Creating Brass Blister Detail

[P_Budzik]

While this particular example is an aircraft part, I use the same basic principles and techniques combining machine process with hand shaping, for creating all sorts of small details.  I hope you find it useful.

 

 

Paul

 

[wefalck]

I have used the method frequently and designed my shop-made micro-mill with that method in mind. One can use it also on somewhat larger parts and economise the material consumption by hard-soldering a thinner spigot to it. One can do this also with bar stock or thicker sheet. The method also works for Plexiglas or Aluminium, of course.

[Bob Cleek]

Interesting process description, but, somehow, turning all that expensive brass into chips for the sake of one little pimple on a plastic airplane model seems like a bit of overkill. We modelers are an obsessive lot, aren't we? It looks like a job for Femo to me.

 

[BANYAN]

For me it's not what materials you use but the end result (realistic and accurate) that counts for me.  I have plenty of brass and aluminium stock, so happy to use that technique rather than learn yet another skill (I still haven't mastered the ones I am trying to apply  ) such as sculpting or evening 'moulding' - whatever floats your boat / best suits your needs I reckon.

 

cheers

 

Pat

[rwiederrich]

I tend to agree with Bob and Pat.  That part could have been made from something far less work intensive.  However, if exposed brass is the theme of your model...it is a necessity. Artistic license trumps reality.

 

Personally I paint everything to replicate the actual item I'm modeling...so I use whatever meets the requirement of accuracy...and simplicity....not to mention structurally.

 

There is no bare wood or metal on a sailing vessel...or any kind of vessel for that matter. Exposed surfaces were treated somehow.

 

I do love the machining work however...……...

 

Rob(Just a simple old man)

[Bob Cleek]

6 hours ago, rwiederrich said:

There is no bare wood or metal on a sailing vessel...or any kind of vessel for that matter. Exposed surfaces were treated somehow.

Not to be picky, but... teak, particularly decks, is often left bare and only washed with seawater. Any wooden fittings that rely on friction, such as handrails, cleats, and belaying pins, are often left bare. Bronze fittings are rarely painted at all.

 

But I do agree with painting everything to replicate the actual item I'm modeling, except where the entire model is left unpainted to depict structural components or for stylistic purposes... with the reservation that even wood left "bright" should always be coated with at least a clear sealer, and doing a really good "woodie" is a rare accomplishment. Most all of the kit attempts end poorly. (IMHO... your mileage may vary.)

[rwiederrich]

7 hours ago, Bob Cleek said:

Not to be picky, but... teak, particularly decks, is often left bare and only washed with seawater. Any wooden fittings that rely on friction, such as handrails, cleats, and belaying pins, are often left bare. Bronze fittings are rarely painted at all.

Wood decks are a gimme......Hand rails,cleats and belay pins of a non rusting alloy ...to include bronze fittings are also included on the gimme list.

 

Treat everything else or lose it.......

Shipshape me maties.

 

Rob

[Bob Cleek]

3 hours ago, rwiederrich said:

Wood decks are a gimme......Hand rails,cleats and belay pins of a non rusting alloy ...to include bronze fittings are also included on the gimme list.

 

Treat everything else or lose it.......

Shipshape me maties.

 

Rob

 

Aye, that's true!

 

Actually wood decks, other than teak, are not left bare, but oiled or otherwise sealed. The recipe for "ship soup" is 50% linseed oil and 50% ("Stockholm") pine tar, with a dollop of Japan drier added. This is the same stuff used to slurry standing rigging, but with lamp black added. Teak on naval vessels was not favored because teak splinters fester very quickly. It was also expensive, although it found some favor once Britain colonized areas where teak grew. Aside from the Navy, where ships were kept "Bristol fashion" and decks regularly "holy-stoned" (sanded with stone blocks) to keep the deck wood bright, generally, merchant ships' decks ended up close to black because the lamp-blacked tar that might drip from the rigging in the tropics or otherwise get tracked around, ended up being the dominant color after a while. Trivia, perhaps, but possibly helpful to some modelers.

[wefalck]

To get back to the original topic: this technique is also useful for producing flat identical parts of complex shape. The outside shape is milled as per the video and then you saw off the parts of the desired thickness with a circular saw. In order save material, you may start with some rectangular stock to which a stem or spigot is hard-soldered. If you have a independt 4-jaw-chuck for your lathe, you can also turn the stem onto the rectangular stock, which may be the method for materials that cannot be soldered.

