(quoted from post at 15:13:54 03/06/19)
This is all such great information, and I am grateful for it!! THANK YOU! I might use that 2K surfacer for sheetmetal only. I know I do have that fiberglass kit car to do, I sanded the old paint and primer on half of it with a DA sander 4 years ago and its been sitting outside since. Sorry.....not trying to start a new topic.
Yes I have used Urethane Enamel paint and it yeilded a nicer finish (even with my lesser prep work than we have been talking about) but I have alot of the Ironguard Enamel paint to use. Alot are working tractors, so it should be just fine ; but for a few select ones I'll probably use the Urethane Enamel.
One more question. I wanted to clarify on how to sand after the 2K primer surfacer is applied (either my product I have or any other type).
Sanding the surfacer is IMO one of the higher skilled and most important parts of a good restoration and only practice will make you understand it completely. You can watch videos to get an idea. I like to apply the 2-3 coats as per the label, block sand w/ 180, then 240, then prime back any bare places and DA sand with 320/400 and possibly higher if the top coat needs it (you should not need to go higher than 400 for a solid color, but pearls metallics can go wonky).
This is a very generic guideline because the condition of your specific piece will dictate your starting grit, and how much you sand off with each grit will dictate when and how much you need to put on. Heck, every time I outline the process it comes out slightly differently just because there is nothing "set in stone."
You may find it necessary to start at 120 and by the time you have it "level" you may already need another coat. Any time you add another coat, you want to 1. make sure you have epoxy on any spots you sanded back to metal and 2. give it that 24 hours to dry down.
The smoother your bondo is before surfacer the better. Don't just spray surfacer over the 36/40 grit scratches in the bondo...get it up to at LEAST 80 with a DA and preferably more like 180. Same with adding a coat of surfacer to sanded surfacer -- In fact now that I'm thinking about it, I'd recommend surfacer only being applied to 180 scratches and no rougher. The rougher the scratch is that you are trying to fill, the higher your chances get of it shrinking back into those scratches. Does that make sense?
Before you ask about "blocking" or "block sanding"... you seem to be willing to spend on the correct tools. The longest block that you can manage on a given panel is the one you want to use. I love the Dura-blocks and you can get a pretty large set of them for a decent price and have multiple lengths.
Some guys like to use a guide coat...I haven't much use for it because my vision is still good enough to get by without it (or was last time I blocked a project). Basically guide coat helps you see low/high spots.
You do NOT use a sanding block for bondo. For that you want what is called a file board. These are much more rigid. I don't normally see any need to keep file board paper around outside the standard 36 grit.
You might find that you have a low spot that is more than the surfacer can take care of, but the bondo is too hard in comparison to the now surrounding surfacer...so you just keep ending up with a low spot at the edge of the bondo. For this situation you want "finishing putty" and make sure you get the kind that has hardener. Basically it's an easier sanding bondo that is made for smaller imperfections and sands easier.
Auto part stores that carry sanding gear have notoriously high prices (like 2x). Unless you are best buds with someone there and really want to support "local" business, I'd avoid them. Paint stores are certainly better but you might find it easier to order from somewhere online (i like autobodytoolmart and autobodystore) if they are a bit of a drive.
I could keep going on but I'm afraid too much will just pile on confusion. Just plan on having to redo a couple pieces to get the hang of it. You'll find that once you start doing body work, 90% of what you sprayed/spread on the car ends up back on the floor as dust and swept up.
Couple safety tips: Any time you sweep up paint/primer/bondo dust, put it in a steel bucket and keep water over it. That stuff can start smoldering and then you'll be without a shop. Also, keep a real cartridge respirator on while sanding, not those crappy dust masks. Don't be one of these guys that says "that dust doesn't bother me!" Protect yourself.
What are you using for lung protection while spraying paint, btw?