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zrxkawboy

Posted 2013-12-21 3:22 PM (#417707)
Subject: learning auto body repair

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Posts: 168
100

Location: SD

Has anyone here taught themselves auto body repair/paint? I have some cars I'd like to fix up, and am realizing I'll probably never be able to afford a professional restoration. I am good with mechanical work, but have very little body experience. Any recommendations for DVDs, etc? I wish I had someone to teach me, but I don't. (No local tech schools, either.)

ttotired

Posted 2013-12-21 5:44 PM (#417729 - in reply to #417707)
Subject: Re: learning auto body repair

Expert 5K+

Posts: 8445
5000

Location: Perth Australia

Best way to learn is to just get in there and do it

If you expect perfection to start with, you will be disapointed, just try for perfection

Oh, and get a good hammer and dolly set and a good sander

Doctor DeSoto

Posted 2013-12-21 7:08 PM (#417747 - in reply to #417729)
Subject: Re: learning auto body repair

Location: Parts Unknown

The guy I learned from told me half the game is knowing when to stop. By this, he meant, stop
beating the metal and move to bondo, or you got it close enough with the bondo, and now it's time
to move on to poly filler or primer and wet sanding.

Basically, it is going to work like this .... dents or rust need to be cut out, pounded out, heat shrunk,
etc. When you get this close ("close" being a relative term), you hit the working surface with a 36 grit
wheel to get a biting surface, and finesse a light coat of body filler (bondo) to minimally fill the low spots
and just film the high spots. Too much bondo, and you just bust your hump sanding it down to the actual
depth you then need to work at. Rinse, repeat as needed.

This is where knowing when to stop comes into play.

So, you think you have it pretty darn close (there's that word again), you go over the body with either
a polyester type filler for fine work, or if it is REALLY close, move directly to priming and wet sanding.
This is where you get the car as perfect as you can. This is what the finish paint will go on. This is a
LONG and tedious job with 20 acres of #@! car body to make perfect. When it is all where you are
satisfied, you take it to a location of minimal wind, airborne contaminants, and overhead birds, and
tack cloth the entire surface just before tossing your color on it.

Shoot all primer and paint in even strokes of same distance from gun to surface. Learn the stop-n-go
trigger method for each end of stroke to avoid build up at your double-back point. Paint should go on
light, with more strokes, as opposed to heavy and fewer strokes to avoid runs and drips. There is a
fine balance between that perfect wetness and having runs. Go on too dry and your surface is rough
as a cob and uneven, metallics won't flow right.

Once you have a happy paint surface, let it sit overnight, wet sand entire surface with Ultra-Fine and
do it again. Repeat for a 3rd coat, or as many as makes you happy, call off the dogs, and allow to cure
for 5-10 days in a dry, low humidity location. Now, you are ready for final wet sand. You will start at
220 grit to knock down orange peel and other surface irregularity, moving then to 480, 1000, and on
to Ultra-Fine. Another massively tedious job. You are creating the finish product that should look REALLY
nice. After Ultra-Fine, all that is left is polishing. Your local paint supply place can recommend grades
to work through to do this best.

Much of this is a learned "finesse" and only wading into the fight, or getting advice here and there can
develop.

One more thing .... paint is measured in gallons, not coats. If someone says "This car has 21 coats of
lacquer", you know he's an idiot. If he says "We put 3 gallons of material on", he's at least familiar with
car painting and what he's dealing with. Ask your paint supply dudes about materials and coverage to
match your desired surface depth and overall finish.

And ask all the questions here you like.

57plymouth

Posted 2013-12-21 7:53 PM (#417751 - in reply to #417707)
Subject: Re: learning auto body repair

Expert

Posts: 3578
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Location: Blythewood, SC

I taught myself. Don't be afraid to make mistakes and grind it back down.

57plybel

Posted 2013-12-21 10:40 PM (#417756 - in reply to #417707)
Subject: RE: learning auto body repair

Extreme Veteran

Posts: 594
500

Location: Melbourne, Australia

I initially taught myself as a teenager and still love it 30 years later.... back then from books, now from Youtube.... Short courses are available at colleges, some at night and are a good mix of practical experience and hands on approach. Our class had no theory.....

About 20 years ago, i settled on my preferred method...

Work metal, grind, weld, patch etc, then etch prime , then epoxy prime, then filler work, reprime and seal in epoxy any more filler work with epoxy, use a longboard to shape/flatten, Dress down with fine grades of paper ( all dry work so far) Topcoat...

