Zaggs Fw 190D-9 211164 - Black <4 and his continuing scratchbuilding adventures...

[Zaggy]

At the behest of Würger, and to save from completely hi-jacking Evan's "Braun-Vier" thread, I shall continue my mad ramblings here... The point we're upto (for those who havent noticed the last posts in the aforementioned thread) is that I am experimenting with PE, in order to create accurate Engine Mounting Arms - previous PE experience has been limited to knocking up PCB's, so going from boards to parts is actually proving more of a leap than expected!

So... on with the show... This is what we're trying to make:



The current (new) acetate that I have is just not doing the trick - I tried three times, with gradually better results, but it was wearing on my patience. I have some idea's on how to improve things, but I'm here to MAKE parts i need NOW; not experiment! The removal of the acetate was shocking the toner after transfer - so making a fast quench in water when its hot, or removal of the acetate while things are still hot would be a better plan, but we'll worry about that later.



... see; and while that MIGHT work (there is still toner down in the 'light areas'), I just dont want to be playing with maybe's...

BUT, when digging up some degreaser and chemical cleaner, I happened up a few sheets of Press-n-Peel, for printing PCB's; thus I thought I may as well try them. Print out, line up ( SOOOOO much harder through a mostly opaque sheet!!!!), iron on to CLEANED Brass... Not perfect, but we at least now have something to play with:





As you see, there a few little issues; minor surface contaminant in one spot (probably dust or something between the brass and toner) and the odd lift mark where insufficient heat was used, but on the whole, it will do. You'll notice that small issues can be corrected with either some ordinary modelling paint or with a permanent marker or anything that will form a barrier between the etchant and the metal.

The next step is to mix up a small batch of etchant (Ammonium Persulphate in my case), keep it between 70-80degC and etch the parts for 5-10mins...


Dan

[Airframes]

Good stuff. The process seems slightly strange to me, after many years in the Graphics industry, using (or demonstrating) high-density, fine grain litho film for photo-etch work. But then, this method will be a lot cheaper on materials and equipment I guess !

[Zaggy]

Airframes, high density litho would be perfect for this if you wanted to knock out more than a small run - if I had access to stuff like that, I would be tempted to start an Etched Parts company. The best I can do is use the Gocco machine at Uni (the pre-stretched, light sensitive screen stuff, which is awesome for small run T-shirts, Aircraft Markings (I'm told Air Force here uses machines like this to generate certain stencils and markings on an 'as-needed' basis), which I dont think will be able to do consistent 0.2mm lines for example...

As for costs, if you can get Laser OHP Acetate working for you, you're well sweet! As is, my expenditure for this project (if I didnt have some of the stuff laying round) would be something like:

Ammonium Persulphate Crystals (diluted 1:5 by volume (crystals:hot water)) - of which I have used maybe 2-3% : $12.95
0.005" Brass Sheet @ 4 x 10" - of which I have used maybe 10% (I need to find a cheaper source of Brass!!!) : $4.99
Press-n-Peel Blue (4 Sheets per pack) - of which I used maybe 10% of one sheet : $35.00 (this stuff has gone up, I paid $30.00 in an emergency for my pack about 2 years ago)

So its not quite Pocket-Change if you go out and buy just the stuff you need to START with, but over the life time of the products, its pretty reasonable! And it works!!! Prices of the stuff I have listed here, is the RRP ($Australian) for my closest sellers - that being JayCar (for the Press-n-Peel and Ammonium Persulphate) and Frontline Hobbies (Brass); eBay is your friend and will provide all of this stuff cheaper!

Now, I bet you all want to know how the Etching went... Well it took all of 7-8minutes, but thats the next post...


