Made a start on my petal extensions ..

[Vipersan]

Early days yet ...and the weather ain't helping ..
Having decided to return to my original idea of papier mache ..
The first layer went on yesterday ..and barely managed to dry before ..the rain came ..
Covered as best I could overnight with a plastic sheet ....and subjected to yet more rain this morning ..
Anothe coat of thinned pva glue ..and a hairdryer later ..I started fitting structure ribs ..again in paper ..
If this actually works ..then the cast in paper will be removed ..and the reverse side then built up in fibre glass mat and resin ..and the front side in resin and fine beads ..
sanded down smooth ..waxed and mould release applied ..
Hopefully this will then be the completed reverse mould ...and I can start to make the actual petal extensions ..


..at the moment my hands are freezing and I'm typing with one finger ...
This afternoon ..I shall be entreating the gods to refrain from 'p1ssing' on my work..
rgds
VS

 

[Vipersan]

Managed to get a few dry hours in today ..and fitted the last of the paper constructed support ribs/framework ..
Heading nicely toward that first coat of fibre glass resin ...followed by matting and resin ..
Then hopefuly I'll be able to remove the inverse mould and take it indoors to work on it ..
I'm amazed just how durable the papier mache has been ...considering it has been subjected to at least half a day of rain ..and a sprinkling of showers..
It still retains its shape to within mm's
Here are a few quick snaps before it gets too dark to see..
rgds
VS

 

[Vipersan]

..Working with fibreglass is a lot easier than I thought it would be ..
First layer on today.
Yes its messy ...
Yes its expensive ..considering how much resin I'll need ..
but should make for a good job when completed..
As usual ..some progress pics
rgds
VS

 

[Lazarus]

Hugely impressive, old friend.

Reminds me of the days when the cheapo cars that were all I could afford were largely held together by fibreglass!

 

[Vipersan]

Hugely impressive, old friend.

Reminds me of the days when the cheapo cars that were all I could afford were largely held together by fibreglass!

..Don't be too impressed yet Gordon ..
I've got to get it off the dish surface in one piece yet ....
Now that _will_ be ...sharp intake of breath time...
lol
;)

 

[Vipersan]

Stage 1 now complete ...
The casting came away from Christinas surface without issue thanks to the papier mache..
now to remove all the paper ...and make good the reverse mould surface ..which _should be accurate to the original surface to within a few mm
here are the pics..
I'm pleased so far..
rgds
VS

 

[Lazarus]

I am pleased, also.

No skill in my recent Black ultra upgrade, but plenty in yours. Ingenuity, too.

Bonzer.

 

[sonnetpete]

Well done VS. I'm moved to write to 'Blue Peter' to put your name forward for a badge.....

 

[Lazarus]

No point - he'll only adapt it to make it bigger and better!

 

[Vipersan]

...And now we arrive at the _not_ unexpected problem of the increase in diameter relative to the cloned section..
from the photos you can clearly see how much this is ..
actually ..its more than I imagined ..but you don't know till you try ..
..and not having an original extension petal to clone from ..what choice did I have ..
I guess Christina will look more like a daisy than a dish ..If I continue ...but just how effective will the dish then be daisy shaped..
oh well ..this is how it has to be.

..got the choice of cutting the mould to follow the outer rim of the dish ...or attempting to make up the gap you can see ..
But this will still leave the outer circumferance ...daisy shaped..If I exactly follow the mould that is

What would you choose ?
rgds
VS

 

[Topper]

Hi VS, well it is only my opinion but I would ignore the final shape of the dish as that does not matter it is purely aesthetic, I would have thought it is better to make sure the mould matches the outer edge of the dish

 

[Vipersan]

Hi VS, well it is only my opinion but I would ignore the final shape of the dish as that does not matter it is purely aesthetic, I would have thought it is better to make sure the mould matches the outer edge of the dish

Agreed Topper ...
The important factor is that the extensions follow the dishes interior curve and follows the outer rim of the dish ..
But there I have the 2 choices ..
Either cut the mould to follow that outer rim curve...which would result in a smaller surface area on each petal ...or make up the gap you can see with more fibre glass ,,by re applying the mould to the dish surface ..and building it up in the middle ..
but I now have the advantage of knowing how much is missing ...ie ..the gap..
Either way ..work has stopped until recently ordered supplies arrive..
;)
rgds
VS

 

[lanab]

You won't get the curve right anyway, i would buy thin aluminium sheets instead and start work on the dish from the center by applying sheets on top of the current petals and then weld the sheets together, then remove it and work on the back structure of the sheets,sheets being thin makes them adjust to the shape of the petals easily.