My preferred top coat is acrylic laquer for old cars ... Very forgiving for first timers and a great result if the time is put in.

General hint.... dont expect heavy primer to fill in rough/quick/shoddy work.... take the time to sand in various steps..., allow paints to flash off and fillers to harden properly before painting.... AND if you can feel a bump or transition between the repair and the good metal, you will probably see it in the finished job.

I avoid wet rubbing until paint is topcoated but most people do not.... I just put the time in to rub it out....

There are many many ways to attack body and paint and as mentioned prior, knowing when to stop is a big thing... topcoating is relatively easy; the prep work takes up the bulk of the time!!!

Below pic is of my Galaxie painted by me at home 4 weeks ago !....Colin

(gal rr resize.jpg)

Attachments
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gal rr resize.jpg (164KB - 121 downloads)

Doctor DeSoto

Posted 2013-12-22 12:13 AM (#417762 - in reply to #417756)
Subject: RE: learning auto body repair

Location: Parts Unknown

Aussies have an even harder go it it than those in the northern hemisphere, as they have to do all
their wet sanding backwards !

57Kelii

Posted 2013-12-22 12:25 AM (#417767 - in reply to #417707)
Subject: Re: learning auto body repair

Elite Veteran

Posts: 698
500

Location: Los Angeles, California

whats all this about bondo?....John uses lead for his work. I thought bondo was the bad way of doing things.

ttotired

Posted 2013-12-22 1:06 AM (#417772 - in reply to #417707)
Subject: Re: learning auto body repair

Expert 5K+

Posts: 8445
5000

Location: Perth Australia

To me, lead is old school bondo

The problem with lead is you need to use an acid flux to get it to tin (stick) to the metal and if not removed completely, it will cause rust to form under it.

It also takes a lot of skill to use properly, not to mention the probability of lead poisoning ect ect

The limited use of body filler is normal in the modern age, the heavy use is to be avoided (to thick and it will crack and shrink)

The most important thing with any filler (lead or bondo) it that it must be sealed or rust will form under it.

If you fill over a rust hole or a hole in a weld and leave it raw on the backside that you cant see, you can be pretty sure that you will be fixing it again in a couple of years (at best).

You have to remember that bondo is a plastic (as are most paints) but is pourus even when hard, thats why you should paint it as soon as you have finished working with it.

Lead isnt pourus and that is its big advantage over bondo.

Even though I said above that its best to seal a hole behind lead, lead can be used to seal a hole but you have to be sure that it is fully tinned on both sides of the hole so moisture cannot get under the lead where it may not have tinned properly.

The proper use and aplication of bondo is perfectly acceptable in normal panel repair.

You wont find much in a brand new car as the stamping and panel fixing (attatching) methods do not require it.

Most modern cars these days are put together with adheasives and liberal amounts of seam sealers that basically hide spot welds in areas that are semi hidden (inside trunks ect) and you will find if a panel is joined (rear 1/4 panel to roof skin) that a smear of filler would be used there or the join would be designed to be under a trim piece.

It takes a true craftsman and many hours to be able to repair a panel thats rusted out or heavilly dented without the use of some sort of filler and my hat goes off to them for their skill and patiance

LD3 Greg

Posted 2013-12-22 1:12 AM (#417773 - in reply to #417707)
Subject: RE: learning auto body repair

Expert

Posts: 1906
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Location: Ontario, Canada

I think Doc just wrote the book! There you go! Do it his way and if you don't like the result, grind it out and try again. When it comes to finish, just don't change chemicals in mid stream.
Greg

LD3 Greg

Posted 2013-12-22 1:30 AM (#417774 - in reply to #417772)
Subject: Re: learning auto body repair

Expert

Posts: 1906
1000

Location: Ontario, Canada

Further to what too tired has said, every seam or patch must be waterproof. In my opinion there are only three ways to do that. Solid steel(perfect weld), lead solder or polyester resin(fibreglass). It takes skill to apply any of these to be absolutely sure.
Greg

57plybel

Posted 2013-12-22 1:32 AM (#417775 - in reply to #417707)
Subject: RE: learning auto body repair

Extreme Veteran

Posts: 594
500

Location: Melbourne, Australia

I will moonwalk (backwards) across the shop floor just for you Doc !!

