Scratch Build Soviet Project 667 BDRM Delta IV SSBN K-18 "Karelia" Scale 1/140

[Davidh]

Hello all,


I've never done photo etching. One day I will.

Still going through the slow process of finding the little imperfections in the hull and sanding and filling them out. However in the back of my mind I remembered that I needed to create the last set of pieces for appendages. The rear facing condenser scoops. There are four of these condensers, two on either side of the rear and lower hull. Again, like the forward facing scoops there are few really good close up picks available for me to pull detail from so I have had to get their overall design from a far from a few good but far off photos.

Once again I designed these scoops in Blender. You spend your time producing as accurate as possible one piece. then you just hit shift-D and you have a duplicate, then another and then another..




As far as I can tell there is a grill at the front. I don't know the precise details of it but have recessed the structure only a little. The back end of the scoop reduces and curves down to the center point quite rapidly. After duplicating four I then copied them to a separate file as they were originally build around the overall 667 model. Then send them to the printer. Initially I have found that it is easy to get the scale slightly out with any given print. I started by printing out at least two sets of four each in two slightly different scales in the aim that I'm going to get it right. After about the third go I got it right. I also needed to make sure that they aligned correctly with the model and also the side view drawing that I have been working off.







Of course when the print job is finished, the surface is quite rough and needs a fair amount of sanding. I combine this with spray primer. It requires several layers of primer and sanding. I also combine this with
filler especially in areas where the layering is quite noticeable. Gradually I worked my way down to finer and finer paper. It was a little tricky to spray and work around the grill.





Gradually after lots of layers we get down to 800, then 1200 wet and dry. Then a few coats of primer.

Like the forward facing scoops, I have decided to fix a small round brass piece on the underside of the condensers coops. This is so that you can have the scoop fixed really securely onto the hull. The round brass section simply gives more surface area to affix and helps the parts stay fixed on the model. I took the brass pieces off the masters from the forward facing scoops. This allows consistency across the parts.




Like the forward scoops, I have used styrene markers to position the scoops on the hull. So I took some 3mm styrene and cut out the profile of the scoop and then cut three more. Then I drilled out the holes that corresponded with the brass pieces that attach to the scoops. These styrene profiles will then be glued to the hull in the relevant locations. This will make it easy for the assembler to get the right spot on the hull.




More later,

David H

[He Who Shall Not Be Named]

Do you custom etch those metal stencils, Dave?

Found more stencil making pictures, Andy. And an early acid-etching process that was used not only for parts, but also for painting and scribing stencils -- old-school!

[HardRock]

I very seriously doubt that Mate, but thank you all thje same. I'm enjoying looking at your work - and DaveH's as well for taht matter.

[He Who Shall Not Be Named]

Light bulb moment! Topredo shutter door stensil! New concept! I feel so dumb.

A guy who built THOSE masters …….. feels dumb?! bull-****! I've learned as much from you as you've learned from me, pal.

David

[HardRock]

Light bulb moment! Topredo shutter door stensil! New concept! I feel so dumb.

[He Who Shall Not Be Named]

Do you custom etch those metal stencils, Dave?

My collection of scribing stencils is a mix of those commercially available, and formed by me. My custom stencils are either punched, drilled, milled, and filed to shape from plastic sheet, G-15, aluminum or brass sheet; my own acid-etching process is employed to produce some types of engraving stencils; or uniquely vacuformed or GRP laid-up stencils formed over the area to be engraved.



Use of the commercial stencils -- some specifically sold for engraving, others, simple plastic drafting forms -- is fine for the standard geometric shapes like squares, circles, straight lines, and the like. But You have to make your own stencil for shapes unique to the subject getting engraved.







The more exotic scribing stencils are the vacuformed or GRP laid-up ones used to engrave missile hatches, torpedo tube shutter doors and sonar dome windows.











David

[Subculture]

Do you custom etch those metal stencils, Dave?

[He Who Shall Not Be Named]

I am so pleased to see you working the scribing problem, David.

Scribing Bondo is difficult, as you observed. But infinitely easier than scribing wood!

And when you start scribing your next project -- with a proper substrate (gel-coat or RenShape), employing refined engraving tools, and handling those tools with the experience you have gained these last few months -- you'll be amazed at the qualitative difference between it and previous engraving work.

I assure you, sir, once you realize how much you've improved in this area, then you'll appreciate the beatings I've been giving you about the head and shoulders over the matter.





Onward!

David
The Horrible

[Davidh]

Hello all, wow this thread has been busier than Parramatta road on Friday afternoon.

Darn you HWSNBN!

