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Discussion Starter #1
What follows over the next few weeks will be a basic, easy to understand (I hope!) tutorial on how to assemble, paint & weather a hydrocal structure kit. If at any time you have a question or comment please feel free to chime in, that's what this thread is for.

Basic overview of hydrocal kits. OK. People often ask me why would they want to build a hydrocal kit when they could just buy a Walthers or DPM plastic kit? While those two manufacturers make fine products, as a small manufacturer/craftsman I can offer something that they cannot. An original pattern that is hand carved one brick, one stone at a time. The larger manufacturers almost always use injection molded plastic as their method for producing kits, and to create the tool and die work with this amount of surface detail is simply cost prohibitive. As you can see, when the patterns are all hand created their is a certain "organic", real look to the model when finished. I can add chipped and missing bricks, cracks and other surface weathering that you're just not going to find in a plastic kit. Basically you just end up with a much more realistic looking model IMO.





The kit I'll be using for this build is our HO Scale DD1000, Addams Ave. Part One. $54.95 + $10 S&H. If you'd like to build along I'm offering this one kit as a forum special for a flat $50.00 postpaid (US only) until this "build" is finished. Contact me off list if interested.

What do you see when you open a plaster kit? Not 30,000 sticks of wood for one thing. : ) Usually there are 4/6 hydrocal castings, plastic windows and doors, signs, styrene for the roof, misc. small details & a set of instructions. The kits are simple, yet look great when finished properly. The detail is all cast into the castings. Most of the "work" is painting the structure. I call that the "fun" part.



OK. I'll be back in a day or so and get started with the actual construction. If you have any questions feel free to fire away. Cheers!

Randy Pepprock
Downtown Deco
Dioramas Plus
5323 Fiddler Ct
Florence MT 59833
406-273-0942
[email protected] (email)
 

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I like your buildings, I really like your buildings. I do N scale, and I see at your site that you offer N scale. It looks perfect for what I am trying to do. Modern diesel trains operating thru an old town with mostly old historic buildings. Your web site is going in my favorites.
 

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DownTown,

Nice idea for a thread. That said, I'll be the one to step up to the plate and ask the ignorant question:

What exactly is "hydrocal"? I'm assuming some type of plaster, but what are it's special features? Rigidness? Durability? Carvability? Etc. What ingredients / pour method makes it different from any other plaster?

I'm sure plenty of guys here on the forum will already be up to speed with those answers, but I'm hoping you can take a moment or two to clue in the clueless ... like me!

Thanks!

TJ
 

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Discussion Starter #4
It's not an ignorant question at all. Hydrocal is simply a hard casting plaster. it is stronger and holds detail better than run of the mill patching or casting plaster. It is still soft enough to cut or carve if you need to. Even harder is hydrostone, which for my money is too hard and dense.

DownTown,

Nice idea for a thread. That said, I'll be the one to step up to the plate and ask the ignorant question:

What exactly is "hydrocal"? I'm assuming some type of plaster, but what are it's special features? Rigidness? Durability? Carvability? Etc. What ingredients / pour method makes it different from any other plaster?

I'm sure plenty of guys here on the forum will already be up to speed with those answers, but I'm hoping you can take a moment or two to clue in the clueless ... like me!

Thanks!

TJ
 

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Discussion Starter #5
Part Two. Cleaning up the castings.

The first thing you need to do is to clean up the castings & remove any excess flash. Because the parts are hydrocal and not plastic or resin, in most cases all it takes is a few minutes with an emery board, a sanding block and/or an x acto knife. Make sure the bottoms of the castings are flat and that there is no flash where the walls join. If I need to make sure the bottom of a wall is flat I will often just lay a sheet of 60 grit onto my work bench and slide the part back and forth over it a couple of times to make sure it's flat.

