PDA

View Full Version : FRP vs Urethane Discussion


dorkidori_s13
07-19-2018, 12:26 PM
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!

EFITTZY
07-19-2018, 01:27 PM
Some very valid points here, thanks for sharing

deolio
07-19-2018, 01:51 PM
what is this, a reading forum?

dorkidori_s13
07-19-2018, 02:05 PM
what is this, a reading forum?

yes, yes it is... shuuuuuuush!

blo0d
07-19-2018, 03:11 PM
what is the FB 240 group?

dorkidori_s13
07-19-2018, 03:22 PM
what is the FB 240 group?

240sx Owners Club... roughly 85,000 members

tuzzio
07-20-2018, 08:05 AM
roughly 85,000 members, 84,985 of which are completely brain dead

Quoted for truth.

zenkicpe
07-20-2018, 08:40 AM
hahahahaha

EJ8 944
07-20-2018, 10:57 AM
Nice post, informative.

dorkidori_s13
07-20-2018, 11:09 AM
Quoted for truth.

hey, i dont mind helping to educate people. i dont see them as brain dead (was a little shocked that you changed my wording)... its just that not everyone has the time, dedication or attention spans to learn or research for the information ive picked up and committed to so heavily over the past 16 years (especially in the last 5 years getting into manufacturing aero bits). i prefer teaching people and hoping they learn something new versus ridiculing them for being ignorant simply because they might be new or they dont have the same level of dedication to put toward these cars and all the silly history behind them and the parts like i have/do :)

e30gangsta
07-20-2018, 01:19 PM
This is a great post. Well written and informative.

!Zar!
07-21-2018, 11:35 PM
FRPenis .

stuckonfresh
07-22-2018, 12:19 PM
great post, thanks!

ixfxi
07-22-2018, 06:42 PM
OEM aero parts are NOT polyurethane, they are ABS plastic.

Where are you getting this info from? Factory lips and sideskirts are not made of ABS. ABS isnt even flexible.

I'm not claiming to be 100% right on this, but closely examine any of our bumpers or sideskirts and you'll see the stamping that specifies what type of plastic its made of. Typically a thermoplastic, polypropylene or polyurethane....... or a blend of it.

FRP sucks because its fragile, hard, and when painted - easy to chip. Plus, having them painted is also a ton of work. But hey, its a low-buck solution to replicating these aero parts - I get it. The way I see it though, OEM or bust.

KiLLeR2001
07-22-2018, 08:30 PM
OEM front bumpers / lips are some form of urethane. OEM side skirts and rear valances are your ABS plastic.

dorkidori_s13
07-22-2018, 08:38 PM
Typically a thermoplastic, polypropylene or polyurethane....... or a blend of it.

which at the end of the day is NOT a pure polyurethane. front bumpers and lips consist of blends of materials (not just polyurethane). OEM bumpers are much more flexible than standard side skirts and valances yes, however, they dont suffer the same type of problems from exposure to heat like pure polyurethane parts are prone to.

HOWEVER, the factory S13 kouki lip IS pure ABS plastic. the lip i molded my urethane replica from was brand new out of the box. it was amazingly thin and it was very understandable why they broke/shattered so easily versus the OEM 180sx zenki lips (and even the OEM 180sx chuki lip).

FRP sucks because its fragile, hard, and when painted - easy to chip. Plus, having them painted is also a ton of work. But hey, its a low-buck solution to replicating these aero parts - I get it. The way I see it though, OEM or bust.

unfortunately, your response seems quite weighted in personal opinion. FRP parts are easily prepped for paint when produced properly (my parts only require scuffing with 400 grit sand paper before primer). FRP is far from fragile when made properly (again). if the part is flexible and can absorb impact, this helps prevent cracking and shattering versus parts that are primarily made using filler in their resins (a cheap way to save money on parts production). OEM parts are nice and all, but "OEM or bust" is a response showing more personal opinion versus fact. OEM plastics are nice and all, but when they break... they are a pain to repair. side skirts and valances crack and break very easily, especially with how old the plastics are now. MOST of the used OEM aero parts left on the market now are dried out, sun damaged and brittle. in turn, this makes the parts easy to break... in some cases, even easier than your claim against FRP based parts.

