Hi new member and new project

[mittaw]

Hi folks.  Having spent many years messing around with cars from restoring old classics to modifying them,  mechanically and bodywork wise my brother and I are now looking to make our own vehicle.  Ambitious Yes... but if you're going to do something you may as will do it properly.   

We're based not far from Bristol and I was interested to see such an active membership.

For our project we fortunately have access to large industrial cnc machines and are looking to create the body work using them to create the lightweight panels etc.  We have the car body work designed in draft in 3D package for our donar vehicle and are looking to start Preliminary work on the shaping of the bodywork using a foam based mold to start with using cnc machines

We're pretty Ok when it comes to cnc metal work however on softer foam based products we're a little less clued up and I'm currently trying to research what would be the best. .. and affordable foam based product to cnc to create the base shape on which we'll start laying out the base body work. 

If anyone has any recommendations or experience with foam based cnc work I'd be grateful to hear. I will of course share or experiences .... and failures I'm sure. .. with this process of anyone is interested.

We're currently researching this in depth but I thought I'd also ask in case anyone knew. 

Thanks in advance to any thoughts or suggestions

[Bulldog Bri]

Hiya and welcome to the club.

Wow that does sound ambitious. All I can say is good luck with the project, I'm just finishing off and waiting for my IVA date to get my home built 7 on the road, it's taken a long time and a lot of fuss but in the long run hopefully worth it

[mittaw]

Thanks for the welcome.  Yes ambitious but sometimes you have to go for it.

Good luck with the IVA too

[dave_bence]

Hello and welcome

I can't help much with a project like yours, other than to wish you luck

[Pilgrim Anna]

Sorry I have no advise for you. But did want to wish you a very warm welcome to the club.

[Moleman]

Welcome to the club mate. I shape & machine foam all the time for work but you wouldn't want to use this stuff, Yes it is the best you can use & very easy to work with but it's 2 grand for a 4 foot x 10 foot sheet. 
I will ask if there is a cheaper option.

[Iancider]

Mittaw,

Welcome.  I used to commission models made in foams years ago and they always used "engineering" or modelling foams and they are typical High Density Polyurethane - basically seating foam gone wrong and with no compression yield at all.  Very high cutter speeds are used because the material has no resistance and many small passes may be made to get a really accurate shape.  If you are going to use the foam as a core to a mould then it needs to be oversurfaced with a build-up resin that fill in all of the little surface holes.  It would then be machined again a little larger to allow for the surface thickness and then hand sanded with progressive fine grits and then finished with a surfacing paint (to which mould relase would be applied when you use it as a core (male) or cast (female)).  When making moulds always make sure there is a draft angle to allow the moulding to be withdrawn from the cast - typically 1-1.5 degrees with a polished surface and considerably more if you aim for a texture. 

There are loads of demos on mould making on YouTube.  Most people have to make do with pattern making by hand and cardboard template cross sections so it is great for you if you can do CNC!  If you make a fractional scale model in hard wax it can be used to make a male cast and then make several clay or plaster casts that can be painted-up to how they look.

I know from the days of model-making it is always wise to make a full-size mock-up in rudimentary materials - corrugated cardboard is often a good choice and then spraying the whole surface.  This is important to see how light bounced off the surface makes it look - curves change dramatically according to paint colour and texture and of course painted-on feature lines.

I should add all of my words are from studying the art and not from practical experience - I am not as brave as you.  I will be very interested in the progress!

Good luck
Ian

['The Gaffer']

Hi and a warm welcome to our club. I dont know anything about what you are trying to do but good luck and keep us posted

[mittaw]

Thank you for the warm welcomes.

@moleman, thanks I think that foam week break our budget quite quickly and place considerably more frowns on my lass than she has at the moment on the whole idea.  But if there are cheaper options I'd be interested to know.

@ Ian, great advice there and certainly food for thought.  Castingsv we know well but like you say we're looking at options at the moment and the things you raise are certainly things that need to be on the radar. We're looking to make a mock up first like you mention to test dimensions comparability to the original real thing and symmetry but yes paint and light is also key.

Still very early days yet but I'll let you know how we get on.  It's a long term project but hopefully worth it.

Cheers

[Camber Dave]

Hi Mittaw

Welcome to our world.

I have in the works a car body being created with high density foam.

Martin, the car owner is hand shaping one side at the moment. His company supplies and Hotwire cuts the basic profiles. As well as normal packaging uses, this foam  is used in the Film /TV industry for props.

After finishing one side Martin will send it to one of his customers to be scanned and the other side copied by 5 axis milling.

PM me for contact details for Martin and call in to see what is being done.

BTW I can validate your suspension design before you weld up the chassis........

Dave

[mittaw]

Cheers Dave, we looked into the foam last night and it looks perfect but pricey from what we can see.  We've therfore decided to create a 1/4 size prototype using the foam you suggest.  This way we can adjust the 3D model and cut again without incurring higher costs.  Once we're happy we'll move to full scale.  We're looking to the cnc machines to do most of the base body work where we can.

3D scanning is a good call too.  We've got access to this alsoso we can adjust or base model to any real world adjustments that we have to make.

I'd be very interested in seeing how your doing things. I'll PM you shortly.

As an aside, I must say how helpful this club is from the outset.  We're looking forward to sharing our project and I'm sure many failures on the way with you.

[Bulldog Bri]

Have you made any drawings, sketches or design ideas yet. As a couple of years back we had another member starting a design all in CAD, we were getting a lot of pics put up for us to comment on but then just stopped . I've tried to look back to find it but no luck, can anyone else remember the thread?

[mittaw]

We've got a 3D model prepared and just need to convert this to a CAD based format which will hopefully happen this weekend. we've got to break the model down further though into sections for the cnc machine to manage as best we can before we work up the CAD versions in detail though. When we've got a bit further with the design I'd happily post images for comment.  At the moment we're trying to convert the base 3d model down into sections depending on how we will produce the body production wise.

As for the project disappearing we're not saying this is overnight and we're in for the long haul which is why we're looking and researching as much as we can before jumping in.

[Hairy Santa]

Have you made any drawings, sketches or design ideas yet. As a couple of years back we had another member starting a design all in CAD, we were getting a lot of pics put up for us to comment on but then just stopped . I've tried to look back to find it but no luck, can anyone else remember the thread?

do you mean the chap in Rumania who used the expanding foam and carved the car from it - it was cleverly done, and looked bloody good

[Bulldog Bri]

No. There was a member who was posting up CAD drawings quite classic in style, people were asking for larger wheel arches and to change the lights, etc. Think it was green last we saw it. Bit Healey-ish

[Camber Dave]

This one perhaps

http://bristolkitcarclub.co.uk/smf2/index.php?topic=2593.msg24298#msg24298