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SV reX
SV reX MegaDork
4/17/23 12:22 p.m.

I wanna have a body built that resembles this that would fit on a golf cart chassis

Trent
Trent PowerDork
4/17/23 12:30 p.m.

You start by making the plug, The Heinkel Trojan/Kabine shaped object out of plywood and filler, then you make the mold from the plug, then you can pull parts from the mold. 

The problem with composites is that you have to essentially build the part 3 times by the time you have one piece to work with.

 

I do quite like the idea of a Trojan/Kabine roadster.  Isetta type cars are fishbowls and any sunlight is punishing

frenchyd
frenchyd MegaDork
4/17/23 12:32 p.m.

I'm assuming you want to DIY?  I'm also assuming you don't have the original?  
   Make a pattern.  Start with a bunch of styrofoam   blocks glued together.  If you have an eye for copying it's straight forward. But even if not you can make cardboard cutouts to transfer one side to the other.  
 If really no skill along those lines.  Use a projector to display  the pattern onto the foam blocks and cut away  excess foam.    
  Once it's roughly in shape.  Spread a layer of bondo on and smooth it out.  Double check your work with the projector. 
 

Trents right you make the part 3 times but basically it's just laying fiberglass over the pattern.   Then relaying the fiberglass in side the mold.  
    There is a bit more.  You need a release agent ( PVA  is my choice)  and gel coat.  The pattern you can cheap out by using Fiberglass Matt.   The part you can use matte or cloth.  Cloth will be stronger. 
       There are plenty of examples on U Tube.  But there are some tricks to make it less messy. 
   Oops!   I see you are thinking of a production run, not a 1 off.  Forget about splash molds and plan on using plywood for edging. If high numbers planned use aluminum or even steel.  The mold will be a lot thicker as well.   

SV reX
SV reX MegaDork
4/17/23 12:39 p.m.

I was actually asking about contracting with someone to build the body (and I would do the assembly)

DIY is not impossible

Toyman!
Toyman! MegaDork
4/17/23 12:42 p.m.

Contact these people. 

http://cuttingedgecomposites.org/index.html

They can probably help you out but I bet it won't be cheap. 

 

Keith Tanner
Keith Tanner MegaDork
4/17/23 12:47 p.m.

You could also try Jim Simpson and see if this floats his boat. Composite folks can be a little squirrely to deal with overall in my experience.

If you can create a 3D model of what you want, that might open up some options. 

Keith Tanner
Keith Tanner MegaDork
4/17/23 1:02 p.m.

New business idea: SendCutSend, but for composite body parts.

californiamilleghia
californiamilleghia UberDork
4/17/23 1:06 p.m.

Is there a standard golf cart  wheelbase and width ?
 

Are you planning on making them to sell ,  or have a fleet to rent out at the races !

Kendall Frederick
Kendall Frederick New Reader
4/17/23 1:11 p.m.
Keith Tanner said:

New business idea: SendCutSend, but for composite body parts.

With 3D scanning reaching hobbyist availability, and with 3D printing at large scale possible, I see this in the near future.  I'm working on learning metal shaping skills just as they go (even more) obsolete..

 

triumph7
triumph7 HalfDork
4/17/23 1:15 p.m.
frenchyd said:

I'm assuming you want to DIY?  I'm also assuming you don't have the original?  
   Make a pattern.  Start with a bunch of styrofoam   blocks glued together.  If you have an eye for copying it's straight forward. But even if not you can make cardboard cutouts to transfer one side to the other.  
 If really no skill along those lines.  Use a projector to display  the pattern onto the foam blocks and cut away  excess foam.    
  Once it's roughly in shape.  Spread a layer of bondo on and smooth it out.  Double check your work with the projector. 
 

Trents right you make the part 3 times but basically it's just laying fiberglass over the pattern.   Then relaying the fiberglass in side the mold.  
    There is a bit more.  You need a release agent ( PVA  is my choice)  and gel coat.  The pattern you can cheap out by using Fiberglass Matt.   The part you can use matte or cloth.  Cloth will be stronger. 
       There are plenty of examples on U Tube.  But there are some tricks to make it less messy. 

If you use styrofoam be careful what resin you use.  Polyesther will melt styrofoam but you van use epoxy resin. 

What I'm using on the Fmod is a material called Divinycell.  It comes in blocks or sheets and can be formed with a heat gun and edge glued with Gorilla Glue.  It can also be used with any resin and fabric.

SV reX
SV reX MegaDork
4/17/23 1:26 p.m.
californiamilleghia said:

Is there a standard golf cart  wheelbase and width ?
 

Are you planning on making them to sell ,  or have a fleet to rent out at the races !

