HOW TO WORK WITH HYDROCAL
AND OTHER MODELING TIPS -
INTRODUCTION - PATTERN BUILDING
Well, I've gone this far sharing my knowledge I might as well go all the
way. Most manufacturers are very tight lipped about sharing their knowledge.
It's not like you can find it for free on the Internet. It takes years of
searching, experimenting, trails, and errors. Fortunately for you I am compelled
to expose these techniques to you. I guess in part my way of giving back
to the hobby what its given me. Trying to improve it. I could ask commercial users
to turn away, but that's like asking a teenager not to look at a Playboy magazine.
Johnny, what are you doing in there? Just playing with trains, of course. I could
ask you to donate to my retirement fund for what you think its worth- a dollar,
Maybe that's not such a bad idea...
I wonder if it will work? Donations to date: $35.00. Every penny counts!.
Oh well... My plan to marry rich didn't work either... I am hopeful that you will
appreciate my efforts and support me by purchasing my castings and kits, buying
Builders In scale products, telling your friends to buy them for you as a gift
(we all win then). I'll be very pleased with a secondary reward like that.
But back to our pattern building. Having explained how to easily reproduce your
patterns, it is important to explain how to produce the patterns in the first place.
I didn't start out building patterns for a huge project. That took time, practice
and experience. You'll still need to do that. I started out just trying to do a
simple stonewall, then some brick, and so on. I worked up to the master patterns.
I built the stepping-stones first, the brick and stone stock patterns from which
I could then make the roundhouse, station, or factory building.
Being able to easily, and inexpensively, reproduce a pattern that I
had spent many many hours was a major step in my model building. It took
something precious, one of a kind, and turned it into something I didn't
have to be afraid of screwing up. I could take a brick wall that I had
spent half a day or more hand scribing and by the use of a rubber mold I
could have a small stack of them by mixing a little plaster (Hydrocal). I
was then free to try all sorts of things, like experimenting with coloration,
cutting and chopping them up into new patterns, or anything I wanted. This
really opened up my modeling to all sorts of possibilities.
My first attempts at pattern building were rather crude. An example is
a my first brick pattern that looks like warped cinderblocks laid by a
drunken mason. For some reason I had used waxed paper (as a moisture barrier and
mold release) which crumpled up when I poured the plaster in. The surface was
wrinkled and the bricks were way over-sized. It was really bad, something like a
drunk mason would build out of warped cinderblocks but I learned a lot from the
About the same time (fall 1983) I discovered Thomas Yorke kits. I was amazed
by the scale brick and stonework he had accomplished. Well, I figured if he could
do it then I could do it so I went back to work. What I needed was a better
starting point, a flatter surface, let's see, I had a sheet of plywood handy, and
then I needed more control so I employed drafting techniques with very careful
measurements and I was on my way.
A FRESH START
I abandoned the wax paper for Vaseline smeared (lightly) on a plywood base.
I generally use good quality 3/4" plywood. It can be used over and over. The
3/16", 1/4" or whatever thickness pattern is desired is achieved by tacking
stripwood strips to the base to create a box in which Hydrocal is poured. I
learned that bubbles are the enemy. Evil things! Using "wetted" water (like
we use for scenery, adding a few drops of detergent in a quart of tap water)
is used to wet down this mold box. And tapping it vigorously to help the trapped
air bubbles rise off the surface that we want nice and smooth. And we scrape
the back flat before it set for a nice even slab.
In about fifteen minutes the fresh slab is strong enough to be pulled
from the form. I use a single edge razor blade to smooth the wood grain and
remove any imperfections, and we are ready to start scribing.
I'm not sure where the tip to my metal scribing tool came from. It was
just laying around by workspace so I put it to work. It's a steel needle
point about 3/32" diameter and 1-1/2" long. I've mounted it in a pair of
pin vises, one is miniature which fits in a larger wood handled X-Acto- the
idea being that it fit comfortably in my hand for hours and hours. Some of
these tasks have been marathons, starting Friday evening and lasting well
into Saturday afternoon. Boy, I'm glad those are over. My hands ache just
thinking about it. So it's very important to have a comfortable tool.
With that in hand, the next thing we need is precise measurements. Now
a real brick is something like 2-1/4" x 8-1/2" x 4-1/4". Bricks will vary,
as will the amount of mortar but we want to boil it down to something we can
easily measure. I decided that the rows could be 3" tall and the widths should
be 9". Those are pretty easy to find on my HO scale ruler. So I measured 3"
increments down both sides of my wall carefully marking them along the edge
after I had chosen (or cut) the straightest horizontal edge as my baseline.
