Body/paint cliff notes

Ight , so I've gotten a few guys pm me requesting steps and procedures for certain body related projects. So in an attempt to maybe help those and others the following is a good bit of info that I will add too over the next few days or so.

Rust repair:
1.only remove as much metal as necessary. Both the patch,ground location and the area around the patch must be CLEAN metal, backside too.
2. If the repair runs relatively close to a body line or edge push the cut lines to about .250 to .750 from the edges. This will cut down on warping due the strength being greater in that area.
3. Spend time fitting the patch you want a 1/16th to a 1/8in gap to fill with the wire. I generally make the patch a little oversize and then cut thru both panels with the 1/16in cutoff wheel. This gives the perfect gap for .023 wire 1/8in gap is good for .030 wire.
4.Turn the heat up you want the Weld to lay flat and grab the inside edge if the cut. You want to "spot" weld the seams, just aim for the gap and hit it, wait for it go from brite Orange to almost brown "looking thru the helmet" before hitting the next spot. You should clip the wire anytime the wire cools, ie after the 4 consecutive hits. This allows the first hit to be clean and flat same with puddle welds especially. Use a small flatblade screwdriver to keep the gap level, this is EXTREMELY important. Tack the perimeter in multiple places. This doesn't guarantee it will hold the edges level you still will need to pay close attention that.
5. Do no more than 4 hits before moving to another area of the patch. Keep an air blower close and as soon as you finish 4 hits , cool it down with the air. DO NOT SPRAY WITH WATER OR USE A DAMP CLOTH
6. Hammer and dolly the seam flat as you go, grind with a fresh 24 or 36 grit grinder, do not heat the metal.
7. For puddle welds start on the outside edge and burn around the edges as you approach where you started push the puddle into the center a pull out, a spiral motion if you will. For a successful puddle weld the two or 3 panels MUST be FLAT and tight against each other ie clamped. Also if you have multiple layers your burning together let the wire burn the bottom layer then work the puddle up to the top, then allow to cool a little and then spiral it out, if you try to do multiple layers without that quick cool down the puddle will fall out the back.
8. Dress the Weld with a 5in grinder, roloc, or my new weapon of choice DeWalt electric 4in flap disc grinder. Leave some Weld material there don't grind 100% flat. On small places I will grind it flat and then metal file it and not use any filler, but that's just not practical on larger areas.

Filler application and usage:

1. If a rust repair has been done and or you are filling a large depression ie something deeper than 1/4in. Granted you shouldn't be filling things this deep,..but things can happen along the way that won't allow the metal to come back out enough. This is where you use a fiberglass strand filler such as Duraglass, Dynaglass etc. These are waterproof fillers and also very strong with excellent adhesion. These products are much more suited to the applications above.

2. Surface prep for "Duraglass" and filler is as follows, heavy grind scratches 24 or fresh 36 grit don't throw sparks use low speed and random directions to give the proper "bed" for the product.

3. Application: warm the metal if it's cold, heat gun is preferred, the first few passes over the area push the material in deep in the scratches, then soften psi and move where needed, once it's built to desired shape and height, pull the edges in nice and smooth this will save you lots of work.

4. once tacky shape with the "cheese grater" I generally only have to lightly work my primary filler with 36 as I do 95% of the work with the grater. But shape as needed with 36. Filler is for shaping, putty is for smoothing,.. generally. Block with angles as much as possible, blocking in a straight line usually doesn't end well especially for a novice. Even psi on the block let the paper do most the work. Once the material is lowered almost to level, feather the edges in this is very important, once the edges are feathered, then slide over the entire repAir area as a whole, if you try to lower the area as a whole till the edges feather you will pull to much material out every time. Once you get the area close with the 36 or 40 switch to 80 then 120. If it feels like it should, take the DA with 180, if your proficient with it and soften a 4in perimeter around the dent, removing any stray 80 scratches etc. Keep the da flat and work the edge in. If you feel your not that good wuth a DA yet, then just use your block and do the same. That's a better practice anyway just more time consuming. Follow up with 320 if your doing a spot repair. If your prepping for a full panel prime/block session no need for the 320. Do not go over the filler with 320 its fine to do so on very small repairs smaller than a silver dollar. Otherwise the 120/180 grit will give a much better tooth to hold the primer. And if your using a quality primer shrinkage isn't an issue, especially if doing a "show" job where you'll be repriming with a surfacer or more filler primer.

