Block sanding, share your tips, tricks?

[Rocket88]

Well, it's been primed for almost a week now. My bro and I laid the high solids on pretty heavy, we started sanding tonite. It looks pretty good so far, got a few low spots and a couple small places that need a bit of "Half Time" (tm).
Any tricks or tips you can share to help get the Olds straight would be appreciated!
Here's a couple pics before we started sanding.
http://photo.starblvd.net/~rocket88/3-3-5.jpg
http://photo.starblvd.net/~rocket88/3-3-3.jpg
http://photo.starblvd.net/~rocket88/3-3-4.jpg

[12pack]

spray a light dusting of black paint ,then start block sanding.this will show you all the highs and lows good luck. it looks great .

[chopolds]

You've got a tough car to do, lots of compound curves, and then reverse curves, some very tight, like on the quarters.
Lots of running water, keep flushing all the sanded paint off, so it doesn't clog the sandpaper and scratch the primer.
Change sandpaper often. The fresh, sharper new paper will cut 'true' and flatter than worn stuff.
Always keep your sanding block front-to-back, at least on all your long panels. You're most likely to see waves on the long surfaces front-to-back (F-T-B), so that is the way you need to do your final sanding pattern, and orient your long board, too.
Use a 45* from horizontal, sanding pattern, in between F-T-B sanding. Change direction, so you sand in an X pattern, but always finish up front to back (and still keep your block oriented F-T-B). This even works on curved areas, but be extra careful to keep moving, and not cut 'flats' into the surface.
For reverse curves, use a piece of radiator hose, fuel hose, or soft sanding block, to match the shape of the area you are sanding. I still use a flat block on convex curves, though....they still need to be "straight", and changing sanding directions with a flat block yields great results.
Use the guide coat, as suggested. It's the bodyman's best friend. But use use it correctly, don't just try to sand it off, it is used as an indicator, to FIND problem areas. Also be sure you sand it with a light touch, as sanding too 'hard' can flex panels, or force a rubber block to follow waves, or shallow dents instead of trying to cut them flat.

[hatch]

Chop...good tips!

Will this car be wet or dry blocked and is this the first coating of primer(catalyzed)? If it is the first, I start rather agressively with 80 dry. Since the next layer is also a catalyzed product, the scratches will fill and stay down ok. I use a stainless ruler the same length as "stickit" board paper. I used to use a stirring stick, and still do when good flat ones are available. I very rarely use a rubber block anymore due to the fact there is almost no flex and wont conform to the low crown areas.

I agree and want to emphasize the importance of NOT running straight front to back in your sanding pattern...always at a 45 degree while moving front to back of the car.

[roadstar]

chopolds summed it up rather well. Just make sure you guide coat everything you sand. Your eye can see what you can not feel. Also when dry sanding with 80 or 150 the sanding dust will cover scratches that should be getting sanded out, with a guide coad this wont happen. On inside curves use some sort of round block. They sell rubber tear droped shaped sanding blocks that work well for wet and dry sanding.
I like to use the hard cardboard tube thats in side the large roll of masking paper. It can be cut to the size of sand paper you are using.

And lastly pay attention! the biggest mistake I see with inexperianced guys(or gals) is they don't know when to stop. This is very important when using a guide coat. Yes you want to sand the contrasting color off and level the coat you are sanding but when low spots show up be carfull not to just keep sanding and dig a hole or sand all the surrounding primer off. When the low spots show up you have to deal with them differantly sometimes. If it is a little ding or a real low area you my want to use some polyester puty. If the spot isn't so deep you will want to load some extra primer on that area on the next prime coat.

And one more thing to keep in mind. The finer the grit the less affective it will be for making something straight. Now I said straight not flat. IF you have an area that is alittle wavy, wet sanding with a fine grit paper will make it nice and smooth but will not level the area.

I'm sure I could ramble on for hours. SO good luck and don't ever be affraid to ask questions. THe guys who know everything are the worst technitions I have ever delt with.

[Elmo Rodge]

Like Chopolds said. I would add that when you're using the hose trick on reverse curves (also on creases) keep the hose aligned with the curve but sand at a 45* so you don't saw a groove in it. Wayno

[Dooley]

If your using a garden hose to wet the car and or paper, cut the brass threaded end off so if it hits the car it does not nick your primer...

[C9]

The RRT has a great Tech Post on block sanding.

Written by a pro - Carl Brunson - who's turned out more than a few terrific paint jobs in his Las Vegas Speedway paint shop.

Go here: http://66.34.61.147/tech/articles/sanding1.html

[Rocket88]

Thanks for the tips guys. My bro and I have been putting them to good use for the last few days. We're thinking of using a guide coat on the tail of the car. Can we just use some spray paint, or do I have to haul the gun out?

[FONZI]

You can use spray paint. Also, the body supply shops have this deal it is like a big shoe polish applicator. It has black ink or something in it. you just pat the panels down with it and it leaves a great guide coat. They are like 20 bucks i think.


FONZI

[justice]

Just use some black rattle can paint. It works great!
I usually use satin black,but it reallydoesn't matter if it is satin or gloss. You just need a contrast.
In a pinch, any dark color will work.

Justice

[DrJ]

You really should guidecoat every square ince of the car, not just the rear end like you mentioned.
You will probably find a ding of some depth about every 8" all over the doors and fenders, and maybe even some "crescents" on the roof.
You'll be glad you did.

[Lockjaw]

Pay particular attention to the areas like the drip rails and character lines around windows.Make shure these are sanded so paint will adhere.You dont want bubbles or non adhesion of the paint at a later date after all your work.Also clean well between coats of primer. Looks like everything else is covered.

[Tinbender]

Spend the money to buy real guide coat. It's cheap, and works better than paint. I use SEM #38203. If you leave any behind, it won't react with anything you spray over it. Even better is 3M #0586 dry guide coat. It's a powder, with an aplicator. You just wipe it on. A little more money, but goes a long way.
I like to "stick sand" You can get sticks made for 5 gal. cans at Lowes. These are nice and straight. I cut them down to the size of my paper, & sand the edges and corners slightly. I wrap the paper around them, then tear off the strips as they dull.

[Tinbender]

One more, 3M Stikit hand pad. #05586. It works with stikit paper for dry sanding, or tear w&d paper in half, then fold in thirds. This 3 dollar block is the perfect density rubber. Firm enough to cut straight, but flexes just enough for crowns.
Also, use guide coat on filler work. Helps to get your filler straighter, so you will spend less time blocking primer, and saves material.

[wideglide74]

The only thing I know about wet sanding is that your finger tips will be a little extra sensitive when you touch your cheek and it's ALOT of work. Congrats on sticking to your project as that's a little more difficult than wetsanding. Looks good...