epoxy primer question

[richard2717]

I am new to the epoxy primer but figured I would give it a try on my bucket truck. The bottom of one of my bins rotted out over the years so I have cut it out and am getting ready to bend up a new one. Original was black steel sheet but my plan is to make the new one out of 18 ga galvanized. Question is, will the epoxy stick to galvanized with just the normal 80 grit sand scratches or am i up for a battle to get it to stick? In years past I have always used self etching primer, should I just stick with that? I could not find anything on manufacturer googling (Matrix Epoxy)

Thanks

[nsb29]

You have to wash it down with vinegar or leave it in the rain to neutralize it before it can be painted. I don’t know about epoxy call SPI they can tell you, they have a great product

[mongocanfly]

I've seen lots of galvanized painted...and it never sticks....maybe there is a secret....

[richard2717]

Originally Posted by mongocanfly

I've seen lots of galvanized painted...and it never sticks....maybe there is a secret....

Never had an issue with sanding it a bit with 180 then self etching primer. I have other large panels in the wheel wells of this same truck that I did back in 2014 and have had zero issues so far. I did let them age outside in the weather for a month or so after I put the panels on. Looks like I might just stick with that method for the galv. and just use the epoxy on the boom since it is regular steel.

[nsb29]

Having left it outside is the reason you didn’t have a problem

[richard2717]

Originally Posted by nsb29

Having left it outside is the reason you didn’t have a problem

Correct, I guess my question should have been if Epoxy should have been treated differently as far as prep than the self etching.

Thanks

[Jrainman]

wash the sheetmetal with water born degreaser to get the oils out ,after you dry it you can sand it to create a tooth for the epoxy to adhere ,but you can also use vinegar instead of sanding ,the vinegar is a acid and will create etching in the sheetmetal so the epoxy primer will adhere, this method has been used for a very long time . leaving it out side will will do nothing but make it in to a used old sheet, witch will eventualy wear the zinc in the sheet away and after a point in time the sheet will start rusting .

[nsb29]

Vinegar neutralizes the galvanizing it is not going to etch the metal enough to form a tooth at least not in a reasonable length of time. The reason for leaving it outside is to let it get rained on that is what neutralizes the galvanizing not just sitting out in the sun for decades

[StingRay]

There isn't a vehicle made with steel panels today that doesn't use galvanized. Every paint system has the correct primers and metal treatments for galvanized materials. There are some subtle differences in types of galvanized surfaces though. Most automotive will be a wipe coat that has a smooth surface. The type of metal jn a grain bin or your furnace ducting is quenched and has an uneven surface and appearance.