Questions About Composite Body

[Lil4X]

I don't remember where I read it, but I seem to remember something about the panels being attached with adhesives. That sounds like a great idea, particularly because it shouldn't transmit sound while remaining weather-tight. That could be a considerable cost savings during assembly as well, as robots apply adhesive and present individual panels to the frame.

 

[Lil4X]

Modern Corvettes stand up very well, but it wasn't always so. I restored a '58 and a '62 as a means of making money for college using my minimal fiberglass boatbuilding skills, and 'glass fabrication was largely an art rather than a science in those days. Early Corvette bodies, like early fiberglass hulls, suffered from delamination between the layers of resin-soaked fabrics - and it usually took about four of five years to appear. At least the Corvettes didn't sink.

My concern with the Elio's finish is primarily what long days in an open parking lot will do to the plastic finish. I'm thinking car cover here for those days I leave it baking in the sun.

 

[Brent Geery]

Shouldn't the color be molded directly into the panels? This would seemingly be much cheaper than painting, more durable and give a perfect color match when replacing panels.

 

[goofyone]

The sheets of SMC fiberglass reinforced composite material will be provided by Plastics Research Corporation who specialize in very high strength composite materials. http://www.prccal.com/

The material is provided in rolls and these rolls are stamped into molds in a way similar to metal however the molds are very hot to cure the resin in the press.

The panels will be painted as this type of SMC fiberglass reinforced composite material is not really suited for high gloss colored resin. The panels are painted using a modern powder coating process. The equipment for painting and stamping this material is already in the Shreveport plant as it was also used by GM.

Adapting SMCs for powder priming ( http://www.compositesworld.com/articles/innovation-driving-automotive-smc )

Just when SMC suppliers thought they had solved OEM paint line compatibility problems, several automakers, notably General Motors (GM) and DaimlerChrysler in North America, started replacing traditional solvent-based spray primer systems with powder coating systems. Because the electrodeposition coatings are water-based, and many topcoat systems were moving to water-based or low-VOC (volatile organic compound) systems, the primer applied between these two steps had become a target for solvent reduction. While the switch to powder coating was no problem for steel (large appliances have been powder coated for years), SMC parts, even those incorporating the new toughened resins and sealers, did not fare well. During cure, the primer on many SMC parts developed a rough, "leather-like"surface — a clear cause for rejection.

In search of a solution, GM's SMC expert Hamid Kia assembled a team that included resin suppliers AOC and Ashland, paint supplier Red Spot Paint and Varnish (Evansville, Ind.) and molders Continental Structural Plastics (formerly Budd Plastics, Troy, Mich.) and Meridian Automotive Systems (Allen Park, Mich.). GM research identified the cause of the problem: Moisture and air were absorbed into SMC during transport and storage, then released from molded parts in the 350°F/177°C primer ovens. The source of the absorption was found to be the industry standard low-profile additive polyvinyl acetate (PVAC), which formed microvoids as the SMC cured. "We found that all organic materials have this problem to some degree,"explains Mike Dettre, business manager for closed mold resins at AOC.

Both Ashland and AOC reformulated resins with alternate low-profile additives that limit the moisture pickup to less than 0.3 percent — less than half that of SMCs that incorporate PVAC — yet still achieve the same level of molded surface finish. Although the reformulated resins, with existing sealers, stopped the problem when the parts were painted soon after molding, parts still failed if allowed to sit for more than a few days, especially in humid environments. Since then, Red Spot has developed a new sealer that prevents moisture uptake for longer periods. The sealer has, to date, passed tests. A second round of testing in warm, humid weather is planned for summer 2007 at GM's Shreveport, La. assembly plant, after which the new materials can formally enter the approval process.

 

[outsydthebox]

The sheets of SMC fiberglass reinforced composite material will be provided by Plastics Research Corporation who specialize in very high strength composite materials. http://www.prccal.com/

The material is provided in rolls and these rolls are stamped into molds in a way similar to metal however the molds are very hot to cure the resin in the press.

The panels will be painted as this type of SMC fiberglass reinforced composite material is not really suited for high gloss colored resin. The panels are painted using a modern powder coating process. The equipment for painting and stamping this material is already in the Shreveport plant as it was also used by GM.

