Jennings Posted January 20, 2016 Share Posted January 20, 2016 Aluminum is very easy to work, and it looks to me like it would make a very good medium for photo etching small details. Why did this occur to me spontaneously in the middle of a snowstorm today? Quote Link to post Share on other sites
KursadA Posted January 20, 2016 Share Posted January 20, 2016 (edited) Aluminum is very easy to work, and it looks to me like it would make a very good medium for photo etching small details. Why did this occur to me spontaneously in the middle of a snowstorm today? Short answer: Aluminum, while being "very easy to work" with mechanical means, is a light metal that oxidizes very quickly. It does not lend itself to etching with safe chemicals. Reliable etching of aluminum requires nasty chemicals (see below), which no sane cottage industry operator should want to use. Long answer: Most small-scale industrial (and literally all DIY) photo etching uses ferric chloride. Ferric chloride is inexpensive, recyclable and relatively safe to work with. It works very well with copper, brass and mild steels. I have made many homemade printed circuit boards as a budding electronic enthusiast many years ago, and despite having many accidental spills I never hurt myself with ferric chloride. It is hard to etch aluminum safely with ferric chloride though: Aluminum reacts rather violently with ferric chloride and can dissolve rapidly while releasing hydrogen - trust me, I tried. Industrial aluminum photo-etching is done with very strong acids like muriatic acid, something you certainly don't want to have around the house or your cottage manufacturing facility unless you really, really need it. I guess it is somewhat easy to see why cottage manufacturers don't want to deal with strong acids to etch aluminum, while safe etching of brass or steel is possible with relatively benign chemicals. Edited January 20, 2016 by KursadA Quote Link to post Share on other sites
Jennings Posted January 20, 2016 Author Share Posted January 20, 2016 True, but about 0.00001% of PE is actually manufactured by the cottage industry. I don't know of a single one who doesn't simply contract it out to professional etchers. Quote Link to post Share on other sites
KursadA Posted January 20, 2016 Share Posted January 20, 2016 (edited) This is the reason, whether you believe or not. Unless there is a particular advantage in using aluminum, not even industrial manufacturers will deal with the kind of chemicals required for aluminum. There is a wide range of "professional etchers" : These days I am getting in contact with various PE makers to expand my product line, and most of them seem to be doing their etching in house. I also fail to see what (if any) advantage there is by using aluminum as material for for scale modeling PE sets: at this scale the primary advantages of aluminum (strength, weight) do not really matter. Since you seem to have amazingly precise statistics about the industry, maybe some of your contacts can shed some light into why the remaining 99.99999% do not provide at least a few aluminum PE sheets.;-) Edited January 20, 2016 by KursadA Quote Link to post Share on other sites
ChippyWho Posted January 20, 2016 Share Posted January 20, 2016 These days I am getting in contact with various PE makers to expand my product line... That's what ye call a teaser! I'd love to know what this expansion implies, and look forward to seeing it brought to accomplishment. Going back to my cycling heyday ('80s-ish), aluminium bike frames could be made astonishingly light and rigid -I recall hefting an unnaturally gorgeous Klein Attitude that hardly weighed as much as the front wheel on my '89 Stumpjumper. Buuut...the stuff had no flex in it at all, and would invariably fracture before it bent. Whether this is an issue for an etched detail medium depends on how much you need to shape it; fold-lines may be a big trick, curved surfaces definitely so. Then again, titanium...! Quote Link to post Share on other sites
Litvyak Posted January 21, 2016 Share Posted January 21, 2016 ... muriatic acid, something you certainly don't want to have around the house ... Unless you're my dad... he's got a couple jugs of the stuff. Just.. "I might need it sometime". Quote Link to post Share on other sites
FM-Whip Posted January 21, 2016 Share Posted January 21, 2016 Industrial aluminum photo-etching is done with very strong acids like muriatic acid, something you certainly don't want to have around the house or your cottage manufacturing facility unless you really, really need it. Muriatic acid (another name for hydrochloric acid - HCL) can be found in any decent-sized hardware store in the U.S. It's commonly used to etch and clean concrete. John Hairell (tpn18@yahoo.com) Quote Link to post Share on other sites
Jennings Posted January 21, 2016 Author Share Posted January 21, 2016 This is the reason, whether you believe or not. I didn't say I didn't believe it, I merely said that cottage industry producers don't produce their own PE. Quote Link to post Share on other sites
KursadA Posted January 21, 2016 Share Posted January 21, 2016 (edited) Muriatic acid (another name for hydrochloric acid - HCL) can be found in any decent-sized hardware store in the U.S. It's commonly used to etch and clean concrete. Of course it has its uses, and it's widely available. That does not make it a pleasant substance to deal with. I never said it was plutonium; it is just not something you want to risk messing with just for the sake of photo etching aluminum for hobby purposes; even in a small industrial setting. Edited January 21, 2016 by KursadA Quote Link to post Share on other sites
