Unwrapping before Christmas

The trek Southward to warmer, drier destinations has been very relaxing. We have arrived somewhat refreshed.

I have been unwrapping and examining some of the projects that will require a degree of finishing before their service life can begin. Most of the finishing touches are minor in nature because these castings are so clean. This can only be attributed to high grade raw materials and a series of near perfect temperature pours.

The aluminum pulleys that were cast in the summer need some de-burring, hand scraping, machining of the journals and balancing before the installation on the wind powered grey water pump here. They match the belt specification on my stock drives perfectly confirming my correct calculation for shrinkage after the pour cooled.
The counterbalanced flywheel for the offset tine drive in my drum style fast composter is also close to perfect, only requiring tiny adjustments for balancing. Some scraping to improve the aesthetics will be desirable and amount to a few hours labour.

For now, the unpacking will be on 'hold' until some minor repairs are completed on the homestead. It seems that some the Summer winds were a little more severe than anticipated. My grounds keeper hadn't indicated there was damage in our last communication - puzzling. Perhaps I will fire up my gasifier and cast some aluminum corner caps for the awnings rather than repair the flimsy siding channels that are in place there now. The castings will be more rigid and durable so I won't have to replace them for ten years or so. The runners will be a little tricky to place due to the complexity of the mould but a little extra bulk should fill the voids adequately. A material recovery melt for the 30 or so pounds of shredded aircraft aluminium that I have on hand here should accommodate these caps.

I did prepare for some melting activity by transporting 20 ingots of reclaimed aluminium (about 130 pounds) for raw materials for when I get the urge to build something after Christmas. My neighbor dropped off 2 broken tops from old gas bar-b-cues (it is always good to educate your neighbors as to what you can use). These will yield about 18 pounds of ingots and will only cost me a dinner for him and his better half. We would entertain them anyway but it shows good exchange practice, Having collaborated before in couple of industrial control projects, we have become quite good friends.

I plan to provide some working diagrams of the miniature downdraft gasifier in the near future and perhaps I will dig up some photos of the first one built. It is a very simple and safe melter that anyone can build with new or used parts. It can be sized to use 2 to 5 pound aluminium capacity standard refractory crucibles and uses wood chips or charcoal for fuel.

Enough unwrapped for now, until next time.

Wrapping up for the season

With the Winter cold in fast approaching (our average temperature is averaging minus 2 Celsius right now) it is time to close down my outdoor foundry. The wind breaker tarps set up to reduce shock cooling are not very effective in preventing cooler air below 10 degrees fro affecting the melts.

Although I have some decorative castings that require some finishing, anodizing and electroplating, things pretty much wind down up to Christmas. This is a yearly ritual as we prepare to spend several months in Lubbock, TX over the winter.

Collecting high grade source materials will become of my main 'metal' activity over the winter (as I'm not really into metal type music). There are still so many usable raw materials that your neighbors can collect for you as re-claimable as you educate them as to what you need. I'm talking about nice clean salvageable with no food residues or sugar.

However, one of my winter projects will be to build a shredder so that aluminium soft drink cans will be able to be washed of the sugar syrup that very often is a part of their weight calculation (up to 30%). I will approach only the individuals in my immediate area that are known to transport their cans directly to the recyclers. I will be able to offer them the same price per pound, maybe slightly more and save them the extra transportation costs. I may even offer to pick them up with my own electric vehicle to add more value to the convenience. This may mean the investment in a small portable balance for accurate weight.

Being rather eco-conscious, I tend to promote my methodology for my metal melting as environmentally friendly. The cooling to on my main furnace reclaims most of the heat to be recirculated by preheating the incoming air to the process through a heat exchanger and therefore reducing the amount of fuel used by ~2/3.

In Spring and Autumn, this heat is used to contribute to space heating in the house by warming the mass storage area. In summer, the flue gas is used to provide mechanical power through Stirling engines to charge my storage batteries and pump my technical water. The flue gas is then cooled using a precipitate shower to capture the energy through a second very simple heat exchanger and transferred into my home heating physical plant. It then is to supplement domestic hot water heating that is solar chimney heated, year round.

The effluent is further processed to neutralize the suspended fly ash and sequester the carbon dioxide - a 2 part process. There will be more about this process in a future installment as my very small 'non-contribution' to the global warming problem
I'm continuing to pack up the bare necessities into my equipment trailer to be 'tagged behind' the executive tent om the long road to Texas. Most of my time n the winter months will be spent in designing and writing as preparations are made for the next melt season.

Cheers.

(c) Copyright 2008. All rights reserved. The author is a regular contributor in good standing the Electronic Commerce Quality Writers Group jpitm

Metal Crucibles

I have had very good result with home fired crucibles.

The proportions of the materials used in are critical in rendering a vessel that will pour 'clean and last for multiple melts. Many formulae have been published although my experience has also been trial and error for my own melt furnace characteristics.

The key to their construction is rendering the clay as 'gas free' as possible by throwing it during kneading to remove all the air bubbles before molding your final shape.It should have as consistent a wall thickness as possible (the pros use a forming tool that looks like a tuning fork to unify the walls) when they are spinning each vessel on their potters wheel.

A very good book for technique is found at:
http://www.lindsaybks.com/dgjp/djgbk/cruc/index.html
The late Unca Dave was a backyard genius (in my humble opinion).

Good luck with your future melts!
Ian.

(c) Copyright 2008. All rights reserved The author is a regular contributor in good standing of the Electronic Commerce Quality Writers Group This short discourse was recently published by the author in - Home foundry (yahoo groups ) jpitm