An important step is to "test fit" the plastic doors and windows before you get the building assembled and painted. If you don't you might find that after the building is all painted that some of the parts might not fit because the openings needed to be cleaned up and perhaps enlarged a hair, then you'll mess up your nice paint job & it will need to be touched up. When hydrocal dries it shrinks a tiny, tiny bit, and while I always try to take that shrinkage into account when creating the master patterns, it's not an exact science. So test fit the doors and windows now, and then set the parts aside until later. I use an x acto w/a #11 blade or, if needed, an x acto w/a small chisel blade to shave off a hair off an opening.

This isn't really that big of a job. From beginning to end it only took me about five minutes to clean up the flash and test fit the parts for this kit.





Next step, gluing the hydrocal parts together. Remember, I'm running a special on this kit until this build is complete.

Randy Pepprock
Downtown Deco
Dioramas Plus
[email protected]
406-273-0942
 

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Randy,

Great job so far on a clear and well-presented "how to" thread. Looking forward to watching the process develop.

Thanks,

TJ
 

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Discussion Starter #7
Part Three. Gluing the hydrocal castings together.

I prefer to use 5 minute epoxy to glue the hydrocal castings together. I've heard from guys that like to use white glue, yellow carpenters glue and ACC super glue and while any of those will work, I'll tell you why I don't like to use them.

If you use white glue (such as Elmers or Eileens Tacky) you will have to wait overnight for each joint to dry, plus if you use a lot of water in your weathering process the glue may soften and the joint may fail. That's bad.

I think most yellow "carpenters" glues are waterproof but you'll still have to wait over night for each joint to dry. I just don't have that much time. : )

ACC "super glue" will work, IMO however, it is not the ideal glue for hydrocal because the hydrocal is so porous. Sure you could use gap filling super glue or prime the castings before hand but that just sounds like too much work for me. The other thing is, for me anyway, is that super glue always seems to "go off" or set just as the wall wiggles and it's crooked. It's all or nothing w/ACC.

So I use 5 minute epoxy, and mix up very small batches and do one wall at a time. That way it gives me a few minutes to make sure my wall is straight, true, and where I want it, but by the same token, in 5/6 minutes I can move on to the next wall and get that one up & in place. Usually within 30 minutes I can have the basic building glued together and I can move on to the painting.

This is important. Unlike wood, cardboard or even plastic, hydrocal has no bend or give. You can't bend or "tweak" any of the parts into place. So if somewhere along the assembly process you were off by a bit, when you get to gluing the last wall in place you won't be able to "squeeze" it into place. You'll have to either do a bit of sanding to get the part to fit, or, if you somehow ended up with a gap, fill or disguise it. No biggie, it's just something to be aware of.

Because you will sometimes have to sand a bit of the edge of the last wall to get it to squeeze into place, I always have you assemble the castings in a certain order, with the wall least likely to be seen by your viewers (usually, but not always, the back wall) to be the last to be put in place. That way if it's less than perfect at least it's not staring you right in the face on the front of the building.

OK. I'll update this later today or tomorrow w/pictures. Let me know if you have any questions.

Randy Pepprock
Downtown Deco
Dioramas Plus
 

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Discussion Starter #8
Part Three (continued).

When I glue my castings together I try & not have any squeeze out onto the "outside" of the model where it will show. The easiest way to do that is to not put the glue right next to the very edge of the castings. Leave yourself a little "squeeze" space in case some of the glue wants ooze out of the joint. In this case I have marked w/a blue marker where the glue should go.



Only mix up a tiny bit of the epoxy at a time. Here I've mixed it up and added my first wall. I used a piece of styrene to make sure the side wall was "square" w/the front wall. I propped it up w/a roll of tape & "babysat" it for a couple of minutes to make sure the wall stayed where I wanted it.



Next I added the other side wall.



When I test fit the rear wall I found that I needed to remove a tiny bit off of each side to get the part to ease into place. Remember, do not try & force the part into place. You will break it. I gave it a few swipes with a sanding block & then glued it into place. You don't need to worry too much now about any small gaps or seams, if you've got them we can deal with them later in the build.





Finally, I carefully cut & test fit, and then hot glued in a few scraps of cardboard to add strength to the structure.