My friend wants one for her golf cart community (until she learned the price), and I figure it would probably be possible to sell them in small production runs in a town that has over 10,000 golf carts

Keith Tanner
Keith Tanner MegaDork
4/17/23 1:37 p.m.
Kendall Frederick said:
Keith Tanner said:

New business idea: SendCutSend, but for composite body parts.

With 3D scanning reaching hobbyist availability, and with 3D printing at large scale possible, I see this in the near future.  I'm working on learning metal shaping skills just as they go (even more) obsolete..

 

I don't know if it would be better to print the plug or CNC mill it. I'll bet the latter would be a whole lot faster, and large format mills are more common than large format printers. But definitely the hobbyist ability to generate models has improved considerably.

Fun reading.
https://diyblog.commonfibers.com/blogs/process

Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
4/17/23 1:45 p.m.

Contact jmc14. 

He's done an abarth sp1000 sports racer and his cheetah roadster thing. I think he works with a fiberglass company to have the bodies built.

 

nocones
nocones PowerDork
4/17/23 1:53 p.m.

I'm intrigued.  I will learn with you as I want to make a P50..

frenchyd
frenchyd MegaDork
4/17/23 2:33 p.m.

Fair enough.  I think a professional fiberglass shop could do what you are asking. Do you have any of those around you?  
     I know there are some in California  and We have one here that does the hot rod air scoops,   Bucket T' bodies, race  car bodies,  etc.  But the time required would be about the same as you doing it yourself plus whatever time it takes to fit in their schedule.  Oh and shipping.   Plus they need to not only be paid for their time but a profit on top.  
     As estimate is going to have a good deal of padding since they have no experience  with you as a customer.    Something that can be a breeze or a night mare.   
    
   I'm optimistic but I suspect The younger me could do the pattern in a 24/ hr weekend. And have the mold ready by the following weekend.  ( probably 12 hr. ). 
      I'd know how to avoid reverse drafts or if required how to deal with them.   ( that's what traps parts in a mold) I'd also plan on using a light Matt material and make what's called a splash mold. Since I'd only make one part out of it.  
   There are short cuts like trimming the edges when the fiberglass turns leathery using a sharp utility blade rather than waiting  until everything gets hard and creating an itchy dust storm of fiberglass  using a cut off wheel.  
 If you want I'll walk you through the process. 
         

frenchyd
frenchyd MegaDork
4/17/23 2:42 p.m.
triumph7 said:
frenchyd said:

I'm assuming you want to DIY?  I'm also assuming you don't have the original?  
   Make a pattern.  Start with a bunch of styrofoam   blocks glued together.  If you have an eye for copying it's straight forward. But even if not you can make cardboard cutouts to transfer one side to the other.  
 If really no skill along those lines.  Use a projector to display  the pattern onto the foam blocks and cut away  excess foam.    
  Once it's roughly in shape.  Spread a layer of bondo on and smooth it out.  Double check your work with the projector. 
 

Trents right you make the part 3 times but basically it's just laying fiberglass over the pattern.   Then relaying the fiberglass in side the mold.  
    There is a bit more.  You need a release agent ( PVA  is my choice)  and gel coat.  The pattern you can cheap out by using Fiberglass Matt.   The part you can use matte or cloth.  Cloth will be stronger. 
       There are plenty of examples on U Tube.  But there are some tricks to make it less messy. 

If you use styrofoam be careful what resin you use.  Polyesther will melt styrofoam but you van use epoxy resin. 

What I'm using on the Fmod is a material called Divinycell.  It comes in blocks or sheets and can be formed with a heat gun and edge glued with Gorilla Glue.  It can also be used with any resin and fabric.

That's why you cover the foam with Bondo.   Once the pattern is ready then spray with PVA ( from your fiberglass supplier)  and to ensure a quick release I use a good paste wax.  
 Yeh, it's overkill but I've never had a part stuck in a mold.  

STM317
STM317 PowerDork
4/17/23 2:43 p.m.

I'd be really curious what kind of numbers you might get for a whole body like that.

I looked into having a custom hood reproduced a decade ago. The shop I checked with wanted like $10k for molds and then $150-200 per piece produced.

MrJoshua
MrJoshua UltimaDork
4/17/23 2:48 p.m.
Robbie (Forum Supporter) said:

Contact jmc14. 

..... abarth sp1000 sports racer..........

 

End thread.

GaryC83
GaryC83 Reader
4/17/23 3:00 p.m.

In reply to Keith Tanner :

Nobody wants to pay what it actually costs....

I know guys that do both 3d printed plugs (they have a 4'x4' 3d printer) as well as CNC'd foam stuff. They make all sorts of CF panels for vintage cars, race cars, street rods, OE'S, etc. 