Dan

[Zaggy]

Success! But for those interested and that have been following, I'll walk thru the process:

Now that the Brass is Prepared (making sure we have everything joined to a 'fret' and all frets joined to a 'backbone', so we dont lose them in the etchant), we need our etching tank. This may sound high tech, but I ran with the SAME set-up I have used to make PCB's - a rectangular chinese dish sitting in a metal baking tin. Into the tine we pour some hot water - maybe an inch or two - then into chinese dish, we pour 5 parts hot water, followed by one part Ammonium Persulphate. ALWAYS ADD CRYSTALS TO WATER, not the other way round... As benign as Ammonium Persulphate sounds (and is, with respect to etchants), it will seriously hurt you if you treat it with contempt, especially if you decide to splash it in your eyes or take a sip. DONT DO ANY THING DUMB, take your time and if you are worried, wear goggles and latex gloves. Once you're used to it, its no different that handling say Lawn Weed Killer or something... Now mix the crystals until the totally dissolve.

Clip something onto your prepared brass and fully submerge it into the etchant. This is my spectacularly complex and high-tech looking setup:



Regularly agitate the etchant - I just stir it for a minimum of 20-30sec each minute, and in this case, I was flipping the brass over every few minutes. The reason I use a metal tin is so I can use that to monitor temp; 70-80degC is uncomfortable to touch, but doesnt instantly burn. If you can comfortably touch it, you temp is probably down to 50degC or so, thus add more hot water to bring the temp back up... Once things are going, you'll notice the etchant start to gain a blue-green hue and a close look (DONT GET TOO CLOSE - remember your EYES!!!!) will reveal bubbles. The Blue-green is the copper being dissolved out of the Brass Alloy and the bubbles I believe are excess oxygen from the reaction. As the Brass reacts, it begins to take on a lighter, duller look; see...



... as things progress, you'll get to the point where the etchant eating through one side of the brass, reaches the etchant eating at the other side; this means you're all but there. The below photo shows about the 5 minute mark - you'll notice just how effective my ordinary 'Staedtler Lumocolor CD/DVD' marker pen actually is, but any water proof permanent marker should suffice. This perfectly illustrates the repairs to frets and parts, as well as the extra fretting added between each part fret and the 'sticky-tape' backbone. What you're looking at in the back of the mounting arms and Cowling Braces (x3) and the front of the radiator flap actuator mounting ring - and some flaky looking brass!



Once you can see through the places where there is NO pattern on either side PULL IT OUT. If you've properly agitated, the etching should have been nice and uniform. In my case, I was slightly premature in removal as one side of the actuator ring still has a THIN sliver of brass where it shouldnt be (left side, between a brace and an arm) - I also lost two small legs on the ends of the short cowling support braces, but that was likely due to them being too thing - anything you draw should really be a minimum of 2.5 - 3 times the thickness of the brass. Still, here is the result:



Now, close looks will reveal the front and back are misaligned by some 0.2 mm, but to put things into perspective, the Actuator Ring is only about 13mm across, so the parts you're seeing a REALLY SMALL - the Cowling Braces (such as the long 'thing' under the pair of engine mounts) are only 1.0 mm wide, the largest bits (Mounting Arms) are about 23mm long!

So? Thoughts? Obversations? Questions? Next will be to try and use the Mounting Arms (well, I guess they're mounting arm faces) to create the correct width of arm...


Dan

[Zaggy]

Also, just quickly before I head to bed (3:45am local), there is no requirement for your parts to be 'double-sided' either; you could quite easily print your mask onto one side of the Brass and cover the reverse with something like red electrical tape (so you can more easily see when you've etched through). You could also go the other extreme and have surface detail on both sides, pulling the piece out of the etchant half way through to add some 'black marker' and stop the etching at the desired depth.

I'm also going to get my hands on some 0.010" (10 thou) Brass and play with that, to see if I can get the detail rendered a bit deeper. The 5 thou arms I have now work, but I wonder if 10 thou (allowing me to raise those 'circles' on the arms out to 5 thou above the lower surface) will look better? Or perhaps I should just go straight for the 20 tho (0.55mm) copper plate i have here?

