Help wanted: How to make look plaster like old concrete

[finescalerr]

Not perfect? It's a perfect replica of imperfection! And, I should add, an excellent representation of concrete. -- Russ

[mad gerald]

*DANG* ...  ... now THIS looks the part!

Sorry it took so long to get back to you, but was trying to find the correct photos...no luck ...

... nevermind ...

...did fined these of a 1/35 "Panzerturm" build....its not perfect, but maybe of some use.

The concrete here was made by casting plaster (Hydrocal) into a wooden form made of strip basswood, to give a "board form" texture. Once the plaster was set (not fully dry...it was still cool/damp to the touch), the forms were removed. Some of the plaster stuck to the forms and caused a "spalled" look to the surface in areas. I then came in with a Micro-Mark wire pencil, and dabbed/stabbed at the surface to create pitting/texture, and represent damaged, poorly cast/poured, or decaying surface areas.

Once this was completely dry., I used very diluted Floquil "Aged Concrete" and old dirty Floquil paint thinner, to stain the surface.  This same effect could be achieved using highly diluted Vallejo acrylics.

... thanks for your efforts - very much appreciated!

I'm gonna try the technique you described, first with the plaster I bought (may be the wrong choice: it's called "modelling plaster" and has a very even surface and is brilliant white) and if I fail, I'm gonna get me some Hydrocal, which seems to have quite a different consistency and texture ...?!

Have located a local dealer which stocks this, which I guess must be familiar?

http://www.conrad.de/ce/de/product/210203/Spachtelmasse-Lightwight-Hydrocal-900g

Cheers

[marc_reusser]

Gerald,

I don't believe the Hydrocal is light-weight. The product I use is from a company called Woodland Scenics.

M

[mad gerald]

I don't believe the Hydrocal is light-weight. The product I use is from a company called Woodland Scenics.

... umm, well .. this item mentioned in my link above IS from Woodland Scenics ... just wondering now ... even when I visit Woodland Scenics' website http://woodlandscenics.woodlandscenics.com/show/category/TerrainFormation, they show a picture of their Hydrocal with the addition "lightweight" on top of the package ...  

Cheers

[marc_reusser]

Sorry.....didn't check the link because I was onmy phone. Yes, that is what I used....didn't recall that it was lightweight.

[Scratchman]

Here's another sample of old concrete.



Gordon Birrell

http://www.flickr.com/photos/77318580@N00/

[mad gerald]

G'evening all,

at first I'd like to thank you all for your input - really appreciate this forum and its members ...  

Even I did not manage neither to get Hydrocal yet, which is available over here, but IMHO fairly pricy (about EUR 11,50/kg) nor to get Floquil colours, which are really hard to get (only one online shop with a delivery time of approx. 3-4 weeks), I started another attempt:



To get rid of the bright white of this modelling plaster I put quite a dose of coffee in (not joking) and removed the stripwood boarding a while before the plaster was set completely (still damp), but only a little plaster kept stuck on the stripwood boarding. Nevertheless this time I got some structure. I used a toothbrush (not having a Micro-Mark mini brush with brass bristles) dabbing and stabbing the surface to get some more structure.

Umm, well ... it worked so far ... curious if the colouring will turn out satisfactory this time ...

Cheers ... and Happy Easter      

[nk]

Gordon, The texture is crucial, and goes 90% of the way to making your concrete look right. I use very dilute washes of all different shades of both oil and acrylic paint as well as very dilute India ink. Repeated application of the dilute washes will give good results. Also I have found that the plaster will absorb the diluant on the paint almost immediately giving a hard edge to the wash. What I do to counteract this is to apply a lot of solvent to saturate the plaster first, then applly the wash and you will find that the edges of each application blend nicely. I have not had any problems with the plaster and paint acting like a chromatography experient, which is a relief!

Narayan

[mad gerald]

G'evening all,

your help ... and the circumstances, I finally managed to get hold of Floquil/Polly Scale colours and a box of Hydrocal ... enabled me to give this modelling technique another try.

I've got some plaster test objects on the left (including the big one in the background), precoloured with a shot of coffee, and 2 Hydrocal test objects on the right. During the first attempt I was not patient enough to apply various layers of thinned Floquil/Polly Scale and common water colour (objects in the background and second row). Then during the second attempt I used the same colours, but highly thinned and in several layers.

To achieve more structure on the surfaces I followed Marc's suggestions and removed the stripwood boarding while plaster/Hydrocal where still damp and used a wire brush to intensify the structure.

Compared to common plaster the Hydrocal seems to be less heavy, but more fracturable ... may be, I did not mix it precisely enough ...    

At least IMHO the results show - as Russ would like to say  - a noticable improvement ... I hope so ...



Cheers

[finescalerr]

A successful experiment. -- Russ

[marc_reusser]

Based on the photo, I like the coloring/finish of the one on the far bootom right the best. They all seem to have too much tan coloring to them (they look more like a limestone than concrete)...A warm grey with hints of tan is good...they just seem too tan. The middle left and right ones look to opaque and "painted" to me.

Though the color is too tan for concrete, I think that the effect you achieved on the large piece is intersting for an application such as old plaster  building walls...like those that can be seen on old buildings in many European villages, especially Italy, Spain and France.


Marc

[Malachi Constant]

Looking good ... while I agree with much of what Marc said ... here on the east coast of the US, I've seen ALL of those shades of concrete!  It's a more humid (wet) environment here ... with more rainfall and lingering dampness than found out west ... so concrete is discolored by all of the organic materials falling from trees and plants, plus wet soil, molds (fungus, not the molds we use to make castings!), etc, etc.  So depending on the specific location, the surrounding vegetation and how much sun exposure a specific area gets, any/all of those colorings can be found here.  I've traveled in Germany a bit, but I didn't really study the sidewalks there!  (In Paris, however, I did notice that people are rather relaxed about letting their poodles "decorate" the sidewalks.  Damn poodle people!)   -- Dallas

[granitechops]

Here's another sample of old concrete.



Gordon Birrell

http://www.flickr.com/photos/77318580@N00/

Gordon any idea how old that culvert is?

very interesting shaping on the back face almost in the style of wood panelling
Why would anyone go to that trouble to get that effect? unless he was an old stone mason in a new trade carrying over his pride in his work?


Sorry for the intrusion Gerald, following your thread with interest
photo showing texture that I acheived on concrete path under building,
colour doesnt show up well I am afraid

[mad gerald]

Sorry for the intrusion Gerald ...

... no problem, Don ... 

... A warm grey with hints of tan is good...they just seem too tan ...

... may be, my approach was wrong ... I'd better start with a warm grey, followed by some highly thinned layers of tan - instead of the other way round ...  

So I definitely have to raise my supply of acrylic colours, especially Vallejo acrylics ... suggestions? Smoke? Black grey?

Cheers

[Ray Dunakin]

I've been wondering about that culvert too. It's pretty fancy for a culvert, and it looks like the pinkish parts have been painted or stained.