DuPont Corlar Industrial Primers

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Darrin Burt

I would like to know if anyone here has experience with DuPont Corlar industrial primers. They feature a line of epoxy paint that I figure would be just the ticket for restorations.

Has anyone used these products- got any good or bad stories to tell?
 
Hi, Darrin Burt! Welcome to the SPI forum! Are you planning on using SPI products in conjunction with the Corlar industrial coatings? Perhaps if you were more specific about the process and materials you have in mind, and what you are refinishing, you might get better information.
 
darrin, i have use quite a bit of corlar epoxy in the past, 10 years or so ago. i used to work for a really big yacht manufacturer. corlar was used on all the running gear. shafts, rudders, struts, etc. while it was great for that stuff i would not use it on a car. that stuff is meant for bridges, ships, big steel stuff......well as the name implies heavy industrial. its the kind of epoxy you put on with a 3/4" nap roller lol. just a slop it on type coating. keep it off a car. epoxies for automotive finishes are a bit different and have a good working window, easier to use and apply in a controlled manner and meant to work with automotive coatings. not saying the corlar wont work but there are too many unknowns on application, sanding and compatibility with topcoats.
 
Thanks guys for the welcome and advice. Sorry I have not posted sooner. My wife has recently undergone heart surgery and I haven't had a lot of time for the other stuff in life.

In answer to your questions, I have a vehicle that will be in a very humid environment and I figured that if this primer was good enough for marine use then it would do fine underneath my vehicle. Is there a better alternative to protecting sheet metal?
 
SPI's premier product is their epoxy primer. It is designed specifically for automotive use, and has excellent adhesion to steel and aluminum without any complicated preparation. This makes it ideal for the hobbyist. The only caveat is the requirement that temps above 65F be maintained. I'm told that epoxies that cure in low temperatures give something up in terms of toughness, but I will have to defer to Barry to explain that further. The Corlar primers you are considering are made specifically for outdoor low temperature curing, but I suspect that ability comes at a price in terms of some other property, most likely adhesion or chip resistance.
 
if you only want the corlar for the underside of the car and it wont be painted then by all means thats fine. the spi epoxy is just as good though. the corlar is by far thicker though. the sacrifice you with the corlar is ease of use. its not user friendly and definitely does not look good if it is going to be seen. the stuff goes on like tar. like i said it heavy industrial stuff. ships and bridges. its kinda like putting down a 100% solids epoxy floor in a garage.
 
I sprayed ruddy brown corlar on the underside of a 58 Impala convertible restoration back in the 80's. Dupont didn't have much for automotive epoxies back then but the Corlar was definately more durable than the lacquer primer most people were using. SPI is way better though, and I think CRASH is right about cold curing epoxies giving up durability-all of the thick PPG industrial epoxies I tried were the same-poor chip resistance and poor adhesion compared to SPI.
 
I appreciate the replies- I will look into SPI Epoxy. What is the best prep for this epoxy? By that I mean what sort of tooth should the substrate have for best adhesion?
 
Jim do you buzz it with 80 grit after media blasting so it's easier to clean? I find it too rough of a surface and the rag clings to the surface if I don't hit it with 80.
 
no i know what you mean though. i dont touch it. i will blow it off and spray it OR i will spray the part down with 700 or 710 until its dripping then i will blow that off and spray.
 
So you are saying that after sandblasting you do not clean the substrate? I have heard differing views on cleaning blasted steel and would like your opinion on the subject. Thanks!
 
I clean with the 700 water based cleaner, but I sand it first to make it easier to clean. I find that pieces of the rag will stick to the metal if I don't hit it with 80 grit first. I know some guys will use Dawn dish detergent, followed by a 700 cleaning.
 
I really try and clean it before the blasting but afterward i will usually just drench the part in w&g remover then blow the remover off the panel. Some small parts i have been know to just blow off and epoxy. I have seen no benefit either way. I am blasting with crushed glass though which is a very clean media.
 
danp76;34236 said:
Jim do you buzz it with 80 grit after media blasting so it's easier to clean? I find it too rough of a surface and the rag clings to the surface if I don't hit it with 80.
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I reuse my blasting media (Silica Sand) so it's a requirement to clean the bare metal before primer. I use both solvent and waterborne cleaners and regular toweling. The fibers that remain are easily removed with a simple rub with a new clean maroon scotchbrite and compressed air before applying primer. Do not primer over the fibers left from the towel. In theory if the part was completely clean before blasting and if you used new media that was for sure known to be clean then you wouldn't need to do a wash before priming. JMO
 
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