[Wurger]

Please keep the thread running here. Looking very interesting.

[Zaggy]

... will do Würger; shant be as interesting as "Making your own PE" for the foreseeable... Need to actually APPLY this stuff and finish the build; however, Im now planning on etching up parts of the Fuel Cell Bays, refueling ports and all doors (refuel, side, MG 151's, etc)...


Dan

Oh and with this knowledge, there is little, if any reason for any of us to have to go out and BUY the simpler PE stuff; things like the Eduard 'Reeds and Small Animals', Simple Ladders and maybe even those PE ammo-belts. Anyone with a modest or better Image Editing or Drawing program (say Illustrator/Photoshop or Corel or even the good old FREE Paint.NET or GIMP) and a Laser Printer, can knock this stuff out on their first or second go!

[Airframes]

Looks pretty good.

[stona]

Fascinating stuff. It takes me back to my old chemistry days in a bizarre sort of way. I can't honestly see me attempting the process but your thread is both enlightening and entertaining and I shall definitely be following your progress.
Keep up the good work!
Cheers
Steve

[vikingBerserker]

I agree, this is pretty interesting!

[Zaggy]

Whilst I dont need them for this project, I am considering knocking-up some patterns for some 1/48 Fw 190 stuff for the 10 or so Fw 190D/Ta 152 kits I wish to build; what I am thinking is i) Wooden Flap set (for Fw 190D-9/-11/-13 and Ta 152E/C, ii) doors and panels (lower engine cowl, refuel points, radio bay, wing gun ammo bays, that left side door, etc), iii) Seat belts + ammo belts and maybe, just maybe iv) corrected 190D, 152H and 152E cockpit panels (late D-series Fw 190's often used a mix of Panels from both the 190D and Ta 152 series; for example, the D-13 side panels are Ta 152E parts). The last two are obviously fairly simple, requiring no precision folding/bending. Thus, if ppl are genuinely interested, I'll share whatever patterns I make - the cockpit panels are probably overkill, cosndiering how little of an Fw 190 cockpit you can see when its installed, but some ppl like doing that stuff....

@stona & @vikingBerserker : it has been REALLY interesting actually! As the above passage probably suggests, Im fighting a little to remain interested in the project and not just dart of on a tangent and make all these 190D- & 152C-/E-/H- parts (oh, I could make a 152H flap set too!). But long term, this could save a lot of us Modellers a decent amount of dollars if ppl are willing to share their patterns.

But back to the project for a second - does anyone actually know how thick these Fw 190D engine mounts are supposed to be? Mine are currently about 0.6mm which looks too thin still, but 1.3mm (which I thought was correct) looks too thick!

Dan

[Wayne Little]

Dan, that looks great man....interesting stuff....

[Zaggy]

@Wayne - I'll post some pics when I get this first arm finished (painting, washing and setting up connections to the engine ATM) and aligned... I've also go the radiator flap actuator ring mocked up, but that needs a little more work...

oh and as for the mounting arm, Ive kind of split the differenceat about 1mm - it 'looks' right and gives me something to drill into so the engine mounts can fit into the arms.

[Wayne Little]

Cheers mate!

[Zaggy]

OK, the macro lens and flash makes the metallic paint look thin and like there's dust all over everything - which there isn't - but I'll share anyway... So for your viewing pleasure, this is the Aires Jumo 213 (without the kuhlstoff tanks and various plumbing installed and a basic coat of two metallic colours) with my etched mounting arm, laminated onto two layers of 0.5mm plastic card.





The 'golden' hue is the colour of the Resin and Brass leeching through the metallic paint due to the brightness of the flash; under all other light conditions, it looks totally different. If I have time, I will try for other pictures later under better light conditions...

I'm not 100% sure, as I haven't looked too deeply into it, but I have a feeling the Aires engine represents the slightly longer Jumo 213E variant - would explain the slight differences I am encountering, when compared to the Jumo 213A-1. Not proven yet though, by any measure...