Even More... Metal Casting with Foam

More Lost-Foam Metal Casting

This page is yet another catch-all for a series of dis-jointed images that on their own simple don't have the strength or content, to sustain even my attention to post them... In an effort to clear the backlog of pictures that I've got waiting to be posted, I will attempt to patch together a semi-coherent collection that are all loosely associated by, if nothing more than the fact that I took them, though hopefully Metal working related.

If you've been following the ramblings to this point, you may have noticed a burst of new content over the last few weeks, this is directly attributed to the intense cold we've been enduring this winter (2003) and my refusal to waste personal and combustible energy on the effort of melting...

FatBoy revisited with Blower Modifications

The small white blob with the wires hanging from it is a Cheap Light Dimmer switch from Home Hardware... It is rated at 600W and explicitly states "not to be used for inductive loads". In true anti-establishment fashion, I thumb my nose at The Man and wire the unit into place.

The motor for the blower is a General Electric brushed type unit. The Dimmer allows me to have an enormous scope of control over the air flow to the furnace unit.

It should be noted that the lower 1/3rd of the dial is non-operational in that the motor actually stalls... I've never left the motor in a stalled condition for fear that either windings or the controller itself may be damaged.

Here is the blower mounted to the furnace frame as described elsewhere somewhere on this site.

Prior to the controller a huge amount of fuel was being wasted by the sheer volume of air that would shoot a column of burnt and burning embers straight out the top exhaust hole of the enclosure.

The primary benefits are substantial fuel reduction, greater control of the heat being applied, and much quieter operation.

The actual burning enclosure is still holding-up quite well and is relatively unchanged, with the exception of a new melting pot (third one so far...) The lifting mechanism has also been simplified as the mini winch looked neat, but was a hassle to utilize in a hurry. The new set-up is a 1/2" square tube that the lid is tied to with the original steel cable. The far end of the tube is bolted through the upper back section of the frame assembly. The near (business end) of the tube is simply lifted and hooked to a long bolt off to the upper right of the frame.

I had originally intended to weld a set of 1/8th" plate ears and a swiveling bracket to the tube, but the thought of possibly destroying the refractory concrete lining made me revise that plan.

New fuel source

After starting with Ironwood and hard maple, I became sick of the labour associated with cutting hauling and cubing to a reasonable size for the furnace. I moved to Oak skids that a friend would drop off periodically, but still a significant effort had to be expended.

If I'm going to be on the end of chainsaw, it'll be for the insatiable appetite of our home heating demands, which is a commitment in and of itself.

I used Charcoal for a brief period (approx 8 to 10 20lb bags) but found the price to be significant and availability an issue after the fall. I do have to say that Charcoal is significantly cleaner burning than any wood that I've had occasion to try.

Wood pellets are the near perfect fuel for now, as they are cheap ($4.00/50lb bag) and available year round. The consistency of the product also has advantages in terms of gauging the amount of work that can be accomplished on a Sunday afternoon.

The package touts 8000BTU per pound, which is a meaningless number unless put into some sort of context... Lionel Oliver has some excellent comparative data between oil, propane, gas and wood, including the relative conversions between the their respective units of measure. A chart can be found at the bottom of this link...

http://www.backyardmetalcasting.com/oilburners.html

The only issue that I see with the pellets is the massive amount of white smoke that billows out for about the first 5 to 10 minutes after first igniting. As we have very strict burning regulations during the dry summer months, it would be simply asking for major grief to use this after May or before October in this area, and likely could never be used in an urban setting.

Drill Press Tailstock - Bank Pulley Turning

Above is a simple casting that I made to help in the production of foam pulley forms. The idea is that this acts like a tailstock of sorts for the threaded rod when chucked into the drill press. Even though there is very little force being applied to the edges of the foam, the rod does still have a tendency to deflect and the blank ends up being either elliptical or out of true in some other fashion.

The fixture bolts to the table and the rod spins loosely inside the 3/8ths hole in the pipe. It is somewhat louder that I'd like but has made a significant improvement in the accuracy of the forms.

Sand Screening

After checking at Canadian Tire, Home Hardware, and Home Depot, I found the solution to my sand screening woes at Walmart of all places.

Pictured to right is a bacon splatter screen, or so Walmart calls it... It is much smaller than the door/windows screening that I've been using to date, and yields a very fine sand. As I don't have any point of reference beyond the screen door mesh I can't say that this is a #100 mesh or a #150.

All that matters is that it's cheap and readily available at Walmart.

This is a theoretical experiment that didn't ruin any thing, so I've continued on with it (not really knowing whether the screened sand improved things or this mystery component.

I screened a quantity of wood ash into the sand and mixed it thoroughly. The fine wood ash appears to aid in the compaction of the sand around the piece being poured and almost makes the sand seem viscous.

I added the ash in approx 1:20 proportions, where the ash is 1 and sand is 20. If nothing else I enjoy adding to the mythology of arcane knowledge and eye of newt simply can't be had this time of year anywhere.

Young Metal Caster

Over the holiday season we had a full house of my wife's family over a 5 day period. With 12 individuals interacting and enjoying each others company I selflessly opted to hole-up in the workshop, and keep as low a profiles as possible.

Of the numerous objects that were cast this is one that a niece made that turned out rather nicely.

She used the hot glue gun to apply the stitch pattern of a baseball on a foam sphere, and embossed her initials and a small heart.

Here is the finished piece, unfortunately this was taken during the dying days of the old Panasonic Camera, so it doesn't do justice to what it actually looked like.

My brother-in-law (from Vancouver) made a Vancouver Canucks NHL logo in 3d. The team logo is a whale like fish in a hyida indian art motif. He got it closer than I would have had the patience for.

He has the pictures in Vancouver, I will post when they make their way back east to Ontario.

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