Clay, Application to Refinement


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The frequently asked questions page will deal mostly with questions that are asked on the forum. I will place the most relevant questions that relate to the construction of the scale model here so that the answers are readily available. 


This will hopefully encourage newcomers and novices to participate in discussions regarding the techniques and methods involved in the construction and clarify any uncertainties that you may have.



With regards to the 1/5 scale corvette model, how many hours do you think you will have invested in the project?

Basil P.


Hi Basil,

To answer your question first, if the model was going to be constructed with all the drawings provided it would probably take approximately 3 to 5 weeks of continuous work i.e. 200-300hrs.

I will probably have between 500-700hrs due to working on the project as a part time basis. It is difficult to estimate the amount of time as I am trying to update the website at each stage. I normally have several things going at the same time, model armature, tools, wheels and jigs, so you can see it is a long term process at the moment.


And how much clay ?
Is there any way to calculate how much clay you need for a project ?
I'd like to make a 1/4 model. I don't know how much clay I need....
I know it depends on the design I choose, but it could be good to have an average idea for each scales...
See ya


OK Seb, the answer to your question.

The amount of clay that is used on a project will vary depending on the scale that you use. On the Corvette project (1/5 scale) I will probably use between 60-100lbs (27-45Kgs) This is because the shape is already determined, the vehicle is already a production model.

The buck for the model can be made close to the finished article. I will probably make the buck 1 inch (25mm) undersized, this will give a thickness of clay that should be stable in my garage environment. Any clay scrapings can be re-used providing there are no contaminates.

If a design is being developed then you will use more clay due to design changes. You would probably use 50% more clay.
If you are going to build a 1/4 scale model Seb, you will automatically need more clay due to the larger scale. I would guess that you would need approximately 100-170lbs (45-77Kgs) This will allow for numerous changes providing that the model armature is reasonably close.

You may find that I have over estimated the amount of clay but I would hate to run out of material before completing the project.


Ok Steve,
for the moment I just have 1.3kg of Chavant Y2Klay.
Only 1.3 kg because I wanted to feel the product and see if it's good for me before to order more.

I know Y2Klay is 40% lighter than other clays at the same volume, so does it mean it will take me 40% less weight than the quantity you said for my project ?

Do you think Y2Klay is a good clay to hold small details and acute edges, even with a 1/5 scale ?

For the moment, I have problems to keep my straight edges and fine details with the Y2. But it seems to be a hard Klay so...
Maybe I need to "approach" my designs with clay modeling as close as possible, without being worry about small details.
And then to apply a hard coat of gel coat ( or what kind of product ? ) to be able to "sculpt" it and sand it for perfect edges and small details in this more hard "compound" ?

If this is the way to hold fine details , I will consider to do a 1/5 scale instead of a 1/4.
What do you think ?
Thanks again for your help. Seb


Hi Seb,

Yes, the model would be that much lighter if you use Y2Klay. The amount of clay used would be the total volume, so basically it would take 2-3 boxes of clay at a guess of any of the Chavant industrial clays available.

Check their distributor list for a supplier closest to your location for the best price.
Below is a list of industrial clays available through the Chavant website.
If you have no luck, contact Chavant direct, they are very accommodating.

To retain detailed edges and sharp lines, it takes practice and will come automatically over time. On detail lines you can use masking tape to hold the edges crisp while you model up to the line. Also you can insert various thicknesses of fishing line along detail lines or around features to retain the edges.

Most of the hard styling clays are suitable for detailed work. If you are going to have super high definition then you may have to insert a separate piece into that section of the model. This is commonly done for head lamps and tail lamps. The lamp clusters are completed in a more suitable material then inserted as a separate piece.

As far as what scale to use, the smaller the scale the more you have to "cheat" to obtain a visually correct model. The smaller scales when increased to full size need more refinement due to the scale factor.

The trade off on a smaller scale model is that you are using less material and the model is that much lighter than a larger scale model. You also need less space for the project i.e. garage.

Hard Styling Clays (Standard)

CM-50: A "medium hard", dark brown formulation, considered the softest of the Hard Styling Clays.
J-525: A "hard" light brown formulation.
CM-70: An "extra hard" dark brown formulation.

