Resin prepping/sanding tips?

[SCOFFMAN]

I'm finally starting work on my Coyle reproduction/recreated/dummy stunt blaster casting or whatever you want to refer to it as - it's a big chunk o' cast resin. A nicely cast piece of resin but being resin it still needs some prep work.

I've already cleaned it thoroughly twice with warm soapy water and an old toothbrush to remove any remaining mold release. I'm about to start sanding it to remove the casting seams. As I have never worked on a resin kit before (just all-metal and polystyrene kits) I did my homework and checked out a number of websites on prepping resin for painting.

However, I've run into a number of varying suggestions of what grit of sandpaper to use as a starting point. All of them suggested using wet-sanding but some suggested starting at 200, some at 320 and some at 400 grit and then work your way up from there to around 800 grit. 200 seems way too coarse to me. For those of you that have worked on resin kits before, what would you suggest for a starting point? The seam lines are not very heavy and I do need to be careful of details near them.

Also I've read of the technique of "ajaxing" a resin model using a paste made from Ajax cleanser and water and then applied to the model with a soft brush or sponge in order to roughen the surface a bit in order for the primer to adhere to it better. Is this a step that is necessary and/or recommended? I know that for the final sanding of the whole casting I'm going to want to use 800 or higher grit paper to be able to roughen the surface for painting but yet not damage fine details.

And finally is it recommended to prime the casting and then wet sand it and then apply another coat of primer, or just apply a single coat of primer and then paint? I realize that the more coatings of paint and primer that get applied the more potential there is for filling in fine surface detail (such as lettering and screw-heads, etc.) but I'm looking for the most durable finish I can get while still preserving the details. I'm planning on using PlastiKote sandable primer after having read on a number of forums this is one of the preferred brands of primer for use on resin models.

Thanks for any advice anyone might have!
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Fiery the angles fell, deep thunder rolled around their shores, burning with the fires of Orc.

[joberg]

Yep, seems to me that 200 grit is too rough to start anything on the resin.
As you said "Ajaxing" is a good starting point (I sometime uses acetone to remove the first "shiny" layer of the surface and then start to sand at 300). As for too much layers, there's a solution: airbrushing instead of spray-cans...I know, it can be a bitch to clean everytime, but if you want to keep the details...I'm sure others will chime in with their tips; good luck with your project

[amfx74]

Hi Scoffman,

I have been modelling with resin for some time now. Here is what I usually do. after cleaning with soapy water.

I tend to give it a clean with 99% alcohol to remove anything still left on the surface. Acetone can sometimes leave a sticky surface depending on the composition of the resin.

I always sand with wet and dry paper using it wet and if I need a little more sanding power use it dry and brush away the dust. Be careful not to breath in the dust. Start with 280 grit if there are rough bits or you are sanding back. I then move to a 400, 800 and for really fine areas or to polish up the surface a 1200 grit. To add a really high shine to the surface, Brasso polish does the trick. This has to be washed off thoroughly.

For removing mold line with detail near it, I use the edge of an xacto knife blade to scrape the line off.

I don't always use a primer but will use a good quality matte black spray paint. This is followed by airbrushing the rest of the base colours.

Other weathering is usually done with old brushes. I sometimes use the model paints that you can buff to put on added metallic sheen.

[SCOFFMAN]

Thanks for your tips guys! joberg, I am going to be airbrushing the resin... actually this will be the first time I've used an airbrush to paint a model. I've been using rattle-cans and brushes for years but I finally broke down and bought a compressor and deluxe airbrush kit from Harbor Freight when they had it on sale last month. Actually I bought an identical second airbrush kit as well so I can do two colors without having to clean out the brushes and bottles in-between. I know the HF airbrush isn't the best, but it got good reviews for the price and I found a lot of tips and info about it on the web (there's some good YouTube videos on using it and well as breaking it down and cleaning it, etc.) I've been practicing on paper using some acrylic paint I had kicking around to get a feel for it. The difference in control is amazing. I'm probably even going to try decanting the primer and thinning it down a bit and airbrushing it on as well instead of using the spray can so it doesn't go on so heavy.

Thanks again!
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Fiery the angles fell, deep thunder rolled around their shores, burning with the fires of Orc.

[amfx74]

Hi SCOFFMAN,

If you need airbrush help PM me. I sell and review airbrushes. Have started a review blog on it at http://www.ausairbrush.blogspot.com/

I had a look at the Harbour Freight Deluxe airbrush and for that price, get as many as you need colours, you can't go wrong. It is probably from Taiwan and is mainly a copy of a Badger 150 with a bit of the 155 Anthem (the needle setup) plus the usual 1/8 air fitting fitted.

[joberg]

Yep, if it's a double action it takes some experimenting many products out there for many types of works...good luck!

[noble]

If you are painting something, I wouldn't go past 400 grit.