FRP vs Urethane Discussion

[dorkidori_s13]

I started a thread on one of the larger 240 forums on FB, thought I would bring the conversation here as well...

At the moment, there seems to be a HUGE misconception of FRP versus Urethane based parts seeing as so many of you are demanding urethane produced items. I would like to clear the air and try to dispel some rumors/misinformation...

First, PROPERLY MADE fiberglass parts WILL take a beating just like OE ABS plastics and urethane! The bulk of parts currently in the S-Chassis scene (and car scene in general) are cheaply produced items made in China/South America/Mexico with very little (if any) quality control or care for the final product is put into them. Lots of these parts are either made paper thin, or are produced with tons of filler in the resin compound. Paper thin parts will break and tear easily since there is nothing to them. Thin parts also tend to be very wavy in their gel coat finish. Parts with too much filler will shatter upon impact as they are very stiff, cannot absorb impact, wont flex and generally have a hard time complying to the desired surface of the vehicle.

FRP parts that are properly made WILL absorb impact, WILL flex and shift with impact and will not shatter like poorly/cheaply made FRP items. Parts from companies like mine (DorkiDori AutoCouture) or Shine Auto Project have been formulated and produced to actually flex, bend and deal with impacts to not only help with the longevity and durability of the product, but we both go thru great lengths PRIOR to molding to ensure the parts fit the car properly and formulate blends of resin + fiberglass that are worth the investment. The majority of bigger "replica" brands out there producing parts for our cars are using molds that are ancient and havent been recast off the original plugs in over a decade. The molds tend to be warped and out of shape which causes fitment issues when applying the parts to the car (as Im sure some of you have found out due to having utilize rivets to hold pieces on). My molds have been produced to a level that allows for thousands of pulls with no chance of deformation to the molds. Fiberglass molds tend to be cheaper and easier to produce, can allow for single part orders and production is relatively quick on parts.

Now onto urethane. Urethane is a nice material to work with. It is durable, it is flexible and it is cheaper to produce parts than FRP in a few ways... However, one thing I think a lot of you guys dont realize is that it DOES have its flaws. Urethane molds are expensive to cast (about two to three times the cost of FRP based molds) as they are a double sided mold that requires the use of dowels, magnets and clamps due to being a low pressure casting based system. Urethane parts have to be run in larger quantities due to the material itself being sent in large drums, the machines have to be completely cleaned out of any urethane left in them (either different type of urethane or currently used urethane so it doesnt harden). Ive started noticing a lot of you guys running urethane kits having issues with sagging (as well as deformations due to shipping from folding the parts). Urethane is a plastic that needs to be supported. Urethane is a softer material than ABS plastic which requires some form of structure underneath to help keep its shape in warmer weather (ABS plastics are also prone to sagging in larger pieces like bumpers). Without it, what happens is the part will actually take on new memory once heated cooled a 5-10 times. This is the nature of plastic! When folded and crammed into a confined space, if the plastic is heated and then cooled numerous times (which can occur during shipping in summer months), you will begin to form new memories in the plastic where the harsh folds have occurred. This is why with my own parts, I refuse to fold items inside of a box or bubble wrap.

Ive seen a lot of you guys go on (as well as videos and pictures) about how urethane parts can be run over, hit with things etc etc... Well, what a lot of you dont realize is that if you bolt (yes nuts and bolts) the parts to your car properly, they will tear when presented with enough impact. Tearing and repairing urethane (and ABS plastic) is a difficult process that involves a tool called a "plastic welder". Think of it like a soldering iron for plastics. I know some of you prefer drilling holes and using zipties, but zipties dont hold the parts to the car strongly enough to allow for the sort of impact force necessary to tear the part. I want to bring up cold weather as well... Should you impact a speed bump, parking block, large rock, wall tap or anything else that could impact the urethane while driving in the cold, the urethane based part will break or chunk outif it dips below a certain temperatute (Ive already seen this happening to various kits around the web). Plastics becomes stiff and brittle when cold, and this leads to shattering much like FRP can be shattered.

Both materials, when produced properly, are great to use for body kits, HOWEVER, both have inherent flaws that need to be considered. FRP is NOT the cheap, horrible material the bulk of you think it is (quite a few automotive brands have done and still produce fenders and other body panels in FRP). FRP has a horrible stigma that stains our scene due to brands out there who make "cheap" parts that are mass produced with no quality control and very little R&D put into making a product that is durable... These kits are cheap for a reason (foreign manufacturing, no quality control, no R&D). Urethane is a nice material that tends to be a trend that comes and goes in the car scene on a regular basis (Ive seen numerous waves of urethane based parts rise and fall in the 16 years of being involved in the import scene). While it is durable, its does have its inherent flaws in warmer and colder weather that FRP is not susceptible to.

I just wanted to present this information to you all and clear the air a bit. Im sure some of you will have negative opinions, comments and input about what Ive just written, some of you may have positive things to say and I may have cleared up some lingering questions for you... But in NO WAY is one material superior to the other. Both FRP and Urethane parts have their ups and downs, both are extremely durable when made correctly and both can be broken and destroyed in the same fashions. There just seems to be A LOT of misinformation out there about both materials and I would be happy to answer any questions you guys may have about both seeing as Ive spent the last 5 years dedicating my life to producing parts in both materials, have customers who have beat the hell out of both types of parts I produce in said materials and I have a lot of hands on experience with both! I would love to share my knowledge with anyone who is curious.

PS: OEM aero parts are NOT polyurethane, they are ABS plastic. ABS plastics are produced using very very VERY expensive solid metal high pressure based molds that require basically human sized vices to hold them in place and clamp them together during the molding process. Just for a bumper, the mold cost is roughly $20,000-$30,000 depending on size and complexity! Not to mention the cost of producing a production ready plug!