Moulding Canopies

[A.A. Barry]

Gents, which way is the best method of designing and moulding  your own canopies, the are hundreds of ways, which works out the best???? and what materiel and where to get it?........     eh umm, in detail please?

A.A.Barry

Edited By A.A. Barry on 25/03/2010 10:57:44

[Ed Darter]

coke bottle & a wooden plug usually does the trick....

make a wooden plug of the required shape. Cut the end from the coke bottle and insert the plug into it. You need to make sure the plug is firmly pressed against the plastic of the bottle, by packing the underside of the plug if necessary. Then gently heat with a hot air gun or similar.

Edited By Ed Darter on 25/03/2010 12:23:05

[Lee Smalley]

it depends what method you use!

i used two frames clamping acetate sheet heat the sheet up just so it sags and then push frames over mooden plug, let cool then remove fairly simple just a bit of a mess making the frames etc

[RonSpencerUK]

Lee

 

Where do you get the acetate sheet, and what grade/thickness do you use? 

[A.A. Barry]

YES, very enthrawling post this must be,   uuuuummmmmm, must be a well known art, meaning everybody that knows, thinks everybody else knows

Not So.....there must others out there in this large membership, who have there ways to mould one.................??????????

 thanks to the 3, yes 3 .. gentlemen who did

A.A.Barry 

[Richard Wood]

I used to build up canopies with balsa block & sheet & then spend a few

happy hours carving, planing & sanding to shape. Followed by filling the

grain with sanding sealer & more sanding & repeating this until happy

(or fed up).

The end result was sprayed with dark blue,black or silver.

Whether this method is useful depends of course on the type of canopy

you're doing.

That's 4 replies now mate which TBH is sometimes a good score.

 

Edited By Richard Wood on 26/03/2010 09:49:07

[A.A. Barry]

Richard , Ta, not sure what you mean by TBH????

B 

[Richard Wood]

To Be Honest

 

[Lee Smalley]

you can get acetate sheet from any good model shop and most bad ones too its used by the dolls house fraternity and the plastic model makers, its been many years since i last did it i can't remember what thickness i used i think i experimented because the canopy i was making was a deep one so i had to usequite a thick sheet, if however you are doing a shallow style then of course you can use a thinner sheet,

 

here is my old method

make 2 wooden frames just smaller than the sheet you want to use (normally A4) make the frames so that you can screw them or clamp them together when the sheet is in between, i then used to use an old electric fire and hold over (with gloves on) until the sheets sags (you will have to experiment here) and the push over the plug you have made (the plug is better if it is on a plinth of some form )  please note if you manage to set fire to anything i will disavow any knowledge and move to france

[A.A. Barry]

Gents, 141 "visits" and only 5/6 replys, obivesly, a lot of interest, but not much input from those who know, "which is the.....

A.A.Barry

[Matt Halton]

I made a plywood box (years ago now) about 2.5ins deep, A-4 paper sized. Drill holes accross the top layer about 1/2"apart all over it.You then need a frame,mine is 2 layers from 1/2"\sq hardwood, this is to clamp the material with.

 

embed some nailpoints into one frame with epoxy,and drill corresponding clearance holes into the opposing frame., I have attached some pics for you.

 

You need a domestic vac cleaner, ensure it isn't bunged up before use, empty or replace the bag too.

 

I use tape, vnyl,or metallic tape to seal the frames together. Make up a rubber seal to fit around the frame base.

 

Heat oven to full power, use bricks or similar to support the frame in the oven,or you might find your material has sagged onto the oven shelf frames.

You need to work very quickly when removing the heated plastic from the oven, make sure vac cleaner in on before you do this.

Last tip, do this while the wife is out,it will only get her back up.

 

I hope this helps-remember, most importantly,the box has to be airtight.

Experiment with epoxy covered pink foam-don't doit, you need wood,or plaster,or even car body filler, I found this to work best.

A car body filler plug,easily the best method.

Pet-G sandwiched between frames

Plug in position-note vacuum cleaner hose taped on to tube built into the unit.

After moulding

Fresh from the oven.

Adding canopy frames with paper-optional.

Edited By Matt Halton on 05/04/2010 16:03:26

[A.A. Barry]

Thanks Matt

A.A.Barry

[Erfolg]

Have a look at the "Mikes Models" website.

 

There are two methods, described there. In my opinion the cartridge gun and paint stripper/heat gun method works very well, using anything from coke bottles to sheet.

 

Worth a look.

 

Erfolg

[Tim Mackey]

I cant see it ?

