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Plaster rocks

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Plaster rocks
Posted by SD Fan on Tuesday, January 20, 2009 8:04 PM

What would be better to make plaster rocks out of  those woodland scenics molds, hydrocal or scuptamold?

The only thing we have to fear is fear itself, or maybe ballasting some track.
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Posted by ARTHILL on Tuesday, January 20, 2009 8:39 PM

I use Plaster of Paris. It is cheaper than Hydrocal and I like the texture. I have not tried Sculptamold because I couldn't imagine it working well.  Seeing I am now carving most of my rocks out of styrofoam, I will stick with P of P for what I do.

If you think you have it right, your standards are too low. my photos http://s12.photobucket.com/albums/a235/ARTHILL/ Art
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Posted by twhite on Tuesday, January 20, 2009 11:22 PM

Actually, and with all due respect to my buddy Art, Sculptamold can be used well in rock molds.  The trick is to mix it 50/50 with water, making it a 'soupy' mixture, then pouring it into the molds.  It has to set longer in the molds than plaster or Hydrocal, but during that time, the plaster grit that makes up part of the Sculptamold mix itself, settles into the mold crevices.  It's a slower method than plaster or hydrocal, but I use it out here in California, because the dry climate in my area makes Hydrocal set up way too fast, and Plaster of Paris turns out to be too heavy for what I need.  Sculptamold, being a maiche type material is lighter than plaster, just a little heavier than Hydrocal, and takes enough time to set up that after you've pressed the mold into the portion you're working on and peeled it off (total time from pouring to pressing to peeling is about 25 minutes) you have a nice gritty texture that will take additional carving very well. 

Here's part of the Sierra Buttes I'm working on.  95% of what you see is from Sculptamold castings blended with Cripplebush rocks. 

I like Sculptamold. 

Tom Smile

 

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Posted by Don Z on Tuesday, January 20, 2009 11:59 PM

With all due respect to my buddy Tom, I prefer to use White Art plaster. It dries to a pure white color and has a much finer finish texture compared to Plaster of Paris. It also takes washes of color very nicely, can be carved once applied and it sets in a moderate amount of time. Here is an example of my rockwork that was created with homemade latex molds:

Don Z.

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Posted by MisterBeasley on Wednesday, January 21, 2009 6:59 AM

With all due respect to my buddies Don, Tom and Art, I like Hydrocal.  The very fine grain brings out the details of the mold.  That's not such a big deal with the low-resolution Woodland Scenics molds, but this one is from Dave Frary.  Just to be difficult, I waited until the Hydrocal was almost set up, and then curved the mold around a form to get a curved wall:

After cutting down the casting, painting and weathering, I ended up with this"

More recently, though, I've started using Bragdon Foam.  This isn't a great picture, but I'm really impressed by the quality of the castings you get from this process:

Bragdon Foam is a 2-part resin mix.  It's very labor-intensive, unfortunately, but the results are very good.  The Bragdon molds themselves are very high quality, and the casting resin brings out all the small details.  www.bragdonent.com if you want to check their web site.

 

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Posted by jacon12 on Wednesday, January 21, 2009 7:24 AM
With all due respect to Art, Tom, Don and Mr. B.... they all look great! :)
 HO Scale DCC Modeler of 1950, give or take 30 years.
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Posted by bogp40 on Wednesday, January 21, 2009 6:43 PM

I tend to have the best results using Hydrocal. Whether casting a production mold or custom, using Hydrocal has allowed me the most versitility for cutting, carving or curving the final result. I will always color the plaster with powdered masonry dyes to eliminate any white chipping to show from any future abuse.

This spot was done with simple molds for pouring the stepped sheets, cut, carved sanded for fit

Fitting of the pieces

Finished area

This spot was done w/ Woodland Scenics production molds

Mant times slabs of colored Hydrocal are used as starting stock to rip/ cut on a bandsaw and glue in place for retaining walls, pilasters and caps.

Wetting the dried plaster allows for ease of shaping or carving.

Modeling B&O- Chessie  Bob K.  www.ssmrc.org

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Posted by BlueHillsCPR on Wednesday, January 21, 2009 7:26 PM

The rock work all looks really good and I can't tell the plaster from the sculptamold, from the hydrocal, etc.

In regards to cost, I have heard that Hydrocal, if purchased in a large sack from a building supply company is much cheaper than when purchased in boxes through a hobby or craft shop.  I haven't tested that theory myself though.

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Posted by DeadheadGreg on Wednesday, January 21, 2009 9:02 PM

hey bog, do you happen to know which WS rock mold you used in the last 2 pictures, specifically the 2nd to last, for the one over the tunnel portal?  THAT is the type of rock I need for my layout.

