If the panel is new or bare metal you are trying to protect short term and will be welding on it then use weld through pmr. If you are preparing the panel for finish work then you can use self etch pmr and then cover it with a urethane pmr. Another option is to shoot epoxy pmr over the bare metal. The epoxy is probably the best sealer, but it is temperature sensitive and requires you to follow a time schedule. The epoxy is probably going to offer the most protection. I would shoot urethane over the epoxy within the time the data sheet specifies. Body shops prefer the self etch and urethane, as you can begin working them in a few hours. I used self etch then a high build urethane (UPOL brand) on mine, and we did epoxy followed by the UPOL on my friends Cutlass. Both with outstanding results. We really took a liking to the UPOL, you can block the heck out of this stuff!
I am not sure about cold galvenizing, but I know if you weld galvenized metal it is very dangerous.
i used weld through primer on mine. the problem i found is that the start of the weld on the primer is difficult. the mig wont make a good contact with the metal the primer causes a slight film. the solution is to spray the weld primer on then once the two pieces are inplace with the primer between you scratch the hole area of the primer and then proceed the weld. after you are done i wash the area with a metal conditioner for extra protection. this will kill rust dead....
If the panel is new or bare metal you are trying to protect short term and will be welding on it then use weld through pmr. If you are preparing the panel for finish work then you can use self etch pmr and then cover it with a urethane pmr. Another option is to shoot epoxy pmr over the bare metal. The epoxy is probably the best sealer, but it is temperature sensitive and requires you to follow a time schedule. The epoxy is probably going to offer the most protection. I would shoot urethane over the epoxy within the time the data sheet specifies. Body shops prefer the self etch and urethane, as you can begin working them in a few hours. I used self etch then a high build urethane (UPOL brand) on mine, and we did epoxy followed by the UPOL on my friends Cutlass. Both with outstanding results. We really took a liking to the UPOL, you can block the heck out of this stuff!
I am not sure about cold galvenizing, but I know if you weld galvenized metal it is very dangerous.
I've been debating on what to use on the inside of the rocker panel. Would you epoxy it or weld thru or combination of both?
Engine Test Stand Playlist: https://www.youtube.com/playlist?list=PLwoxyUwptUcdqEb-o2ArqyiUaHW0G_C88 restoring my 1968 Firebird 400 HO convertible (Firedawg) 1965 Pontiac Catalina Safari Wagon 389 TriPower (Catwagon) 1999 JD AWS LX Lawn tractor 17hp (my daily driver) 2006 Sequoia 2017 Murano (wife's car) 202? Electric car 203? 68 Firebird /w electric engine 2007 Bayliner 175 runabout /w 3.0L Mercuiser__________________________________________________________
I would use Por 15 or Chassis Saver anywhere I would not be topcoating. I would pour it in through the access holes, then spread it around with a piece of rag on a steel rod.
The rocker is in two pieces so I can spray the insides before welding them. The issue becomes what should I use so that the heat from the welds will not affect that paint.
Engine Test Stand Playlist: https://www.youtube.com/playlist?list=PLwoxyUwptUcdqEb-o2ArqyiUaHW0G_C88 restoring my 1968 Firebird 400 HO convertible (Firedawg) 1965 Pontiac Catalina Safari Wagon 389 TriPower (Catwagon) 1999 JD AWS LX Lawn tractor 17hp (my daily driver) 2006 Sequoia 2017 Murano (wife's car) 202? Electric car 203? 68 Firebird /w electric engine 2007 Bayliner 175 runabout /w 3.0L Mercuiser__________________________________________________________
Sorry I was thinking convertible. The POR will probably start to burn from the heat? I would guess you will still have the access holes, so prob do the weld through then after you are done do the POR and perhaps undercoat.
Weld thru also contains zinc and the price between cold galvinzing compound and weld thru primer is pretty significant. I have read a few different forums and just have not decided what to use.
