How to build a resin kit

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How to build a resin kit

Postby dreinecke » Mon Sep 03, 2012 5:29 pm

For some specific cars or body styles, the major slot car manufacturers may not be in a position to produce the car as they may forecast it as a low-selling slot car that will not offset the expense of tooling molds and manufacturing costs. Often, the only way to get that certain car that you want is to turn to a resin caster. Most resin kits are designed with medium modeling skills in mind and all kits are of varying quality. Some are slush cast (meaning a single-sided mold of the outside of the body of the car that resin is poured into and simply swirled around until cured) and some are two-part molded (where an outer mold and an inner mold are created. This allows consistent wall thickness of the cast part). Almost all resin kits will require sanding, gluing, and painting, and some might even require the builder to add mounting points for the chassis used.

While not a comprehensive list of building procedures, the following steps should help you during your resin kit build and have you racing quickly:

1. Inventory the kit parts – ensure you received all the parts listed in the description of the kit.

2. Remove all flashing. Especially around the window areas, wheel wells, and bottom of the rocker panels, etc. I find using a sanding stick sold at most hobby stores works well and they are available in various grits and sizes. I personally go to my local Wal-Mart and buy different grits of emery boards from the ladies cosmetic section as they are dirt cheap and work just as well. Just don't tell anyone... :oops:

3. Trial fit all parts. Ensure the bumpers and interior fit properly. Each of these may need some flashing clean-up or minor sanding. Ensure the interior tray fits over the chassis you plan on using.

4. Trial fit the chassis. Once the other parts have been checked out, test fit the chassis and drill the holes for the mounting screws or create the necessary mounting points. This is the best time to do this, before you lay any paint that could be damaged if you do so later. Measure and trim any axles to the proper width if needed in order to fit underneath the body shell. I then like to screw the chassis completely on and take a few laps at this time. This helps ensure that there is no tire rub or other clearance problems. Besides, it is an excuse for track time!

5. Trial fit the glass. This is another important step that seems out of place, however, it is really the best time to do so. Do you really want to paint up your kit, only to find out later that there is more sanding or flashing that needs to be dealt with? I didn't think so! Glass is often a finicky part. I find it easiest to trim the part carefully, continually refitting it to check for alignment. Go slowly. It also helps to cut it down to the center rib if so equipped. This means there is less glass attaching to the roof, and can make the windows fit that much better. In some cases, such as on my Datsun 510 kit, even though the quarter glass has been molded together with the front windshield and rear glass, the best way to fit it is to completely remove the quarter glass and install each part separately.

7. Rough up the body to allow the primer something to “bite” into. I like to use 0000 Steel Wool to rub the body and parts down. Sometimes resin is a little too smooth and can cause problem with paint adhesion. This usually won't show up until you are masking a two-toned car, remove the tape, and pull up paint and primer. :doh: In lieu of Steel Wool, 1500 grit sand paper works, however be careful you do not remove trim and detail from the body. I blow off or rinse off all parts when done.

8. Wash the body and parts in soapy water or Wesley's Bleech White prior to priming. I keep a resealable container full of the Wesley's and usually just throw the body and parts into it for about a 15 minute soak. I then rinse the body in cool water and allow it to dry. This is necessary as most casters use a resin release in order to ensure the parts come out of the mold easily and it also acts as a barrier to keep the resin from eating at the silicone of the mold. Some casters use a release that is very oily and paint products will NOT stick to it! Cleaning it up as described takes care of that problem.

9. Prime the body and parts before painting. It is very important to get a good base down for the remaining paint work to be done. I use Duplicolor Automotive Spray Paint, however, many other paints such as Tamiya, Testors, Humbrol, etc. are available. Just be sure to get one that is compatible with the type of paint you are planning to use, such as Lacquer or Enamel. I spray all sides to each part and let dry according to manufacturer's recommendations. The great thing about the Duplicolor paints is that they dry very quickly. I can usually handle a primed part in about 15-30 minutes.

10.Paint the body and parts. At this time I also paint and detail the interior tray.

