I do everything they teach you in autobody school but i learned most of it in my 8 years of wood finishing for excessively high end home renovations lol. we do renovations starting at like $30000 and go up to $250000 in my experience just for cabinetry install. exacting customers with money to burn and very particular taste.
autobody isnt that far off. we dont finish to the same gloss typically, but when you ahve 2200sqft of solid color to spray out consistantly, lots of opportunity to practice.
my limitation is the wood shop though. impossible to keep the shop clean with the amount of material im spraying in a given day. even at 68% efficiency the guns specify, you can see how much still ends up on the floor or on the walls.
I used valspar automotive products. I could get exact specifications next time im at the shop to read the labels. basically i used their 2k sealer surfacer, basecoat and ac2100 production clear coat. they have a faster snap dry clear but when working with a large panel, id rather give it the time and not have to worry about flashing while im still applying a thick coat.
I scuffed everything with my festool electric orbital with a well used 150grit pad. this took the caps off all the nicks and deep goudges ect. i filled with proform flowable 2k filler, sanded again with the orbital and a block with 150-320 grits. applied first sealer coat fairly wet to the rough surface and allowed to dry overnight. applied more filler where there were large dents. or chips that are difficult to see on the base part. wet sanded 400 grit with a block, applied second wet wet coat of sealer, let dry overnight, wet sanded entire bumper by hand with 400 wet/dry no block this time.
after that i went over the whole peice with a grey scotch pad to rough it up a bit and make sure i got everywhere. there was a little orange peel by the time i finished the 400 wet sand, but it was gonna be silver and i just stopped caring as most of it was gonna be covered by front splitter.
at this point i hade 7 ish hours in prep time on a bumper most body shops would chuck in the garbage.
after all the sanding is done, blow it all off really thoroughly, wipe it down with a alcohol paper tower to get rid of skin oils ect. tack rag.. apply 3 coats of color, focusing on even covering, 5-10 minutes between color coats at 15C shop temp. after last color coat i cleaned the gun and mixed up the clear. apply a medium wet coat of clear immediately after final paint. ie, the time it takes to swish out the gun and mix up the clear is about perfect. took a half hour nap and applied final wet coat of clear.
then leave and dont come back for a weekend lol.
I was using a devilbiss Tekna prolite for the entire project. A lot of body shop guys really like SATA for this... i own both brands in my shop; Satajet 4000RP and Two Tekna prolites.. the Jet 4000 is a beautifully german peice of kit. very nice chrome coating that cleans up super easily. devilbiss sprays exactly the same pattern, comes with 1.2, 1.3, 1.4 nozzle sets and its significantly lighter and more comfortable in hand. its also half the price...germans coating is nicer though.
anyway. One Tekna prolite with 1.4 nozzle for the sealer mixed 4:1:1 (base, catalyst, reducer) used the 1.2 nozzle for the base which is mized 1:1 with reducer and the clear which is also 4:1:1.
for everything ive painted so far, i spend $210 on material including the filler. to finish the front splitter and rear bumper im gonna have to buy a whole other kit. sealer, base, activator, clear. i have reducer left.
by the summer i might just go ahead and set my tent up and spray the passenger side with all the door handles attached ect. then the whole car will have fresh paint for under $500 lol.
i guess the short of all that, the secret is really just being able to put down a wet coat without getting runs. the sealer esp has to be put on wet to give you a nice surface to paint. ideally, you would be able to forgoe the entire wet sanding process with a wet enough final coat of sealer. all my small plastic parts were done this way. all i had to do with them was scuff and put on silver.