DRCRAIG

My Feedback: (31)

Greetings all,
Does anyone know how to, or who can, duplicate a vacu-form
canopy from a vintage kit without destroying the original? I
have been in touch with Parkflyer Plastics but their process
warps the original because of the heat invoved in the process.
Thanks in advance for any and all advice.
Craig

PatternPilot

My Feedback: (58)

sent you pm

MTK

It might be easier in the long run (and lighter) to cast the canopy in fiberglass. It's a 2 step process that's not too difficult.

It requires making a mold first and then casting the part.... Mold making requires a good release wax like PartAll and a fine spray of PVA. Then after the PVA has dried, one can build the mold from the original part using a good lay-up epoxy, cabosil for thickening and some heavier glass for the reinforcement layers

Part making also requires the same waxing and PVA spraying for easier part pulls. For vintage pattern models, glass weight doesn't need to be extravagant since the canopies tended to be small and nonweight bearing;I use 1 layer 0.6 oz first as a fill layer and1 layer of 1.8 to 2.4 oz second.This process will exactly duplicate the original part

doxilia

My Feedback: (3)

Craig,

Park Flyers may destroy the original in the process but the replacement that you'll get will be better. We have had several canopies done by them and they all turned out great.

David

bandit_av

My Feedback: (1)

Hi Craig
I had to lots parts copies of detailing for my jet (lamps covers, new hatch etc. etc.) so, there are lots of
youtube videos about making molds with a lot of materials choices.
personally for my needs i found out that to make molds or copy parts, I like to use a special silicon for molds.
but, it is costly, so for big parts, I'm using a special polyurethane (which I can't remember the name, and it is not
matter because your options for materials are much much bigger than for me in my country).
Search the youtube for making molds and you will find your answer for almost any need, and how to do it.

best regards
Avi

bandit_av

My Feedback: (1)

Forgot!!!
If your wishes is for clear canopy you can do a hard mold using the hard polyurethane material and after that you can
use a clear thin material like in the link... http://shop.optotronix.de/index.php?...ing-Sheet.html
and it is done with heat gun and a lot of patience .

Good luck
Avi

8178

My Feedback: (17)

Here is a link to how my friend Tony made one for my Blue Angel using a priceless original MK canopy http://www.rcuniverse.com/forum/m_4107817/tm.htm

Jon Wold

8178, thanks for the useful link. I've wondered about the same thing many times.

If you're willing to risk the canopy though, it's quite easy to make a carbon copy (pun intended) as per Ola Fremmings handy guide: http://ofremmi.info/HowTo/CarbonCano..._and_epoxy.htm

8178

My Feedback: (17)

Interesting idea!

In our case the original canopy was on loan and priceless, so we could not risk any damage.

bjr_93tz

I used to just build up a couple of layers of plaster of paris into the original then pop it out.

It didn't do any damage to the original and the plaster "plug" had a smooth, reasonably hard surface to vac form down onto.

Different plastics may respond differently to plaster but I didn't have any problems, although I made sure I didn't mix up a huge batch and just fill the whole original canopy up so as to avoid any surprise heat buildup.

hrdflite

LAST POSTING IS THE EASIEST WAY TO GO .PLASTER BUCK,

Pattern One

My Feedback: (73)

Hi Everyone,

I use: Durham's Rock Hard Water Putty available at Home Depot. I found that plaster will crack over time. I pour the water putty into the original canopy after applying serval coats of a good automotive wax. Let it cure for a few hours then it just pops out. Depending on the canopy size it does take some time to cure. For that I borrow the home oven set at about 200 degrees. You do not want the water to boil that is left in the plug. I run it through several cycles and it cures very hard and very smooth.

I mix the water putty in a mixing bowl with a mixer so it looks like pancake batter. You need to make one pour. I found if you try smaller pours in layers that you get too many bubbles and imperfections. After the canopy has completely cured I spray on a cheap spray bomb automotive primer. After the primer cures I sand with 600 grit and then 1000 grit paper. My two cents.

Leo