Primer Application:

1. Start with another round of a epoxy primer over your completed body work. If you opted to epoxy prime initially and are looking at minimal bare metal spots around your repair areas. You can just scratch up the epoxy with 120/180 and go straight to your Filler primer. Pretty much all filler primer is "DTM" now anyway. That's "direct to metal" btw so no concern doing so. I myself always use Polyester primer first for its superior build,adhesion and lack of shrinkage. Polyester is like liquid filler, don't try to use it as such but it builds very thick but WILL FAIL and lift if you don't have enough grit under it or apply it too heavy too quickly in contours. Or if you put it in direct sunlight too soon. Poly primer CANNOT be painted over it must be coated with a Urethane primer. It isn't intended to be wet blocked either. I apply a minimum of 4 but usually 5 coats. Spray with a guide coat such as lacquer based spray bomb, base coat, or actual guide coat in the spray can. Just a even mist coat the purpose is to show you Highs and Lows during the blocking process. Let dry for few days, Then start the blocking process with 100 grit on several different blocks. This is where you start laying your foundation for what you see when looking down the side of a painted vehicle and separating the novices from the pro's.

2.A "Durublock" set is essential as is pool noodles, paintsticks, rad/coolant hoses etc. Use what ever fits the shape your blocking, keep as even psi as possible and use as long a stroke as possible. Treat the primer like filler, like a huge dent if you will. Work with angles as much as possible, just because the guide coat is gone does not mean the area is flat. Once the initial guide coat is gone I either spray with Dewaxer and visually check it or apply another round of guide coat, I prefer the powder guide coat for the second time. Once you have the poly primer where you want it it's time for the Urethane primer.

3. Same process as above but with a longer cure time, minimum 1 week with exposure to Sunlight, more without out. Treat it the same as outlined above just use 220 and water, followed by 320, then with 320 go to a Semi-firm sponge or a "Wonder block" they are a gift from the heavens, firm enough to stay flat and not disrupt your blocking efforts but soft enough to follow body contours and pull the blocking lines out. Big long strokes here with a decent amount of even hand psi. Once you think it's good, go over it again. Then it's decision time if you feel like it's where you want it then go over it with a soft hole sponge with 400 using big long strokes, this is pulling tbe 320 scratches out in preparation for sealer. 400 provides an excellent tooth with out worry of shrinkage, 500 is ok too, but I prefer 400. Now if you want to go the extra mile, once you finish blocking with 320, you will reprime yet again with a primer surfacer, this is my most common practice it sands like butter and gives just a nice even bed for the paint to lay. It doesn't do any real filling or building just takes care of sand thru spots, scratches small pinholes that got missed etc. No more than 3 coats and few days cure time then block with 320 and finish it out with 400 on the semi firm and then soft sponges. If you use the surfacer you can bypass the sealer before the color.

Dry blocking Urethane primer: I've gotten where I don't water block too much anymore. So the rundown for that is as follows, start with 220 and block as outlined above. Use air to keep the paper clean and try to use longer strokes and vary the angles even more so than if it was poly primed. Use a guide coat as much as needed to shape it. Then you will switch to 320 on a softer wonder block, soft sander or semi firm hand pad. All your doing here is softening the 220 scratches. If you want to go the extra mile, put some 320 on a soft sponge pad and using long strokes with even and light psi, follow the shape of the panel.

Paint prep:

1. Wash it a couple times, psi wash etc use Joy or dawn etc dish detergent, it will help pull grease from your hands and the environment off. NO CAR WASH soap it's got crap in it you don't want on the surface. I usually will wash it with a red scotch brite pad, it will bust up the dried sanding dust instantly.

2. Dewaxer , simple process wipe on, wipe off. I use rubbing alcohol on occasion too.

3. I wash my hands really well then blow the surface as i wipe with my hand your skin is the best tack rag. Then I grab a tack rag and Blow and Tack at the same time, light psi with your hand and open the rag up and fluff it up kinda like a shower loofa or whatever them things are called that your wife uses. I will then lightly blow just air over the surface. Tack in-between coats as needed, but alot of times I won't seems like you do more harm than good , it's a judgement call on your part, booth conditions etc play a part in that. But generally the less messing around you do and the faster it's sprayed the cleaner it will be. If your planning on cutting and buffing, don't worry about making it wet just go for nice even consistent coats. Last thing you want is a run, they are difficult to remove and almost never come completely out.