OK, on to everyones favorite subject, "To seal or not seal hydrocal parts before you paint them". Fasten your seatbelts....: )

Randy Pepprock
Downtown Deco
Dioramas Plus
 

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Discussion Starter #9
Step Four. Sealing/priming the castings.

Ah, "to seal or not to seal...".

First, there is not a right or wrong way to build models or enjoy our hobbies. What follows is strictly my opinion based on painting hundereds of hydrocal castings;

I always recommend at least "sort of" sealing plaster castings to remove some of the porosity. Perhaps "priming" would be even a better word than sealing. I use flat white spray paint. A couple of light coats. That way when you apply either your paint or stain it will flow on more naturally and evenly than if you applied it to raw plaster. It allows you to get a smoother looking, more even tone to the base coat. You also have a little bit of time to "work" the color. You have less of a chance of the color coming out too intense or dark as well. Finally, when your painting/staining is all done, you can ever so lightly "buff" the surfaces with very fine steel wool or polishing sandpaper to make all of the details and highlights "pop out". It's sort of like dry brushing but instead of adding paint you're taking just a tiniest bit of paint off the tops of the high points. It really "makes" the model IMO. Understand that I'm not saying to seal the plaster so that is like plastic or resin, but rather, just enough so that each and every brush stroke does not get soaked in instantly.

Not sealing the castings, IMO, increases the risk of the following happening: A blotchy looking, uneven finish that looks "brushy". It also increases the chance that you'll end up with "solid looking" dead toned walls, rather than richly toned parts that look like they have natural age, patina and years on them. You don't have any time to "work" the color you're adding, as each and every brush stroke is soaked in instantly. True, you can "build up" colors, one thin wash at a time, but you can do that ever better when the castings are sealed because you can control it so much better. Also, unsealed you have to wait long periods waiting for the castings to completely dry so you can see what the actual color looks like. Sealed you can put a fan or hair drier on the parts & see what you've got in a few minutes.

I've tried both (sealed & unsealed) & IMO sealed works best and give you better results. Tom Yorke & CC Crow have recommended sealing hydrocal castings in the past as well, and both of those guys have slung their share of plaster over the years.

I think that usually (and I could be wrong) is that the guys who swear by unsealed castings have not ever actually tried to paint/stain sealed castings before. It sort of goes against their natural intuition. I mean, why take one of the unique proprties of hydrocal away? After all, isn't that what makes plaster parts look so cool? Again, IMO, not entirely. Usually what makes a plaster kit look so much more realistic is the original, hand carved master patterns.


Randy Pepprock
Downtown Deco
 

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I may be getting ahead in the questioning, but if you're sealing to prevent top-coat paint from "soaking in too quickly", does that presume that you're topcoat paint will be a thinned watercolor (as opposed to thicker oil-based)? Or will any paint soak into the plaster if it isn't primed?

Thanks,

TJ
 

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Discussion Starter #11
Yes, I use water based acrylics. And yes, any paint (oil or not) will soak in instantly to unprimed hydrocal. As it is, even with a primer, the hydrocal is 100% more porus than plastic or resin. So you'll still get a good, flat finish.

Randy

I may be getting ahead in the questioning, but if you're sealing to prevent top-coat paint from "soaking in too quickly", does that presume that you're topcoat paint will be a thinned watercolor (as opposed to thicker oil-based)? Or will any paint soak into the plaster if it isn't primed?

Thanks,

TJ
 

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Discussion Starter #12
OK, let's get some color on this thing! First off I gave it 2 or 3 medium/light coats of flat white primer. I used Krylon primer but have used other regular non primer flat white spray paints with good results too.



I let it dry for an hour or so (over night is even better) & then got out my first two colors. I prefer a more "orangish" brick color, so I used Folk art Terra Cotta # 433 as my base. This is a cheap acrylic craft paint. Apple Barrel and Cermacote are similar brands & have similar colors.

I used a scrap of cardboard as a pallet, a .49 "chip" brush & some water to lay this first color on. I did it dirty, wet & quick. the most important thing is to not put the paint on too thick (unthinned it's almost as thick as Elmers glue) and that your brush strokes all end up going vertical rather than horizontal. I'd say I had the paint thinned about 75% or so.

