Rough time with Woodland Scenics " Smooth it"

Discussion in 'FAQs' started by Biased turkey, Mar 22, 2008.

  1. Biased turkey

    Biased turkey Active Member

    I tried twice to make a road using WS smooth-it material.
    Both times I had the same problem: When pouring the material, it creates bubbles.
    My road looks more like a piece of lunar landscape , or as it was hit by a squadron of Stuka dive bomber.

    Any suggestion to fix that problem will be much appreciated.


  2. doctorwayne

    doctorwayne Active Member

    I'm not familiar with that product, Jacques, so I can't offer any comments on why you ended up with built-in potholes. However, you should be able to patch them easily using pre-mixed drywall compound, which is available in everything from small plastic tubs all the way up to 5 gallon pails. The best way to apply it is with a small drywall knife, but a regular putty knife will work, too. Just squish it into the holes, then scrape away the excess. If the hole is deep, the filler may shrink somewhat as it dries - you can decide if you want to do a second coat or leave it as a noticeable patch. Dry wall compound sands very easily, or you can smooth it (after it has hardened) using a damp sponge. Of course, these white patches will need to be touched-up - I find that a wash of PollyScale paint, in an appropriate colour, works well, and craft paint should also be suitable.

  3. nachoman

    nachoman Guest

    I am wondering if it is reacting to the foam somehow...

  4. Russ Bellinis

    Russ Bellinis Active Member

    I was at Home Depot the other day and picked up some spackle in a squeeze tube. It goes on pink, then turns white as it dries. It would appear that it would work great for filling in those little holes. Then all you need to do is paint your road when all is dry.
  5. PWRR-2207

    PWRR-2207 Rogue Islander


    I did not get bubbles but I mixed it for at least 3 minutes and tamped it in place like concrete and cement that I poured in 1:1 projects/construction.

    The only other thing I can think of that I did that was not in the instructions was use a piece of wood dipped in a bowl of water that was wide enough for the road to smooth and level the roads.

    Does the foam have a coat of paint, preferably a latex paint?
  6. RonP

    RonP Member of the WMRC

    fill the holes with what ever you got i'd ude thick plaster with a putty knife.
  7. ezdays

    ezdays Out AZ way

    Just a guess, but it sounds like you're creating gas bubbles in the mix because of some chemical reaction. Perhaps you have something in the water, like maybe it's too hard. Or even if you're using an water softener, that might do it. You might try mixing it with distilled water, and don't mix it too long, that might be creating air bubbles. In either case, they're probably rising through the mix before it sets.
  8. TruckLover

    TruckLover Mack CH613 & 53' Trailer

    thinking that may be the case

    Mix up a smaller batch and spead it over the road to see if it will fill it in.

    I use this stuff for all my roads and I havent had any problems
  9. Biased turkey

    Biased turkey Active Member

    Thanks to all the helpful members on this forum who took some of their precious time to reply.

    To Kevin : I don't think it is reacting to the foam because , as seen on the picture, the bubbles seem to be located on the surface and not from the area in contact with the pink styrene foam.

    To PWRR-2207: That was a quick test, so there is no latex paint on the piece of styrene I used. But I can repeat the test with some painted styrene foam using the tan paint I use on my layout.
    I used some piece of .030 sheet styrene to smooth and level the road, but it wasn't dipped in some water.

    To ezdays and TruckLover : you raised an intresting point here . Montreal water is quite soft ( being a homebrewer I requested that information from the Montreal water treatment plan ) . But I'll repeat the experiment using distilled water

    To RonP, Wayne and Russ: The easiest way is just to fill the holes with ...
    ( and that brings me to another question ) . I'm confused with the various products available, spackling compound, joint compound, drywall compound etc...

    Could someone please be kind enough to explain ( from a model railroader point of view ) the difference between those products ?

  10. doctorwayne

    doctorwayne Active Member

    I think that it's merely a question of local terminology - I've always considered them to be the same stuff, albeit perhaps from different manufacturers.

  11. RonP

    RonP Member of the WMRC

    Plaster is plaster, the only differance I see is the weight and drying time.

    Durabond 90 is heavy and sets in 90 minutes. AKA drywall compound aka joint compound

    Spakling is differant it is a substance that makes texture on drywall or other const. materials. It is lighter then drywall compound
  12. doctorwayne

    doctorwayne Active Member

    Durabond, in any of its varieties, is a patching plaster, and is not similar to drywall compound. It can be used to fill fairly large holes, and won't crack as it cures, even in very thick applications, as it uses a catalyst in the setting process. It also dries very hard, and is difficult to sand. I have used it as an undercoat for drywall mud, though, mainly for its ability to fill deep areas without cracking. I used it also to form the scenic contours of my layout, applied over screen, and it is strong enough to allow me to lean on it to reach distant areas.

  13. RonP

    RonP Member of the WMRC

    I'm a headstrong Frenchman and didn't notice sign1
  14. kinggargantuan

    kinggargantuan New Member

    i read somewhere that some modelers use vibration to get bubbles out when pouring resin. maybe the same kind of logic can be applied to your roads.

    tapping on the table once you've finished pouring your mix might help get some of the bubbles out.
  15. Biased turkey

    Biased turkey Active Member

    Doing some tap-shoe on the table sign1

  16. Biased turkey

    Biased turkey Active Member

    kinggargantuan, I didn't want to make fun out of you with my reply.
    As a matter of fact Woodland Scenics recommends to tap on their "Paving Tape" after pouring the "Smooth-It" plaster.
    Last Friday, at my LHS I checked the height of the paving tape and it looked like it is about 1/16 " but for casting my smooth-it road I used some N scale cork roadbed that is 1/8" high. That might be the problem
    Maybe 1/8" is too deep and that's what might create the bubbles.
    Thanks for your suggestion.

  17. woodone

    woodone Member

    Air Bubbles

    When you mix your material, you can whip air into the mixture. They will rise to the surface once you pour the mix into your forms.
    Just after you mix your materials, try tapping the bowel or what ever you are mixing the materials in. Tap it several times on a hard surface, you will see some air bubbles surface. Pop the air bubbles and tap again.Pop air bubbles. You will have to do this several times, and that should help.

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