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5,518 Posts
Discussion Starter #1 (Edited)
This is Tunnels and Rock portals
This is the next step after this tread Simple track laying and Mountain building read it first. It will explain the fine details

Start with a piece of scrap ply and draw up this pattern for a single track and 1 3/8 off each center rail to sides and add center to center dimension for total width.
Tunnel and Rock portal (1).jpg
It is NOT attached it's just sitting there to show you that tis is set for a steep cliff side entrance portal.
Tunnel and Rock portal (2).jpg
This one is set for a sloped side entrance portal.
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Cut piece of screen for tunnel approximately 12 in wide and as deep as you would like to go, recommend no more than 1 foot. I will be only showing for a 6" deep tunnel, that does work well.
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Wrinkle and smash wire un fold and do it again!
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Mark center of screen.
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Attach screen to center of frame leaving 1/4 sticking out of the front. I used a hot glue gun to put these together, Caution I wrap tape around my fingers to keep from burning them to a crisp from the glue coming threw the screen. You can also staple them in.
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Work around the frame attaching the screen keeping the winkles but keeping in mind clearance for your train.
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Fold the excess down to the frame do not trim any off.
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Use a scrap piece of ply covered in either tinfoil, or plastic not paper it will stick. Thumb tack the edges of the screen down to the board. You can also tack the frame down to make it easier.
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I make tunnel entrances for curved track wider in the rear just to make sure they fit.
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Place a piece of base and track in the opening and check all sides to make sure there is plenty of clearance.
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Check it against you larges piece of rolling stock.
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Mix a very small amount of mud and set the centers of the tunnel, also cut a scrap piece of wood to hold the center back up.
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Mix the mud thick enough to not go threw the screen, thin coat the top lightly.
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Smooth the inside of the tunnel as you go, don't worry about the look of it just yet.
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Continue coating the outside till you cover most all of it, let completely harden.
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Remove tunnels and turn over, coat inside of tunnels in light coats till finished.
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Let completely harden go to next step.

5,518 Posts
Discussion Starter #2 (Edited)
Tunnels and Rock portals part 2
This is a slight variance in the project just for an end purpose. Allot of dead end sidings need a little extra protections from run away trains, also use rail stops! and I needed a site for the tunnels.
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Install tunnels aligning to the center of the track, or where they should be, put the track down first!
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Cut screen for faces/portals of tunnels. Wrinkle the screen twice to get finer detail.
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Tuck the screen in around the opening of the tunnel.
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When you set the screen to the face take in mind what the contour should be if it were blasted out.
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Coat the face with light coats to keep the finer detail.
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Put on several light texture coats and not a heavy coat it will rune the details.
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5,518 Posts
Discussion Starter #3 (Edited)
Tunnels and rock portals final page
Do not worry about making the rock or earth edges perfect most will disappear with scenery additions.
Tunnel and Rock portal (39).jpg
If your doing an older layout round the top corners of the tunnel more. The tunnel dimensions follow modern rail road standards you can decrease it to be smaller just make sure your largest equipment will fit and make it with a little tolerance.
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Yes the paint is still wet. this is just a base coat to seal it.
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The hard scenery can place a vital role in braking up the grade and also protecting the engines and rolling stock from the plummet of death.
Tunnel and Rock portal (44).jpg

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you can paint the inside of your tunnels before or after you place them, just increase the darkness as you go to the rear of the tunnel.
Tunnel and Rock portal (46).jpg
Blocking all light from the back of the tunnel will give you that finishing result.
Tunnel and Rock portal (47).jpg
This area is now ready to get scenery added to it! Next How to?
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You can use commercial tunnel portals also with this method, incorporating walls in the scenery will enhance it too! This is from the last layout I built.
Tunnel and Rock portal (49).jpg
Thank you.

636 Posts
Once again - great stuff Sean - Thanks for taking the time to show these techniques, it's very generous of you!

I really like that technique of using drywall compound.

Question: In the previous "How to" you mention using the dry mud and mixing it. Can you not do the same with the pre-made mud and water it down a bit?

5,518 Posts
Discussion Starter #5
Ready mixed drywall mud or joint compound does not have a curing or hardening agent in it, it requires heat and air to dry.
As you build up the layers it makes it tougher to get the water to come out for it to set. The moisture from each layer will re-soften the previous layers and make the structure heavy and soft and could collapse it.
I've tried all different types of construction materials over the years to do this and the combination that I have come up with works great, not to say other methods might not also work. I just did not get satisfactory results with other materials.

45,020 Posts
I have a 5 gal bucket of drywall compound, it's less than a year old, and it's got terminal mold. I used a fraction of it fixing some walls. Fortunately, it was given to me for free, leftovers from a remodeling project. I have some dry mix that I've had 8-10 years, when I mix it, it still works as well as when I bought it.

788 Posts
Man, With step by step how too"s like these that Sean has been posting this is the best site ever! Thanks Sean! :thumbsup: :thumbsup: :thumbsup:
With the Help of you guys here My table is growing in ways I never even thought of when I laid the Mainline! First the Mountains then the Tunnel portals to finish. I did almost the same as you show here I just adjusted the wood cut out shapes to fit what I needed. Wow, what will Sean have me building next????? This makes me want to scratch build everything possible for my layout and use as little as possible store bought decorations or landscape!

Also I started with the pre mixed Joint compound (oops) dries way too slow. And all the above reasons are valid too. Sean advised that I get quick set compound (dry bag) and mix small amounts. I did and it worked much better. I will post pics on my WIP: thread tonight! Thanks again Sean!

Ok here is what I came up with so far as per Sean's Expert step by step. Don't be scared guys. This was super easy! Anyone with a little skill / patience can pull this off.

Hope you don't mind if I share a pic of my Mountain's here Sean. :dunno:

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