Next we take the metal straight-edge (scale ruler) and carefully line it up
with the hash marks and scribe our horizontal lines. It's real easy to screw-up
here and you quickly learn you do not want to do that. It may take several
hours to get back to this point and it is practically impossible to erase your
mistakes. All those years of drafting ink on vellum paid off! You might wonder
why I don't use a T-square. Just mark one side and scribe across. I tried but I
found it tended to wonder. By forcing myself to carefully align both sides
I was able to keep the lines more uniform.
The lines are best drawn with a light even stroke. I initially thought all
the work had to be done within the first few hours after pouring the Hydrocal
however I later discovered that I could prolong the period by keeping the
pattern wrapped in wet paper towels overnight. You can draw it out to 24 hrs.
or so- But ideally it's best done in those first few hours. Scribing is aged
Hydrocal (after wetting) is possible but the lines tend to be coarse and easily
chip. It's fairly quick work to scribe the straight continuous lines.
Okay, with those done, we can start doing the vertical mortar lines. They
are 4-1/2" scale inches apart ever other row (or course). Boy, is this
tedious but you'll quickly get the hang of it. Hopefully there's a good
football game (or two) on and it's raining- Be consistent and don't let them
Oh, I've jumped ahead a bit. I should mention marking the hash marks for
these. Of course it is important to keep these square so I employ a small
machinist's square. Actually I have several, 1", 2", 3" and 4", and a couple
in between (I'm a tool freak). Depending upon the particular pattern I'll use
whichever square works best. For smaller patterns I'll use the square and
just one set of hash marks to set the scribes. On larger pieces I'll mark them
top and bottom and run my ruler across, after setting the marks with the
square. Just remember it's every other row. It's easy to goof up.
Real brick walls are usually laid double thick if not more. They are tied
together every few rows with "headers", or bricks that are set perpendicular
to the other's full (9") face. This is what's referred to as a common standard
bond. Typically these occur every seventh row. So every seventh row you'll
just see the 4-1/2" ends of the header bricks instead of the regular 9". I
scribed these on my HO pattern inline with the other bricks where they
are typically off set. On the larger scales I've corrected this error. No one
seems to notice and there are probably some real walls done that way.
But think about these things as you lay out your design. Of course there are
lots of other types of bonds, Flemish, English and so on...
I should also mention laying out your door and window openings. Where I
have just described laying out a full brick pattern I'll use the same method
to layout a specific wall pattern. These are best done in the beginning.
There's no sense in wasting time scribing bricks in an area you're going to cut
out or cover up. Arched bricks over the openings can be scribed too using a
pair of dividers from a drafting set. Careful measurements are required and
a good study of the prototype.
Once all the scribing on the face is done we can cut the edges. Though I
now employ a band saw the finish work is always done with a hobby knife and
file. Before I started using the saw I would use repeated strokes of the
hobby knife to cut through the entire thickness. It's simply takes a little
time. If the Hydrocal has died the edge is dressed and trued by filing. I use
square or precisely angled wooden blocks to guide this work. I have a large
(10") Bastard mill file that I have tacked down to my workbench allowing both
hands to be free to hold the work- so very precise angles or square edges
can be accomplished without much effort or error.
With the edges cut fresh we can continue our mortar lines around them.
Hydrocal modeling is truly three-dimensional. Using the tiny square (or
simply a square cut from brass) and other such aids to keep them straight and
square. The window openings and such can be hand cut away, using repeated
strokes. Wetting the area with a few drops of water will soften hardened
plaster. I'll also use flat-faced router bit mounted in my drill press to
mill out these areas. If the pattern is going to be molded I do not cut all
the way through. If I did the resulting rubber would interfere when I go to
scrape the back of the castings flat. So I leave a little there (1/16" or so)
that will have to be cut out before assembly. The mill is good for this as well
as flatten the backs of my patterns. We'll discuss that more later.
Once we are done with all our scribing we can move on to mold making. There
I will describe how to prepare the master. It needs to be sealed, rubbed with
Vaseline... and other magic tricks.
How 2 make a rubber mold of your pattern.
See next clinic: MOLD MAKING
It's pretty satisfying to have created such a thing. And very rewarding to
be able to cast as many of them as you want later on. It makes all that hard
work worth it. Obviously by my description it's not something many people are
going to do. With that in mind I should remind you the importance of respecting
such work and not reproducing it without their creators permission.