I've got paintjobs from my youth and humidity blisters caused by moisture in the airlines, dampening of the floor to keep dust down and improper drying after wet sanding are now all big no-no's to me ! Have learnt lots but am still learning to this day....

The harsh Australian sun is evident on the many factory paint jobs having the clearcoat totally breakdown and disintergrate after 6 or 7 years ... over a wide cross section of car brands...imported/locally built.

Repaints tend to fair better where the film thickness is greater but I'm still not sold on 2 pack (catalyzed) paint for my money... I use it on wheels, chassis, drivetrain etc and of course all repair work over bare metal. To me, the lacquer seems to offer both a mechanical and chemical bond where as the 2 pack offers just the chemical bond.....

My 2c.... Colin

Doctor DeSoto

Posted 2013-12-22 8:13 PM (#417901 - in reply to #417775)
Subject: RE: learning auto body repair

Location: Parts Unknown

I have not painted a car in 20 years, but from my ancient experience, also like using lacquers. Had one
client insist his Packard be painted with nitrocellulose lacquer ! Lacquer offers easy working and repair as
key advantages. The finish is more "period" in appearance, but cannot really be brought up to those crazy
over-restored super finishes like some modern 2-part paints can. I am a low tech kinda guy and want a
period look, so lacquer still seems the way to go. I will research "the scene" when I get to that to see what's
latest and greatest and if I need to adjust my sights.

jimntempe

Posted 2013-12-22 8:20 PM (#417903 - in reply to #417707)
Subject: Re: learning auto body repair

Expert

Posts: 2312
2000

Location: Arizona

I always heard that the disadvantage to lacquer was that it only lasts about 10 years and then starts to craze badly. That was what happened to my 69 Firebird. The red on the roof was a mess in less then 10 and by 10 there were lots of areas on the body that were crazed badly. But it did shine really nice for the first 8 years or so.

Doctor DeSoto

Posted 2013-12-22 9:40 PM (#417912 - in reply to #417903)
Subject: Re: learning auto body repair

Location: Parts Unknown

Acrylic enamel (common Earl Scheib, el cheapo paint joint material) crazes badly after a few years
like you describe.

zrxkawboy

Posted 2013-12-22 10:29 PM (#417918 - in reply to #417707)
Subject: Re: learning auto body repair

Veteran

Posts: 168
100

Location: SD

Thanks so much for the words of wisdom, guys...I do appreciate it!

57plybel

Posted 2013-12-22 11:41 PM (#417924 - in reply to #417707)
Subject: RE: learning auto body repair

Extreme Veteran

Posts: 594
500

Location: Melbourne, Australia

The enemies of lacquer are film thickness and heat and indeed, it can craze and crack within 10 years, especially in daily driver status.... repaint over repaint definitely speeds up the process.

The old school of thought was multiple coats of primer and blocksanding. Swelling and sandpaper scratches were eventually visible and poor work was not hidden for long. Lacquer is also porous which doesn't add to durability...

A tip from a master painter about repairs sealed in epoxy (under and over filler) sealed the deal for me... I still have Galaxie repainted panels from 1996 with NO breakdown in finish using this method.

Using the lacquer primer / lacquer topcoat method, I have a repaint from my youth still with me.... side panels still shiny from a 1987 repaint but roof and boot (trunk) crazed and had to be bare metalled....

Which leads me to clarify my view that for collector car/ garaged car - lacquer or 2 pack is fine

For daily driver cars - expect a limited lifespan from lacquer or put in lots of maintenance via polishing/washing/waxing

For home application - lacquer is easier and definitely safer for your respiratory system...

If you have access to ovens and booths and lots of ca$h, 2 pack paint might be the one for you!

I last bought nitrocelluose lacquer (pre 1960 GM technology) in the late 90's . It was even easier to buff than acrylic lacquer but scuffed easily (brushing your jeans against it) and I believe is what the 50's show cars were finished with.... they often were repainted within 3 years....' nuff said!

Glad to see you trying to do it yourself Jeff !

Colin

57plymouth

Posted 2013-12-23 9:49 AM (#417959 - in reply to #417707)
Subject: Re: learning auto body repair

Expert

Posts: 3578
2000

Location: Blythewood, SC

I've only used Urethane Enamel. I've had nothing but good results. It sands and buffs easy, which is good since I don't have a paint booth. I'm one of those people that likes to use modern paint, so laquer is not something that I'm likely to use.

I painted all of these cars.

Edited by 57plymouth 2013-12-23 9:52 AM

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