Adhesive?

Elmers White Glue, put down on your form first, then sprinkle the coal look a like, glue will dry clear.

Totally agree with ChooChooPaul.  Why not try a test using clear plastic packaging and either straight up or diluted Elmers white glue and see what looks good to you.  You could also check the adhesion.

bd

Aileens Tacky White glue. Get it at Michaels.  

Either plain old white glue or the Tacky Glue will probably work best. Liquid glues will form a better puddle of adhesive and get pulled up into small gaps by capillary action and to a better job of holding irregular-shaped stuff like gravel/coal bits. Tacky Glue's advantage is that, like its namesake, it's tacky and not entirely permanent so it's easy to remove what it's holding and then clean off the residue with water. Traditional white glue holds tighter, but can still be rubbed off/peeled off from smooth surfaces and the rest generally comes up with more vigorous application of water and scrubbing. Pick what seems to be best for your use.

The 3M spray adhesive is great for flat surfaces with a large surface area. (One of its primary uses is as a pressure-sensitive adhesive substitute) How well it works on irregular surfaces varies, often depending on how much liquid you can get to build up so there's enough for the other surface to pick up. On exposed surfaces, it may eventually dry out, loose its adhesive properties and flake away.

The only way I've done coal loads is with white glue, it worked well and I didn't feel the need to look for alternatives.

Hey Kevin,

I bought some "Aqua" brand, black aquarium gravel at Walmart, and it really looks like coal.  The gravel is heavy plastic, in medium size chunks, and has the same semi-sheen and shape as lumps of dug coal.  It comes in a two- pound bag and is really cheap.

Because the gravel is plastic, I did not want to use white glue to put it down in my hoppers.   Instead, I got a thin piece of flexible styrofoam, and coated the foam with a medium layer of clear silicone caulk (making sure that there was double the amount of caulk down the middle of the sheet than around the edges).  Then I piled the coal on the foam and pressed it down in a realistic mound on the foam.     After I let it dry over night, I looked for any small "holes" or "gaps" in the pile, put a dab of caulk in them, and place a piece of "coal" in it.  No caulk shows through.

After this, I had a sheet with a mound on it, and it was still relatively flexible.   So, I just pushed it down into my hopper cars.

Here's a picture:

The trick to doing this is to carefully measure the length and width of the inside of the hopper car and make sure you cut the foam to those dimensions.  AND,  the ends of the sheet must be cut at an angle, slanting downward, so that the ends fit flush against the insides of the ends of the hopper.  Otherwise, you will be able to see the white foam on the ends when you put the sheet of coal down inside.

As you can see in the first picture, I used the same method to put ballast in two gondolas. 

Once the caulk is totally dry, and you give the sheet a little shake, no more coal or ballast ever falls off of the foam.   And, you can take it in and out of your cars at will.  And, you will not be squirting glue down inside your hopper car.  The weight of the sheet and the firm inside fit against the inner sides of the hopper hold the sheet securely in place.

Perhaps this method may give you some ideas on your project.  I got my thin piece of flexible styrofoam from the inside packaging on a locomotive box.

If I ever decide to put a coal pile in my layout, I'm going to use this plastic gravel, because it really looks like coal.

Mannyrock

Assuming you are placing the coal on a plastic sheet that fits into the hopper, then white glue on the plastic sheet. Cover with coal and let it dry. After adding more coal use white glue cut in half with water and a few drops of dish soap and spray it on.

I actually use windshield washer fluid to dilute the white glue as it already has the detergent and alcohol to eliminate the surface tension and soaks in better.

Pete

@Norton posted:

Pete

Say, that's a nice looking engine.   Judging by the size of the Kadee coupler, I'd guess this is HO...(?)

Mark in Oregon

@Strummer posted:

Say, that's a nice looking engine.   Judging by the size of the Kadee coupler, I'd guess this is HO...(?)

Mark in Oregon

O scale with a 1 gauge (1/32) scale Kadee.

Pete

Looks great Pete.  I can see why you would need that thin plastic sheet over the existing plastic coal.  (My hopper cars were totally empty.)

If you turn your car sideways, does the white glue "let go" and spill some coal pieces?

Mannyrock

No its solid as a rock. You may have to shake a few loose pieces after the load is finished but nothing more after that. Ballast is done the same way and those are portable modules in that picture and traveled many miles without the ballast falling off.

Pete

@Strummer posted:

Say, that's a nice looking engine.   Judging by the size of the Kadee coupler, I'd guess this is HO...(?)

Mark in Oregon

Three rail HO?

@gunrunnerjohn posted:

Three rail HO?

I thought I could see a center (third) rail, but wasn't sure, so I didn't mention it.

Using a #1 gauge coupler is not a bad idea...

Mark in Oregon

Looks like white glue is the winner. I’ve got plenty of that. I’m putting the gravel directly onto the supplied plastic load that comes with the car. Looking forward to this project. 👍🏻 Thanks for all of the helpful hints.

Great information !!!

Thank you to all posters !!!

CB&Q Bill

@Patrick1544 posted:

Aileens Tacky White glue. Get it at Michaels.  

Functionally no different than Elmers.  One might say White Glue is White Glue is White Glue.  Get it anywhere. Grocery store, Drug store, Lowes, Home Depot, Walmart, Dollar store.................... Buy a gallon it has a Gazillion uses.  However beware it is not waterproof and will dissolve if wet enough, long enough.  Elmers professional wood glue a yellowish version of white glue is much more water resistant than any white glue and dries "almost" as clear.  Almost as many brands available as white glues also.    j

@gunrunnerjohn posted:

Three rail HO?

Yep.  Marklin back in the fifties had a center rail. Today it still has center rail sliding pickups and tiny contacts on the top of the ties.    I had a girlfriend back in high school who's father had a beautiful 10' x 20'  Marklin layout with center rails.   They moved to the US from Belgium and he brought his trains with them.         j

Here is DON KANEs version that I have used for my loads.  Works great and looks fantastic.

@JohnActon posted:

Yep.  Marklin back in the fifties had a center rail. Today it still has center rail sliding pickups and tiny contacts on the top of the ties.    I had a girlfriend back in high school who's father had a beautiful 10' x 20'  Marklin layout with center rails.   They moved to the US from Belgium and he brought his trains with them.         j

Yes, I know about Marklin, but it looks nothing like the track in the picture.

@Norton posted:

O scale with a 1 gauge (1/32) scale Kadee.

Pete

Am still curious about this; care to share your technique?  It looks like that 1/32 Kadee is about the same size as the average O gauge "lobster claw"...🤔 🙂

Mark in Oregon