I am very intrigued with the concept of scratchbuilding a locomotive.
I have the Scratchbuilding a Steam Locomotive MR articles from 97 that lasted 8 issues or so.
I don’t recall any photo-etching in there.
I was just on the Priest’s layout website: http://www.emporiasub.com and there’s some mention of photo-etching brass on there.
Does anyone know what this process consists of?
(being an engineer, this hardcore stuff sounds quite appealing i.e., I’d really did the concept of spending several years building a killer diesel engine from scratch).
Unfortunately, although I design parts to be machined day in / day out, I don’t have free access to a mill & lathe, or any fancy machinery, and would like to do these things at home in the garage.
I’ve heard about it over the years but an not familiar with the procedures.
I checked out the link. Impressive. One thing I’ve wanted for the longest is “See Thru” Grills for GE U Boats. If this system can be used to make them, then I am interested!
They offer two versions: #83123 for continental US shipments and #83123F for international shipments (two hazardous chemicals omitted/you have to find them locally)
first of all you have to produce the masters. this is a drawing with lines along the parts of the sheet brass you want to be etched to half the thickness of the metal (to etch all the way through you simply etch through half the thickness from both sides) next the drawing is copied onto transparent film. i have used OHP film in a laser printer. i dont believe inkjets produce an ink which is as opaque as laser toner but i am more than willing to be corrected. next you have to coat the metal to be etched in photoresistive chemical (i am sure there is a posh name for it but the stuff i use is just called “photoresist” the film is placed very carefully over the sensitised metal and the whole thing is then blasted with UV light. all the parts of the film that were exposed to the light will be etched when placed in acid and all the bits that were covered buy the toner on the OHP film will not be etched. or is it the other way round? (i have used both positive and vegative photoresist and can never remember which it is.
this is great fun but i would actually advise against using a ready made kit. i would buy the parts and make up a kit myself.
there are some very good web sites explaining the process.
2 things though…
Firstly heated bubbling acid is not good for the people in the room! it makes you feel very sick (trust me i have done it ) so if you age going to heat the acid and bubble it you will need a fume extractor that takes the air a good distance from your house.
secondly. this is seriously addictive. before long you will be making your own professional PCB’s and even taking up victorian photography! collodian wet plate pictures are great fun to make! and etching pictures is very rewarding!..