Billet (cylinder) or Block Size Approximate Block Dimensions Net Case Weight
2 lb. Blocks 2?" x 2?" x 5" 50 Pounds
5 lb. Blocks (CM_70 only) 4?" x 4?" x 5?" 50 Pounds
10lb. Blocks 4?" x 4?" x 11" 50 Pounds
2? lb. Billet 2?" x 12" 50 Pounds
3 lb. Billet 3" x 8" 60 Pounds

Hard Styling Clays (DeAired)

These "extremely hard" formulations are the firmest of Chavants Hard Styling Clays. Entrapped air is removed making the clay more dense, smoother and ideal for achieving fine extrusions.
DeAired CM-50
DeAired J-525
DeAired CM-70
P-40: A SULFUR FREE. The hardest styling clay we produce that can be melted and poured. P-40 has a reduced working temperature requirement (115?). Higher wax concentration provides greater resistance to model cracks. Available in brown (natural color variations may exist in P-40).
I-307: Reduced sulfur content and reduced working temperature requirement (120?). Higher wax concentration provides greater resistance to model cracks. Hard but softer than I-305.

Billet (cylinder) Size Approximate Billet Dimensions Net Case Weight
2? lb. Billet* 2?" x 12" 50 Pounds
3 lb. Billet 3" x 8" 60 Pounds
6 lb. Billet 3" x 16" 48 Pounds
*(Special order only. 2500 Pound Minimum.)


The same high level of quality expected from Chavant is incorporated into this new formula. Y2 Klay offers the consistency, adhesion, cohesion and surface development Characteristics found in Chavant clays since 1892.
Billet (cylinder) Size Approximate Block Dimensions Net Case Weight
1.75 lb. Billet 2?" x 10" 35 Pounds


Hello, I'm new to modeling with clay. I have tons of clay but no skill whatsoever with shaping and sculpting it. (it is much harder than it seems, for me anyways) Would someone like to help me out. Like tell me the process of building a clay model. I have the dimensions of a 1/18 scale model of my own design. Would someone tell me how I go about doing this?? I know I make a template background of the basic shape of the car to work off of. Anything important? How do I get it ready for paint?

Thank you very much for your time!!!


Hi fastback33,

I'm all for jumping in the deep end but first let's check to see what you have learnt to do this job. There is a lot of information on this forum from other participants, also the website covers a lot of information as to the type of tools required. First checkout all the postings, there may be information that you can use to get you going, next read the information on my website, use the content page to navigate.

For the size of scale model that you are making, the amount of tools will be minimal. A couple of small scrapers can be made from silverware ( see Finishers Unique on the website) You will also need a couple of steels to obtain a good surface finish. You might be able to get the steels from your local art supply, such as Kemper tools.

The technique section of the website is still in progress at the moment so once I know that you have some tools to get your job going we'll get into the actual process of making the scale model.

I need to know what tools you have to do the scale model so that you can be guided in the right direction. By making or buying the tools to do the model you are automatically thinking about the end result.

Let me know what tools you have and we'll go from there.


Steve, I have everything I will need, except steels, which I believe I can make on my own. Sorry about not searching the site, but I have been turning the internet upside down trying to find help with this. But thank you very much for wanting to help me out!!


Checkout the illustration that I've created using your model information. The first thing to do is to make a modeling platform from 3/4" plywood. The size should be about 4" bigger than the finished model on all sides. This will allow you to work the model and still have grid lines visible for duplication. Mark-out the board with a suitable grid, such as every 1" or 25.0mm, marking the center line of the board first then grid either side. Then mark the grid for the length of the board next.

Make a plywood plinth that is as long as your distance for the wheel centers (wheel base). The width should be as wide as the inside of the tires. This allows for the wheels to be butted up against the wooden plinth during modeling and the length will not interfere with any ground plans, front and rear. Fix the plinth to the modeling platform with double sided tape. This will allow you to remove the model when you are finished.


When you have this process complete, glue your foam and clay block on top of the wooden plinth using a 5 minute epoxy mix. Make sure it is centered both ways to the plinth. Also make sure that the glue doesn't spill over onto the modeling board otherwise you'll never remove your model.

If you look at your sketches you may have noticed that I've sweetened the lines using French curves. It may pay you to do the same as you will be using these drawings as the master guide. The plan drawing needs to be completed and should relate to the overall width of the model. You will also need four wheels and tires and the size should be reflected in your side view drawing. By putting the wheels and tires on the side view you can determine whether the vehicle has too much ground clearance and if the overall proportions look correct.

Well I think this is enough information for you to progress with for right now. Once you have completed this stage let me know and we'll go from there. 

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