Author Topic: Shrinkcasting HO scale vehicles to N scale  (Read 5944 times)

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Plumcrazy

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Shrinkcasting HO scale vehicles to N scale
« on: March 16, 2013, 11:38:10 PM »
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Hi Everone , I wanted to share some of my experience on shrinkcasting . I first read about shrinkcasting on this and other N scale forums . The best one I read was on Trainboard.com How to cast n scale vehicles from larger scale masters by rasputen . After I read rasputens Post I had to try my hand at shrinkcasting.

I have been shrinkcasting for a few months now ,and I have been getting good results

I start by making a silicon rubber mold of the vehicle I want to shrink to N scale . In this case an HO scale  Motomax Mercury Bobcat .








After the mold has cured it is ready for casting . I usually cast the Hydrospan in three different ratios of resin and water . I use two 2 ounce medical dispencers to measure the proper portion of resin and water ( I find Dram measurements work the best)
The first casting I use 1 part resin to 4 parts water the second casting 1 part resin to 4.5 parts water ,and the third casting 1 part resin to 5 parts water this gives me a better chance of getting closer to scale

Hydrospan cures very quickly so I use refridgerated water to slow down the curing it also has to be mixed thoroughly I mix it for about 20 seconds .This only gives you about 1 minute to pour in the mold .


when the Hydrospan mixture has set it has the color and the consistancey of a poached egg white . It can be removed from the mold in about a couple of minutes ,but you have to be careful ,because the casting is fragile . I set the castings aside to dry . I takes about 5 to 7 days to dry out and shrink to its final size



I measure the shrunk castings and pick the one that is closest to the N scale size of the vehicle (usually within .010 of an inch or closer)


I now make a silicon mold of the newly shrunk vehicle . After the mold cures you can start casting with resin to make the n scale model







The newly cast bobcat trimmed can be used as is ,or hollowed out and have windows added


I hope this post is helpful

Alex

LV LOU

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Re: Shrinkcasting HO scale vehicles to N scale
« Reply #1 on: March 16, 2013, 11:55:12 PM »
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I've been dying to try that stuff..Hey,here's a stupid question..Since it's so easy to damage the casting removing it while it's still mushy,why not just let it dry right in the mold,and let it remove itself?

pennsyfan1361

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Re: Shrinkcasting HO scale vehicles to N scale
« Reply #2 on: March 17, 2013, 01:57:00 AM »
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Alex, Great article on how to shrink vehicles. I really like the job you did with the autorack car loaded with AMC Pacers and Gremlins with clear cast windows.  8)  Looking forward to seeing more of your cars. Thanks Rich 
« Last Edit: March 17, 2013, 06:58:02 PM by pennsyfan1361 »
Modeling  PENNSYLVANIA RAILROAD 1956-1966 Harrisburg and the Northern Division                                                                                                     CONRAIL 1976-1983 Harrisburg Division

Plumcrazy

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Re: Shrinkcasting HO scale vehicles to N scale
« Reply #3 on: March 17, 2013, 10:30:10 AM »
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I've been dying to try that stuff..Hey,here's a stupid question..Since it's so easy to damage the casting removing it while it's still mushy,why not just let it dry right in the mold,and let it remove itself?
Not a bad Idea ,but I usually make about three of each model ,and this would tie up the mold

Plumcrazy

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Re: Shrinkcasting HO scale vehicles to N scale
« Reply #4 on: March 17, 2013, 10:37:21 AM »
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Alex, Great article on how to shrink vehicles. I really like the job you did with the autorack car loaded with AMC Pacers and Gremlins with clear cast windows. 8) Looking forward to seeing more of your cars. Thanks Rich 
Thanks for the compliments Rich ,and thanks again for showing me how to post photos     

jimmo

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Re: Shrinkcasting HO scale vehicles to N scale
« Reply #5 on: March 17, 2013, 11:53:50 AM »
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On that first mold box, you should give the sides a little more mold. On an object that size you need about a 1/2" or more of sidewall unless you are not planning on using it after the initial cast. Over time they tend to bow in and that makes for some weird castings.
James R. Will

Ed Kapuscinski

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Re: Shrinkcasting HO scale vehicles to N scale
« Reply #6 on: March 17, 2013, 12:11:45 PM »
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Whoa. So this really is a "reduce it in a xerox" type thing... that's pretty awesome!

