Resin Shrinkage

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prisoner_1079
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Resin Shrinkage

Post by prisoner_1079 »

I was wondering, when designing a master for a resin kit, is it necessary to build the original slightly larger than the ship should be in order to counteract resin shrinkage?

Also, on a related note, if one were to make a kit of something that has multiples of the same part, would it be ok to make a mold of the single piece, then use the resin copies to make a mold with however many copies of the part you need for the kit? Or is it better to just make several individual molds using the original master?
Currently building: 1:2500 Prolemy Tug/Freighter and Finish painting Gold 2 X-wing from box scale ERTL X-wing based on XW Alliance game. See website for progress.

https://heimdudebro.wordpress.com/
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Johnnycrash
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Re: Resin Shrinkage

Post by Johnnycrash »

prisoner_1079 wrote:I was wondering, when designing a master for a resin kit, is it necessary to build the original slightly larger than the ship should be in order to counteract resin shrinkage?
No, it is not necessary to build the master over-sized. UNLESS, you are looking to cast it in metal. Whole different ball game.
Also, on a related note, if one were to make a kit of something that has multiples of the same part, would it be ok to make a mold of the single piece, then use the resin copies to make a mold with however many copies of the part you need for the kit? Or is it better to just make several individual molds using the original master?
Make one, mold it, cast it, and you are ready to roll. Not necessary to make the same part over and over. If you have a part that has a base shape that is the same, but with left/right handed details added to it; Make the base shape, mold it, cast it, detail it out handed. And you are ready to roll. Again. :)

The shrinkage on modern resin is very minimal. Some more than others, of course, but usually in the 1% or less range. And for most of the modeling applications, that's not a factor for fit and finish.
John Fleming
I know that's not what the instructions say, but the kit's wrong anyway.
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prisoner_1079
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Post by prisoner_1079 »

Ok cool, thanks for the tips!
Currently building: 1:2500 Prolemy Tug/Freighter and Finish painting Gold 2 X-wing from box scale ERTL X-wing based on XW Alliance game. See website for progress.

https://heimdudebro.wordpress.com/
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aussie muscle
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Post by aussie muscle »

or if you use a two-part resin, like body filler, you wont get any shrinkage because the reaction is chemical based, rather than evaporative.
"Look at Walter [Koenig], after Star Trek, he became an actor!" - Phillip Fry, Futurama.
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Joseph Osborn
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Post by Joseph Osborn »

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prisoner_1079
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Post by prisoner_1079 »

I knew it was gonna be Seinfeld as soon as I saw the youtube link.

:thumbsup:
Currently building: 1:2500 Prolemy Tug/Freighter and Finish painting Gold 2 X-wing from box scale ERTL X-wing based on XW Alliance game. See website for progress.

https://heimdudebro.wordpress.com/
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