How to Reproduce?

[Dzimm]

6 hours ago, AZJeff said:

I am a retired mechanical engineer who worked with LOTS of plastic molded parts in my career, so here are my two cents:

 

Owing to their size, the original parts were probably created by some short of sheet forming compound.   This is a plastic sheet resin that is heated, and placed into a mold where it is pressed into shape and then allowed to cool.  Sometimes the material has glass or mineral strands added to increase stiffness of the finished product.

 

Making a duplicate of this part would, of course, involve first making a die (mold) that is essentially an inverse image of the part, both inside and out.   Of course, the mold has to be "tweaked" so that the softened plastic does not pull too sharply in corners and whatnot, and thus tear, so an exact inverse image is not usually the shape of the final die.  Believe it or not, in low volume production, this could actually be made from hardwood, like maple.  

 

Once a die is made, then a suitable material must be found.   Sheet forming compounds in large sizes and thicknesses can become pretty expensive in low volumes.   It might cost a couple of hundred dollars just for a sheet that is 6 feet long and "x" wide.   Of course, the compound you choose also needs to be formable in the die you create, as the "stretchiness" of various resins are different.  This might mean some trial and errror experimentation might be needed, and you might end up creating several unusable versions before the die is optimized.

 

All of this, of course, would required a facility with a large oven to heat the resin sheet, and a the ability to fixture the mold halves and compress them together once the heated sheet is placed into the mold.

 

Owing to all of this (cost of raw sheet material, cost of die development and fabrication), making a duplicate of the OEM part in low volumes  would result in some pretty high piece part costs.   This makes creating parts from fiberglass or carbon fiber MUCH more cost-effective.

 

Making the part in fiberglass or carbon fiber would be done similarly to the way boat hulls are fabricated.  A wooden mold is still needed, but it's only the inverse of the outside of the part is required, so the mold cost is lower.   The actual part is them "laid up" by hand, with sheets of glass or carbon mat soaked in resin, and then applied to the mold (which has been coated in a mold release compound.)

 

This method is tedious from a labor perspective, but does not involve a fancy facility with an oven and mold presses.  It also is more fragile, as noted previously.

 

All things considered, unless you are indepenently wealthy, the idea of "tooling up" to make a OEM equivalent to the original "spoiler" is pretty much problematic.

 

Sorry to rain on the parade here.

I certainly had no plans on going all out on equipment for this.  Just wasn't sure if there was any 1 or 2 part compounds I could pour into a fiberglass mold that don't require heating or a press.  I found some urethane options used in prop making but they would be expensive for something this large.  

 

I've got to get the part cleaned up and get a nice surface on it.  Then make a mold and try a fiberglass part first and see what the result is.  

[Sir Sam]

I'd vote you go modern with this. Get the sucker straight, cleaned up, and ready, maybe even mounted to a bumper.

 

Then 3d scan the object, tweak the model as needed. Then see what your next step is, could make a wood positive to form a fiberglass negative on, then use polyurethane to pour into a mold.

 

You could 3d print sections of it out of various materials, hell you can 3d print and then use it for lost was metal casting and make a cast metal one(and as always you need to account for material shrinkage).

 

[Pete M]

3d printed Lambo

 

[Jeep Driver]

Yeah, I'm a bit over the 3D BS. Small parts, prototypes and so forth.......maybe, otherwise, total BS. 

 

There is a member here who is going to try 3D printing tail lights, ain't gonna work for several reasons but I'm not going to be the one to tell him. 

 

There is no substitute for good old fashioned hand-work and sweat. This really is a generational loss, there is an app for everything idea will be death of craftsmanship. 

 

The car below was hand built, metal finished, no paint, no bondo..........pure anadulterated talent. 

 

[Jeep Driver]

On 7/12/2019 at 12:36 PM, AZJeff said:

I am a retired mechanical engineer who worked with LOTS of plastic molded parts in my career, so here are my two cents:

 

Owing to their size, the original parts were probably created by some short of sheet forming compound.   This is a plastic sheet resin that is heated, and placed into a mold where it is pressed into shape and then allowed to cool.  Sometimes the material has glass or mineral strands added to increase stiffness of the finished product.

 

Making a duplicate of this part would, of course, involve first making a die (mold) that is essentially an inverse image of the part, both inside and out.   Of course, the mold has to be "tweaked" so that the softened plastic does not pull too sharply in corners and whatnot, and thus tear, so an exact inverse image is not usually the shape of the final die.  Believe it or not, in low volume production, this could actually be made from hardwood, like maple.  

