The wheelwell bubbles on my '54 Chevy had to be repaired with fresh steel because of lurking deadly rust, now I'm having trouble with those countors. If'n I use a flat block I keep undercutting below the welds and end up with flat spots. It's a real******. What do you guys suggest? It seems that flat palm sanding gives you the best control, but damn if I know!
Nads...every sanding job is different. High crown or low crown determines what you use as a sandpaper backer. To exagerate....smoothing a bowlingball takes different tools than smoothing a door panel. I learned a way to make panels flat when I was just starting to learn bondo work...this method is for panels that have damage in many areas....It's the edges of bondo that show in your paint...no edges means no flaws. When doing a panel, coat the whole panel with mud. If you can't get it right, recoat the entire panel. I've got a pile of blocking tools and sometimes make a special one for a special job. Anything from cut up yardsticks and metal rulers to foam pads and smooth radiator hoses....use your imagination. I always stay with 80 grit until the panel is right. I suggest hand tools only until you know how to make a panel right, before you attempt air tools....good luck
You have a long board,,,, Are you using the stick on sandpaper that comes on a roll? Well get some, and make a flexible board out of some Plexiglass or lexan about 1/8" thick, as wide as the paper and about a foot long. Epoxy a semi hard foam 1/2" square "handle" on the back to hang onto if you want. Stick the paper on it and sand in cross hatches so you don't sand flat spots into it. Wife has a tool kit with different sizes and shapes of these sanding boards that she uses a Honda R & D some of them are 1/2" wide and only an inch long!
I got one of these little foam flexible sanding blocks called a memory block from the paint store whenI was working on the pontiac, and it's awesome for doing curves. I just used sticky DA paper on it and it made life alot easier on the curves on the tailights and stuff on the 60, it'll conform to ANY shape. and it was only like $7
You might want to consider using "fart block" when you get close to your final shape. It conforms to the surface and does a great job of blending in difficult areas, but the odor it gives off will gag a maggot, hence the name. It's commonly used for cleaning BBQ grilles, so you should find it at most builder-supply stores. Probably wouldn't want to use it when enduring even a slight hangover . . .
I would suggest using another methode when coating the panel with bondo. Cut the edge of a hard flexible plastic sheat to match the correct courve or contours of the panel, and use that to scrape off the bondo before it hardens. Then you will get close to the desired shape before sanding. (Btw: What do you call a tool to apply bondo in english? I would call it a spatel)
For bondo edges, pits and small touchups I use glaze.Its a 3m product Im told its like primer in a tube. Doesnt use a catylist just spread it on.I was told use real thin coats and block it out. Sands nice with 400 W/D. Feder
60's Style -- Fart block is the black, relatively soft grade of pumice. Just wanted to throw in this caution because there are other grades of pumice that could do major damage to metal, to say nothing of what they'd do to filler.
Nads go the the paint store and ask for a flexable sanding block. 3M makes them, they take the sticket paper. Also keep in mind you won't see waves in a round panel like you will in a perfectly flat panel. I'm not saying leave it choppy though. And make sure you do like Hatch said in the first reply, Always recoat the entire area when you have low and or high spots. And don't even think of sanding with anything finer than 80 grit untill the repair area is as straight as you can get it. One thing I found out is when spreading fillers most of the time you are flattening out the spreader markes before you actually start to make the panel straight. (I would be a millonare if I could invent spray on bondo.) But anyway one way to really level your work is to finish the filler with 80 grit and then use a ultra high build primer and block it the first time again with 80 grit. This will make the panel very straight and then the following prime coats you are only filling sand scratches. Grits like 150 and finer will tend to follow the panel wrather than straighten it out anymore thus these grits are just recomended for smoothing. I could ramble on all morning but I think 30 years of experiance might take up alot of band width . Good luck and how about some pics of what you are working on.
Another proponent of the "fart block" method. This stuff works awesome for knocking down excess filler and really does conform immediately to whatever panel you are sanding. I used a few bricks of the stinky stuff when I prepped the body and fenders on my '40 sedan. If the wife walks into the garage, just blame it on the dog.
I'm going to have the same problem on the**** end roof bit of my Morris. Reckon I might use a long strip of narrow paper and drag it to and from across the curves, like dragging a towel across your back after a shower Hopefully the curve will slowly take a rolling roundy.
Whoops, wrong pic. Those tidy looking pie cuts are actually bowed, liked a fat broads backside in tight ski pants. It'll need some careful hammering, or a pound of bondo, depending on my skill/enthusiasm level that day
When I worked in the body shop, I used to either use worn out scotch-brite pads (the red ones), wrapped in the appropriate grit 6" DA stick-on sanding disc, or those little square wedges of foam aftermarket companies use to protect the corners of new sheetmetal in the boxes. They will conform to curves, but still be flat enough to not cause dips in your filler work...
Roadstar...we used "spray-on" bondo in Sweden twenty-five years ago! One just have to hurry up and clean the gun before it hardens! I am actually surprised it has not made it to the US, since they don't replace panels the same way they do in Europe...
my whole car is a bulbous curve, there's hardly a spot on it that won't get at least a touch of filler.. it's the fast and bulbous bondo baby
[ QUOTE ] Roadstar...we used "spray-on" bondo in Sweden twenty-five years ago! One just have to hurry up and clean the gun before it hardens! I am actually surprised it has not made it to the US, since they don't replace panels the same way they do in Europe... [/ QUOTE ] Well WTF! I want some then. Smoothing out the uneven filler is half the work when you are doing a large area. And leave it to the Sweeds to come up with thechnoalgy like that. I use a Car-O-Liner frame rack and they are manufactured in sweeden and I dont't think there is a better product on the market. It is so accurate and well built, But hey look at the Volvo
Seems I am taking the easy way out! One of our "big box" hardware stores, (Canadian Tire) sells a three disk finishing sander. (the 3 disks form a triangle) Each disk can "seek" it's own angle because it's on a "gimbled" shaft. (they demonstrate it on a bowling ball) Because there are three disks, each supports the other. (the sanding disks, three inch in diameter,****orted grits, are the "peel and stick" type. Have been trying it on the corners (top roof) of my '28 Tudor and it seems to work. It will work on concave or convex surfaces.
I used what amounts to sprayable bondo a decade ago. It was SEM prime. It had MEKP for a catylist so it's bondo. Smelled like it, sanded like it and took forever to kick in December.
it deffinately helps to make patterns that have the desired contours and check your progress often. when you think you are there put some shiny dark paint on it, the reflection will show all.
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