Sunday, January 25, 2015

DBR1: initial cleanup of the body

Lots of new things to learn here. The Profil 24 kits look a lot like the Porsche 908 kit from MFH that I have been struggling with for something like a year and a half now; you get the larger resin bits in a bag and smaller stuff in a series of little sealed baggies. Unlike a styrene kit, parts are not numbered on trees, and often include fairly large pieces of sprue or remnants of ports for resin delivery or air evacuation as the mold is filled. Figuring out what is the part and what is the sprue can be challenging. Also surface detail will be rougher than a good styrene kit, so count on lots of wet sanding. That being said, some of the larger mechanical components (engine, gearbox) can be molded as a single item where a styrene kit might devote 20 or 30 pieces to this.

So let's get to it.

I started on the exterior body panels: body, doors, hood, rear hatch and gas filler cap cover. The goal was to clean them up enough that everything fits with minimal gaps. There is lots of scarf and bigger stuff to clear away, for instance in the fender vents in the picture above.

The first thing I discovered is that resin is a lot softer than styrene, and you will want to be careful with the Number 11 blade. The panel scribe and a set of nail files from the beauty section of the local drug store are your best bet. Test fit regularly to avoid taking off too much material.

The left side door has a bit of a gap but I think that will be OK at this point. The rest of it all fits reasonably well.

The Tamiya primer went on with some flaws, not visible in the picture above. A wet sanding with 1000 grit and a second coat of primer may not have improved things, and I am not sure that 1500 or 2000 grit is the answer. Pictures below show some strange behavior at the leading edge of the hood, and on the nose of the body.

Online, it seems that removing mold release agents requires scrubbing with isopropanol alcohol, followed by soaking in water and dish soap; my soaking in dish soap may not have been enough and may be the cause of the blotchy primer. A stronger primer, such as Rustoleum auto primers from the auto parts store, also seems to be necessary according to a range of online resources.

A parallel step was an initial cleanup of various chassis bits. Figuring out how this all fits is a challenge as there are few doweled joints. A lot of test fitting, both joining of chassis bits to each other and to the body, give an idea of where everything needs to go. Clamping everything properly while glue sets will be critical.

So anyway I'll let it all sit for a week while I go back to the office and see what it looks like next weekend.

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