I use JB weld steel epoxy for filler. It takes a while to dry, but it sands well after it's dry. I find an epoxy filler is better for filling larger gaps then Testors or Squadron plastic putty. You might also try MIlliput epoxy filler.
Jeff White
Alma, IL
I have made tanks of various sizes to represent such things as propane tanks built up from ordinary pvc pipe fittings and end caps from Home Depot. Irrespective of the size/length of these tanks, the seam hiding process is the same. First I use 150 grit to obtain a flush face on each mating surface by sanding on the 150 grit paper lying on a glass plate (or a smooth finished tile piece ). I then follow up with 400 grit wet dry paper to refine the mating surfaces. I use a dowel or piece of pvc pipe with the same internal diameter as the fittings to ensure alignment and then use 2 step pvc cement to join the surfaces and align. If styrene is the material then regular plastic cement is used. After joining-and this is critical- where the seam appears I then use Bondo (from Walmart) to coat the seam and let it dry overnight. Next I secure the "tank" in a Panavise (use the plastic vise guards ) and GENTLY sand the seam with 400 wet dry grit paper cut into strips. I sand as if I was shining shoe polish on a shoe - hence using narrower strips of grit paper to localize the abrasion process. In some rare cases you may move up to 600 wet dry grit paper to make things really smooth. The type of wet dry paper I use is the gray garnet psper, not sand-colored sandpaper. I always spray a light coat of primer on after all sanding- if any imperfections remain I will remove the primer and spot re-Bondo were needed then resand. In every case I have done this I obtained a smooth seamless joint when finally painted (over primer).One more thing- using a "hacksaw" to cut a plastic material creates a wider kerf than necessary doe to the convoluted blade. I use a Zona saw with a high number of teeth per inch or you can even go with an old Atlas track saw.
Cedarwoodron
sandusky Any ideas?
Any ideas?
Yup.
(This works on modernish tank cars with smooth sides. It might be adaptable to sides with detail by using shorter strips. Too short, and the pieces can be cocked, though.)
I'm assuming you want to join two end pieces to make a single body. You don't have to have a precision cut, just an adequate one. It doesn't even have to be square. But you SHOULD do the best you can--take care!
To make the join, take some strips of Evergreen .060 x .250--four of them. Make them almost as long as the completed tank. Glue them, standing on edge, onto one piece, longitudinally, and arrayed at 90 degree spacing around the circumference. It is (obviously) important to do a good job of this task. This will leave four prongs "out in the air" to receive the other piece. Slide it down the guides and glue the two halves together. Let them dry well. Several days is good.
You can then remove the Evergreen strips. The two halves should now be joined*. Fill in the gaps with 3M Acryl-White Glazing Putty. When dry, you can GENTLY file off the high spots with a fine file. And then sand. Use steadily finer paper, maybe from 320 down to 600. Keep re-applying the putty and sanding until you've achieved perfection. Which you CAN do.
Ed
*If, as you are doing this, you find way too much gap in the joint, you can fill the gap with epoxy. Like the putty, you can file and sand it, though it will not let you get a really fine surface. Coating it with a thin coat of the putty should fix that, though.
sanduskyI'm on my second tank car with only moderate success hiding the joint.
I suppose that it depends on the style of tank with which you're dealing: modern frameless ones, with few reference points cast into the body shell, will be a bit more difficult than older style cars with straps holding the car to its underframe.On the latter, I set a pair of dividers to mark the cut-lines, and use a cast-on detail, such as the tank straps on the car shown below, to guide one leg of the dividers while the other leg scores the cut-lines.Make the cuts on the waste portion of the material, and then, as David suggests, sand to the cut-line. I have found that moving the piece to be sanded in one direction, rather than back-and-forth, helps to avoid uneven results - don't rush this step. With care, you should be able to get results that will require little or no filler, especially when using solvent-type cement.When you've finished the sanding, coat both mating surfaces with MEK, and let them sit for a few seconds, then re-coat both, and bring the surfaces together with some pressure. Don't worry if some material oozes out of the joint: once it hardens, it can be cleaned off using a chisel-type blade (bevelled edge against the work surface).If you need filler, I've found Bondo's Glazing and Spot Putty much easier to use than any modelling-type filler, and it's a lot cheaper and has a much better shelf life, too. It comes in a tube, so make sure that when you remove the top, the tube is upright, as there's usually a fair amount of solvent present on top of the filler. I use a small screwdriver to stir the filler right in the tube, and even without bothering to mix the contents thoroughly, when you withdraw the screwdriver, there will be an amount of filler/solvent on the screwdriver's shaft. I scrape that onto a chisel-type blade, and use it as an applicator to add the filler where it's needed. This filler is meant to be applied thinly, but since it hardens fairly quickly, you can do successive applications without too much delay. I use fairly fine wet/dry paper for sanding (use it dry), even on the initial coat, as it's very easy to sand. Re-apply as necessary.
I found this Varney tank at a train show, and the owner offered it for free - my kind of price! It's shown with the parts for a Tichy underframe...
The tank was a bit too long for the frame, though, so I used a hacksaw to remove a slice from each end, just inside of the cast-on tank bands. In the photo, the tank portion has already been sanded back to the scribed lines, while the ends have yet to be sanded back to the edge of the cast-on bands...
Here's the re-assembled tank on the Tichy underframe. No filler was needed for this one, although my luck's not always that good...
Here's the finished car, with a few added details and lettering from Black Cat...
This one is an Athearn car, and because it represents an insulated car, had no visible tank straps. I made the cuts, as described previously, just inside the handrail stanchions nearest the car's ends. Once cemented back together and the oozed-out material from the MEK joints shaved off, I simply left the self-filled cut lines as joints in the insulating jacket...
...another shortened Athearn tank, this one was cut just inside of the double tank straps. As you can see, no filler was used, even in that gap just to the right of the "X" ...
...no wonder customers have been claiming that they were short-changed on product!
Wayne
Here's a few tips from another rookie kitbasher, 1 use a piece of tile as a working suface, 2 you're going to need 400 grit wet or dry or finer to achieve a finish that doesn't look grainy, 3 don't sweat the details, 4 if you can get the joint to where you can see it but it's not the grand Canyon then call it good and use a rattle can to paint, the thickness of the rattle can paint will hide little imperfections.
Now here's something I haven't tried but might work, use some nail polish to cover the seam, sand it smooth and done, again might work, might not.
Good luck, and please share some of the details, I will eventually be working on some 150 ton crude oil cars to run with my super coal gondolas.
Steve
If everything seems under control, you're not going fast enough!
You want to sand the cut ends smooth and flat before glueing. If the saw left marks in the cut ends you want to start with 120 Grit sandpaper and follow up with 220 grit to smooth the cut ends. A home mde jig to hold the cut ends of the tank at right angles to the sandpaper helps. You need to stick the sandpaper down onto something flat, like glass or Masonite. I use MEK for styrene work myself. If the two cut ends are sanded good and smooth and square you should only get a little squeezeout when you stick them together. And you probably need to sand the joint with 220 Grit after you glue it together.
David Starr www.newsnorthwoods.blogspot.com
I'm on my second tank car with only moderate success hiding the joint. Original bond with MEK; then Testor's gray putty thinned slightly with MEK to work into the (not very big) seam. Next round: Clear nail polish/MEK/putty. Still not building up the way I want to. I don't if I'm removing the material (thereby re-exposing the seam) I've added when I use the razor blade in a scraping approach (like woodworkers do) to try to get a smooth surface.