paddywil
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| posted on 4/11/15 at 02:23 PM |
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Thanks for the tips and advice.
Previously I've made GRP panels by making bucks from MDF, stacking them and continuing on from there... I think as there is a strong likely hood
of doing more that one run of panels, I'll probably do the same again, but have the panels CNC milled, rather than forming them by hand...
Despite that, the aesthetics of an aluminium bottom section are quite tempting...
As russ said though, I'm looking at bring the space frame higher up, then having single piece side panels rather the removable top at the front,
instead making removable panels where required.
As this is going to be a road car I may stretch to paneling the inside of the tub in ali purely for aesthetic reasons.
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twybrow
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| posted on 4/11/15 at 08:30 PM |
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quote:
Originally posted by Neville Jones
Russ,
The amount of time and effort put into the fairness of that last csm layer, dictates how much filling and fairing is done on the final article.
Yes, the final surface will need a complete all over skim then sanding, but the choice of material makes a significant contribution. CSM will need a
good deal of elbow grease.
The moth hull was a 4x4 twill,(carbon in this case, but glass is easily had) which draped really easily over the plug. The filler was epoxy/balloons,
and when finished and sanded, prior to paint, very little of the balloons was left. Mostly small patches between the weave. This is countered by the
amount of resin that needs to be applied when using cloth over foam in a mould. With what I built, you just paint on some epoxy on the inside,(after
thorough dewaxing and sanding, before HE gets picky and pedantic) then in goes the foam then a layer of carbon over that. I should have taken some
pics, but this sort of thing is fairly routinely done around here, for one-offs, for many years, and isn't seen as out of the ordinary.
With the Lotus32 shape, the biggest problem in putting the car on the road will be headlight positions. Mounted up high, just inside the wings, might
work. I've seen that done before.
Cheers,
Nev.
Nev - to clarify, you are describing a method for making the plug aren't you? You can of course apply a similar approach and build the mould
directly by building up a very thick tool surface, and then either machining the final geometry or working it back by hand using templates to check
the profile. Of course the latter is a ball ache but would save the need to make a plug for a one off.... Either way, finish with resin then paint
to seal the surface. We made some very large complex tools this way, which remained vacuum integral for 20 parts.
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Neville Jones
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| posted on 5/11/15 at 09:38 AM |
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No, I described a method to make a one-off on a male mould-plug.
As it happened, the finished hull was given a high gloss finish, and a mould was taken off it.
The plug could easily have been given a high finish and a mould taken, then the hull built in the mould.
The end result was a usable plug, a finished hull, and a mould. But one-offs are built like this regularly.
Another method is to make up a timber former, with transverse stations and longitudinal battens, cover it with core foam, then laminate over that to
get the outer skin. Turn it over and put in the inner layer. Many ways of doing one-off composite work, other than going through all the hassle of
high gloss perfect plugs, then moulds, then moulding from the mould.
If you only want one, then you go about it the quickest and most economical way.
Cheers,
Nev.
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