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Discussion Starter · #1 · (Edited)
Seventy hours of body work and I will soon be spraying paint!!

A couple of weeks ago I posted pics of my "Gray" (primer) doors, hood and trunk. (Thanks for the comments on that post!) Today I am ready to spray primer on the body!:w00t: I didn't expect to be at this stage until after Xmas but managed to spend several rainy days at body work. "70" hours put in so far...starting with the grinding down of seams. Won't be spraying the body for awhile :sad: since I have to construct a temporary paint booth. I do hope to have paint before the year is out!:001_smile:

A few comments and I welcome advice!

First, all automotive paints are now water based and I have never sprayed a water based paint before. Anything in particular to watch for or spray as you would oil based auto paint? (I haven't researched this yet.)

I knew the body work on my MKIII would be a challenge and I wasn't disappointed! It was hard to get some areas right. I would run my hand over what I thought was finished and find a small hollow or slight wave and .... more "Rage Gold". I found the lower rear fenders difficult....partly due to the way the body sections were bonded. Question, are the body curves (lines) at all forgiving or will every minor flaw show up in paint? (I know that priming will reveal some).

I searched threads for advice on how to install side louvers and found several different methods. I decided to sand nearly flat the lip inside the fender (FFR body cut outs did a poor job here...good elsewhere) and round the edges of the opening. I will probably bond mounting brackets for the louvers which are from Performance Automotive. Any other "good" way? (I don't want to use velcro!)

Thanks for all the advice and comments since the donor teardown!

Rocky

Some pics taken a couple of hours ago.







 

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I installed the FFR louvers with Lowe's "industrial strength" velcro and have 6000 miles on the car over the last 6 months w/o an issue. took only minutes to mount, and will be easy to remove if i need to get a wrench in there.
 

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Discussion Starter · #5 ·
You're Right!

I hope for your sake that you will be sanding the gel coat more thoroughly than you have in the photos before you prime. At this point you are not ready for spraying.
Got ahead of myself in the post...finished body work today and did a quick hand sand to find inperfections. Not ready to prime body and lots of sanding to do!

Rocky
 

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I had 300+ hours in mine all in. If you can feel it, it will show. There is no such thing as too much block sanding. The fender issues can be corrected but it takes time. Please don't take this the wrong way, but I really think you have unrealistic expectations. It looks like you are just getting started on the body - It needs a lot more block sanding to look smooth and straight with paint.

Keep up the good work - Scott
 

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Please don't take this the wrong way, but I really think you have unrealistic expectations. It looks like you are just getting started on the body...
Like Scott, not to be discouraging but as a reality check please realize that working the parting lines to the point you are at is the easy part. Blocking and flattening of the main body plus fitting and matching contours of the doors, hood and trunk are where the time really starts to add up. You're doing good so far; keep after it and remember it's not a race :thumbup1:

Re: Louver mounting. I used industrial Velcro on one car and bonded then glassed ELEVATOR BOLTS on the other:



Both are still holding. Needless to say the Velcro was less work.

Jeff
 

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Discussion Starter · #9 · (Edited)
Too Exicted!

Guess I was getting too exicted by the progress. Thanks for the reality ckeck...took that deep breath and had a good night's sleep! I have never painted a fiberglass/gel coat body... what I have done was keep older trucks/jeeps etc. looking reasonable by replacing rusted areas with tin, fiberglass and body fill! I know this is different but I honestly thought that a couple of days hand sanding the body would bring me to the priming stage. :001_rolleyes: Fact is, I want to do this right the "First Time" and I have until the summer comes around again! (at least until the end of April)

When block sanding the body, what grit is commonly used prior to primer? Start with about 280 and go up to 400 or 600? I have read posts where people have removed most of the gel coat but I don't see the necessity of this. Your comments and good advice will be taken gracefully....and put to practice!

Jeff, the fitting and matching contours of doors, hood and trunk has been completed (At least I thought so!). Most of this was done when the body was on the car. Should I be placing the doors, hood and trunk on the body while completing the main body work? What you mean by "blocking and flattening" of the main body?

Scott, the fenders are good now...after several coats of rage and much sanding...and some fustration! I can close my eyes and run my hand in any direction on the fender and not feel bumps, hollows or waves. I have found lots of "dimples" in the gel coat....thus lots of sanding to do.

Rocky
 

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No shiny spots on the gel coat...you want the whole thing to be dead flat before you prime. Check the instructions on your primer, it will tell you what level of grit to use. I had the entire winter last year in body work (mostly nights and some weekends), plus another 100 hours in paint and finish/detail.
 

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Jeff, the fitting and matching contours of doors, hood and trunk has been completed (At least I thought so!). Most of this was done when the body was on the car. Should I be placing the doors, hood and trunk on the body while completing the main body work? What you mean by "blocking and flattening" of the main body?
Rocky,
In doing both Mk3 and Mk4 bodies I have found that to match up the moveable panels (doors, hood and trunk) with the main body they need to be installed on the chassis along with the windshield and splash panels. At that point it takes filler to both the panel and body to get all of the curves and contours to match up. Here are a couple of pics that show how in some areas the body needs to be brought up to meet the panel while in others the panel gets filled to meet the body:





By "blocking and flattening" I mean going over the broad surfaces with a longboard sanding block to work out the waves and imperfections. Gel coat actually acts as a pretty decent guide coat while doing this since the shine remains in the low areas. Once you've gotten it all consistently flat as mctavish mentions most of the dips should be gone. As for grit, when using a high build product like Slick Sand or Featherfill taking it out to 400 (actually even 320 for SS) is sufficient to hide under a couple of coats.

