What are the differences in epoxy and urethane primers? What are the deciding factors in choosing one over the other?
one is a lot better than the other one... i use...epoxy... it is hard enough to be polished out to slick and shiny.. ...the other is easier to sand but will rust through if exposed to damp conditions. in this pic.,this epoxy has been on for about 4 years...rubbed to a shine with a 3000 grit sanding pad. ...GFF...:Handshake
My truck is done in a urethane and will also polish out shiny dries hard as a rock.Its sits outside 24/7 no problems with rust through
You dont...These guys are just playing with there primer till they actually paint their cars.Ideally you only want to scuff the stuff with 320 to 400 grit before painting...the primer has to have some tooth(roughness) so the top coat will stick to it.These guys will scuff it up before actually painting at the least (I hope).
LOL...your funny...but seriously...they dont use more than they have to in most collision shops...Restoration shops though...they use LOTS of it.
Epoxy is used on bare metal. Urethane is used over epoxy. If your car isn't bare metal use a good urethane primer like PPG K36. I like PPG NCP 271 high build epoxy as it is a direct to metal primer or over cured paint. It is all I use.It is expensive at $270 a gallon and $85 for a quart of hardener.You can tint it as well with what ever colour your car is.Urethane will not stick to bare metal. Price wise urethane is cheaper than epoxy