Canopy molding anyone offering this service?

[Dennis Toth]

Is anyone doing canopy molding service? I carved a plug for a Barnstomer canopy and tried the shrink the coke bottle method not good. Would like it if someone does molding to pull a few canopies from my plug.

Best,    DennisT

[Tim Wescott]

Is anyone doing canopy molding service? I carved a plug for a Barnstomer canopy and tried the shrink the coke bottle method not good. Would like it if someone does molding to pull a few canopies from my plug.

Best,    DennisT

Hunt down Nick Zirolli models.  They did a canopy on a plug of my making.

They did an excellent job reproducing absolutely every flaw in the plug -- pay that in mind before you send it out.  I thought that the plastic would smooth out irregularities, unlike a fiberglass mold.  I was wrong.

[Tim Wescott]

This article has directions for making a plug as perfect as you can get it.  And it has a link to Nick Zirolli's plans service.

[Dennis Toth]

Tim,
Thanks for the information in carving the canopy plug, that's just the way I did mine.

A few years back Dave Midgley molded a lot of canopy's, anyone know if he is still active?

Best,    DennisT

[Air Ministry]

Dunno how youd go with This Bloke . https://parkflyerplastics.com/cart/index.php?main_page=index&cPath=46_67 think he's onto it .


P E T G is Soda pop Bottles , to us ! wash cut hole in bottom , shove the plug in , Throw in a packer & wedge to minimise shrinking reqd.

The start rotateing it , wearing gloves , maybe over a gas flame , going primarilly for the high slack & tight Conture areas firstish ,

Coke seems to be best shrikage / thickness . Some are useless .  1 1/2 litre spring water bottles are thin but good ' test ' pulls .
Gotta BLUE mineral water bottle at Aldi , havnt had em for yonks , but If I buy a dozen , theyll be on the shelf for decades .

for people with tatoos ,

for people without  ,

for normal impatent people ,

[Dennis Toth]

AM.
Thanks for posting those videos. I have tried this and am getting close. I think I need to use my industrial heat gun (I have tried a regular monokote heat gun and it is close but not quite there) for more heat to allow me to pull and stretch the bottle nose piece around the front of the canopy.

Best,     DennisT

[Trostle]

It will help if you cut the neck off of the bottle before you try to shrink it.  At least try it as an alternative if yo do not get satisfactory results.

Keith

[Air Ministry]

These gas cookers for camping , or a gas stove , work well .
Why did hitler commit suicide ?
He got the gas bill . 



The heat Guns are good . BUT - youve got to watch you dont scorch it , AND the plug .
So reaklly you want to finish the plug in epoxy or suchlike , with a bit of temperature resistance .
DOPE seems to de laminate , crack , blister & scorch , if the shape of the plugs anything but easy ,
within a few ' pullings ' .
The Thin spring water bottles are likely best for initial test pulls . SOME makes of soft drink bottle are way.

Some of these things have quite varied contours .


Mk VI Spitfire .


P 51




called the ' K ' = Dallas - Canopy , more steamlined aft , perhaps ? these bubble hoods were initially refered to as ' BLOWN ' ( Bpressure moulded ? )

you can pick the teardrop bulge aft ,



nitt picking / rivet counting , but in our case , where in what  sequence you go with the heat has a influance , so with no vacume , youve got to be selective stretching the ends etc early .

ALSO help to have a way bigger bottle than the plug - Only just big enough youll usually shrink the ends in & or split them / gettem to thin .


less shrinkable & compliant than others ( Virgin Vs recycled plastic ? who knows . maybe they arnt all P E T G )

Ive found the Australian coke boottles seem better , any with lots of surface detail on the bottle  wont loose traces
of it , unless you try a dozen times .

May be best if its being trouble to shrink in say three stages , letting it cool completely between .

I throw a stick / plank / block or whatever under the plug in the bottle usually , to take up the slack .

[Air Ministry]

This ones a example where you want to go in stages , polling it in AT THE ACUTE EDGE at the forward front , and holding with tack pins , tape , rubber bands - used them to pull the lower edge back .
POING .
once id got it going down .



But overall , most shapes are pretty basic . You only want to watch you dont scorch the mould / plug . 

[Gary Dowler]

I had canopies made by Parkflier plastics, as someone posted in their link.  He did a terrific job.  I made the plug that he worked off of.  Word of caution, the plastic WILL reveal every flaw in your plug!  It MUST be completely free of wood grain or other defects.  He sent me three for a pretty nominal price, and then asked if he could use my canopy to ad to his offerings!  So, if anyone needs a good canopy for a 1/9 scale PT-26, youre welcome! LOL

Gary

[AirClassix]

The late Bill Sawyer did a great job; I heard that Bill Little acquired Sawyer's molds, etc.  It would be great if someone could continue that service ...