 

Once a die is made, then a suitable material must be found.   Sheet forming compounds in large sizes and thicknesses can become pretty expensive in low volumes.   It might cost a couple of hundred dollars just for a sheet that is 6 feet long and "x" wide.   Of course, the compound you choose also needs to be formable in the die you create, as the "stretchiness" of various resins are different.  This might mean some trial and errror experimentation might be needed, and you might end up creating several unusable versions before the die is optimized.

 

All of this, of course, would required a facility with a large oven to heat the resin sheet, and a the ability to fixture the mold halves and compress them together once the heated sheet is placed into the mold.

 

Owing to all of this (cost of raw sheet material, cost of die development and fabrication), making a duplicate of the OEM part in low volumes  would result in some pretty high piece part costs.   This makes creating parts from fiberglass or carbon fiber MUCH more cost-effective.

 

Making the part in fiberglass or carbon fiber would be done similarly to the way boat hulls are fabricated.  A wooden mold is still needed, but it's only the inverse of the outside of the part is required, so the mold cost is lower.   The actual part is them "laid up" by hand, with sheets of glass or carbon mat soaked in resin, and then applied to the mold (which has been coated in a mold release compound.)

 

This method is tedious from a labor perspective, but does not involve a fancy facility with an oven and mold presses.  It also is more fragile, as noted previously.

 

All things considered, unless you are indepenently wealthy, the idea of "tooling up" to make a OEM equivalent to the original "spoiler" is pretty much problematic.

 

Sorry to rain on the parade here.

The only thing I'd like to add here-

Two things-

 

The process and the makeup of the materials, companies that produce/manufacture these products such as air damns have about 80 years or more of experience and science behind them, they know what works, what does not, what to do, and what not to do.

The home enthusiast/hobbyist does not.......so.......unless you are in the business.............

 

 

Also, I follow many custom builders, if reproducing parts such as this air dam where so easy they'd all be doing it...........they don't.

 

[13 Legion]

I agree with everything that’s been stated. It’s just the basis of economics... supply and demand. There is close to zero supply left, and unfortunately about the same amount of demand. I can’t fault a person for trying to be creative and actually produce this. I read earlier in this post where these air dams were made for a one time use( wear and tear). Which then would lead to having to make at least a few of them. Even if it seems at least they are strictly for aesthetics. The air dam will undoubtedly get scratched, chipped, and/or cracked at some point. Good luck though Dzimm. I’m wishing you the best in your endeavors to actually make something work. Money obviously is the issue, but you can’t kill creativity. Don’t give up.

[Jeep Driver]

7 minutes ago, 13 Legion said:

I agree with everything that’s been stated. It’s just the basis of economics... supply and demand. There is close to zero supply left, and unfortunately about the same amount of demand. I can’t fault a person for trying to be creative and actually produce this. I read earlier in this post where these air dams were made for a one time use( wear and tear). Which then would lead to having to make at least a few of them. Even if it seems at least they are strictly for aesthetics. The air dam will undoubtedly get scratched, chipped, and/or cracked at some point. Good luck though Dzimm. I’m wishing you the best in your endeavors to actually make something work. Money obviously is the issue, but you can’t kill creativity. Don’t give up.

While it's on my mind...........and to bounce off your post.............

 

I like custom work, one-off(s) and I'd like to see more of that here..........hell, I'd like to see it here, period. 

 

For those of you who follow Foose's work, the C28, C10 + Z28 project. 

 

 

Foose does not reinvent the wheel, here is where talent combined with experience and imagination comes into play.

Take what you've got and make it work. 

 

Custom badge-

[13 Legion]

Agreed bro. You have to take in to account though..... His net worth is over 18 million. You stated earlier in another post you were looking at lights that were what 1,000 dollars? We have guys that are just trying to keep their rigs running with JY parts( like me!) that paid less for their Comanche. Creative or not, capital helps!

[AZJeff]

2 hours ago, Jeep Driver said:

The only thing I'd like to add here-

Two things-

 

The process and the makeup of the materials, companies that produce/manufacture these products such as air damns have about 80 years or more of experience and science behind them, they know what works, what does not, what to do, and what not to do.

The home enthusiast/hobbyist does not.......so.......unless you are in the business.............

 

 

Also, I follow many custom builders, if reproducing parts such as this air dam where so easy they'd all be doing it...........they don't.

 

These are VERY good points that I did a less eloquent job of describing.   Making this kind of stuff isn't cheap or easy.  Look at how much suppliers charge for the fender flares for an XJ/MJ, and the demand for that part is MUCH higher.