I paint the whole thing, rather than trying to dinky bob around the details with a small brush. I've found that if I try & do it that way the structure can look "brushy" rather than having a nice, even tone to it. Make sure you get all of the cracks and crevices of the windows, door jambs and trim. you don't want any white showing. Also paint a bit around the inside of the top of the building to get a little color on that as well. The whole thing took about 5 minutes. The paint is still wet in this picture.



I also used a bit of Raw Umber to "break it up" a bit. Here's where having the castings primed really works to your advantage. Because each and every brush stroke does not soak in instantly, you can "move the paint around" a bit, and add more paint if needed, or scrub it off with a little water if you got it on too thick. Again, vertical, not horizontal.



Note. I used Raw Umber # 485, not "Real Black" as shown here. I just grabbed the wrong bottle when I shot the photo.

OK, I know it doesn't look like much yet, but this is the basic start. Onto the trim & other details next.

Any questions or comments from the class?

Randy Pepprock
Downtown Deco
Dioramas Plus
 

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Discussion Starter #14
Yes, sort of. Actually I will next use Poly S Concrete to get a start on those details (which is pretty light) but I'll cover that in the next installment.

Randy

I assume a darker color will cover over the lintels and such later? (I.e., no need to mask them off here?)

TJ
 

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Discussion Starter #15
Next I painted the concrete & stone sections Poly S Concrete color. I like the Polly S for this because it covers and flows on well.



I then masked off the tile section on the pawn shop...



...then misted it first with the flat white primer spray paint...



...then when that was dry I spray painted it Krylon3509 Jade Satin.



I then masked off & spray painted the "Marble" on the liquor store flat black. Satin or even a slight gloss would have been better but I didn't have any on hand & was to lazy to run into town & get it. : )



I spray painted rather than brush painted the tile & marble sections because it would be smoother & introduce a new finish or texture into the building.

We're getting there. Once we get past these basic undercoats we're really going to start to get the fun part.



Questions or comments are welcome.

Randy Pepprock
Downtown Deco
Dioramas Plus
 

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Randy ...

Starting to "pop" quite nicely. Concrete color on the lintels and such looks very good. Maybe rub in a little thinned-black (or darker gray) into those stone mortar joints, and rub it off all of the high spots?

TJ
 

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Discussion Starter #17
Yeah, we're getting there. There's about 3 or 4 more simple steps to go yet. Will post more in a day or so. Have to get a big Dioramas Plus order off to our new Japanese distributor first though. Thanks for following the thread.

Randy

Randy ...

Starting to "pop" quite nicely. Concrete color on the lintels and such looks very good. Maybe rub in a little thinned-black (or darker gray) into those stone mortar joints, and rub it off all of the high spots?

TJ
 

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Discussion Starter #18 (Edited)
Someone asked this, which I thought was a good question;

"So, you start off with a light brick color "wash". Why so light and transparent? "

I responded;

"Good observation. I believe in something I call "scale color". Which means that the farther away from something you are, the lighter it gets (to your eyes).

Stand right in front of a brick wall. It's dense and dark and a fairly solid color. This is the color most modelers choose when painting a brick model.

Now stand across the street from the building. If you're honest the color should appear lighter. Now stand a block away. Lighter still. Look at building in the distance. Even lighter. Whether it's the haze or atmosphere or whatever the farther away something is the lighter it looks.

In most cases the closest a building will be on a model RR may be about an arms length away. That's what, 300 or 400 "Scale" HO feet away? So IMO the colors should be lighter.

As I weather this it will get darker too. But if you start too dark you have nowhere to go but darker if you want to weather it & show age. So I start light."
 

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Discussion Starter #20
I did not mask off when I painted the concrete. I used a med/small cheap o hobby brush. It was actually pretty easy because of the detail in the castings & the paint covered well.

When you painted the gray concrete color - what kind of brush are you using? Did you mask prior to painting that as well?
 
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