Dennis

[Dennis Toth]

Well, more heat did not help just couldn't pull the nose down. The Barnstormer canopy is a little different than most in that it is tall and peaky rather than smoothly curved. I will try again starting with a bigger bottle like a 2-liter bottle. I will put the plug near the center and try to work the nose down first then do the sides and back. Will let you all know.

Best,  DennisT

[Air Ministry]

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yea . try a 2 x 1 under the plug . Or a piecwe of particle board / stuff . maybe cut at a angle( deeper fwd - up to 30 deg . ? ) maybe superglued .

The bigger bottle'l give you more shrink , pull it in all around , mostly from the other side . so the tensions ready to pull it round the plug .

If all else fails , two sticks ( four actually ) screwd together each side of a sheet of acetate or whatever . the Garden stuff at the builders supplies maybe .
tho is fairly wastefull . Oven 7 gloves ( or stovetop ) catch it as it smookes / sags , Great Fun . 

Heres a ' PLUNGE ' moulding one , where you nail the plastic sheet to a hole that matches the canopy plug .    http://www.ffscale.co.uk/page4f.htm



ply or blah board .

[Tom McClain]

Hints and Tips
•   Shrink Form Your Own Canopies, RCM, January 1996, Dan Simenson.

   How to "Shrink Form Your Canopies" was worked up as a simple way of making canopies for scratch-builders.  It utilizes the plastic in 2 liter pop bottles, either clear or green tinted.  With essentially free material and your hot air gun, you are ready to try it.  It works well for canopies up to about 8-1/2" long and with the Alternate Method up to 11-1/2" long.  That seems to the practical limit, as an opened up and rolled out 2 liter bottle gives a piece of material about 13-1/2" long.  They are fuelproof and are not affected by acetone, MEK, or dope thinner.  RC-56 cement works well for installation.  Currently, I have several in use: an 8-1/2" on a .10 sized "Turbulent City," two 5"x3"x2-1/2" deep units on .40 sized models and an 11-1/2" on a .65 sized sport model.  This process works for making engine cowlings also, but that's another story.

   The canopy pattern or "plug" can be carved from any clear wood: balsa, pine, cedar, poplar, etc..  For best results, the plug should extend about 1/4" beyond the edges of the desired canopy.  Final sanding of the plug should be with 220-grit paper.  Do not paint.

   (1) Mark a trim line and center tics on the plug with a felt tip permanent marker.  Remove the label and cut both ends from the 2-liter pop bottle.

   (2) Slip the plug and a scrap block of wood into the bottle, positioning the plug in the center of the bottle.  Wedge a small block between the plug and block of wood to make a snug fit.

   (3) Start shrinking the bottle around large bottom block first.  Keep the gun moving.  Next shrink the sides, then around the plug at the ends.  Avoid too much heat at the very ends or they may curl up.

   (4) When almost shaped, go over the whole surface carefully to get the last ripples out.

   (5) Trace trim line and center tics on the plastic with a felt marker.  Marks can be cleaned off later with acetone or thinner.

   (6) Cut canopy along the trim line.  After final fitting and cleaning, attach with RC-56.

Alternate Method for Canopies Up To 11-1/2" Long.

   (7) Cut ends from bottle as before.  Split down one side.  Pull Sheet snug from front to back over the plug, placing tacks at each end beyond the trim line.  Then pull down at the sides and tack or nail in place.  Tacks or small nails about 2" long and can be used and need not be driven all the way in.  There will be large "billows" along the sides, but they will shrink up.

   ( Apply heat to the large wrinkles first, alternating sides as you work from the center towards the ends.  Finally, go over the entire surface carefully until it is smooth.  Trace the trim lines and center tics before cutting out the canopy.

[Trostle]

To add to Tom's excellent outline on how to do the canopy shrinking process.  I want to emphasize that the resulting canopies are quite sturdy and completely fuel proof.

I have found that carving the "plug" from bass wood works very well.  It can be sanded to a very smooth surface.  It really is not necessary to coat the plug with any finishing material, but finishing resin works very well.  Whatever wood grain there is that appears in the plug does not become evident in the finished canopy like other canopy forming processes.  After installation, the canopy can be finished with whatever clear coating you would want to use with any other installed canopy.  The clear coating will not peel off, even after years of service.

This process will give you a canopy you want for your design and not have to compromise with a commercial canopy that is not quite the right size or shape you want for your model.  The material is cheap.

Keith

[Steve Helmick]

NW Skyraider's Eternal President, Mike Potter  has a vacuum table and will make a kustom kanopy from sheet plastic. He's a member (skyshark58) here...sometimes hangs in the Navy Carrier forum.  Steve

PS: True "Basswood" is quite a bit harder to get (and more $) than Poplar, which is very close to the same stuff and available at most lumber yards, Lowe's and Home Depot. Really nice stuff with close grain and few knots. Basswood's Latin name is "Tilia Americana". There are many varieties of Poplar, each with a different Latin name, of course. But trust me, go to your local lumberyard or home improvement store and buy Poplar.