Terrain and terraforming

[gavino200]

I'm starting to think about the terrain of my current layout project. I know very little about this, and for me it's probably the most intimidating aspect of layout building. I'm going to use this thread to build an overview for myself as I learn. Hopefully, it may help another beginner in the future who is at my stage of development.

 

I'll use this first post to catalog the main materials available for the project and as a kind of index. As I deal with specific techniques and products I'll post below and perhaps make a direct link. 

 

My current layout will have two main terrain levels. The track itself will only have gradients in sections that link different loops. For example the main line will be at ground level on the high side of the layout, but it will be an elevated track on the low side of the layout. Likewise, a suburban commuter line will be at ground level on the low side of the layout but will briefly become a subway on the high side of the layout. Likely I'll also have a "mountain" of some kind, and I'm toying with the idea of including a bit of coastline. 

 

Challanges

1. Basic loop levels and the heights involved. 

2. Mountains hills and valleys

3. Subterranean sections

3. Track underlay 

4. Lift out sections and accesability

5. Gradients (as few as possible)

 

A further challenge that I'd like to attempt in the future is to build a street on a slight incline. House fronts would have to be terraced. It's rarely done in modelling but when it is, it looks great. I won't attempt this until my skills have developed and likely I'll make a designated thread for it with a link here. 

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Materials 

 

 

Sheets of extruded foam

 

Three main types

 

Dow Blue

Available here in 2'x8' sheets

Thicknesses available 1/2, 1, 1 1/2, and 2 inchs

My local big box price - a 2x8 foot sheet of 2 inch thick Dow super tuff costs $39.74

Celotex (pink)

Available here in 4'x8' sheets

Thicknesses available 1, 1 1/2, and 2 inches\

 

Corning Pink Foam

Two types: Formula 150 and Formula 250

Formula 250 has a higher PSI rating. It can take more weight than formula 150

Available in big box stores. vouched for by inobo (see thread below)

Best variety of sizes available.

 

Formula 250

Available in 4' x 8' sheets

Thicknesses available 1/2",  1", 1 1/2",  2"

At my locals big box store a 2x8 foot sheet of two inch formula 250

costs $34.94

 

Big box price for a 2x8 foot sheet of 1 inch thick formula 150 

costs $19.55

 

Also available 

4'x 50' "fan-fold" stack with thickness of 1/4 inch - big box price $49.65

1" thick 2'x2' and 2'x2 small project boards

 

Thickness conversion - American to metric

1/2"    = 12.7 mm

1"        = 25.4 mm

1 1/5" = 38.1 mm

2"        = 50.8 mm

 

White styrafoam

Bix box price 14.5 inch x 4 foot sheet of .75 inch thick costs $8.48

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Foamboards

 

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Trackbed

 

Cork - can be bought pre-cut for n scale tracks - generally 3mm thick for N scale

Can also be bought in sheets or roles

 

Foam - Woodland scenic foam pre-cut for n scale tracks

Can also buy similar foam from other sources. 

 

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Gradient/incline premade foam

 

 

 

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Instruments and tools

 

Hot wire foam cutting instruments

Various saws

Rasping instruments

 

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Glues 

Loctite foamboard adhesive

https://www.homedepot.com/p/Loctite-PL-300-10-fl-oz-Foamboard-Adhesive-12-Pack-1421941/202538705

 

 

 

 

 

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Instruction videos and learning links

 

To be added

Edited February 8, 2021 by gavino200

[inobu]

Corning Pink foam is the better foam.

 

Make sure you get a small fan to blow the fumes away from your face as you cut with the Hot Wire.

 

Watch the temps of the hot wire as higher temps causes the foam to become toxic.

 

Inobu

 

 

[gavino200]

The first decision is to how high to make the lowest point on the layout. This could be as low as cork or foam roadbed on the plywood layout top. However I'm playing with the idea of a beach or small port at the low end. In that case the sea would have to be lower than the track. the would also give some freedom to model some extra level variability below track level. But I don't want to make the high side too high either. So it's a balance. 

 

Fortunately, this is somewhat simulated by an area on my old layout where the foam was irregularly removed to take it apart. This is one inch foam. It seems like it would be enough for a beach or port. Perhaps 1.5 inch would be a safer bet. 

 

Edited December 11, 2020 by gavino200

[gavino200]

The next decision is more difficult. This is the height difference between the low and the high side. It's dictated by to track-based considerations.

 

1. The double viaduct will be ground level on the high side, but elevated on the low side. I've decided to kitbash viaduct piers so this is not the limiting factor. I'll adjust the pier height to the terrain level difference rather than the other way round.

2. The ground level commuter train on the low side with go underground briefly on the high side. It will have to cross under the double track. There'll need to be some space between the top of the tunnel and the trackbed above it. 

 

Likely height difference between high side and low side with be the thickness of two sheets of 2' corning pink foam.

 

This is a convenient height. The thickness of two layers of 2 inch pink foam is 101.6mm. This will likely be a small bit more when taking adhesive into account, but it's very close. The height difference can be eliminated by carving a minimal gradient into the foam or adding a small stand to the piers. The stand may be advantageous for noise reduction anyway.