Good luck!
Jeff
 

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As JKleiner said the movable panels basically suck. FFRs estimate of 40 hrs on an MK4 is Waaaaaaaaay off. To get it right both doors had to have mating edges skimmed, the hood had to have the edges skimmed, the deck lid's curve didn't even get close to matching the body. I used 2.5 gallon of rage gold getting the panels to fit right. Mine pretty much looked exactly like his in those pictures before primer. Then it took slick sand twice to get all the tiny imperfections out.

Keep at it, a straight body with perfect fitting panels is so worth it. People refuse to believe we did our own paint/body.
 

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Discussion Starter · #15 ·
Thanks!

Thanks for the comments and information. To clarify, the 70 hours and counting (now 80 after today!) did not include the fitting of doors, hood and trunk and getting the gaps correct. And after today....there and many more hours of sanding left!

Jeff, I did the work on doors, trunk and hood with the body on and windshield mounted....but seeing your pictures either mine was "good" to start with:001_smile: or I haven't got a very good job done!:sad: Today I block sanded and, without realizing it, "flattened".

I did take some pics of today's work but had a problem with photo bucket.:mad: I have the rear section "blocked and flattened" to 400 grit. I did find a couple of problem areas but delt with it (Rage!) and things look good!

Heading to the cottage tomorrow to convert to winter set-up. I'll post some pics next week.

Rocky
 

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Being that these cars are very curvacious it actually can hide poor body work better than on a conventional car like a Camaro or a Mustang.
I think I have got everyone beat with regards to the amount of filler used.
 

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Discussion Starter · #17 ·
Pictures from Today

I still have problems with photobucket so I used "Flickr" to post these pictures from today... I hope this works! They show the rear drivers side after much sanding today...220 to 280 to 400 grit. Two were taken after wiping with dry cloth and the third after wiping with damp cloth. There is quite a difference from the pictures in my first post of this thread.

Rocky




cobra body 001 by rocky guy, on Flickr


cobra body 002 by rocky guy, on Flickr



cobra body 006 by rocky guy, on Flickr
 

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From my experience using such fine grits at the body filler stage is counter productive... 80 grit to 120 grit is a better choice at this stage. Get the filler surface 95% perfect with the mentioned grits then spray on the polyester filler, block with 120 grit out to 98% straight then use the Urethane primer to get to the final perfect flat surface. I sprayed the first coat of Urethane then did a "quick" initial block with 120 grit then switched to 150 grit for final. Then another round of the Urethane and then 320 grit swipe followed with a final 400 grit before sealer and paint.
One important thing is to change out the sand paper OFTEN, It may feel like it has lots of bite left but after only a couple square feet of sanding it looses its sharp edge and what happens is you end up putting undulations on the surface if you try to get the most of it.
 

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Discussion Starter · #19 ·
From my experience using such fine grits at the body filler stage is counter productive... 80 grit to 120 grit is a better choice at this stage. Get the filler surface 95% perfect with the mentioned grits then spray on the polyester filler, block with 120 grit out to 98% straight then use the Urethane primer to get to the final perfect flat surface. I sprayed the first coat of Urethane then did a "quick" initial block with 120 grit then switched to 150 grit for final. Then another round of the Urethane and then 320 grit swipe followed with a final 400 grit before sealer and paint.
One important thing is to change out the sand paper OFTEN, It may feel like it has lots of bite left but after only a couple square feet of sanding it looses its sharp edge and what happens is you end up putting undulations on the surface if you try to get the most of it.
I understand changing sand paper often is needed....never heard of "spray on polyester filler"....my limited experience from years back only used "primer". Is the use of the polyester filler a standard procedure and is Slick Sand a example? Also, your forth thumbnail shows your body with fill...at what stage is this?

Thanks for the info, Rocky
 

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....never heard of "spray on polyester filler"....my limited experience from years back only used "primer". Is the use of the polyester filler a standard procedure and is Slick Sand a example?
Yes. Slick Sand and Feather Fill G2 are high build primers manufactured by Evercoat; basically sprayable fillers. After the initial bodywork they are applied and then block sanded, theoretically burying sanding scratches, as well as minor waves and flaws. Featherfill builds 2-4 mils per coat, Slick Sand 4-6 per. SS has a longer pot life. After using both I prefer SS, though not by a wide margin, simply for the higher build. You'll find a little more discussion in my Mk4 bodywork thread linked below.

CC but is spot on in his post above ;) I do most of my shaping and cutting using 120 and 150 then go down to the 320/400 that I mentioned previously as a last pass before spraying SS or FF.

Jeff
 
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