 

Talking about parts for polystyrene models: I would probably make those from Plexiglas stock, as this can be glued (or better 'welded') to polystyrene with either the usual liquid cement or with methylene chloride.

[P_Budzik]

Not quite sure you fellas realize how small the part is, check out the reading on the caliper ... I think you would find it very frustrating to make it out of plastic or wood and keep it sharp.  Second, because it's so small, material loss really isn't an issue.  Third, you don't start with square stock because the part is transferred to an indexing head on a milling table, so it is much easier than trying to recenter the stock.

 

The point of the video was to demonstrate a method and develop the concept of putting together multiple processes.  It started by first thinking how are you going to accurately locate the part, so you need a pin (gluing a free floating piece of plastic is hit or miss).  You need convenient way to hold the part when you are doing the free-hand work.  So turning the part off on the lathe solves both those issues.   Using rod stock gives you a center to work from.  The basic shape is generated on the mill and the depth was only .050".  Because it's so small, it only takes a few file strokes and sandpaper to work out the shape.

 

These techniques are not new and have been used by professional model maker machinists and taught to me nearly a half century ago.  I made the video to answer questions from modelers, with no experience in machine work, who want to purchase a lathe or some single machine that they think will be useful.  They don't understand that the majority of parts that they see I've created involve multiple process, not only related to the machines, but also tools like a grinder.  You don't just buy a magical machine and start spitting out great parts ... there's a pretty steep learning curve ... even for setting up the machine.   So when someone asks me about getting into miniature machine work ... I have a simple example that I can point to and say to them, "do you really want to go down that road?"  Especially in the day of 3D printing, which you know will only keep getting better.

 

It's an homage to classical technique that I like to keep alive ... and I had hoped that people could see it for that.

 

Paul

 

 

Edited March 15, 2019 by P_Budzik

[kurtvd19]

Paul:

Thanks for sharing this technique.  One of the hardest things I had to learn over the years was how to think of the machining that might be required to make a pert.  This video shows that starting with a round piece can produce an elongated shape rather than thinking you need to start with a piece of flat or bar stock.

I find your videos very educational and they have helped me a lot.

Kurt

[rwiederrich]

Well explained.  With further understanding of your *Purpose*, it fully becomes clear why the process was presented.

In the model ship world, this principle is alive in my world....I almost couldn't have it any other way.

Multi-media, and multi fabricational processes are fully employed in my shipyard.

 

Rob(thanks for the presentation)

[wefalck]

As said, this technique is very versatile for many small parts. Here the sequence of creating a ventilator from round brass stock using some fancy machine tools and accessories:

 

Turning the shaft of the ventilator in an excentric 2-jaw-chuck. The future cowl is to the left. One could have this done in an ordinary 3-jaw-chuck or collet, but would have needed round stock of about twice the diameter and needed to remove a lot more material.

 

After parting off the ventilator it is transferred to the upright dividing head in my micro-mill, where the back of the cowl is round-milled. The dividing head is driven by the worm-drive for this milling operation.

 

Then the inside was milled out in the same set-up.

 

The back of the cowl is shaped on the micro-grinding machine using a diamond disc. The back is closed with some copper shim soldered on and then hand-shaped.

 

Collection of ventilators produced from round brass stock in this way. The height of the head of the smallest is 3 mm and the shaft has a diamater of 1.2 mm.

 

Using this technique I have produced a variety of parts for my current project (SMS WESPE 1876), including rectangular bollards, chain stoppers of various kinds, etc.

 

Another application was milling the outside shape of 2 mm-blocks in brass and Plexiglas:

 

In the same set-up they were then drilled and slotted, or rather the sheaves were part-milled by turning the blocks in the dividing head over the predetermined angle.

For all the machining operations I made myself a table in which I calculated how much the mill had to be fed in what position of the set of future blocks held in the dividing head.

 

This is a powerful technique, particularly when you can transfer parts from the lathe to the mill and vice versa without loosing concentricity and, hence, the reference point.

 

Paul is right in saying that it requires a good kit-out and some practice in machining, but it is quite do-able with a bit of patience and I am entirely self-taught.

Edited March 15, 2019 by wefalck

[druxey]

Well done, both Paul and Wefalck, for demonstrating the application of machining techniques to complex shapes.

[gjdale]

Thanks for another excellent video Paul. You have a real knack for explaining and demonstrating techniques - I always learn something from watching these. Thank you for sharing your knowledge and expertise.