Thanks for sharing this cool technique.

SW1500, here I come... lol (j/k, that'd be more of that real modeling that I don't do  :lol: ...)

randgust

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Re: Shrinkcasting HO scale vehicles to N scale
« Reply #7 on: March 18, 2013, 02:41:07 PM »
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This is just awesome, one of those things I'll have to try even if I have to invent a reason.   And it's not April 1 yet, wonderful!

Those of you that have been Atlas N forumites for a decade or so will remember "N Scale Norm and the Amazing Shrink-Ray" adventure by Warbonnet Fan (Verne).  Norm's now retired to my layout and we'll have to go over to the Home tonight and rouse him from a game of Timetable Bingo (KCLA-23!) to see if we can get him fired up about this concept.

I think this is a great trick, not sure I understand it... But I sure would love to have some of the vehicles that the HO guys get.  Wonder if anybody makes a 1970 Opel Kadett station wagon?  If you're reading too much into that statement, you should be...

DKS

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Re: Shrinkcasting HO scale vehicles to N scale
« Reply #8 on: March 18, 2013, 02:47:49 PM »
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Wonder if anybody makes a 1970 Opel Kadett station wagon?
Ah! My very first car. Fond memories of that little beastie...

My one concern about this process is the potential for IP infringement.
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jnevis

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Re: Shrinkcasting HO scale vehicles to N scale
« Reply #9 on: March 18, 2013, 03:53:10 PM »
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Ah! My very first car. Fond memories of that little beastie...

My one concern about this process is the potential for IP infringement.

I think you'd be OK as long as you only did them for yourself.  As soon as you gave one, or sold one, to soemone else it would be an issue.
Can't model worth a darn, but can research like an SOB.

Catt

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Re: Shrinkcasting HO scale vehicles to N scale
« Reply #10 on: March 18, 2013, 04:09:35 PM »
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Quote
I think you'd be OK as long as you only did them for yourself.  As soon as you gave one, or sold one, to some one else it would be an issue.

I doubt that giving one to some one would be an issue your not making a profit from someone elses work.
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sirenwerks

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Re: Shrinkcasting HO scale vehicles to N scale
« Reply #11 on: March 18, 2013, 04:10:40 PM »
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Simply amazing.  I can think of a ton of HO models I would like to shrinkcast.  The only thing I would do differently is remove the wheels prior to casting the original and cast the final outcome in a clear resin to get the see-through effect.
Now seeking Pacific NW N scalers to create a Modutrak-style modular club featuring NP's shared mainline between Seattle and Portland. PM me if interested.

ljudice

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Re: Shrinkcasting HO scale vehicles to N scale
« Reply #12 on: March 18, 2013, 04:35:15 PM »
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That is amazing...

bbussey

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Re: Shrinkcasting HO scale vehicles to N scale
« Reply #13 on: March 18, 2013, 05:11:58 PM »
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I think you'd be OK as long as you only did them for yourself.  As soon as you gave one, or sold one, to soemone else it would be an issue.

With the (low) quantities that would be realized, as long as the items are not sold it wouldn't be an issue.
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randgust

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Re: Shrinkcasting HO scale vehicles to N scale
« Reply #14 on: March 18, 2013, 05:15:34 PM »
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Ah! My very first car. Fond memories of that little beastie...

My one concern about this process is the potential for IP infringement.

Good God, David, isn't it enough we already look like each other?   We had the same car too?
I'd need to put prototype-sized oil stains everywhere around a model.  Head gasket leaked constantly.   Actually ran out of gas on dates because the gauge stuck, and couldn't be kept in alignment.   Was a good snow car though, one good benefit for being significantly underpowered.   So of course, everybody that's ever had a 70's Pinto, Gremlin, Chevette, Opel or Vega wants to recreate the memories!

I agree there's likely infringement issues in there.  I know if somebody took one of my (or your) products and resized it down with this stuff (TT?) there's be some throat clearing when it's clearly made from a master that is already copyrighted.   And the 'personal use' doctrine is accepted as long as you buy a copy of the original work to work from.    I do the same thing with decals, but yeah, I buy the original set and don't resell them.