PHISH REUNION MARCH 6, 7, 8 2009 HAMPTON COLISEUM IN HAMPTON, VA AND I HAVE TICKETS!!!!!! YAAAAAAAAY!!!!!!! [quote user="jkroft"]As long as my ballast is DCC compatible I'm happy![/quote] Tryin' to make a woman that you move.... and I'm sharing in the Weekapaug Groove Wake up to find out that you are the eyes of the world....
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Posted by bogp40 on Wednesday, January 21, 2009 11:36 PM

DeadheadGreg

hey bog, do you happen to know which WS rock mold you used in the last 2 pictures, specifically the 2nd to last, for the one over the tunnel portal?  THAT is the type of rock I need for my layout.

Greg,

Not sure off the top of my head. Been a few years since I did the double portal. That mold is a favorite of mine and I try not to use it too much as the detail of the casting does stand out. Next time I'm at the club I'll locate the molds and see what # it is. I do remember it is somewhat rectangular and a single digit. I have seen it quite often at stores and shows so it is popular.

Modeling B&O- Chessie  Bob K.  www.ssmrc.org

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Posted by loathar on Thursday, January 22, 2009 11:49 AM

For rocks, plain old plaster o paris. Cheap and it takes stain well. I tried Sculptimold, but found it doesn't stain/paint as well as PoP.

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Posted by Gary UK on Thursday, January 22, 2009 1:14 PM

I know exactly what one that is, got it myself and i can recognise it easily. Il have a look and report back later!

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Posted by Grampys Trains on Thursday, January 22, 2009 2:56 PM

Hi: Greg, that might be layered rock, C-1241.

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Posted by mechengr on Thursday, January 22, 2009 3:27 PM

Just my 1/2 cents worth -

 I'm in the same thinking as Loather on this at this time. I've had very little success with either Sculptamold or Hydracal actually taking stains very well. I think one must be good at painting Sculptamold or Hydracal to have the appearance of rock (the pictures do show such ability). Stains just don't do the job for me and my efforts at painting, (as opposed to staining), have not been accepable to me.

Richard

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Posted by Gary UK on Friday, January 23, 2009 11:59 AM

Grampys Trains

Hi: Greg, that might be layered rock, C-1241.

Thats exactly what i make of it too!

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Posted by loathar on Saturday, January 24, 2009 9:51 AM

mechengr

Just my 1/2 cents worth -

 I'm in the same thinking as Loather on this at this time. I've had very little success with either Sculptamold or Hydracal actually taking stains very well. I think one must be good at painting Sculptamold or Hydracal to have the appearance of rock (the pictures do show such ability). Stains just don't do the job for me and my efforts at painting, (as opposed to staining), have not been accepable to me.

I bought some WS cast walls and portals that were supposed to be hydrocal. They took stain really well. But they weren't light and broke really EZ. I wonder what they're REALLY using to cast those?

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Posted by twhite on Saturday, January 24, 2009 10:32 AM

mechengr

Just my 1/2 cents worth -

 I'm in the same thinking as Loather on this at this time. I've had very little success with either Sculptamold or Hydracal actually taking stains very well. I think one must be good at painting Sculptamold or Hydracal to have the appearance of rock (the pictures do show such ability). Stains just don't do the job for me and my efforts at painting, (as opposed to staining), have not been accepable to me.

Richard: 

I'll agree with you that Sculptamold does not necessarily take staining well.  Though I've found that if you give it a base stain while it's still drying, it will saturate in a little better.  Actually, to get the color I was looking for on the Buttes, I gave the Sculptamold (and the Cripplebush mixed in) a light gray latex base from a spray can, then over-colored it with thinned tan and earth stains.  Then I used Bragdon weathering powders applied with a Q-tip for highlights.  

Not using Hydrocal, which as I previously stated sets up too fast in my climate to really work with successfully, I can't speak for how it takes a stain. 

But perhaps Don Z can chime in here with how his Art Plaster takes stains.  From his photo, it looks as if it does very well. 

PS:  Don, how heavy is that Art Plaster?  As I've told you before, I really like the results you get!

PPS:  Bob K:  That's some BEAUTIFUL rock-work! 

Tom Big Smile

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Posted by selector on Saturday, January 24, 2009 11:03 AM

I have used the WS moulds with both hydrocal and PoP.  Both turned out well, but I would rate PoP a bit more friable and easily damaged.  Hydrocal is the harder of the two to paint.

-Crandell

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Posted by Grampys Trains on Saturday, January 24, 2009 5:59 PM

Hi: I would be in the hydrocal camp. I made my rocks with WS molds and hydrocal as separate pieces. Then i applied them to the layout with Sculptamold/Structolite mix. I colored them using Dave Frary's method in his modeling the Pennsy Middle Division book. I applied, (spray or brush) an alcohol/ink wash as many times as necessary. Then a thinned brown latex, followed by more alcohol/ink before the brown dried. When I got the color I wanted, a final dry brushed light gray, almost white, was applied. These represent rock color found in Pennsylvania.

 

 

 

 

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Posted by SD Fan on Saturday, January 24, 2009 6:22 PM

Wow. Those are some nice rocks. Some to the best I have seen.

Well, i went ahead and bought some hydrocal today. My first set of rocks are setting now. Hope it turns out all right.

