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  #61 (permalink)  
Old 04-15-2012, 08:12 PM
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Should be O.K., however if you do have trouble you can thin it out with acetone to get it to flow better just watch out because it does have a tendency to run easily. I have a 2.3 tip on my primer gun and beleive it or not I still have trouble spraying some of these polys straight up. I have tried a lot of these polys such as nason, upol, cars, etc. The one I like the best as far as spraying like a 2K is the Omni MP 243. But as far as the slick sand goes don't remember having much trouble spraying that one.

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  #62 (permalink)  
Old 04-15-2012, 08:16 PM
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My problem is I never spray that poly or a skim coat of polyester putty for that matter without KNOWING that the coat WILL without a doubt be the last application of filler applied.

This is a hard lesson learned, if you spray that polyester primer and it doesn't fill the low spots, you will have a lot of work to correct it, basically starting over. If you apply a polyester putty over those low spots and sand it flat with (you know what's coming) NICE, NEW, QUALITY, SHARP sand paper so you CUT it flat, then apply the polyester primer you will KNOW it's the last application.

Brian
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  #63 (permalink)  
Old 04-15-2012, 08:26 PM
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I would agree with MartinSR Josh. Get the low spots up with filler before you go to a primer. You can't go back to filler! All the knowledge in the world is useless without patience. Keep us posted.
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Old 04-15-2012, 08:41 PM
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Agree with that statement Brian, but much easier said than done. I have a friend that is trying to block out a car he is restoring to sell, have been over there many times trying to guide him through it, and he does have some bodywork experience and is VERY eager to learn more. What I see him struggling with the most is skimming the low spots and getting that skim coat to feather in with whats already sanded. That is where the frustration really takes over for the guy who is desperately trying hard to get it right. This is a lesson hard to teach someone right in front of you let alone over the internet. Just trying to help.
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Old 04-15-2012, 08:49 PM
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Here is the mistake he is making, he is trying to "blend" those spots in. It is as simple as pie, you don't do that. This is my point, you don't ever put the last coat of filler on, a skim coat, until you KNOW it will be the last.

You don't even try to blend those spots in, not any more that is that a skim coat over the top will cover any imperfections.

Here is my "Basics of Basics" on the subject.(Click here)

With this method you don't have to baby these low spots, you apply filler and you CUT it flat using NICE, NEW, SHARP, QUALITY paper. This paper can be much coarser than you would use to try and "blend" it in, being it is much coarser it will CUT it flat very quickly.

Once you have the panel flat, (as flat as needed where ONE coat of polyester putty or primer will finish it) all the lines nice and sharp, where ONE thin skim coat will finish it, you spread or spray a polyester putty on the entire area and block it to perfection. I have a guy I have worked with for ten years still calls that last skim coat of polyester putty "Primer" because of what I taught him years ago. You look at it as a primer coat to fill pin holes and sand scratches and poor feathers, that is all you are asking it to do.

This method was taught to me by a very good bodyman and I have passed it on to many guys in the shops I have worked and watched them turn from someone who fights filler to a two application mad man.

Brian
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Old 04-15-2012, 09:01 PM
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Thanks Brian, sounds like the same problem he is having with this hood. Will pass it on.
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Old 04-15-2012, 10:46 PM
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No problem. I know it's not the same as having someone walk you thru it in person but I try to write my "Basics" in such a way that I put the tools in your hands. When I wrote that piece I didn't even have a digital camera for goodness sakes, it's about 12 years old.

Look at one of current "Basics" and you will see plenty of photos.

Brian
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Old 04-16-2012, 10:48 AM
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Looks I'm adding another skim coat then, except this time I'm skimming the area I currently didn't have skimmed under the hood scoop, and then will skim the entire hood cutting it with 40 grit. I'm sure it will come out a lot better this time.
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Old 04-16-2012, 06:57 PM
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First off you won't get FLAT with a DA on a HOOD!

You need to long board. If it's just a skim coat, then long board with 80 grit.

Yeah may be time consuming but flat is time consuming.

Once you think it's flat. Shoot it with 2k primer. Shoot a guide coat on it and then again long board it with 120 grit. Watch what your guide coat is telling you. Are you low in any areas? High because you show metal?

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Old 04-19-2012, 01:50 PM
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anything before the final skim gets 40 grit unless I'm doing a production job with existing paint. Most of the times I'm coating something with epoxy on it or just bare metal so it's not an issue. I do most of my cutting with a mud hog then it's a block with 40 to true it up. The key to get yourself to a final skim is proper evaluation of the panel. Without that you're just fooling yourself. Before I lay anything on it I know exactly where everything is. I then spot fill certain areas after metal work so when I skim coat that one area that's a little lower than the rest it isn't gonna make that skim coat a waste of time. My tool to find everything out about a panel is good hand feel from multiple directions, guidecoat, and/or blocking on it to reveal to me where it's messed, but it's a culmination of all this, not just one of them. Sometimes guidecoat won't tell you jack but your hand feel will, and sometimes it's the opposite.
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Old 04-19-2012, 02:06 PM
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An excellent trick for a novice is to take a yard stick or something with a similar smooth edge. Hold it on it's edge and rock it back and forth on the panel. It will quickly show you low spots on a roof, hood, or other low crown panel that someone with limited experience may not feel.

John L
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Old 04-19-2012, 04:24 PM
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I think I spend more time feeling the body than actually working on it; my hands are one of my main diagnostic tools for alerting me to issues and a pretty sensitive one at that. And then guidecoat, as Tech also says.

I did some paint and body school for ****s n giggles because I was militant about the hobby and since then have had several years developing my craft on this car so it's not like I'm a complete novice. But skim coating is something I had little practice at and I'm feeling better about it after all the good advice. Cutting sooner and with a more aggressive grit are going to be the two singlemost things to help me I think, and I need to start mixing my filler on a bigger pallete too so I can mix more; right now I'm just using my 11x11 pallete with tear away sheets and I remember tech69 saying before he doesn't like them because they're too small.
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  #73 (permalink)  
Old 04-19-2012, 04:41 PM
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I hope I didn't sound like I was talking down to you Josh. I know you already have basic knowledge. There are many people who read these posts and take info away other than those of us who do the posting.

That said, If a tech takes a good smooth yardstick and rocks it back and forth it will rock smoothly. If there is a flat spot it will bottom out on it. Much like rocking chair does if the rocker has a flat spot. This works best on low crown panels that are difficult to "feel" with your hand.

Keep us posted on your progress.

John L
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Old 04-19-2012, 10:51 PM
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yeah, a straight line is good help for sure. One time I had to mud a guys' quarter he welded and he warped it to high hell. It was actually a patch so he had a seam running front to back but also one up/down over the wheel well. It's funny cause as I was doing it I was pissed the guy didn't metal work it while he had access to it while it was cut out and he also warped it. So the whole time I was focusing on the warpage and damage at the seam going from front to back so after some metal working I mud it and realize it was slightly bowed from warpage on the seam going from up/down. I look at footage of that repair( I film my repairs) and I don't think I touched that area once or even payed attention to it but I did rub my hand on it one time and it fooled me. Had I just got out the straight line it would have revealed itself to me right away cause the bow was so big I either didn't feel to the end of it or I dunno. It just fooled me I guess. The next day I brought in my straight edge.
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Old 04-20-2012, 09:45 AM
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That is a good example of what you can run into. Also, it is possible to tap down minor high spots when you touch bare metal. Especially while you are mudding the panel and getting it ready to skim coat. It can take a lot of body filler to build up a panel that has only a small high spot. As you said, the straight edge will make the high spot jump out at you.

John L
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