My 70 is in primer and I need some tips on block sanding. I have an assortment of the new Durablocks- 6, 9, and 24 inch, and also a round one. I just don't understand the concept behind it. Almost every part of the car has some sort of curve to it so on a concave or convex area wouldn't it just sand the highest point in the center or put gouges from thetwo sides of the block? I have tried to sand in a X pattern also but with the exception of the roof there really isn't much room to sand that way without hitting a body line and metal showing back through. I know it is the right way to do it and I want my car to be straight, but I think I'm missing the boat on how it's done. Any advice or tips would be great guys, as the frustration is setting in and I don't want to ruin it. Thanks Jim

"I just don't understand the concept behind it. "

There really is no concept behind it http://www.chevelles.com/forum/smile.gif. Its one of those things you do to do it right- after you put a lot of work into something. A lot of it depends on your bodywork- if its pretty straight, I would guess that 2 applications of primer/surfacer would be enough- once over the etching primer, then block; then after you block and find,fix the highs and lows, another coat of primer surfacer to make sure.

Don't sand on body lines- of course it will go to the metal- its a high spot that is SUPPOSED to be there. Use your judgement as to what is a "body line" and what isn't. Sand away or just to the lines, but not over them.

One thing you MUST do(well, not really but it sure helps) is to FOG some black spray paint over the primer surfacer. Sand till its just gone, low spots will retain the guide coat. Its like body work- you have to know when to quit sanding, or its an endless job. Good Luck

Thanks for the reply. My body work I would guess is pretty good since I didn't see any of it when the primer was wet( well a few scratches but nothing major). I know not to get close to the body lines with the block, what I meant was when sanding in an x pattern the end of the block was hitting up too high and I didn't notice till it was to late. I still just don't see how a flat block can work on curved areas(like the top of the sail panel) when only the center is touching. I have definately put too much time in it to mess it up now. Maybe I will wait and ask a few guys at the local shop to stop out after work and give me some pointers. Thanks again.

One tip you might use is, after you sand a section, spray the section or panel with a wax and grease remover like Spies/Hecker 7010 or PPG DX-330. This will give your sanded primer a gloss so you can look down the panel to see if it is straight or you have sanding gouges. If you do, you can sand some more. Also, don't be afraid to apply that guide coat a second time because sometimes the guide coat can dissapear before your panel is perfectly straight. Good Luck.
Gordon VM
Restoration Motorsports

you stated "I still just don't see how a flat block can work on curved areas(like the top of the sail panel) when only the center is touching"

(fter using previous advice of fogging the black paint over the primer for a guide coat.)

that is what the rounded block is for. it should be tubular. wrap the paper around the tube and continue to sand in the x patern in the curved areas. use the 24 inch block on the flat parts:
hood, top of fenders, top of doors, trunk, and quarters. the curves in the fender, door and quarter use the tube. the round parts of the fender, door, and quarter use the 12 inch block until you get to another curve. when you are done blocking its time to get rid of the block marks (if you are not priming agian and ready for paint) i like to use a sponge pad and a finer grit paper. i also use the x, i, s and - patern, kinda like a thurough wash to even the sanding so no lines show through the paint.


good luck

[This message has been edited by budruski (edited 03-20-2002).]

I see what you are saying- like a natural crown in the fenders... As budruski stated, use that curved block (or a radiator hose, or WHATEVER WORKS WELL!) on those areas. On the other areas, if you want them straight, you just have to hit them with the long board.

Thanks for the replys everyone. I have never done this to a whole car before and I don't want it to be wavy. I think I just got frustrated and needed a night off. I called a friend who works at a restoration shop and he and his boss are coming out over the weekend to check out my progress, maybe I'll ask for a few pointers. Thanks Jim

Great. a dozen donuts and a few coffie's go a long way.

GL