If it was good, likewise let your fellow consumer know why you were happy.

If you are completely new to Ebay then I recommend you watch the closing few minutes of some auctions as this is when all the action really starts to happen.  Refresh the screen often and you’ll see the bids begin to mount up as time runs out.

When you are experienced with it, you’ll find you can drop your bid in the closing few seconds, and providing it is realistic, win that item in many cases for less than your maximum bid.

A big thankyou

Sunday, June 28th, 2009

A very big thank you to Colin and Sarah for inviting us to see their formblock poured earth build over the weekend. It was great to actually touch and feel and get some “face” time with the finished product. They had chosen to go with a rough finish, giving their building some great character.

They were also full of advice on some of the pitfalls they had come across during their build. Things like knowing what mixes they had used. Being able to see the results of their blocks cast with both white and portland cement. Seeing the blocks they had experimented with finish and pour method and some of their other experimental blocks and the results of aggregate and so on was very interesting and informative.

Even though we were planning to start with the garage first, this advice and insight will cut down our own trial and error time – hopefully getting us to the result we want within the first couple of pours.

You can see some of their progress in the blog they have at Building Our Home.

Woodlot management

Saturday, May 2nd, 2009

After making yesterdays post and showing it to a friend, I got the question back “How can you have a wood lot, cut it down and expect it to regenerate itself?”

Here is my simple explanation of how it works. I am not an arborist so some of the terminology may not be pure of explanation, but it will give you the gist.

In forestry management there are 2 techniques used to cut timber and allow the root stock to regenerate. “coppicing” and “pollarding”. Both of these techniques are used by savvy gardeners so they can enjoy the foliage of what would become a massive tree in a manageable and renewable way.

Both of these techniques result in regrowth from the stump of a felled tree. Depending on the species in the woodlot, these processes may be carried out many times with a typical loss of 10% of stumps each time the lot is cut. Cutting can be timed to suit the use of the timber, for firewood 15cm diameter trunks may be ideal, for lumber the trunks may be allowed to grow larger to ensure good straight wood can be processed from the trunks.

We are hoping 5 years between cuts will give us good sized firewood and allow us to maintain the woodlot sustainably.

It is important to make any cuts to the trunks at an angle so water does not pool on the cut stump which can encourage rot in the timber.

This technique involves felling the tree in a traditional manner, leaving half a metre or more of the stump. What then happens is dormant buds in the bark of the stump shoot new growth and these eventually become the new trunks of the regenerated tree.

Careful selection of the shooting growth is then done and the strongest 3-4 are allowed to continue growing while the weaker shoots are smashed off the trunk with a blunt instrument. These are not cut, since the clean cut would encourage more shoots to start from this point.

The disadvantage to pollarding is the resultant growth can be extremely unstable and easily broken away from the trunk. The advantage is in areas with a lot of frosts the buds are higher from the ground and may be more likely to survive.

With coppicing the tree is cut as close as practical to the ground, preferably with no more then 15 cm of the trunk remaining. Again, dormant buds in the bark will shoot and new trunks for the tree will be formed.

Elimination of all but 3-4 of the new shoots happens in an identical way for the same reasoning.

The disadvantage to coppicing is the new shoots are more likely to suffer in frosts and also more likely to be eaten by wildlife. The major advantage is the remaining trunks are stronger than with pollarding and a tree subject to coppicing generally survives more generations of regrowth.

Major advantage of both techniques
Both techniques allow for quick regrowth off of the cut stump. While some root die back will occur, the large root system of the original tree allows for quick water and nutrient uptake into the new trunks. Growth is quick and vigorous.

Major disadvantage of both techniques
The downside to both comes from the ability to regrow new trunks with amazing vigour. Soil nutrient is very quickly depleted around the root zone and heavy applications of manure and mulch to replenish these is required.

So for those who were also curious about just how a woodlot can be regenerated I hope my lay-mans explanation has answered your questions.