Last modified: Sunday, April 1, 2001 1:09 PM



03/17/01-- SPECTACVS INTERRVPTVS I'm back to waiting mode, dammit... The third piece was not a charm, and the electroforming job on the helmet was so poor that I decided to strip it and try again. There's some amount of control you have to properly exercise over the process-- current is supposed to be adjusted at 1/10th an amp per square inch. Calculating square inches for something like a helmet is difficult and folks like me are prone to guesstimating. If you do this, you'd better be willing to ride shotgun over the process-- not turn it on and go to sleep.

I figured that I'd strip the piece by reversing the forming process: use the poorly plated helmet as the anode and a copper strip as the cathode. That's sound science. The big mistake I made was caused by impatience... since I wasn't plating anything, why not bump the current up full blast? That's sound science too. Well, full current generates a lot of heat and apparently the rectifier was not built with adequate ventilation or thermal protection. It died. It's on its way back to the manufacturer for repair or replacement. Who knows how long that will take?

In the meantime, it gave me the motivation to test substitutes for the rectifier: I'd heard of why you shouldn't use a battery charger, so that must mean that someone's tried it. The big problem is adjusting the current flow: chargers are fixed with on/off switches, with no provision for adjustment. So first, I tried a model train rectifier. These provide you with a means of controlling the DC output, but they just don't got the juice to do the job. So I moved on to the battery charger. That worked well for stripping the helmet lickety split. I insulated the cathode connection wire to prevent that from disappearing, but eventually it does get to the point where the conduction to certain areas is cut off, since practically, you can't control where the copper gets stripped when you want it all gone. Good enough though, and the manual cleanup job isn't that bad.

As for plating and electroforming-- that's where you need the ability to adjust current. It helps to have an ammeter, but I only have a VOM designed for low DC current readings. So I was for all practical purposes, flying blind. I tried a dimmer switch, but those are rated for 110 volts-- they have too much resistance for 12 volts of electromotive force. You can use 12 volt lights to limit the current flow, but that's a non-adjustable limiter. You'd need a hefty rheostat to handle the amperage from a battery charger and that's why they make adjustable autotransformers, I suppose.

This exercise convinces me that buying a dedicated rectifier is better for your sanity unless you've got gobs of time to experiment with battery chargers and homebrew limiters. In fact, one company sells a device which allows you to turn your battery charger into 4 separate plating stations-- the problem is that it costs well over a thousand bucks! Of course, you could try dry cells-- those put out 1.5 volts, and adding them in series gives you some measure of adjustability. However, keeping flush with dry cells could get kind of expensive too and you'd have that problem of sagging current as the battery drained.

So I'm back to working on other stuff. The top shield was a small brass ashtray that had an inappropriate design stamped in the center. I was able to pound that out and polish it away completely and in the process, give it the rounded curvature. From this experience, I would have to say that brass is a far easier metal to work with than mongrel steel.

The second shield was a larger copper ashtray and a more ambitious conversion. The center was worked the same way, but the contour from there to the edge needed to be reversed. It originally had a flattened concave flare and it took a lot of pounding to change it to a convex curve, like a hubcap. I started near the center where there was a fairly acute bend and hammered it out with the small side of a door hinge pin. From there, I worked out to the edge using several other tools: the wider side of the hinge pin, an Exacto knife handle (minus the screw on blade holder, a large steel bearing and a couple different wooden stakes. You develop an instinct about the particular stake you need to ease into the proper shaping of an area. You also develop an instinct about the pounding technique; I used a lot of very rapid low force tapping while dragging the stakes around the piece at an angle, centered on the anvil. The instinct thing is hard to explain, kind of like sculpting. I think what you're trying to avoid is changing the shape too quickly and radically, as that might distort the overall shape and introduce dents that would have to be worked out. It's a gradual process.

Forgive me if I sound authoritative about this-- I'm not and my results are far from perfect. I'm sure a real metal worker could do far better and make mince meat out of my amateurish advice. I do feel that I caught "the groove" of what I was trying to do-- it wasn't just random banging with a hammer! Actually, the crude and imperfect hand-hammered look works well in this case, similar to the effect of tarnished metal. The original ashtray was too perfectly formed with concentric circles, like a cymbal. This primitive genre is one where imperfection actually looks right at home. That's probably why I like it so much.