 

Mockup of a tunnel passing beneath a 10 cm high side

 

 

 

 

 

 

Edited December 11, 2020 by gavino200

[gavino200]

I'd like to reuse my old "visible tunnel" but I doubt if I can. It's designed for a very specific curve on a particular piece of board. Fortunately the hardest part was working out how to do it. I still have the templates. I may use this tunnel and section of the old layout to practice "mountain making". 

 

 

Edited December 11, 2020 by gavino200

[gavino200]

11 hours ago, inobu said:

Corning Pink foam is the better foam.

 

Make sure you get a small fan to blow the fumes away from your face as you cut with the Hot Wire.

 

Watch the temps of the hot wire as higher temps causes the foam to become toxic.

 

Inobu

 

 

 

Thanks inobu. I added this to the list. I'll look for some locally. What are the properties that make it a better foam? Easier to cut? Less toxic? More firm? Sound properties?

[inobu]

19 minutes ago, gavino200 said:

 

Thanks inobu. I added this to the list. I'll look for some locally. What are the properties that make it a better foam? Easier to cut? Less toxic? More firm? Sound properties?

I dives me crazy how they say they are the same where as they are not. The way it cuts, chips and forms is different.

The Pink foams cell formation is different which makes it melt or cut better.

 

Inobu

 

[gavino200]

14 minutes ago, inobu said:

I dives me crazy how they say they are the same where as they are not. The way it cuts, chips and forms is different.

The Pink foams cell formation is different which makes it melt or cut better.

 

Inobu

 

 

And that's just Corning pink, right? Not Celotex pink? 

[inobu]

19 minutes ago, gavino200 said:

 

And that's just Corning pink, right? Not Celotex pink? 

Yes,

 

Corning has Foamular 250 and 150. They have a PSI rating where the 250 can take more weight that the 150.

I use the 250 mostly and 150 when I can't get the 250.

 

Inobu

 

 

 

[gavino200]

I'm looking at cork for my hidden storage yard. This area won't be modeled, and I like the look of unfinished cork more than foam. 

 

Possibilities are pre-cut for track, sheets, or rolls

 

3mm seems to be standard for N scale, so I'm looking mostly at 3mm. But I'm guessing that this thickness is so as not to make the rise so dramatic. ie it's for aesthetic purposes, so thicker wouldn't be a problem. It might even be better. It will cover the whole area as a sheet.

 

This is 35 sheets of 2 foot by 3 foot cork sheets, each 3mm in thickness. $69 bucks seems reasonable. 

 

https://www.widgetco.com/3mm-cork-underlayment-sheets?gclid=Cj0KCQiA34OBBhCcARIsAG32uvNjFjJktvVQMLhsYwDQ_plxULrexshMp7mm9itG9gmFiNmUVsYe_2saAjHLEALw_wcB

 

Granger has the same sheets sold individually for $7 each.

 

https://www.grainger.com/product/4NMG2?gclid=Cj0KCQiA34OBBhCcARIsAG32uvMJo1RqWFY38Qd-PTOtIZNrp6_G6osSB41YTYxlPEsbsQBBdrqg8foaAmRiEALw_wcB&cm_mmc=PPC:+Google+PLA&ef_id=Cj0KCQiA34OBBhCcARIsAG32uvMJo1RqWFY38Qd-PTOtIZNrp6_G6osSB41YTYxlPEsbsQBBdrqg8foaAmRiEALw_wcB:G:s&s_kwcid=AL!2966!3!264955916378!!!g!437270349779!&gucid=N:N:PS:Paid:GGL:CSM-2295:4P7A1P:20501231

 

 

 

This is a 4 foot by 12 foot roll of 1/4 inch (approx 5mm) cork for $100. the advantage would be that I could apply the cork to the whole area with no seams. 

 

https://www.schooloutfitters.com/catalog/product_info/pfam_id/PFAM25035/products_id/PRO39990?sc_cid=Google_NOR-RC412&adtype=pla&kw=&gclid=Cj0KCQiA34OBBhCcARIsAG32uvNMW_J5Kny1J0c-7nvGUdJy3Dn3eyVZnDxEDyDSBuOWbBG4rAUt1_kaAuBeEALw_wcB

 

 

Granger has a 4x8 foot roll in just over 3mm thickness for $70 

 

Widget has a variety of rolls in different dimensions, with similar prices to the above.

https://www.widgetco.com/cork-rolls-3mm-36inch

 

 

Roll vs sheet - Pros and cons

 

Pro - a seam-free finish. 

 

Con- it may actually be easier to apply the sheets. Likely the joints wouldn't be much of a problem. 

 

Edited February 8, 2021 by gavino200

[inobu]

Look for a PVC foam like the tool box liners. They are soft and pliable.

 

Cork, dries out.

 

You can get 4x8 roll from a foam distributor.

 

Inobu

 

 

 

 

[cteno4]

Might look at flooring padding. There is a whole spectrum of them out there and at times the local flooring company may have a pile of remnants. There are various density of pvc foams and even composite corks that are made to stay flexible.

 

jeff