Author Topic: Mould making  (Read 96 times)

Offline Joe Wotton

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Mould making
« on: 12, January 2018, 03:05:14 PM »
Hi,I am currently building a retro pattern model (Clipper 3) and have decided to have electric power.
The build went ok until I realised that once the cowling blocks were added I would not be able to install or remove the motor due to not being able to get to the bolts !
The only way I can see to overcome the problem would be to make a one off mould from blue foam but I have never moulded anything before in my life,so wondered if anyone knows of any modelling articles that would help?
Regards Joe

Offline Alan Wild

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Re: Mould making
« Reply #1 on: 12, January 2018, 04:21:15 PM »
I don't remember reading anything specific, Joe, but I used to make one-off chin/undercowls in the 2-stroke pattern days of yore.
Just epoxy tack glue an oversized blue (or pink--either carve/sand OK) block to where you want the part to go, carve/sand it to shape, then carefully cut (scalpel) or fine saw the block free.
Then laminate three or four layers of c.60 gram glass cloth/skinning epoxy, or two layers of 200gram twill weave carbon cloth,and rub in some microballoons into the top layer--the hardest bit is then to get a smooth enough surface finish--never my strong point--by sanding, adding a bit of soft filler of your choice if necessary.
Then trim the margins to shape--easier to see with glass cloth (scissors/scalpel/sanding block)---hack out most of the foam by hand tools , and dissolve out the remains with cellulose thinners.
Drill a few mounting point holes ,reinforce the insides if needed with extra patches of cloth/cyano, and the shape is done.

Offline Joe Wotton

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Re: Mould making
« Reply #2 on: 12, January 2018, 05:18:53 PM »
Thanks Alan,your help is very much appreciated.
Regards Joe