03-17-2011, 12:35 AM
Shifting the thread back toward the subject <ah-hem>, bridge bearings or shoes aren't too hard to scratchbuild if you go with some of the simpler types. Essentially one end or both must be able to move as the metal expands and contracts with temperature changes. One end may be as Gary mentioned, a simple stack of metal plates, while the other may be a set of 4 or 5 metal rods laid on their side perpendicular to the rails. This is easily modeled with styrene sheet and rod, or brass, or cardstock and toothpicks, depending on the scale.
The more complex shoes are best built up in styrene. Yes, you can cast multiples if you like, but I'd only recommend that if you intend to sell or share the castings, or are in need of MANY for your own layout. You can also heavily rust these castings and use them in a junk or scrap pile/load even if you don't use them for a bridge, or if they come out with too many air bubbles. I made a mold for several metal parts that came with a structure kit, for a couple reasons - one, to have a place to dump extra casting resin, and two, in case I needed the extra parts down the road for kitbashing. They weren't highly specialized parts and I have no intention of mass producing them to sell, etc. so I'm not worried about copyright infringement or the like. The first reason is the best, however, since I can make the most of the casting liquid I have on hand when casting any other parts, then just paint and weather the metal plates for a scrap load or junk pile.
This is good to remember when making specialty molds for duplicating parts. If there are large corner areas or blank zones on a mold, find a few detail parts like a stump or some crates or a pile of tie plates and fill in those corners. Might as well make a few detail parts in addition to the part you need for whatever the current project may be.
Now just hold on a minute...how did I get back to casting parts! It must be contagious.
Galen
The more complex shoes are best built up in styrene. Yes, you can cast multiples if you like, but I'd only recommend that if you intend to sell or share the castings, or are in need of MANY for your own layout. You can also heavily rust these castings and use them in a junk or scrap pile/load even if you don't use them for a bridge, or if they come out with too many air bubbles. I made a mold for several metal parts that came with a structure kit, for a couple reasons - one, to have a place to dump extra casting resin, and two, in case I needed the extra parts down the road for kitbashing. They weren't highly specialized parts and I have no intention of mass producing them to sell, etc. so I'm not worried about copyright infringement or the like. The first reason is the best, however, since I can make the most of the casting liquid I have on hand when casting any other parts, then just paint and weather the metal plates for a scrap load or junk pile.
This is good to remember when making specialty molds for duplicating parts. If there are large corner areas or blank zones on a mold, find a few detail parts like a stump or some crates or a pile of tie plates and fill in those corners. Might as well make a few detail parts in addition to the part you need for whatever the current project may be.
Now just hold on a minute...how did I get back to casting parts! It must be contagious.
Galen
I may not be a rivet counter, but I sure do like rivets!