I had three repaired areas to spot prime.

Like a Bozo I taped them off and loaded them up with primer/surfacer. Now there's a sizeable ridge next to where the tape was.

I fully expect to have to reprime after sanding, but would like some advice on how to make the ridge go away with doing the least amount of damage.

I'll be sanding by hand, no tools other than blocks.

Thanks.

Glenn, there is no need to reprime. Sometimes priming right on the tape line is needed but should be avoided. To avoid this you should tape back farther or back tape. You pull the leading egde of tape back over itself, use 2in tape for this. Doing so make a fuzzy edge that sands very easy.

When I do prime right to the tape, I take the block and stand it right on the edge, the one I use is about 1in across on the edge. Then I just sand on that edge til it starts to level out. Dont sand the entire primed area, just on the edge. Once the edge is cut down some then start sanding the entire area. When sanding the edge use nice unused paper as it cuts it faster and better.

Wet sand with 500 grit then paint. Some like 400 but that seems to leave sand scratches when using a metallic, 600 cuts to slowly...Eric

I have to disagree with Eric here (that's a change). I am sure he can do it, as well as I can. But it takes a few years to be able to do it. IF only the primer is sanded, than it can be done. However, to sand ONLY the primer and not the surrounding area is often a tough lesson.

I say, do as Eric said first of course. But don't reply on it and just lay paint on. You need to get it wet after sanding to eye ball the panel and see if it REALLY is flat. I think you may end up blocking it with some 120 or 180 and then repriming it out a little further without any masking around the spot. I think you may find that you would save a lot of time to just do that. But what the heck, Eric wouldn't steer you wrong, give it a try.

Thanks guys, I'll try just sanding the ridge at first, but it's nice to have a backup plan .

About this backtaping...is this how it goes? You get tape that's about 2" wide and go around the area several inches beyond the repair, then you work your way in with more tape barely overlapping the outside tape, and repeat. Then when you prime, you prime to the inside tape, have some flash time, peel the innermost tape, prime to the next row of tape, flash time, peel, prime out farther, ect?

Is that how it's done?

Thanks.

Glenn, theres the "back taping"
http://www.chevelles.com/showroom/backtape.jpg
Notice the 2in tape. Apply the tape to the panel but only apply pressure to half of the tape to get a good seal. The half you didnt apply pressure to you just roll back over itself. You might find you need to tear up small chunks of tape and tape down the rolled over part so it doesnt roll back. Once its rolled over just apply your maksing paper to the 2in tape.

Martin, I know I didnt word my description probably the best way, am not a man of many words :(
I guess the way I see it the edge is just like run or sag. If you can reduce that run first then worry about flattening the rest of the paint you won half the battle.
As Martin stated after sanding use water to check for a smooth transitation(sp?)

Eric, thanks a lot for the illustration. I'll do it that way next time. I suppose the same technique also applies to the color coats as well.

Eric, you discribed it perfectly and your drawings are great. No, my disagreement is how easy it is to do. Sanding a run out to polish is VERY difficult to a beginer. In fact, many pros can't do it. I have a hard time with them, I know. It takes sanding thru a few and or leaving a "tire patch" in the middle of a panel a few times to really learn to respect how difficult it is.

Your back taping is exactly how it is done every day at the shop where I work. The preppers use 3M foam aperture tape though, instead of the 2" tape.

One thing that I want to make really clear Just because you back tape or use the aperture tape doesn't mean you still prime right up to it! DO NOT prime right up to the tape. SAND OR SCUFF right up to or apply the tape OVER the sanded or scuffed area is even better. Then prime your spot and simply use the tape as a stopping point for "overspray" NOT as a place to stop priming.

If you are useing a tape machine simply put your paper on backwards covering the area to prime and fold it back to the tape, same method and cheaper than aperture tape and 2" tape. Mike
I would also suggest reprimeing after you sand the ridge out,just to be sure.Easier and cheaper to do it now than after it's painted!!

Martin you pointed out an excellent point, use the tape ONLY to stop overspray not as a barrier for primer. Even thou back taping and those foam tapes produce a fuzzy edge they STILL PRODUCE an edge. Even with them if not careful you can leave behind a primer line after blocking.

After some thought I guess being a novice, you should block out the primed area with 180-220 and reprime. Basically just cause I might be able to do it doesnt mean you or Joe Smoe can do it.
Last thursday I painted a 99 grand prix se bumper, put 2 nice runs in the thing. I tried the razor blade trick mentioned in another topic, needless to say am glad those runs where down below cause I really messed that up :( It seems some guys out there use that blade to perfection, me on the other hand graemlins/sad.gif

Thanks to all for the info, especially the taping/spraying part.

I think I'll take your advice and hit it with 180 and get a fresh start.

If I tried going around the ridge I'd probably spend hours to put a nice groove in the paint.

Glenn, if you block it now with the 180 with no worry about sanding thru knowing you will be repriming, you WILL produce a flatter panel. That is why I will block my primer and reprime almost every time. It is kinda like the "skim coat" with plastic filler. If you block the primer or plastic filler with no worrys, just block the stuff knowing you are going to apply another coat to fill those scratches and any tiny imperfections, it is much easier than trying to "save" yourself from doing that last step. Being that you are "free" to block to make it perfect without any worry of cutting thru or leaving too coarse of scratches you do a better job. At least that is the way I see it.

Eric, practice, practice, practice. I can't do it either, but I have to think I could with enough practice. smile.gif