kenlilly106 Posted January 21, 2016 Share Posted January 21, 2016 (edited) After looking at the etchant chemistries involved my thought is that aluminum is not practical from a hobbyist/cottage point of view while brass, stainless steels and copper were easily etched at home. So like a lot of things in life it simply "grew" that way as the cottage producers became larger and evolved into large companies, they stuck with what they knew how to do, had the equipment for and what their customers were used to. For those curious about the chemistries involved, ferric chloride is the standard etchant for brass, it also works on copper and stainless steel. It is reasonably priced and does not require any specialized equipment to use, though more advanced setups can be created to agitate and warm the solution to speed up the process. But the process can be carried out at a slower pace at room temperature in simple plastic containers. In contrast aluminum is typically etched with a solution containing sodium hydroxide, sodium sulfide (or sodium cyanide for finer details) and various wetting agents. The solution needs to be heated near boiling and continually agitated along with continuous moving of the parts. There is an alternative solution for aluminum that uses a mixture of nitric, hydrochloric and hydrofluoric acids but is not common due to the hydrofluoric acid content, the caustic solution is the dominant one for aluminum. If I was going to make PE in my garage I know what route I'd go down. Ken Edited January 21, 2016 by kenlilly106 Quote Link to post Share on other sites
Nigel Bunker Posted January 21, 2016 Share Posted January 21, 2016 Etches here in the UK started with the model railway fraternity. Brass has one big advantage over aluminium - it can be soldered, which was the standard methof of assembly for model railway enthusiasts, especially for moving items which might get de-railed. Quote Link to post Share on other sites
echolmberg Posted January 21, 2016 Share Posted January 21, 2016 Just out of curiosity, what's the cost of brass vs aluminum? Eric Quote Link to post Share on other sites
kenlilly106 Posted January 21, 2016 Share Posted January 21, 2016 Based on the prices for shim stock sheets of the same size and .005" thickness, brass is around $13.50 per sheet and aluminum is $10 more. That price difference is roughly the same for sheets anywhere from .001" to .010" thick, after .010" thick aluminum is still more expensive by a few dollars. In terms of material costs, plain steel is the cheapest, brass, bronze and stainless are about the same, aluminum is next, then copper and finally nickel and titanium are about 5X what brass costs. Ken Quote Link to post Share on other sites
Darren Roberts Posted January 22, 2016 Share Posted January 22, 2016 Back in the early 90's, Monogram included a fret of metal, but I don't think it was brass. Was it steel? It sure was hard to bend. Quote Link to post Share on other sites
Drifterdon Posted January 22, 2016 Share Posted January 22, 2016 Back in the early 90's, Monogram included a fret of metal, but I don't think it was brass. Was it steel? It sure was hard to bend. And cut! I believe it was stainless steel. Quote Link to post Share on other sites
jester292 Posted January 24, 2016 Share Posted January 24, 2016 Hi-Tech! Hahahaha Quote Link to post Share on other sites
kenlilly106 Posted January 25, 2016 Share Posted January 25, 2016 (edited) And cut! I believe it was stainless steel. Yep, a very short-lived experiment. Trimaster was also famous (or infamous) for using stainless steel for their PE frets. Stainless can be etched to fine detail and is rigid, which works well for items like scale screens but stainless also work hardens, so any time you have to bend it you typically on get one shot at it. Trying to unbend it for a second try usually results in the part braking at the bend line. I've wondered why VLS uses copper when most everyone else uses brass? Ken Edited January 25, 2016 by kenlilly106 Quote Link to post Share on other sites
11bee Posted January 26, 2016 Share Posted January 26, 2016 In contrast aluminum is typically etched with a solution containing sodium hydroxide, sodium sulfide (or sodium cyanide for finer details) and various wetting agents. The solution needs to be heated near boiling and continually agitated along with continuous moving of the parts. There is an alternative solution for aluminum that uses a mixture of nitric, hydrochloric and hydrofluoric acids but is not common due to the hydrofluoric acid content, the caustic solution is the dominant one for aluminum. All those chemicals demand respect but hydroflouric is especially nasty stuff. HF is in a class of it's own. I don't even like walking past sealed containers of that stuff. None of the above are suitable for "cottage" industry use IMO. Quote Link to post Share on other sites
kenlilly106 Posted January 28, 2016 Share Posted January 28, 2016 All those chemicals demand respect but hydroflouric is especially nasty stuff. HF is in a class of it's own. I don't even like walking past sealed containers of that stuff. Agreed, I work around strong nitric and sulfuric and they don't bother me but I will not deal with HF. Ken Quote Link to post Share on other sites
-Neu- Posted January 28, 2016 Share Posted January 28, 2016 What's in the hasegawa 1/72 F-14 sets? is that aluminium? Quote Link to post Share on other sites
Cobus Posted January 28, 2016 Share Posted January 28, 2016 All those chemicals demand respect but hydroflouric is especially nasty stuff. HF is in a class of it's own. I don't even like walking past sealed containers of that stuff. None of the above are suitable for "cottage" industry use IMO. The HF acid I know is the type they use at fuel refineries (to increase the octane rating I think, I'm a mechanical engineer not chemical :P ) and that stuff is HORRIBLE. The maintenance crew uses fully sealed environmental suits when they work on the HF related equipment. Definitely not something I want to be around... Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.