[Erfolg]

Thats because you looked up Mikes Models

 

What you need is:-      http://www.ffscale.co.uk/

 

Erfolg

[A.A. Barry]

Erfolg,Matt, and others who have contributed, thanks, now I have a chance to at least get some better results than before. now where to obtain the acetate sheet, or what is most suitable in thicknes ??

A.A.Barry

[Alan B]

Thanks all - Interesting thread. You are right Erflog, it was worth a look. I have always wondered how it was done by modellers.

 

Al

[Erfolg]

This thread has inspired, or perhaps a better description is prodded me into action.

 

I am making a sealant gun assembly.

 

I have previously tried the drape method. It worked well, but required a lot of haste, to get a satisfactory result.

 

Although not mentioned (I think) I have also used the male plug and female plattern method. Which required more work than the other methods. That is other than the initial work to build the vacuum method, which is almost certainly the best, large volume canopy system. This male female method, was not as good as the drape system from my own experiences.

 

I have heard of good results from the sealant gum method with pop bottles, for the one offs that we generally require.

 

Erfolg

[Ernie]

Hi guys

I wonder. I've tried the coke bottle bit, but the result is always very thin, and hence prone to damage.

Most full size aircraft avoid the problem, by dividing the canopy into smaller bits, usually with very little curvature

The problem for us, is of course joining the wee bits inder a fine frame

Sorry, don't know the solution, but someone might

 

ernie

[Erfolg]

Ernie

 

I know that there will be many who have more experience of moulding.

 

I have noted a number of phenomena though..

 

Many of the moulded packaging materials, when heated enough, revert to nearly flat sheet.

 

When using previously moulded items, like PET, coke/lemonade bottle, it is essential to get the material hot enough, so that the material tries to revert to a sheet (although i am sure you know bottles are typically blow moulded).

 

What I find difficult is getting to that temperature, to cold and the material is difficult to mould and thins a lot locally. To hot and it blisters or just disintegrates, into a floppy mess.

 

That is why i am hopeful that the heat gun could be the answer, then again maybe not, time and experience will tell.

 

Erfolg

 

 

[A.A. Barry]

THanks all that have made there pic's and ideas available, but what is the ideal thicknes????? 0.25 or 0.42mm any body

A.A.Barry

[Ernie]

Hi AA

It really is difficult to say, it depends on so many variables...ie overall size, heat source available, quality required  (eg the chris foss ones are really thick, and beautifully moulded)

My advice, as is so often the case, is to experiment. I know, it often takes me several tries to get something like that just right.....I'd start with the thicker option

 

ernie

[Erfolg]

Ernie

 

Could not agree more. The minimum thicknessis very much dpendant on the  depth of draw necessary. 

 

Erfolg

[Alan Hall]

I'm building the TN Hurricane and decided I would like to have landing lights and nav lights on it. I bought some LED's on the net and installed them prior to sheeting the wing.

 

I then marked their location on the wing sheeting so that I would know where they are when I added the leading edge and wing tips.

 

I made sure that I did not glue the leading edge or wing tips on the area where the landing/nav light LED's were. When dry,

 

I carefully cut off a bit of the leading edge wing tip' (missing the LED's) and kept these for use as plugs to make nav light covers.

 

I did the same with the landing lights, cutting a section out of the leading edge. I used a razor saw for this fine work.

 

I the added some 1/4 inch balsa either side and on the rear of the landing light plugs and the inner side and rear of the nav light plugs.

 

Lastly I made some holes slightly larger than the plugs in a sheet of 1/8 ply with the intention of clamping some plastic over the hole, heating it with my heat shrink gun and pushing the plug through to produce a clear plastic cover for the lights.

 

Now we come to the nitty gritty. I tried to heat some pop bottle plastic with the gun but it just shrivelled and would not become soft enough to push the plug through.

 

Lastly I decide to try inserting the plug into the inside of a pop bottle with the bottom cut off.  I packed the space behind the plug to take up the slack so to speak and fired up the heat gun. This worked fairly well but took several attempts that exhausted my supply of bottles before I got a reasonable moulding.

 

I've just heard from a mate that easter egg packaging is good for moulding. You know, the two plastic shells that clamp around the chocolate! (I love chocolate!).

 

The biggest problem I have found is sourcing a supplier of suitable plastic sheet for either plug moulding or vac forming which is something I would like to try and do. Has anyone any idea what materials to us and more importantly, where to get the stuff?

 

 

Edited By Bodger on 01/11/2010 21:02:21

[Alan Hall]

I've just measured the thickness of my canopy and it comes out at 0.5mm so I'm guessing that the original thickness was around 1mm allowing for stretching. That equates to around 3/64". Hope this is helpfull.