The only thing we have to fear is fear itself, or maybe ballasting some track.
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Posted by DeadheadGreg on Saturday, January 24, 2009 6:26 PM

ugh, will you just get your layout in Model Railroader and be done with it already?

 

jeez...  some people....

 

 

hahaha you know i love you man. 

PHISH REUNION MARCH 6, 7, 8 2009 HAMPTON COLISEUM IN HAMPTON, VA AND I HAVE TICKETS!!!!!! YAAAAAAAAY!!!!!!! [quote user="jkroft"]As long as my ballast is DCC compatible I'm happy![/quote] Tryin' to make a woman that you move.... and I'm sharing in the Weekapaug Groove Wake up to find out that you are the eyes of the world....
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Posted by Grampys Trains on Saturday, January 24, 2009 7:56 PM

Hey, thanks guys. I might consider that when MR starts accepting photos uploaded from Photo Bucket, instead of having to jump through so many hoops, like they do now. I also don't know anyone on MR's staff, so my chances would be pretty slim.Big Smile

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Posted by loathar on Saturday, January 24, 2009 8:11 PM

DeadheadGreg

ugh, will you just get your layout in Model Railroader and be done with it already?

Yep! Every bit as good as any Trackside Photos pics I've ever seen!

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Posted by Don Z on Saturday, January 24, 2009 9:25 PM

twhite

But perhaps Don Z can chime in here with how his Art Plaster takes stains.  From his photo, it looks as if it does very well. 

PS:  Don, how heavy is that Art Plaster?  As I've told you before, I really like the results you get!

Tom,

The White Art plaster is a lighter weight member of the Hydrocal family. It cures out to 2000psi strength and it takes washes of color very well. Here is a link to some information provided by the company that sells me the plaster:

http://armadilloclay.com/rawmaterials/plasters.html

I have made identical molds from Plaster of Paris and the White Art plaster. The Plaster of Paris casting was noticeably darker than the White Art plaster casting. The Plaster of Paris casting also lost some of the fine details that were in the mold.

Don Z.

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Posted by Gary UK on Sunday, January 25, 2009 4:59 AM

Grampys Trains

Hey, thanks guys. I might consider that when MR starts accepting photos uploaded from Photo Bucket, instead of having to jump through so many hoops, like they do now. I also don't know anyone on MR's staff, so my chances would be pretty slim.Big Smile

Its pictures like those that make me want to smash mine up, stunning work man!

They should put it in MR, thats alot better than some of the stuff i see in there!

Ive been looking at Bragdons method of covering all your rock work with Geso first, that way i figure that any cast material will take stain//color?

Im still undecided but i may give this method a go.

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Posted by twhite on Sunday, January 25, 2009 12:41 PM

Grampys Trains

Hey, thanks guys. I might consider that when MR starts accepting photos uploaded from Photo Bucket, instead of having to jump through so many hoops, like they do now. I also don't know anyone on MR's staff, so my chances would be pretty slim.Big Smile

Grampys: 

So jump through the hoops, already!  Big Smile

Seriously, your modeling is an absolute INSPIRATION!   I for one, would love to see you featured in "Trackside Photos" in MR--I don't think I've ever seen a photo of yours that isn't downright marvelous!Bow

Tom Tongue

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Posted by Grampys Trains on Sunday, January 25, 2009 2:32 PM

 Hi: Thanks Gary and Art. Gary, you may have to experiment a little till you get the look you want. I have at least 30 or 40 rock castings that are buried because they just didn't look right to me. Persistance finally paid off. As to MR, now that I've cut my working hours and have more time, I just may pursue sending in a few photos.

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Posted by HOJason on Sunday, January 25, 2009 3:15 PM

Would you mind sharing your secret of how you blend one rock casting together with another one when they are set on the hillside.  I'm having a hard time trying to put plaster between the rocks to hide the seams between one and the other.  Thanks, Jason

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Posted by Grampys Trains on Sunday, January 25, 2009 3:37 PM

Hi: Sure thing Jason. First, I dry fit the castings. If they don't fit the way I want them, I make them fit, break, saw,etc. I use a Sculptamold/Structolite mix for all my scenery. For rocks, I slap a big gob of the mix on the surface where the rocks are going. Then I spray the back of the casting with wet water and apply a gob of mix to the back of the casting. I try not to get any on the face of the casting. Then I push the casting into the mix with a twisting motion. When its in place, some of the mix will squeeze out. I use a small artist's trowel to scrape off the excess. Then, I use the same trowel to smooth the mix around the casting and fill any gaps. Finally, I use a #4 artist's brush to smooth the joint between the casting and surrounding terrain. Hope this helps.

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Posted by HOJason on Sunday, January 25, 2009 10:09 PM

Grampy,

 Thanks, that was the advice I needed.  I built a wall this weekend by hot glueing the pieces to the plaster shell.  Then to fill in the gaps, I sucked up a soupy plaster mix through a straw and blew it into the small crevices.  It ended up looking like cake icing between the molds.  I'll have to start again, but this time it sounds easier than my previous attemp and as you have shown, much better results.  Thanks for the advice. Jason

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