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How To: Cutting out vac canopies
PorkChopper
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Florida, United States
Joined: November 16, 2009
KitMaker: 34 posts
AeroScale: 12 posts
Posted: Wednesday, May 30, 2018 - 03:40 AM UTC
Good article! I found it looking for tips prior to working with my first vac canopy. I ruined the canopy of a 1/48 JAS-39 Gripen by trying to "gently" polish it with a Dremel. Derp...

I would add the following observations:

- If you have the original canopy, it can be very useful as a form to provide strength to the vac while working with it. It will probably nest inside well.

- Use the sharpest scissors you can get your hands on. Cheap scissors are a no-go for this job.

- Removing the excess "base": Do test cuts. Nibble away at it until you can really tell how the plastic will react (does it crack easily).

- The importance of scoring the plastic cannot be understated. This will prevent cracks from "racing" into areas you don't want them to. Same principle as drilling a small hole in a car's windshield to stop a crack from spreading.

- If you use a razor saw, remember that it generates heat. Factor a tiny bit of melt into where you decide to make your cut. Don't get too close the the canopy's frame. Draw the saw towards you, don't try to move in both directions.

- Finally, go slow and have patience. If in doubt, don't cut, sand.

I took my time, worked methodically, and was pleasantly surprised with the results. I won't hesitate to use vac canopies in the future.
ghostlanc
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Canada
Joined: February 02, 2014
KitMaker: 1 posts
AeroScale: 1 posts
Posted: Saturday, February 01, 2014 - 12:54 PM UTC
Thanks, Jessica. I enjoyed your article, especially the idea of using epoxy putty to form a bed for the canopy. Cheers
chris1
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Auckland, New Zealand
Joined: October 25, 2005
KitMaker: 918 posts
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Posted: Sunday, January 26, 2014 - 07:23 PM UTC
Jessica
Thanks for putting the article together,
I'm not quite so frightened of Vac Form canopies now I know what to do.

Chris
jowady
Joined: June 12, 2006
KitMaker: 1,027 posts
AeroScale: 131 posts
Posted: Saturday, January 25, 2014 - 03:55 PM UTC
Well no plaster or silly putty, just a new blade and a lot of patience ( and a sharpie) and I have successfully cut out my first vac canopy. And I only stabbed myself once( I guess I should add a bandaid to my list of tools)! But it worked fine and the blood washed right off!

Actually the method worked perfectly I stabbed myself because of my own clumsiness.
Jessie_C
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British Columbia, Canada
Joined: September 03, 2009
KitMaker: 6,633 posts
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Posted: Saturday, January 25, 2014 - 07:17 AM UTC

Quoted Text

Also it is not hard and when if you press hard with a knife or other tool the plastic can still flex and crack.



Which is why I stress how important it is not to press hard. Multiple light scoring passes with a brand new blade are far preferable to one hard cut.
Antoni
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England - East Midlands, United Kingdom
Joined: June 03, 2006
KitMaker: 574 posts
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Posted: Saturday, January 25, 2014 - 06:15 AM UTC

Quoted Text


Quoted Text

Fill the canopy with Plaster of Paris



That sounds like a good idea. I think you would have to use a release agent, though.



Never had any problem removing the plaster plug, it usually drops out very easily. You can file down the plaster afterwards and if you have one of those double moldings with a spare canopy back to back you can separate them by cutting through with a razor saw.

The problem with Silly Putty and Blutac is putting it in not taking it out. Some canopies are very thin and fragile and forcing in putty can cause cracks and/or white stress marks. Also it is not hard and when if you press hard with a knife or other tool the plastic can still flex and crack.
Jessie_C
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British Columbia, Canada
Joined: September 03, 2009
KitMaker: 6,633 posts
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Posted: Saturday, January 25, 2014 - 05:22 AM UTC
You can also use silly putty or blue-tack to achieve the same re-enforcement under the canopy without the need to worry about getting it back out later. This is especially useful if you want to cut the canopy open.
Mcleod
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Alberta, Canada
Joined: April 07, 2010
KitMaker: 1,028 posts
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Posted: Saturday, January 25, 2014 - 04:21 AM UTC

Quoted Text

Fill the canopy with Plaster of Paris



That sounds like a good idea. I think you would have to use a release agent, though.
Antoni
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England - East Midlands, United Kingdom
Joined: June 03, 2006
KitMaker: 574 posts
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Posted: Saturday, January 25, 2014 - 04:12 AM UTC
Fill the canopy with Plaster of Paris it will support the canopy and stop any flexing that might cause cracks to form. If a knife blade cuts through the plastic it will cut into the plaster and not deflect. Same if you need to drill any holes for machine guns etc.
jowady
Joined: June 12, 2006
KitMaker: 1,027 posts
AeroScale: 131 posts
Posted: Friday, January 24, 2014 - 06:19 PM UTC
Thanks, I'm just about to cut out a P51 canopy and I'll try this
JPTRR
Staff MemberManaging Editor
RAILROAD MODELING
#051
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Tennessee, United States
Joined: December 21, 2002
KitMaker: 7,184 posts
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Posted: Friday, January 24, 2014 - 04:30 PM UTC
So that's how it's done! Thanks Jessica, very useful.
Jessie_C
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British Columbia, Canada
Joined: September 03, 2009
KitMaker: 6,633 posts
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Posted: Friday, January 24, 2014 - 12:14 PM UTC
Vacuform canopies are not as intimidating as they're made out to be. Here's a simple method to prepare your canopy for use without destroying it.

Link to Item

If you have comments or questions please post them here.

Thanks!