paint and body basics

Need help straightening that dent? Or painting your car? This is the place to be!
BUILDER
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paint and body basics

Post by BUILDER » Sun Jan 13, 2008 10:35 pm

Welcome to paint and body basics.

I will try to cover body repair, prep and paint for the beginner or those who think they want to be a bodyman :lol:


RUST FORMS IMMEDIATELY
To start we will discuss rust, I hear people ask " how long does it take for rust to start after I sand a panel to bare metal?" The answer is IMMEDIATELY! The humidity in the air starts to cause a panel to rust. As oxidation continues rust will get worse.

After a panel has been taken to bare metal it needs to be treated with a metal conditioner or etching primer.

PRODUCT SYSTEMS
Most paint manufacturers have these products, and I prefer not to mix products from different manufacturers if i can help it. Companies have a system that was designed to work together with each other to provide maximum adhesion and durability.

REMOVING RUST
If you have a rust spot that is bad but not through the metal you will want to grind it down, wire brush it, use a drill with a wire brush, or sand blast it until the brown discoloration is gone.

Then you will want to use the metal conditioner as described above, then apply body filler.

FILLING HOLES
If there are holes in the metal or a large section gone, you will have to weld in a patch or even a new panel. NEVER fill with "Bondo" or Fiberglass.


Stay tuned there is more to come!!!

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Class 11 streeter
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Post by Class 11 streeter » Mon Jan 14, 2008 1:32 am

BUILDER, thanks for the writeup, looking forward to your next post (and taking notes)! :D
So you think your project is taking forever eh? Well you've got nothing on me.....

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doc
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Post by doc » Mon Jan 14, 2008 8:27 am

Great start!! Pictures are worth a thousand words.

You didn't think this was going to be easy, did you? :twisted:

Keep it coming.

doc

BUILDER
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PAINT AND BODY BASICS

Post by BUILDER » Mon Jan 14, 2008 7:48 pm

To continue on with the topic of rust repair...

Industrial Coatings
There are many different kids of rust treatments on the market such as Extend rust treatment, rust bullet, POR-15 from eastwood, i wont get into them much because i rarely use them (personal preference).

FILLERS "Bondo"
Moving on to body fillers, after your rust spots have been repaired, you will need to smooth that surface with a filler. There are a ton of different brands/types on the market.

Spot Putty - For a spot putty i like to use a polyester glaze coat like Metal glaze. The polyester putty is less likely to get pinholes (these are little air bubbles in the putty that become holes when you sand it) and has less shrinkage as time goes on.

Note: The putty and bondo products apply and mix the same. Spot putty can be put over the bondo to fill any minor imperfections.

"Bondo" is used where the area you are repairing is larger than a quarter. (that is my rule)

Another rule I try to live by is not to build my bondo deeper than the thickness of a quarter. It will crack easier.

Usually you try to keep your repair as close to the original contour as possible anyway.

Sanding Next
I will be getting into sandpaper and prepping next post. Remember, Ask 100 bodymen a question and you will get 300 answers !!!!! These posts reflect my experiences and training, there are other ways to do things and you may find them easier.

Till next time....keep sanding!

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MNAirHead
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Post by MNAirHead » Mon Jan 14, 2008 8:01 pm


BUILDER
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paint and body basics

Post by BUILDER » Tue Jan 15, 2008 6:48 pm

CORROSION PROTECTION - AVOIDING RUST
Before i get on the sandpaper subject I wanted to stress the point of corrosion protection.

Any time you do rust repair you want to make sure to coat the inside of your repair with some type of corrosion protection. You can use undercoating, paint, or one of the rust converters (to keep moisture from getting to the back side of your repair.)


Now to sand paper!!
Another area with many choices.

RUST REMOVAL - Generally 24 and 36 grit is for your high speed sanders and grinders, used for rust removal and in conjunction with rock grinding wheels when smoothing welds.

PAINT & FILLER REMOVAL Next, 40,80,180,220 grit which is used to sand body filler or sand paint off before a repair is made. They can come in sheets,discs for D/A sanders or long strips for air board sanders.

PRIMER SMOOTHING -Your next area is wet or dry used for sanding primer and paint. most common grits are 220, 320, 400, 600, 1000, 1500, and now they even have 3000grit for sanding and buffing your paint job. The 220,320,400, and 600 are mostly used in sanding primer and sealer when getting your car ready to paint.

COLOR SANDING FINAL PAINT - The 1000, and 1500 you will use to color sand and sanding before you buff.

PAINT BLOCKS & Accessories - When sanding yor primer I like to start with 320 grit using a block ( Durablock has a nice set of blocks in different sizes) and using 3M dry guide coat to show me any low spots that need to be filled or reprimed. I always prime and block with 320 then reprime my work a 2nd time, and block it again using the guide coat to make sure my work is straight.

