Resin Casting: Need Opinions

[GhengisKong]

I am about to start casting parts for the first time ever. Most of them are flat and no real skill needed to cast them. However, I am casting my bashed fuel tank for EMD E6 and E7s and not sure which way to orient the master for casting. As you can see the tabs that hold the tank to the chassis stick out as well as the faux tank shrouding. I don't want to break them when removing the casts from the mold. For that matter, I don't necessarily want to break the master either. What way would any of you guys try and cast this piece? Tank bottom down? Tab side down? Also pictured in the background is the container I planned to use for this mold.

[peteski]

This might be a job for a 2-piece mold (which I haven't tried doing myself yet).

[GhengisKong]

That's what I was afraid of. I might end up making a reverse imprint with the provided clay and then moulding it.

[chessie system fan]

Yeah that's a two-part project.  The only way to make it a one-sided mold would be to cut off the tabs and make the inside a solid block.    Two part molds aren't as difficult as you might think and this fuel tank is simple enough to be a perfect practice part.

The one tip I would recommend is put a little scotch tape over the four latches when making one mold half.  You can remove it for the other half.  I've found that's the best way to deal with holes.

[Angus Shops]

It looks to me like you will need to go with the two part mold.

Geoff