I’ve spent last weekend re-scribing. I really don’t know if the results have improved the situation. However it has caused the traffic going past this thread to pick up.
In all fairness I did most of the scribing before you gave the detailed run down on tools and scribing technique (which I do appreciate) This is particularly so on the missile deck that was scribed months ago.
Also almost all the material I am scribing into is Renshape. Yes I am sold on the material. I have ground down some files to really fine points in order to get a really tight and narrow scribe line.





Anyway I sanded back the missile deck and then pasted over filler into the gaps where the scribing was. I have mainly concentrated on the missile deck as this is where I believe most people’s eyes will firstly look at the detail on the hull. Then I came back and sanded down the filler to get it smooth and flat. I then took out my scribing templates and went over the lines of filler in the grooves where the original scribe lines were laid down.





After a while I found that the filler would often pull up in front of the scribing tool as I worked my way along the groove. Obviously it had no bonded with the material inside the groove. This is something that I have had to carefully work around. It has been frustrating to say the least. To try and manage this I have also gone over the grooves with several scribing lines, starting off lightly at first and gradually working my way slowly deeper and hopefully not antagonizing the filler to lift up. A dragging motion is used. The re-scribed lines look more subdued but I don’t know about consistency. I will be going over it again soon. Jury is still out. I also need to sand around the safety railing.





Anyway, back to what I was talking about earlier with creating a tight interface between the top of the missile deck and the rear of the fin. After sanding around the filler that was pressed into the gap between the sail and deck I then pulled the rubber bands off that I had used to secure down the sail and then very carefully wiggled the sail sideways back and forth until the seal had been broken between the filler and the masking tape. This is quite easy to do, as I pulled away the sail there were little thin bits of filler left formed a flange going out radially from the sides. These were quite easy to sand off. I then checked the thickness of the filler from underneath the sail. In some places it was a bit thin so I simply added some super glue to shore it up. Once the super glue had dried it meant that you could sand around these edges with less chance of the filler breaking off. At the same time being careful to maintain the precise profile of the edge that so snugly mates against the hull.












Anyway, thanks for the contribution everyone. Bob, the joint between the sail and the missile deck, I think has worked out well. AS mentioned earlier I have a couple of weeks of fine tuning ahead of me before the hull gets tooled up and also the sail. I also have to do the rear condenser outlets (I think that's what they are?)

Enough for now,

David H

[Bob Gato]

That would work, sure..the real trick is to catch the bondo while its set but not cured-if you wait till the next day to pull up the tape...it might not work so well unless its a very thin coat.

[DMTNT]

Adding to what Bob said, David - would it be possible to very lightly score along the edge of the tape before you peel it back? That way you can at least encourage which way the cured Bondo will break when you pull it up.

[Bob Gato]

When all the banter is done, I am curious to see how the bondo and masking worked out-I have found that for compound curves, Glad wrap (clear plastic food wrap) and on flat areas-parchment baking paper(my favorite) works well..I hope the tape separates as you expect (if I have to use tape, I wipe it with VERY LITTLE silicon grease on my fingertip)

[DMTNT]

And David, if you read that and didn’t get that I was joking...

…Please let me offer a sincere and heartfelt apology.

[DMTNT]

Mate. A bit harsh. There are VERY few people who can take an idea and make it a reality, no matter how rough around the edges. We are all spoiled rotten by HWSNBN's abilty to produce museum class models with seemingly effortless efficiency. That only takes about 40 years of practice. For the rest of us mortals, results vary with time and experience. DavidH does some fantastic work; I know this because I've seen a lot of it at very close range. His latest challenge is scribing, which will be immencly improved because I know he has just aquired an ENORMUS chunk of Renshape which means that there will be no excuses. Onward Dave!

Oh I was teasing! I don’t honestly think he should do that at all.

I hope David would know that based on the long correspondence we’ve had about this project thus far. All of you - every last one of you are a HELL of a lot more talented than I am. What is incredible is how much we can stand to learn from each other in a venue like this.

For what it’s worth, I still want to buy one of these things when they are ready. I did two weeks ago. I did yesterday when I wrote that. I still do today.

[HardRock]

Ok, I'll try...

David, fabulous work. Now take what you've learned, throw the entire project in the trash, and start over again. Only do it better this time.

Watching in eager anticipation!

Mate. A bit harsh. There are VERY few people who can take an idea and make it a reality, no matter how rough around the edges. We are all spoiled rotten by HWSNBN's abilty to produce museum class models with seemingly effortless efficiency. That only takes about 40 years of practice. For the rest of us mortals, results vary with time and experience. DavidH does some fantastic work; I know this because I've seen a lot of it at very close range. His latest challenge is scribing, which will be immencly improved because I know he has just aquired an ENORMUS chunk of Renshape which means that there will be no excuses. Onward Dave!