mud

you can put mud over 2k primer but if u want it as right as it can be strip the doors put 2 goats of epoxy on the doors let dry over night then do your mud work over the epoxy... this is a lot of work... depending your skill level.. this is much harder because you are now dealing with 2 substrates.. intead of just bare steel......Paint by krusty 1 970 405 6373

 

you can put mud over 2k primer but if u want it as right as it can be strip the doors put 2 goats of epoxy on the doors let dry over night then do your mud work over the epoxy... this is a lot of work... depending your skill level.. this is much harder because you are now dealing with 2 substrates.. intead of just bare steel......Paint by krusty 1 970 405 6373

x2

And if you sand through the epoxy, blast it again. I even use the epoxy as a sealer.

 

no problem with putting it over primer as long as everything is prepped right. follow fillers instructions to see what grit scratches it needs to adhere properly.

 

i deal with this almost daily from customers. they all want to know,
whats better etch primers or epoxy primers?
Dont forget, nothing beats the etch primers for adhesion to the metal, Just wipe a piece of metal with the activator and see what it does...
In my opinion its a toss up, either primer is good, i personally like the etch/2k better but its just my opinion, Bottom line, just leave your parts as is and put the body filler over the primer, just be sure to prep with the proper grit sandpaper

 

mud

the problem with doing it this way is that when you put your mud over anything ..but bare steel.. when you knock your mud down with anything coarser than 150 you will scratch your substrate ....then when you get your mud work done ..prime it, block it, paint it, when all that crap eventually dries you will see those little scratches out on the ends
if anyone tells you different they are lying to you...if you want it as nice as possible just strip the door...it takes about 10 minutes to strip just about any panel if you know what you are doing...pm me if you want more in fo....Krusty

 

the problem with doing it this way is that when you put your mud over anything ..but bare steel.. when you knock your mud down with anything coarser than 150 you will scratch your substrate ....then when you get your mud work done ..prime it, block it, paint it, when all that crap eventually dries you will see those little scratches out on the ends
if anyone tells you different they are lying to you...if you want it as nice as possible just strip the door...it takes about 10 minutes to strip just about any panel if you know what you are doing...pm me if you want more in fo....Krusty

I will argue this with photos and credentials if you want to go toe to toe

 

mud

all im saying that it is next to impossible to get those tiny 80 scratches out on the ends...tell me you have never seen it..?? look at it a year later? polyester is not meant to be on acid anyway ..you sand the urathane primer to mud, it you dont think there will be any etch hangin out ..come on get real..there is going to be etch somewhere.. i was just giving my opinion...nothing you have ever done has schrunk on a scratch?wow im impressed>>>LOL

 

Your fine, no need to knock it back down,in fact at this point your just wasting alot of time and money. I do most my work over high build or 2k primers and never had a hitch.Plenty of show car paint jobs to prove this that are years old.Just make sure to read the directions on what ever filler you use and you rough up the primer with what they suggest. The best way to do it from the begining is to epoxy or etch prime the bare metal, apply filler then use a high build/2k primer to get it completly flat.But in this instance you are fine to keep going without stripping it.

 

Jeff, What etch primer are are using? Your putting it down first & then putting bodyfiller on top correct? I'm not aware of any etch primer that this works well with.
Opinions on the "correct" methods of autobody work is probably more varying than what different engine builders feel is the right bearing clearance.
I really think "which way is better" in this case comes down to the skill & knowledge of the person doing the spreading & sanding. I agree with Krusty that it is likely that the doors will show some sand scratches, however I also believe that Fontaine has & can do filler work over the 2k primmer & not have any problems. The trick is knowing when & where to stop sanding with what grit & also what materials work better in such a case. I personally have done it both ways with good pretty results either way. Have I seen & have made some "scribble" (I call it) out at the edge of the filler spot at some time...yes, once in a while, but minor. These are chemicals, they can change "habits" with different weather, application & substrates & top coats. With a lesser experienced person, the likelyhood that the scratches show, goes up. So I agree with both of you to a point, EXCEPT the lier part!
As to "What to do?" My thought would be...How big of a spot, how many spots, are we talking about? If it's a missed ding or Two or a little damage from rough handling since the primer job, I would sand the primer & swipe. If we are talking...The doors were striped & primed, fully knowing it was just to keep them from rusting & they need several applictions of heavy filler & sanding &/or a large portion of the door needs covered, I would strip it. There, Now one more opinion added to the mix. Lorne

 

Jeff, What etch primer are are using? Your putting it down first & then putting bodyfiller on top correct? I'm not aware of any etch primer that this works well with.
Opinions on the "correct" methods of autobody work is probably more varying than what different engine builders feel is the right bearing clearance.
I really think "which way is better" in this case comes down to the skill & knowledge of the person doing the spreading & sanding. I agree with Krusty that it is likely that the doors will show some sand scratches, however I also believe that Fontaine has & can do filler work over the 2k primmer & not have any problems. The trick is knowing when & where to stop sanding with what grit & also what materials work better in such a case. I personally have done it both ways with good pretty results either way. Have I seen & have made some "scribble" (I call it) out at the edge of the filler spot at some time...yes, once in a while, but minor. These are chemicals, they can change "habits" with different weather, application & substrates & top coats. With a lesser experienced person, the likelyhood that the scratches show, goes up. So I agree with both of you to a point, EXCEPT the lier part!
As to "What to do?" My thought would be...How big of a spot, how many spots, are we talking about? If it's a missed ding or Two or a little damage from rough handling since the primer job, I would sand the primer & swipe. If we are talking...The doors were striped & primed, fully knowing it was just to keep them from rusting & they need several applictions of heavy filler & sanding &/or a large portion of the door needs covered, I would strip it. There, Now one more opinion added to the mix. Lorne

see my sticky at the top on how to prep bare metal, thats the route i stick to in all my paint work. after using dp epoxy i like to lay down a coat or 2 of high build with guide coat and block that out to see what low spots i got to deal with before doing any filler work.That is unless i allready know then its right over the dp,then once all body work is complete the final coat before base coat i like to block with 400-600 grit.If you do any filler work, there must be at least 2 coats of prime to keep from getting fathered edges around your body work/filler.The dp mixed as a sealer would help here or you can reduce k-36/high build primer and use it as a tintable sealer.

 

body filler

What brand filler are you using? Read the label and see what the manufacturer reccomends and do it as they say.

 

you can do your work on the 2k primer. as for sand scratches appearing if you do you filler work properly you should not have them.here at my shop priming over 80 grit sand scatches is not acceptable . i always start with 80 then finish with 180 before applying 3 coats of 2k primer . then apply guide coat and blocking with 320 then if every thing looks good on to 600 wet sand then to paint. never have had a problem with sand scratches showing through