Abeo
07-23-2018, 09:22 AM
Somewhat unrelated, but on the topic of OEM Aero bumpers...

I spent a lot of time trying to figure out how to fix the rough aero bumper I have. It had 2 splits near the fender bolt holes, and a split between the rad opening and vent.

Taking slivers off of the bumper showed that it wasn't a good candidate for plastic welding (meaning it was a thermoset plastic).

After going through a number of professional bumper repair products, I ended up with JB Weld plastic repair (https://www.jbweld.com/collections/plastic-composite-pvc/products/j-b-plastic-bonder-syringe). It was able to bond to the plastic, and was strong enough to bridge gaps where I vee'd out the cracks. It sands well too.

I would have been better off buying a repo from dorkidori, as far as hours put in to fixing that bumper. But I sure learned a lot.

dorkidori_s13
07-23-2018, 10:47 AM
I would have been better off buying a repo from dorkidori, as far as hours put in to fixing that bumper. But I sure learned a lot.

i dont sell s13 aero bumpers anymore. i sold my mold to www.carbonfiberhoods.com and they are having the bumpers produced out of CA now. i cant vouch for the quality of them anymore seeing as i havent seen one of theirs in person yet. all of my logos have been removed from the mold as well.

TheRealSy90
07-23-2018, 04:12 PM
Now why would you go and do that? Especially after all the work you went through getting those made.

dorkidori_s13
07-23-2018, 04:26 PM
Now why would you go and do that? Especially after all the work you went through getting those made.

because people stopped buying them... i sold roughly 150 of em in their lifespan with me. needed the money from the mold for some business related stuff as well as a new water heater in my house lol

the aero bumpers for me were just a hassle to have in my product line anymore. i was selling 1, MAYBE 2 every month or so. profit on them was also falling off greatly as well, so they really werent making me any sort of decent income for the business. demand just wasnt there for them anymore. it was when i announced i was no longer making the bumper and the mold had been sold that people took notice and bought up the stock i had left.

i was happy to bring the option back to the 240sx world again, but people tend to put aero parts off in their builds these days. im more interested in making restoration items and lower cost parts that sell decently. i plan on reproducing quite a few much needed exterior and interior bits in the coming years that are in high demand that most companies wont touch in terms of production simply because their focus is aero instead of the entire car itself.

TheRealSy90
07-23-2018, 05:11 PM
I see, makes sense. I've been waiting for someone to start remanufacturing all the discontinued things that Nissan won't make anymore. S30 Z guys have had aftermarket options for discontinued parts for a while now.

dorkidori_s13
07-31-2018, 01:10 AM
I see, makes sense. I've been waiting for someone to start remanufacturing all the discontinued things that Nissan won't make anymore. S30 Z guys have had aftermarket options for discontinued parts for a while now.

well im planning on bringing out some discontinued items and hard as hell to get interior parts in the coming years. as of 2019-2020 i am focusing solely on S14 parts as thats one side of my business that is heavily lacking! i have 2 more sets of S13 coupe valances in dropping this year and one more set of sideskirts (V5C valance, and my the TypeRC valances + TypeRC skirts).

the small OE bits i plan on doing will all be urethane based parts... mostly things no one will touch (kind of like how i brought out the S13 chuki fender extensions).

Ratpack_Chad
07-31-2018, 09:34 AM
https://i.imgur.com/Byv4ENM.jpg

https://i.imgur.com/m1RwI2c.jpg

https://i.imgur.com/2osCrrl.jpg

Proper FRP does indeed flex vs shatter.

Of course there were cracks after this but all things considered its pretty incredible how well it took the impact. That cone is about half the height of the bumper.

dorkidori_s13
07-31-2018, 10:59 AM
those are some GOOD pictures sir! :D

OBEEWON
07-31-2018, 12:52 PM
I didn't read the first post but I vote C) turkey bacon.

turboshoebox
07-31-2018, 11:35 PM
Most people who say fiber glass sucks are talking about shity chinese replica and not the real deal JDM parts