For you guys experienced with old car body work. What kind and size of sanding block ( rigid or flexible) would you use to block sand clam shell 32 ford front fenders? K-38 with guide coat. Ago
I use several. Depends on what stage of prep, and the area of the fender. Generally more rigid to start, or if I'm trying to level a area. I like dura blocks. Love my little 3m black pad. I'll make something if I need to.
I purchased a set of the flex sand blocks.You can add or subtract the amount of rods in the blocks to make them more or less flexable.I think the longest one I have is like 30 or 36 inches long all the way down to around 6 inches.They were kind of expensive like around $200 for the set but they worked great.
Hey, I've used an " idiot stick '' 5 gallon wooden stirring stick for decades. Were I sanding a panel with a reverse crown in it, I'd probably go for a block of Balsa wood 'bout 3''X4''X 6''-8''. Since you'll be sanding at 30-45 degree overlapping passes, you don't need a really long block for a panel with as much crown as a '32 fender. " The ice cream truck in his neighborhood plays Helter-Skelter "
Alot of it is personal preference. But if you dont have a large flat panel, dont use a large bock. My 6 inch durablock hard pad is my workhorse, but I also love my flex pads, although unless im doing just a special curve its more of a pain in the ass than help. I suggest a 6 inch hard pad, shape is all whats comfortable in your hand... I cant stand the type that auto dave shows above. But at the same time thats about all my coworker will use.
I grew ones the around the boatyard with a set of the 3m ones like above in my hands, great pads , but the dura blocks are sooooo much nicer if you have the ching and plan on using them for more than the one project .
sometimes i just hold each end of a strip of paper and kinda allow it to 'wrap' around the curve and just pull it back n forth while working gradually along the panel...hey it works for me!! no block needed (works best with the coarser ,stiffer grades of paper.)
For concave surface I use a chunk of straight radiator hose. I have a set up with 3" hose what's pretty flexible, then a chunk that fits inside of that one, and one inside of that, on down to 3/4 hose. Each can be used for smaller radius or to stiffen up the outer chunk. I seem to be able to get a flat panel straighter with a rounded block than I can with a flat block. Pretty sure it's the paper contact area not being able to touch the lows, IDK Flexible steel ruler, will curl to 12" circumference and go right back to flat. I've stuck paper on that and used it a few times on some goofy MC tanks. Kind of like a paint stick just more flexible.
That's great on long straight panels too. 4 feet of it sometimes. Like the concave of a 73-87 Chevy pickup 8 foot bed side, 90% of the ones I see refinished are not straight.
They have a hard foam rubber a lot of shippers glue to the inside of cardboard boxes. You can find them mostly in sheetmetal shipped to body shops they can be cut with a large snap blade razor knife and shaped on a belt sander to any shape needed And there FREE i have a draw full.
I recently purchased another Durablock for sanding concave surfaces. It's about 10" long and "teardrop" shaped. I use the heck out of it for all sorts of tight places, and use both sides of it. I also use the same 3M self adhesive sandpaper in small pieces by hand, and like the adhesive back as it helps hang onto the paper while sanding small areas.
I've been having my wife pick up craft foam from target (probably other places too). It's closed cell so sandpaper will stick to it. It comes in sheets roughly 8x11 and is about 3/16" thick with adhesive on one side. Depending on the contour, cut and stick together sheets until I have the right stiffness. I've used it wetsanding and the adhesive holds well - you can't pull them apart without ripping.
i use a piece of hard rubber that is 2"x14"x 3/4" that i got out of a scrap bin from a rubber & gasket place