 

[Vipersan]

Along with more fibre glass mat ...I have also ordered some close woven moulding fabric to get a smoother finish ...and ...some latex ...
Just an Idea I had that this could be painted onto the dish surface ...making a skin..which should peel off ..and allow resin to be painted over it ...the woven fabric then applied to the latex...more resin ..then the mould pressed into place and allowed to cure ..
If successful ..again the mould plus the new fabric ..plus the latex ..should be easily removed from the dish face...
Its at this point I could fill in the missing gap ..
I have a feeling this is the route I shall follow ..
Wish me luck.
VS

 

[Vipersan]

You won't get the curve right anyway, i would buy thin aluminium sheets instead and start work on the dish from the center by applying sheets on top of the current petals and then weld the sheets together, then remove it and work on the back structure of the sheets,sheets being thin makes them adjust to the shape of the petals easily.

Thanks Lanab ...
This is basically what I intend to do ...the only difference is that I want to use the process you mention on a reverse mould ..not on the dish surface itself ..
Once I have the mould correct ...I can then replicate 6 petal extensions ..

I intend to build up a laminate sandwich of fibre glass cloth ...mat ...resin aluminium foil ..and aluminium webbing..but on the reverse mould once its complete.
rgds
VS

 

[Vipersan]

...An expensive learning curve ..
But ..I'm certainly learning ..
Not totally happy with the surface finish ..or the circumferance curves ...or indeed that it was smaller and would probably need 7 segments ..instead of 6 ..
I had a re-think ..
Eureka..Durex ...shows you where my mind is usually...

A giant latex sheath to put over part of Christina..
..and so I ordered 1 litre of latex...
Plus ..
Some woven fibreglass 'roving cloth' ..
More expensive ..but what a finish it would give ..
Assuming it worked of course ..
So I masked of a larger area on the dish surface ...adjusting by eye for the curve variation ..
This wont be accurate but closer than before..
I then painted this area between the tapes with a thin single layer of latex ..
Allow to dry ..turn opaque..
Then paint over it a thin layer of resin ..
Allow to turn tacky but not dry yet ..
Bed in gently the precut roving cloth ...
paint over with more resin ..
Allow to partly harden ..and turn tacky to touch ..
Then apply a layer of ordinary cut strand fibre glass mat ..
Generous coat of resin ..
Allow to fully cure ..
Then I curved a length of 15 mm copper pipe by hand to roughly the right shape ..
layed on the fibre glass ..and anchored with more mat..
I now have a structure rib ..and a handle..

Allow all to fully cure overnight ..
..and panic just before removal ..in case it didn't work ..and the fibre glass mould remain permanently bonded to Christina ..
Well ..I can tell you ..
The Durex worked ..
Here are he pics ...and the latex still has a greater affinity for the dish than the resin ..so is still in place...
Ie didn't peel away with the inverse mould..
rgds
VS

..we'll call phase 1 a costly test run ..
;)

 

[Analoguesat]

Absolutely fascinating

:-worship.

 

[Vipersan]

Absolutely fascinating

:-worship.

Glad you're enjoying it AS ..
Much more to do ...next job is to make the side/rim castings for the mould out of aluminium webbing and attach them...but am very happy indeed with this cast ..and also happy I shall be able to use the latex as my mould release agent ..during the final wing construction.
cheers m8 ..
I'm encouraged by your comment.
rgds
VS

 

[sonnetpete]

....during the final wing construction.

Good Lord........you've moved to Colditz and plan to escape via glider.....tally ho chaps....

 

[Topper]

Absolutely fascinating

:-worship.

It is educational too, I have to say I am surprised by the latex idea however it it works then why not, I would have thought there was too much suction created by such a perfect sealant