Valspar epoxy primer questions

[Ash]

Any body have any experience with Valspar VP50 Epoxy primer?

I'm doing the last few steps for preparation to lay down some epoxy on aluminum. I'm a little confused by the tech sheet though. The last thing I have to do is sand all surface areas. I would have thought that I should wash everything with a mild detergent after the final sanding. But this says to wash it first. this seems back to front to me. Is that wrong?

This is what the tech sheet says:

5. SURFACE PREPARATION
• Wash surface with mild detergent and water.
• Rinse and dry surface.
• Wipe surface with 155 Surface Cleaner (steel) or 170 AquaClean (steel/
aluminum) and wipe dry with clean cloth before product flashes.
• Sand and featheredge substrate with P220 (Primer) or P320 (Sealer) grit
sandpaper or wet equivalent.
• Clean surface with 155 Surface Cleaner or 170 AquaClean and wipe dry
with clean cloth before product flashes.

[shaunp]

Alloy oxidises very quickly, wash it sand wipe it with prepsol or similar, the etch it. Personally I wouldn't use Valspar, bottom end of the paint market for auto finish. Prepsol is always the last step with cleaning other then a tack rag. Aqua clean is most likely a deox agent.

[Ash]

So you would wash it before final sanding, Shaun? I would have thought with the amount of dust created from sanding, you'd want to wash it off as well?

I've already purchased all the product. It also says to not use etch primer.

Also, I'm not a spraying a car. It's an aluminium horse cart frame that I've made.

[shaunp]

It's an epoxy etch primer it's self Id say,  don't wash the dust off, blow it off with air, then wipe it down with lint free cloths and some type of prepsol /wax & grease remove etc prior to top coat, it will be fine.

[Ash]

I had a look at the catalogue and the etch primers are in a different category. Not to sure on that one.

No worries, will do that. Thanks for clarification 

I've got a couple of new boxes of tack clothes, so am good to go there. Nearly ready to mix up a pot and pull the trigger.

[shaunp]

Unless it's some sort of etch its not going to stick to alloy long.

[Ash]

This is why I was concerned about the amount dust from pre-sanding. It is the sanding that gives adhesion.

[shaunp]

Yeah it will give some key, but alloy needs etch, so does steel really. Are you sure this is not an epoxy etch? Most primers will hang on where you rub through the original finish, ie on a repair but on a full panel you want an etch.

[shaunp]

It says sand and feather substrate that means the old paint or primer, not bare metal.

[Ash]

Sorry, I'm not sure what you mean by not bare metal?

This is from the tech sheet.

6. SUBSTRATES
• Properly cleaned and sanded aluminum, steel, galvanized steel or sand
blasted steel
• Properly cleaned and sanded fiberglass and SMC
• Properly cleaned and sanded OEM finishes
•
Note: Do Not Apply Over Self Etching Primers

http://www.valsparrefinish.com/downloads/Valspar_TDS/VP50_TDS_ROW.pdf

and the site

http://www.valsparrefinish.com/primers_other_VP50.jsp

[shaunp]

If that's what the site says then it's an etch or at least a self etching primer ( most epoxy's are) it has to be if it will stick to alloy and Gal with no other etch. Particularly gal. So scuff it up, blow it off with air and a cloth, I use Supa cheap microfiber towels, as you can just wash them and they pick up most dust, use some wax/grease remover etc and paint it. If you have the cleaners they say, make sure, they don't dry on the panel ie as they say don't let it flash off.

[Ash]

I asked at the time and the guy at Autolac said just normal wax and grease remover was fine.

I'm all geared up so am hoping to shoot this down tomorrow.