11. Decal the body. I almost always use decals from http://www.slotcars4u.net on my kits. These decals are very strong and well made. They are also researched extensively and are not a generic decals for a car. Tim Millward is the gentleman that does these decals and he takes some serious pride in his work. He utilizes an ALPS printer that produces amazingly decals. He coats his decals in Future to ensure you'll have a trouble-free installation. He also includes fabulous instructions that include some of the history of the car you are modeling.

12.Final Detail. At this stage, adding trim paint around windows, vents, windshield wipers, and gas caps is a good idea if you are painting them. This way, the final clear coat will protect these areas. If you are using Bare Metal Foil, I recommend not doing so until after the clear coat, as it tends to fog and dull if you coat it.

13. Clear Coat the body. I use two coats of clear depending on my needs: Duplicolor Clear Lacquer and Future. It has changed names several times. I have a Tip & Tricks article elsewhere on my site about how to use it. A great Internet resource has surfaced that describes the different branding of this product. Check it out: http://www.swannysmodels.com/TheCompleteFuture.html

14.I like to use a clear drying craft glue like Elmer's white glue or Tacky Glue to glue the glass parts in. A good applicator is a normal toothpick, allowing you to put a very small amount on at a time. Craft glues clean up easily with water later if you accidentally place it somewhere visible. Be sure to allow the parts to dry depending on your installation method.

15.Interior Assembly. Often I'll use a low-heat glue gun to glue my interior trays in or I'll use the craft glues mentioned above. They are easy to remove later if needed. Only a little dab is needed, so don't empty the gun or cover each seam of the tray as it is not necessary, and only makes later disassembly difficult.

16.Chassis Assembly. Screw the chassis assembly to the completed and assembled body shell. Be sure to check for proper fit and that the tires spin freely inside the wheel wells and that the guide blade is able to rotate properly.

17.Race it! All of my cars see the track. I don't build cars to be shelf queens and believe that if I've spent this much time building something I want, I should at least take the time to run it. Remember, this is still a toy!
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Re: How to build a resin kit

Postby HomeRacingWorld » Mon Sep 03, 2012 8:28 pm

Great start in here sir!
-Harry

"They didn't say you couldn't" - Smokey

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Re: How to build a resin kit

Postby RazorJon » Tue Sep 04, 2012 11:40 am

could I put in 90 alcohol bath before painting and wash with soap water and dry :?:
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Re: How to build a resin kit

Postby dreinecke » Tue Sep 04, 2012 5:13 pm

Do not EVER use alcohol on resin - it will melt. If you can't get Wesley's, use Dawn dishwashing liquid and clean it really well.
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Re: How to build a resin kit

Postby Tigeracer » Wed Sep 05, 2012 7:08 pm

I've had good success with using scouring powder like Bon Ami, after washing with dish detergent and warm water. Not hot, you can warp the model.
I put it right on a soft scrubbing pad, so it makes a paste and rub it down. Rinse with cold water. I use clear resin primer before painting.
If I'm painting a light color, I'll paint it white first, then color on top.
Greg
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Re: How to build a resin kit

Postby hoganracing » Thu Sep 06, 2012 11:26 am

dreinecke wrote:Do not EVER use alcohol on resin - it will melt. If you can't get Wesley's, use Dawn dishwashing liquid and clean it really well.


David knows whereof he speaks. Sometimes a picture is worth a whole lot of words. Here's what happened to a resin body I soaked in 91% alcohol in an effort to remove a bad paint job.

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Fortunately, when it dried out, it more-or-less assumed it's original shape. It wound up looking like it had been wrecked, sort of repaired, and made ready to race again. It still has the scars that resulted from the soaking ;)

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Re: How to build a resin kit

Postby dreinecke » Thu Sep 06, 2012 4:13 pm

I still can't believe it even looks that good!
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Re: How to build a resin kit

Postby hoganracing » Thu Sep 06, 2012 4:32 pm

A few wrinkles and cracks remain, but apparently resin has a memory since it returned to its basic original shape. I can't remember if I repainted it or if I just decaled and futured it after the incident. It kinda looks like the victim of a rollover (which is fairly appropriate for one of my cars!)