Spraying:

I can't tell you how, but it relies on 3 basic things SPEED,DISTANCE AND OVERLAP. If you do all 3 consistent and correctly you will be successful. When I or another pro paints we are flinging the gun all over the place and going fast but that comes with experience. When starting out just watch the "SDO" and you will be fine.

Cutting/Buffing:

There are several approaches first is the what we'll call the "cruise in" finish and the "car show" finish.

For a cruise in finish which is essentially just using a semi firm pad with 1500 paper and then followed with 2000 grit followed by a rough cut compound and then a Polish. Work an area the size of a shoebox at a time then squeegee dry and if there is no peel visible move on. Then use the finer grit paper to soften the 1500 scratches.

Now for the process that makes me people take notice; first you obviously want toake sure you, the car, the bucket, the rags etc etc are clean and grit free.
I start with 1000 if you have a lot of trash, runs etc, you may need to use 800/1000 just be care full as you can make a mess with 800 on fresh clear if not careful. But you MUST Block sand the clear to make it flat, there is no other way, treat it just as the Urethane primer. I use paintsticks, blocks, wood dowels, aluminum stock all kinds of stuff. Work a shoebox size area be carful to not let the block dig in. One wrong move at this point and you can screw the area up for good.

There is a 3rd buffing process, that includes blocking with 400 then semi firm sponge sanding with 600, then applying 3-4 more coats of clear. Then you start cutting with 800 and working up. But to be honest it's a huge amount of work and generally just not worth the all that extra effort. But it's the only way to get that 100% flat surface with perfect light refraction.

...more to come this week

 

Heck yeah thanks for this post!!!

 

Thanks Hugger. This should be made into a sticky.

 

Added some more

 

Thanks

 

Keep 'em coming. Thanks! Never thought of overlapping & cutting the gap with a wheel.

 

Ethan, I am having trouble reaching the center area of my roof with the spray gun when painting. Is there a trick? I even tried standing on a step ladder. Thanks.

 

Take the air out of the tires and or get a platform, this is what I use. You can also narrow up your spray pattern just be careful doing this as it will puddle up if you don't watch it but I only do that on like vans or buses, otherwise I just hold my hose with both my left leg and left hand and stretch.

 

Thanks I will try that. Much appreciated man!

 

I'll try to add some more tomorrow

 

Taking the air out of the tires was such a smart answer, I like the way you think. I like quick fixes

 

You Rock Ethan, I always appreciate your input! You really love helping others, that’s cool.

 

Hi again Ethan. Another question if you don't mind. I have read that it is wise to let high build primer cure to a week or longer before blocking to prevent shrinkage. Do you agree?

 

Very much so , after it spends a few days inside I move them outside so it can be exposed to UV , but yes a week or so is fine. I'll do the primer tutorial next

 

Awesome thanks for that. A primer tutorial would be great.

 

Good post....I was wondering if you have ever used kitty hair rather than duraglass? I started using it a few years ago and I like it better than the duraglass because it seems to dry slower and bite in better. When they first came out with the tiger hair it was heavier and dried too fast,but this kitty hair is very versatile even on fiberglass repairs.

 

I have and it works well too.

 

Just seen this,

I swear after reading this I felt like I wrote this. You do everything I do almost word for word.

Your very first tip, only use what's needed in the patch, I've been telling that to body enthusiasts around here that come to me for advice. Sadly in their eyes since they bought the whole panel they feel the whole thing must go in.


Great read for anybody looking for advice.

How old are you?

I started doing body work at age 15, and now at 51 I've had enough, time to move onto to new things. Owned my own shop for 27 years.

 

I'm 35, been around auto collision all my life, my dad started his first shop doing Corvettes in 79' iirc. He had me water sanding stuff when I was 6, had me welding rad supports in when in i was 10 or so. Started painting when I was 14. Done my first "show paint job" when I was 18. We have owned our current collision shop since 99. My old man has taught me alot and I've developed my own ways. Im currently an Auto Collision Instructor as I simply had my fill of Insurance companie's deadlines and them not allowing me to make repairs like I wanted. That and I want to try to share what I know, this is a dying skill, nobody wants to work , alot of guys in this field have tons of "drama" , and most guys have learned only bad habits from large production shops, and have no real understanding of the correct way to do things. As a shop owner I know you see it as well. I'm hoping I can interject some more truly skilled kids into the field.

Will hopefully have time to sit down and do the primer section this week