NOTE - THERE IS NO MAGIC
Remember if your body isn't straight, your paint job will still look like crap. Take your time and do it right, it's rewarding and fun plus you can brag to your buddies that you did it yourself.

Till next time, keep sanding!!!!

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MNAirHead
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Post by MNAirHead » Thu Jan 17, 2008 10:19 am

Abrasive questions

1-Is there any difference in abrasive qualities
2-Do I use "closed coat" or "open coat" abrasives - what color should they be
3-When do I use a wire brush.. do you use a twisted knot or a "normal"
4-Any "miracle tools" (3M, Norton etc).
5-What mistakes to average folks make?
6-When I use "aircraft stripper" should I scratch through the paint to allow the stripper to work faster?

Thanks.

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david58
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Post by david58 » Sat Jan 26, 2008 10:06 pm

Gelcoat Resoration
http://www.shoptalkforums.com/viewtopic.php?t=41612
Look at this thread Mods.
Hot, humid air is less dense than cooler, drier air. This can allow a golf ball to fly through the air with greater ease, as there won't be as much resistance on the ball.

BUILDER
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Post by BUILDER » Tue Jan 29, 2008 7:14 pm

Here are a few pics of some body shop supplies and equipment that i use on a regular basis. Remember there are other brands and types that you can get.

Image

Here is a shot of my supply cabinet

Image

and here are a couple of useful tools, a masking machine and welder

Image
Image

And last an old bronco I'm painting for a friend.

Image
Image

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pafree
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Post by pafree » Wed Jan 30, 2008 8:47 pm

builder, i enjoyed your thread. how do you control your painting environment/ventilation. we have trouble controlling humidity here in southeast texas.

BUILDER
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Post by BUILDER » Wed Jan 30, 2008 9:17 pm

CONTROLLING ENVIRONMENT FOR PAINT

To answer your question there are several things i do.
  • 1st if i am painting i try do do it early in the day if it's going to be humid, nighttime is not an option around here because of bugs being attracted to the lights.

    2nd is using faster or slower reducers or thinners.

    3rd is allowing more flash time between coats or spraying lighter coats.

    4th is because I'm a little spoiled and i have an air conditioned garage!! :D :D
VENTING TIPS
As far as ventilation goes there are several options and price ranges. If you just do an occasional paint job a 20" box fan and a couple of furnace filters will suffice. If you have an old furnace blower fan you can make a filter box and mount it to a window or dedicated hole in the wall. Or if you have big bucks (or EPA requirements) get a professional filter station or spraybooth.

BUILDER
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Post by BUILDER » Wed Jan 30, 2008 9:32 pm

FILLER OPINION & SUGGESTION
To answer the filler question, I use rage gold mainly because thats what our supply guy carries on his truck, it sands easier than other fillers, and spreads smoother.(my opinion). Other filler products i use are USC Duraglass and AllMetal. For spot putty I use Metal Glaze and Glazecoat.

I have used other fillers like evercoat lightweight and 3m lightweight filler, they are good too.

BONDO & Hardware Store Talc Based Fillers
Not to knock any products but i try to stay away from BONDO brand fillers just because they tend to absorb moisture and crack/ bust loose.

BUILDER
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filler questions

Post by BUILDER » Thu Jan 31, 2008 9:03 pm

Q: filler over primer - or on bare steel?
I will answer two questions here.

I do not reccomend putting filler over primer or paint. Spot putty is O.K. to put over primer or paint. Body filler will adhere to bare metal way better.

I usually prep my area for filler work by grinding off the area to bare metal with a 50 grit roloc pad (you can see a couple in the pics I posted. they are the 3" green discs) then sand the area with 80 grit d/a paper to feather edge the area.

I then apply my filler.

You will get filler on the painted surface where you feathered but when you smooth your filler usually it sands down just to the edge of your paint.

SPOT PUTTY ALERT MAKE SURE that you don't put filler or spot putty on unsanded areas because it will flake off. And yes you can put spot putty on top of the fill before you prime if needed.

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MNAirHead
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Post by MNAirHead » Fri Feb 01, 2008 12:28 pm

Here's the 3m ROLLOC

Image

Experience note .. do not buy the cheap holders.. get something with a steel base... The plastic ones break and/or do not hold the abrasives.

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david58
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Re: paint and body basics

Post by david58 » Thu Nov 17, 2011 2:26 pm

BUILDER what is the best thing to use as a guide coat to make sure my work is straight? Oh and cheapest too.
Hot, humid air is less dense than cooler, drier air. This can allow a golf ball to fly through the air with greater ease, as there won't be as much resistance on the ball.

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