STONE WALL PATTERNS
Hand-scribing stonewalls is a bit easier than the strict bricks. My first
successful patterns were those that are the foundations for my Virginia Horse
Barn kit. They are an inch and a quarter by five and a half, and about 1/4"
thick. The stones are very tiny. The largest might be 12 scale inches with
the majority 6 - 9 inches. This seemed appropriate for a barn foundation.
The walls are nine scale feet tall. I leveled them every three feet, scribing
a horizontal line, but allowing for locking stones to interrupt the line every so
often. I'd noted this practice on stone walls and didn't have any photographs
of the prototype barn. I'd just seen it briefly while passing by. I laid out the
rest of the stones in a random fashion. I scribed them with a mixture of freehand
and straight strokes along my ruler. Most of the stones are rectangular with a
few rounded. Once the mortar lines were roughed in I worked the surface of
individual stones with dots, dashes, and hashes. Probably on only a quarter of
them are texturized and lightly. I took care to match up the stones where the
sides intersect. This will help the joint disappear upon assembly.
Later on I created three larger hand-carved stone patterns. What I call
coarse, medium and fine. The coarse is probably my personal favorite. Medium is
probably a little more prototypical. And fine is larger than I'd like.
I was after the horse barn size and texture but they came out larger and rounder.
These patterns are approximately 4" x 8" and it is difficult to accomplish that much
tiny work. Still, I have found them all very useful, not just for stone retaining
walls, but abutments, piers, foundations and so on. It's great to have a variety.
Besides the hand-carved I have used Jack Work's fracture-faced stone method
to create a whole series of patterns. That method casts individual blocks that
are sawed around the edge, which becomes the mortar line, and the face is chipped
away leaving a wonderfully textured surface. The individual stones are glued
together in ten key sections that interlock, the tenth section interlocking with
the first, so they are continuously interlocking. Cast these key pieces and
put them together in larger interlocking walls, which in turn are molded and
cast, creating an interlocking continuous wall. Take those and make abutment,
piers, portals, and all sorts of things.
One last thought. Consider borrowing a texture as a start for your stone.
I used a rough cedar board as the base to a series of patterns, casting the
plaster there, all I had to do was scribe the mortar lines. The texturing
was mostly done for me.
For concrete I decided the best way to do it was just like the real thing. I
built scale wooden forms with stripwood and then cast the master pattern. The
resulting concrete wall looks just like the real thing. If I were modeling the
modern era I'd make them out of scale plywood so you would see those impressions.
My cedar shake roof patterns were made from miniature wood shingles that I
carefully split to scale size and laid out. It took a crazy long time to do
just a small pattern but I made a mold of that and spliced several castings
together to get a nice 4" x 8" master.
RESEARCH AND DESIGN
One important lesson I learned in art class, was it drawing or painting, that
should be applied here. And that is to spend an equal amount of time looking at
your subject and the painting/drawing/pattern. Easy if its a naked model, and
perhaps less important if it is a brick wall. But stone for instance, study
real walls. See how they were built. Notice the textures on the stones. Are
they rough or smooth, dressed or coarse. Are the mortar lines wide or tight.
Are the stones square or round, large or small or mixed.
We can carry this out into our research and spend hours looking up history,
reading books, studying photos, sketching and planning. What we are doing is
building up a model inside our head. There was the real building long ago, or
maybe it's still there, but 100 miles away from our basement where we now want
to build a model. So maybe 50/50 for a brick wall isn't that far off.
Where are the windows and doors, how many courses up and across are they?
What windows and doors are available? Will these work or how about these? When
I developed the Minden Mill and the Silver Plume Public School I had a dozen or
so photos to work with. I studied those photos and cursed myself for not taking
more. But I had what I had. The face shot of Silver Plume for instance I put in
my slide projector and drew it out in pencil making note of the bricks. So many
courses up, so many across, is the edge of our first window and so on. Perhaps
one of the reasons I never finished Silver Plume is the lack of commercially
available windows. For a building like that you really need the exact match. I
did it anyway, the central face, and stalled on the side walls when the brick
did not match, too coarse, and those darn windows. Still, it's some of my
best pattern work. Minden on the other hand was completed, partly because the
windows were available from Grandt Line and partly because it was a simpler
building. So much is to be said about design and planning. I've only touched on
it here. But study your subject, consider available parts, sketch or draw out
your plan. Think about how the walls will fit, hide the joints if you can on
the sides less seen. How thick should they be? One brick, two, maybe three?
Build the model in your head. Break it down into logical pieces that you can
build- You're on your way.
At this point I'll side track you now to the Durango Roundhouse project if you've
not seen it. You'll see the steps I've taken to make the brick wall patterns, molds, and