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Re: How to build a resin kit

Postby FatUSStig » Thu Sep 06, 2012 5:09 pm

Does one particular type/brand of putty work better than another for filling in the little bubble holes?
Some say that he is a CIA experiment that went wrong, and that he only eats cheese. All we know is that he's not The Stig - he's The Stig's Fat American Cousin...
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Re: How to build a resin kit

Postby dreinecke » Thu Sep 06, 2012 5:23 pm

I use a few different ones...whatever is handy.

I use Squadron putty, or Automotive red spot filler and my favorite is CA glue and microglass bubbles or CA glue and baking soda. Works fabulous!
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Re: How to build a resin kit

Postby Tigeracer » Thu Sep 06, 2012 5:37 pm

Hi Stigs!
Glad you made it over to the new spot!
I use 2 part epoxy putty (milliput brand)
Greg
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Re: How to build a resin kit

Postby dreinecke » Thu Sep 06, 2012 6:50 pm

For holes: Make sure the edges are firm with no loose flashing and tiny bits. Fill half the hole with CA glue and then put a generous pinch of baking soda over the hole...dust it off and do it again till you are just over the surface of the part or body. Sand it even with the part or body.

Cracks and Breaks: Baking soda and CA instantly fills most gaps, fixes nearly all cracks, and it takes to dremeling nicely, but it's a harder surface to sand or file than ABS. If you have to fill a large gap, try using 3M black electrical tape beneath the open cracked surface, then fill the gap with backing soda then hit the backing soda with your CA glue, then you have an instant tough filled gap, that's ready for sanding, and spot premiering to make ready for painting. Once the gap has been repaired, just peal the electrical tape off your part.

This stuff works in less than a second and its a real fast way to fill holes. It goes "off" very hot though, so if you do touch it, just beware of that fact.
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Re: How to build a resin kit

Postby FatUSStig » Fri Sep 07, 2012 11:25 am

dreinecke wrote:For holes: Make sure the edges are firm with no loose flashing and tiny bits. Fill half the hole with CA glue and then put a generous pinch of baking soda over the hole...dust it off and do it again till you are just over the surface of the part or body. Sand it even with the part or body.

Cracks and Breaks: Baking soda and CA instantly fills most gaps, fixes nearly all cracks, and it takes to dremeling nicely, but it's a harder surface to sand or file than ABS. If you have to fill a large gap, try using 3M black electrical tape beneath the open cracked surface, then fill the gap with backing soda then hit the backing soda with your CA glue, then you have an instant tough filled gap, that's ready for sanding, and spot premiering to make ready for painting. Once the gap has been repaired, just peal the electrical tape off your part.

This stuff works in less than a second and its a real fast way to fill holes. It goes "off" very hot though, so if you do touch it, just beware of that fact.


Brilliant tip...I will definately try that out. Sounds a million times better than trying to cram a bunch of quick drying putty into a pin hole. I always seem to get it everywhere but the hole I want to fill.
Some say that he is a CIA experiment that went wrong, and that he only eats cheese. All we know is that he's not The Stig - he's The Stig's Fat American Cousin...
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Re: How to build a resin kit

Postby MoparGreg » Fri Sep 07, 2012 7:44 pm

Theres lots of great information in this thread. Ok Heres one for you resin gurus. I have been after a particular Resin Dodge crewcab for a while now. It was hard to find as they are no longer made. I ended up finding it & it arrived in the post during the week. It arrived like this -

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The roof is obvious & the front panel is bowed like a banana. Also the body is twisted. I spent about 30mins with some hot water yesterday & I had it looking pretty good. It was useable. WHen I woke up this morning it reverted back to its bent & twisted shape. It almost looks like I hadn't reshaped it.

Any ideas on this one? I have to say I was pretty disappointed when I opened the box & saw it. I dont want to have to spend another 12months trying to find another one. :(
Thanks
Greg
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Re: How to build a resin kit

Postby dreinecke » Fri Sep 07, 2012 10:22 pm

Greg,

I've had worse! (In my best Knight voice!)

Hot glue the body to a wooden board. I'd glue an appropriate sized block to the board that goes under the hood and roof to put it back to the right height. Run a hair dryer over it carefully and then let it sit for a few days/weeks depending on the twist. My Flintstone Javelin was 2x as bad...now you know why I was so happy...besides the lousy resin work on it...
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