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Scratch Building - OMG, Gimmy a Brake


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#1 Alyn

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Posted 01 September 2012 - 07:07 AM

I'm building the custom version of AMT's excellent 62 Pontiac Catalina kit. While most cars these days have power brakes with the necessary booster, this kit does not. There's only a small, single piston master cylinder which mounts to the firewall. I wanted to dress it up a bit, so I figured adding a booster would help. Here's how I did it:

The main component of the booster is a fat, round disk. Flat styrene could be sandwiched to a suitable thickness and then cut into a round shape however, by starting with tubing, the part will be perfectly round from the start. Tubing the next size down was used to add some working thickness.

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.080" Flat styrene was glued to the squared off end of the tubing. I didn't worry about the shape of the flat material. That will be trimmed once the glue dries. The thicker flat stock was used once again to provide enough material for rounding and shaping.

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Here's the tube after the .080 was cut down and shaped to match the profile of the tubing. The edges were rounded over to rough in the booster shape.

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The end of the tube was then cut off in a miter box to keep it true. I grabbed a scrap of .030" styrene card stock and then using a file and drill, created a flange where the brake master cylinder will mount to the booster.

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To finish it off, the master cylinder was glued into the center hole of the flange. bolts were glued on for some added detail. I also cut a small slice of aluminum tubing to emulate a brake line fitting. Paint is craft store gloss black and Model Masters magnesium. The jury's still out on whether or not the cap will be spiffed up with some Alclad or BMF.

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You can see the Pontiac WIP here:

http://www.modelcars...opic=45830&st=0

Edited by Alyn, 01 September 2012 - 07:19 AM.


#2 Joker

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Posted 01 September 2012 - 07:17 AM

Neat lil' how to Alyn.
I appreciate the clear uncluttered pixs and the simplicity.
Thanks for sharing the knowledge.

#3 Custom Mike

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Posted 01 September 2012 - 07:25 AM

Great tute Alyn, simple yet very effective!

#4 Alyn

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Posted 01 September 2012 - 07:26 AM

Thanks, guys.

Simple is good !

#5 blueoval92

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Posted 01 September 2012 - 07:43 AM

man you have answered a prayer of mine. i have been trying to find a booster from a kit to use in my current project. im goin get some styrene as soon as i can make a trip to hobby town.

#6 Alyn

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Posted 01 September 2012 - 10:01 AM

I tried some BMF on the master cylinder cap, but couldn't get all the wrinkles out. Then the thought of using aluminum popped up. Don't know why I didn't consider this from the start. I used a piece of 3/16" rod and turned it down to ~ .156" after measuring the existing plastic cap diameter. The top of the cap has a slight bevel leaving the middle of the cap flat. I also bent up some jewelry wire for a brake line. Just have to glue her in place now.

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#7 crazyjim

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Posted 01 September 2012 - 10:25 AM

You make it look so quick & simple, and the part is so effective.

#8 Chuck Most

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Posted 01 September 2012 - 03:44 PM

Good, solid technique!
My only gripe is a personal taste thing- if I were upgrading to power brakes, I'd have swapped in a dual-chamber cylinder. B) That being said, the original fruit jar looks pretty nice with the metal cap and line in place.

#9 jbwelda

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Posted 11 September 2012 - 10:56 AM

that looks really sweet, i am going to have to try it on something.

thanks for posting!

#10 vypurr59

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Posted 11 September 2012 - 01:24 PM



The master cylinder you made looks exactly like the one in this video.
Very nice job, and thank-you for it....will help me in the future.

Edited by vypurr59, 11 September 2012 - 01:26 PM.