03/18/01-- I gave Minx's spear to GFW and since I've already shown you pics of the spear elsewhere, here's a pic of her replacement weapon. The elastic doesn't have much ooomph, so I made sharpened metal arrowheads to ensure that this would be a particularly unsafe toy. This was another one of those fun wood & metal time-killers.


03/24/01-- Once it's done, this is the sword GFW will probably end up with. It's like I said earlier, once you start looking at historical stuff, you're drawn to recreating it instead of just inventing it. With the shield and spear, it's hard to ignore the fact that the figure looks quasi Greek/Roman, so a grip tongue sword from that general period looks most appropriate. (Actually, I think the way it works is that anything else looks weird because we're used to seeing what we're used to seeing.) The blade's made from 16 gauge welding steel with most of a couple hours spent trying to get the blasted thing passably surfaced. This is a good way to get to know your Dremel bits, even if you do end up wasting 'em. This time I did the hilt in putty because its fine grain lends itself better to detail than wood does, and you can knock it out in about 5-10 minutes. It'll prolly be painted an unimaginative black/gray with some silver highlights to make the pinheads blend in better.


03/28/01-- The home stretch, at last. This has been one helluva long, drawn-out project with about half the time spent waiting on UPS Ground Delivery. I should have used that inbetween time more productively. With my rectifier back in bidness, all that should have been remaining was the plating job and the fitting of armor. Instead, I've got a bunch of silly little things to do, like finishing the head, making a belt, the forearm armor and whatever else... and finish the plating. I wisely did work on a few things though, including the shields and swords shown above. I also made a leather scabbard for the sword, shown attached in the Roman over-the-shoulder manner. I think a belt-worn solution would look better but this was easier to deal with considering the number of times the armor has been removed in test fits. The tunic is a coarse woven cloth in a very simple "potato sack" style. That's my kind of tailoring! The leather skirt thing is a little more finalized, with metal buttons. The width of the straps isn't uniform but it doesn't really bother me. I need to figure out a way of distressing them though.

I don't know that you ever get better with electroforming if every piece you do is different. If you're unsure of the proper current, you have to ride shotgun over every piece you make, checking to make sure the copper is depositing acceptably. I haven't done a piece yet that's come out of the bath perfectly, and all have required extensive finishing and buffing. That's not fun. It's a nasty and lengthy process that's hard on a Dremel.

I've run the solution with an airstone to help with circulation problems, but the deposition still isn't as uniform as I'd have liked. Visually, the variation in thickness is not apparent. That wouldn't be a problem if the pieces came out of the bath ready to rock. But they don't -- there's always some surface granularity and discoloration. When removing those surface imperfections, there's the possibility that you might grind through the coating and not knowing where and how thick the deposit is doesn't help. Forming an extra thick deposition should act as insurance, but the gotcha is that thicker depositions have more opportunity to form those surface imperfections that you'll need to fix. Besides, it takes gobs of time to build up a really thick layer.

I've already christened a second bath of solution, just to see if I could get better results. It worked better, but that's an expensive proposition, and not really a (errr...) solution . Much smarter to figure out what causes the problems and fix them-- Contaminated bath? Copper sludge? Finger oil? Uneven thickness of conductive paint? That's the kind of stuff you figure out through practice, which forms good working habits that you eventually take for granted.

The sheen on the pieces is deliberately funkified. The electroformed copper was finished smooth and gleamy, but the nickel plate was left as it came out of the bath; the hazier the better. A few pieces were too shiny and went back in the bath. It was really tempting to buff the pieces to the reflective glaze since it does look neat and gratifying-- but as I said earlier, in the context of the whole piece, it makes it look sort of cheap. The hazy and uneven finish also serves a secondary purpose: It masks small areas where the finish isn't quite so perfect. My comments about grinding through the metal come from actual experience. If I'd been trying to achieve the perfect & gleaming look, I'd have had to figure out how to spot electroform to build up the imperfections and blend them in. My quickie solution was to touch up with conductive paint and let the final thin plating of nickel blend the coloration in. Those spots aren't truly blended in and certainly wouldn't stand up to a round of serious buffing.


PART 2    PART 4