Adapting SMCs for powder priming ( http://www.compositesworld.com/articles/innovation-driving-automotive-smc )

Just when SMC suppliers thought they had solved OEM paint line compatibility problems, several automakers, notably General Motors (GM) and DaimlerChrysler in North America, started replacing traditional solvent-based spray primer systems with powder coating systems. Because the electrodeposition coatings are water-based, and many topcoat systems were moving to water-based or low-VOC (volatile organic compound) systems, the primer applied between these two steps had become a target for solvent reduction. While the switch to powder coating was no problem for steel (large appliances have been powder coated for years), SMC parts, even those incorporating the new toughened resins and sealers, did not fare well. During cure, the primer on many SMC parts developed a rough, "leather-like"surface — a clear cause for rejection.

In search of a solution, GM's SMC expert Hamid Kia assembled a team that included resin suppliers AOC and Ashland, paint supplier Red Spot Paint and Varnish (Evansville, Ind.) and molders Continental Structural Plastics (formerly Budd Plastics, Troy, Mich.) and Meridian Automotive Systems (Allen Park, Mich.). GM research identified the cause of the problem: Moisture and air were absorbed into SMC during transport and storage, then released from molded parts in the 350°F/177°C primer ovens. The source of the absorption was found to be the industry standard low-profile additive polyvinyl acetate (PVAC), which formed microvoids as the SMC cured. "We found that all organic materials have this problem to some degree,"explains Mike Dettre, business manager for closed mold resins at AOC.

Both Ashland and AOC reformulated resins with alternate low-profile additives that limit the moisture pickup to less than 0.3 percent — less than half that of SMCs that incorporate PVAC — yet still achieve the same level of molded surface finish. Although the reformulated resins, with existing sealers, stopped the problem when the parts were painted soon after molding, parts still failed if allowed to sit for more than a few days, especially in humid environments. Since then, Red Spot has developed a new sealer that prevents moisture uptake for longer periods. The sealer has, to date, passed tests. A second round of testing in warm, humid weather is planned for summer 2007 at GM's Shreveport, La. assembly plant, after which the new materials can formally enter the approval process.

Great info!
Nothing is simple anymore, but it sounds like these issues have likely been resolved, as the article stated... "A second round of testing in warm, humid weather is planned for summer 2007 at GM's Shreveport, La. assembly plant".........Thanks again!

 

[Edward]

As long as it isn't ACM (Aluminum Composite Material - basically the aluminum version of particle board). Our cheaper signs are ACM and they don't bend like the sheet metal signs, they simply crack. And they aren't any lighter because they are so much thicker. I absolutely hate working with ACM.

 

[Joshua Caldwell]

At least I don't have to worry about airbags damaging the interior of my car... I expect that the airbag warning light on my dash means it has insufficient pressure to work.

 

[Hog]

Yup, guess it was 30 years ago, time flies when you are getting old! My old Corvette (1969) was really fiberglass back then too, none of this molded plastic stuff. I am sure the stuff is better now, but I still think that damaged panels will be replaced rather than repaired, not because of the cost, but because there really is no good way to repair them and the speed of repairs is just far quicker. However, just because the body costs Elio $300, doesn't mean you could buy them for that. They are buying in contract quantity, you want just one. Expect significantly higher prices on panels.

 

[karl]

I can't picture the aftermarket crash parts business running out to make body molds for our vehicles just yet. These will most likely in my view Elio only sourced parts for some time to come. I always thought that powder coated parts had to be conductive and be able to be able to be heated enough to melt the coating.

 

[Craig]

I can't picture the aftermarket crash parts business running out to make body molds for our vehicles just yet. These will most likely in my view Elio only sourced parts for some time to come. I always thought that powder coated parts had to be conductive and be able to be able to be heated enough to melt the coating.

A new line of powder coatings from Protech Powder Coatings, Montreal, is designed for in-mold painting of SMC.
A new line of powder coatings from Protech Powder Coatings, Montreal, is designed for in-mold painting of SMC. Clonecoat powders reportedly exhibit excellent hardness (4H) and chemical, stain, and UV resistance as a primer or topcoat. The coating is applied manually or robotically at 3- to 6-mil thickness. It replicates the tool surface sufficiently to impart a smooth or textured surface. When the powder cures in the mold, it chemically reacts with the SMC and seals the pores. Commercial applications include mass-transit seating and tactile tiles. Clonecoat is also being considered as a primer for painted auto body panels. Tel: (514) 745-0200 . www.protechpowder.com

https://www.google.com/webhp?sourceid=chrome-instant&rlz=1C1VSNC_enUS582US582&ion=1&espv=2&ie=UTF-8#q=powder coating for smc