Hi everyone!
I want to improve the roof on this building. I have just received a little package containing small dark ballast. I would like to create a tar and rocks roof.
Just before making my first attempt, I need to be sure of all the steps. Is white glue ok for making the ballast remain on the roof?
Do I need to do something else? What about weathering?
Thanks for your help.
II think the white glue, even sllightly diluted, should work.
I think I would try wet/dry (black) sandpaper first., save some work. If there’s not enough texture to that, coarser sandpaper, painted, might be more to your liking.
Good luck,
Richard
White glue is fine. I paint on a thin layer, add the gravel, then add some diluted white glue (about 5 parts water, 1 part glue, and a couple of drops of detergent) with a dropper.
I have problems weathering my roofs. They never seem to look right when I am done.
-Kevin
Like cowman replied above, the black sandpaper is a good way to go in HO scale. Just how small/big are the stones on a Gravel/Tar roof anyway? 1/4’’ and will you be able to see 1/4’’ HO scale gravel on that roof? Some people need to see the stones/gravel to believe it’s there. But in HO scale it’s too large. I use N scale ballast on my HO scale track. That would still be too large, for me anyway, on my HO scale roofs. Some roofs do have ballast/tar on them, ballast being maybe 1.5’’ in size. This could be the look you want.
You may want to put/glue a ‘‘support beam’’ of plastic if there is not one from side wall to side wall against the bottom of that roof. Not because of any surface you put on top, just because it is a wide span and the plastic may droop in the middle in a few years.
If you go the way of sand paper, do not use good scissors.
As with weathing a 3 dimensional gravel roof, a very light touch and very very little dirty white/gray powder/pigment on a foam sponge (like drybrushing, a lot of effort and very little color change), you just want to touch the tops of the gravel here and there to show wear.
Oh yeah, ‘Up on the roof’ Being the part of the structure usually seen the most I think it pays to give them extra attention, and loads of fun too, though I tend to get carried away with the debris.
Straight gravel roof on the right is A.R.M. N scale ballast fixed to a coat of slightly diluted Elmers white glue, weathered with Bragdon powders and Mars black acrylic tube paint to simulate the tar.
These roof coverings start out with strips of either powder coated construction paper or matte gaffers tape. Regards, Peter
With so much water, it’s not going to leak under the roof?
Wow, I really like your roofs. I will save the
Tar and gravel roof will use pea gravel: 1/4 to 3/8" or 6 to 9 mm.
X 1/87 of that will be … very, very tiny.
I vote for a sandpaper roof…
(in metric 1/87 math is easy for this size: gravel will be around 1/10 th of a millimetre in diameter) (that’s really really tiny by the way). (Don’t sneeze until the glue is dry)
Hi ModelTrain,
What is the roof made of? Is it styrene or cardboard?
If it is cardboard you might want to seal it first with primer so that the glue doesn’t cause it to warp.
Regardless of the material, I would suggest putting some sort of internal bracing to keep the roof flat. PC101’s suggestion of putting a support beam between the side walls could serve to support the roof as well.
Dave
Styrene.
HO-velo, beautiful roof tops.
I had to go look at some of my HO scale work in progress.
Looks like I have been using WS fine ballast dark gray #1375. (still looks to large to me, but it works).
When I am tired and do not want to spend alot of time swabbing/brushing a roof with glue, here is a quick way to tar and gravel a roof.
Of course the roof is painted black days, well sometimes years, before I do the gravel work.
Put Painters tape on anything you do not want to get wet with the spray.
Tuck the Painters tape in the corners and edges of the walls and roof.
Get your ballast ready in a shaker cansister and a plastic tub to catch the leftover gravel.
Spray the roof with a coat of clear gloss or clear flat and make it look wet then sprinkle the gravel on the wet coating and tilt the roof so the gravel slides around, side to side and back to front over the plastic tub.
Now tilt the building over the plastic tub and catch the loose leftover gravel.
Here is an extra step if wanted, respray the gravel with a coat of flat clear and let it dry good. Now remove the Painters tape. This top coating will seal the tiny grooves around the stones. Now in two years when you see fuzzy stuff growing on the roof, you can vacuume the roof and not lift off the gravel.
If you get gravel stuck where you do not want it because you coated something you could not cover (like on top of and around the ‘‘metal’’ parts of the roof vent, just lightly scrap it with a small flat screwdriver when dry. I use Dental picks. Or just hire workers to do the scrapping.
WS Fine Gray ballest.
That’s funny, same building and gravel, just different lighting. One looks brown and one looks gray.
I use Rust-Oleum textured and speckled black paint in a rattle can. This is great for getting a flat asphalt roof and also for coating a plastic shingle sloped roof. It’s easy and after it dries it takes a bit of weathering powder very well.
The paint should be treated carefully. It will clog the nozzle easily, so good spray paint hygiene is critical.
Thanks everyone for your help.
I have just received this package. How do I know what size is this ballast? I can just see that the particules are very small.
I will use ballast and white glue for this model and on my next one I will try the sandpaper technique. Because I am a new model railroader, I want to try as many techniques as possible and discover what works best for me.
Thanks again!
Woodland scenics has a chart of fine medium and coarse sizes, by scale
However they package it as Fine … For Any Scale. Got Calipers?
Having actually been on such a roof during one of my college summer jobs in a tall office building, I can testify that the pebbles were pretty small. Almost the size of the ones that get jammed into your tire treads, so I’d say go small with the ballast or rock that is used. It’s not like a rock garden, which you sometimes see on models. I also recall spots of bare tar - and it was a blistering hot summer day and I could see bubbles in the tar, and could smell tar. But even so the visual sensation was of uniformity of appearance – even more so when I looked down at nearby roofs. There was tar splashed up on the inside vertical top of the walls.
One thing I would advise – make the roof well braced not just to be flat, but to be stiff. If the roof flexes that thin crust of stone will crumble and crack.
Dave Nelson
Thanks for the link. But I am looking to my package (picture in my last message) and I can’t find the info I need to look on the chart.
Thanks Dave, this is very good information.
Here is my first rocks and tar roof.
I have used white glue and added ballast one small portion at a time. Next time, I will add more glue because I was afraid that by using more glue it will appear between each ballast particules but it has not. And because I have used only a small amount of glue the first time, ballast was not able to stick on the roof. So I had to do it again and again.
After all the ballast was glued in place, I have added a few touch-ups with three colours of Vallejo acrylic paint (dark grey, medium grey and light grey). I think it looks nice for my first roof.
I have just discovered that I forgot to add diluted white glue at the end. That maybe explain why my ballast had difficulty remaining in place in my first try.
Finally I have added diluted glue on the top of my roof.
I think that my next step should be to weather the vents on the top of the roof and maybe add a tar line.
Aha, I now see you say you are modeling the CN in N-Scale. Would I be correct in saying ‘‘your roofing gravel will be out of sight’’.[:)]
Stef, on the back of that WS bag of ballast, top right corner is a ‘‘Scale in inches’’ showing the size of fine, medium and coarse in the different scales.
That looks like quite an improvement over the smooth plastic roof.
-Kevin