Problem is for one off stuff, it's so labor intensive that most people have a grabber when they get the quotes.  You know as well as anybody the price only comes down in scaling up. And for one off parts...that's hard. When this guy wants a set of CF door skins for say a Studebaker for Bonneville, and then maybe 8 years from now you will get another order. In the meantime you're left storing those molds properly. Or they go to E36 M3, fast. 

stuart in mn
stuart in mn MegaDork
4/17/23 3:23 p.m.

I've been following a Canadian guy on YouTube:  https://www.youtube.com/@ThrottleStopGarage  He's been making carbon fiber body panels for his Volvo 122, and goes into great detail about the process.

Or, you could follow the methods of Ed 'Big Daddy' Roth who built a series of wild custom cars over a period from the 1950s through the 1980s - he'd build a buck using wadded up newspaper and plaster of Paris, cover it with fiberglass, and then knock out the plaster with a sledgehammer.  It was a dirty, time consuming process, but it was cheap.

GameboyRMH
GameboyRMH MegaDork
4/17/23 3:24 p.m.

You may want to look into vacuum-forming sheet plastic rather than FG molding, with this process once the mold is made, you can have a machine stamp out panels in minutes rather than being painstakingly handcrafted over a days-long process, and you can get similar-looking results, possibly with no need for paint.

Edit: Video:

 

Keith Tanner
Keith Tanner MegaDork
4/17/23 3:59 p.m.
GaryC83 said:

In reply to Keith Tanner :

Nobody wants to pay what it actually costs....

I know guys that do both 3d printed plugs (they have a 4'x4' 3d printer) as well as CNC'd foam stuff. They make all sorts of CF panels for vintage cars, race cars, street rods, OE'S, etc. 

Problem is for one off stuff, it's so labor intensive that most people have a grabber when they get the quotes.  You know as well as anybody the price only comes down in scaling up. And for one off parts...that's hard. When this guy wants a set of CF door skins for say a Studebaker for Bonneville, and then maybe 8 years from now you will get another order. In the meantime you're left storing those molds properly. Or they go to E36 M3, fast. 

No argument here. I'm working with some custom circuit boards right now, and the per-cost price for 50 is an order of magnitude less than the per-cost price for 1. It's all about the initial and there's no way around that.

But maybe we can take advantage of improved low-volume manufacturing tech to bring down the cost of that initial tech. It's never going to be cheap, but it would be interesting to take a look. We're getting some castings done, and 3D printing has helped bring the cost that down enough that one-off prototypes are plausible. Small run injection molding is less expensive than it used to be as well. Can we use big CNC mills to make a plug, or maybe even the mold directly? Spray chopped 'glass into it and trim? I guess a large part of it depends on the finish level expected. 

Slippery
Slippery PowerDork
4/17/23 4:06 p.m.
Keith Tanner said:
GaryC83 said:

In reply to Keith Tanner :

Nobody wants to pay what it actually costs....

I know guys that do both 3d printed plugs (they have a 4'x4' 3d printer) as well as CNC'd foam stuff. They make all sorts of CF panels for vintage cars, race cars, street rods, OE'S, etc. 

Problem is for one off stuff, it's so labor intensive that most people have a grabber when they get the quotes.  You know as well as anybody the price only comes down in scaling up. And for one off parts...that's hard. When this guy wants a set of CF door skins for say a Studebaker for Bonneville, and then maybe 8 years from now you will get another order. In the meantime you're left storing those molds properly. Or they go to E36 M3, fast. 

No argument here. I'm working with some custom circuit boards right now, and the per-cost price for 50 is an order of magnitude less than the per-cost price for 1. It's all about the initial and there's no way around that.

But maybe we can take advantage of improved low-volume manufacturing tech to bring down the cost of that initial tech. It's never going to be cheap, but it would be interesting to take a look. We're getting some castings done, and 3D printing has helped bring the cost that down enough that one-off prototypes are plausible. Small run injection molding is less expensive than it used to be as well. Can we use big CNC mills to make a plug, or maybe even the mold directly? Spray chopped 'glass into it and trim? I guess a large part of it depends on the finish level expected. 

To answer the question above, yes. 

These guys use a big gantry style 5 axis CNC to create the plugs to recreate the Talbot Lago molds. 

https://tlccar.com/

The most difficult part is finding someone to lend you the original to scan, or making the cad drawing. 

Slippery
Slippery PowerDork
4/17/23 4:07 p.m.

A great place to look for help is the boat industry. No one has more experience when it comes to fiberglass and molds. 

I dont have any contacts, but here in the Ft Lauderdale area there are tons of boat building and hull repair shops. 
 

kb58
kb58 UltraDork
4/17/23 4:37 p.m.

To the OP, what's the budget for obtaining the reusable molds? That right there will likely answer the question as for whether it's doable.

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