still more... Metal Casting with Foam

...still more Lost-Foam Metal Casting

Wax Dips and Wood Pellets

Deep Fryer & Candles, perhaps a romantic home cooked meal... Actually oily foods don't agree with me the way they used to, and I hate candles as they're such a fire hazard.

So the logical use for these items would be a wax pot for dipping foam molds to improve their surface finish!!!

A box of pure candle/canning wax is almost $5.00 for a pound, while these candles were $2.00 EA and weigh more...

When I thought to use the fryer for wax, I initially thought of just melting right in the chamber... After browsing the Net, and making some inquiries on the "BackYardMetalCasting" forum.. it was clear that wax has a hazardous side...

Oh sure it seems so innocuous and non-toxic but it has a low Flash Point, somewhere between 350F and 400F. I assume that this is the point at which the paraffin will vapourize, should it come into contact with any sort of spark or flame. Well, I don't want to be around when it happens.

The advise to use a double boiler is what I settled on, the fryer is filled with water, that can be brought to a boil in about 5 minutes (whether it's watched or not...)

I used a tin-foil loaf pan that sits in a wire basket (part of the fryer) and can be lowered into the water...

Initially I was concerned that I'd gain quite a bit of dimensional size due to the wax building-up on the foam. I'd dipped the tip of my pocket knife into the wax and it had almost 1/8th" of wax on it.

As it turns out, Foam has such low density that it seems temperature neutral, and the wax makes the thinnest of skins over the foam.

Here are 2 Ball Cranks, an angle plate and Base for the lathe's tailstock, all smoothly coated.

I thought it clever to place the spraygun in the picture as a foreshadow of the next step. A word of caution, don't waste your time trying artsy shit like this, it always backfires...

Paint doesn't stick to wax... especially latex that's been thinned with water, it just beads. So paint first and then dip in wax.

It's hard to make out how smooth the finish is without running your finger over the wax, but it is slick.

The skin is so thin that it's nearly transparent, but it has cleanly filled in the small gaps and pits in the foam. There is no substitute for sanding and basic prep work, as any bits of fluff sticking out are exaggerated, look at the edges of the cross pieces between the foam balls.

Since the water based paint wouldn't adhere to the wax, perhaps the Hi-Temp paint would.

Initially I was only going to try a small test on one piece... it did appear to finish-up nice, so I went ahead and sprayed a couple of coats on all the pieces.

It all looked so promising...

After about an hour this is what I was looking at. I assume that there must have been miniature cracks in the wax that the paint was able to seep through.

I refuse to give-up on the Hi-Temp paint, and now conclude that the process has to be a minimum 2 (two) coats of latex paint, then a wax dip, and lastly the Hi-Temp.

For most of my current pieces, the untreated finish is just fine, but I do want to get into higher-end casting of Plaques and Signs, so this is an investment in that direction.

This is a neat image of a micro pit that resulted where a small amount of hi-temp was able to penetrate the wax coat on a flat surface.

The pit is roughly twice the size of the actual ball in a ball-point pen. The Macro camera is focused so tight that either the pen tip or the pit is in focus, but not both at the same time.

Wood Pellet Fuel Re-Visited...

I call this a "Hot-Glue Occlusion" the liquid metal stops dead at the glue point.

This was to have been a Ball Crank...

Another "Hot-Glue Occlusion" ...

Another wannabe Ball Crank...

You guessed it...

... "Hot-Glue Occlusion"

This was to have been my Angle Plate... Dang! and I wanted to use that...

Understandably, I'm pissed off, I enjoy learning from my mistakes, but 10 individual casting all ending-up like this is like a pants down spanking in front of the class...

Initially I vowed never to use Hot Glue ever again and was temped to pitch the gun and what ever was left of the sticks.

The more I thought about it, there had to be a less obvious answer, that I was missing. Hot Glue had never betrayed me like this before... Going over the Basics, there was plenty of metal, a good head to flow down, the molds were not positioned in opposition to Newtonian mechanics or any other laws of physics or gravity.

I'd moved to the wood pellets, in Nov/Dec for price, availablity and just to experiment. Initially they seemed to work great except for 2 reasons. A) they produce a massive amount of smoke, and B) a significant amount of fuel is lost as it's literally blown out the exhaust hole in a partially burned state. In the winter when there's snow on the ground this isn't such a problem, but this time of year with dry leaves blowing around and grass fires a constant hazard, it's not acceptable.

In an effort to resolve the loss of fuel issue I installed a light dimmer to better regulate the air flow to the fuel, which it does extremely well. I have to assume that the reduced airflow has had an impact of the ability to bring the metal up to temp. The pot does turn to liquid, but to what level? I have no pyrometer or any gauge beyond if the surface jiggles when I tap the edge of the crucible.

In an effort to clear the air on the controversy that surrounds Hot Glue in my mind, I've purchased 2 bags of charcoal and will try to get back on track...

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