Scale Soaring UK

I have been asked a few times how I make my canopy's so I thought I would start a separate thread on how I do it. It is not has perfect has a vacform but you can still get good results and if you are lucky you can get a perfect one. . there is a pit of a kack of it and my need a bit of practice . I hope this will encourage some one to have a go . the p.t.g.e I use is 1 mm. First you will need a wooden stand .then sit your plug on to it

Then you need to remove any dust and then polish with cooking oil this help the petg to slide.

You then need to cut the ptge sheet 4 or 5 in oversize and fix it to 4 wood battens with wood screws. Leave the plastic protective backing on this will be removed when finished and stops you scratching the petg when pulling the plug

You then need to heat up the plastic I use a camping cooker it needs to be a large heat source. And wearing gloves I heat it up in a circular movement but not two close to the heat source. The petg will go soft when it starts to shrink it is ready. Very quickly press it down over the plug in the centre and hold it down DO NOT REMOVE TILL IT IS COLD.

Some times depending on the shape of the plug it will go in one go more the often it will cull up at the ends. To sort this you need to sit with one leg each side like you are riding a horse. Then with a heat gun reheat that area till it goes soft and when it start to srink you need to pull and hold down using a pice of leather the wat till it is cold if you do not it will get bumps in it and if you heat the bump and hold it down it will only come back. The only way to get them out is to reheat and stretch them out

Then cut it off the battans and trim then remove the protective backing. I hope that helps good luck ROO

Nice one Roo

G

Thank you very much. That's absolutely great. Really useful stuff

Quick question.. (from a numpty)

When you attach the battens to the PETG, these are only shown down the sides, you don't form the battens into a rigid oblong? Is that correct?

Thanks

Hi Martyn that is correct they oniy fix to two sides. ROO

Thanks Roo

Hi Roo,
Thanks for showing us your method of canopy forming, I have done something similar in the past.
For my Swallow canopy, I made a frame, similar to an old tennis racquet press, and trapped the plastic sheet between the two sides using wood screws. The apertures in the frame are of different sizes, the lower one being a close fit to the base of the plug and the upper one about 10mm larger all round.
With the plastic sheet held firmly in the frame, I heated it under the grill in the kitchen and waited for the plastic to go soft.
I then placed the plug on the floor and pushed the frame over it as far as I could. It took considerable pressure, and I found I had to stand on the sides of the frame to push it all the way down.
I did find that I had more success when I heated the plug with a hot air gun before pressing the frame down over it.
I love the simplicity of your method, and next time I do it, I will make the plug as you have done and grip the plastic sheet between the battens as you have shown. I will also try the cooking oil option on the plug as you suggest.
Thanks again.
Regards,
Mark

Hi Mark, cooking oil; under the grill; you making lunch or what? Ter.

A few more questions:

1) Can you confirm what material it is that you are using PTGE PTFE - what does that stand for?
2) Where do I get it - tried PTGE on ebay but no results.
3) I see the top quality Lidl oil being put to good use but how 'perfect' does the mould actually have to be - does material stretch across imperfections or show them up?
4) I seem to remember reading somewhere that some people mould a canopy but then mould a second one directly on top of that so the first one effectively covers point 3) - have you ever tried that?

Thanks for the help!

Hi Nigel

Its PETG

Try this: http://www.ebay.co.uk/itm/CLEAR-PETG-Sh ... 1518059054?

However, I am not sure what thickness is used

It is 1 mm thick , that is expensive on ebay re read the thread there is a link to eagle plastics . I pay less than £6 for that,

Try going to your local plastic sheet supplier
I bought a whole sheet of petg 1mm thick 1.2m x 2.4m for $25 NZ. Cheap as chips.
Stu

Sorry to be so late with this question, but I've only just found the thread and it's fascinating as I am going to have to replace 2 canopies in the near future.

One for my 1/5th Minimoa and one for my 1/6th Discus 2. As they are both elderly models I would think that the canopies would be quite difficult, and expensive, to buy!And as a p o o r old retired bloke I need to save all of the beer tokens I can

I have a bag of Mouldmaster plaster of Paris. Would that be OK to use for the plug? I have made a plug for my PSS Foland Gnat, but finished up finding and buying a canopy for it so it hasn't been used so I'm not too sure about it?

It certainly sounds like a good idea to warm/heat the mould even although that would increase the cooling time. I have some release wax for polyester GRP moulding, would that be suitable as a release for the formed plastic?