Block sanding tips..

[71fish]

Alright I have a couple of panels which will soon be ready to block sand.. I would like some suggestions on which primer to use (part # if possible) and techniquies. I already got some good tips from a friend.. so A few more cannot hurt. e.g.

2 coates.. block 180
2 coates.. block 220
2 coates.. block 320 etc..  and prime extra on the highs spots.

what lingth block, technique etc..

Also, I took down a good part of the shaker.. they had a good layer of bondo to smooth it out.. no rust, but there are some waves & dings in the front near the crease. Also, the metal in that aea seem to be weak where you can pretty easily push down and up on this area.. metal gives alot there.. any suggestions how to handle this area or type of issue.

Much thanks as always! I've decided to take my car down to metal and do it right.. within my budget.

-71fish

[ShelbyDogg]

Leave it low and build it back up with Metal to Metal or Bondo.  Once that metal is ground down that thin, you either weld a new piece in or bondo it back up.   For block sanding I have the long handled board that takes a full sheet of adhesive backed air-file paper. You need something big for the large flat areas like doors and deck lids.

Rob

[67Vette427]

Don't forget your guide coat between primer coats for the low spots. I usually block primer coats with a hand size block. It keeps the paper from binding up and breaking too often. I use the long boards usually only on fillers. Pretty much PPG out here in calif. primer-then sealer.

Your grade choice is good. Maybe do a final with 400 but leave the car in the sun between some of your coats for a while just to get some shrinkage out of the way.

When I'm done with the primer's and its a nice car...I'll spray the base color and block that too to see how the body is looking. A bonus is, especially with dark colors is you can put some water on it and see how the lines or flatness came out.

 

[71fish]

Thanks.. what is a guide coat.. and what's the technique?  TIA  It's gonna be black.. so it's gonna be a task. I just don't have the funds to get it done professionally. Kinda sucs, I'm doing this on a black shaker cuda.. gulp!

71fish

[HemiDog]

A guide coat is a contrasting color that is lightly applied over your primer.  You can use an aerosol canned primer, or 3M makes a graphite powder that is rubbed on light colored primers.  The idea is that when you sand, the color of the guide coat will remain in the low spots.  This makes it really easy to either build up the lows, or knock down the highs to achieve perfection.

Just remember, the guide coat doesn't need to be thick, there just needs to be enough to be visisble.

[71fish]

Hemidog---Thanks much!!  Now I recall my friend told me to use the powder.. that sounds better than paint.

[HemiDog]

I have the 3M product and there is enough there to do several entire cars and it was about $30.  You don't have to wait for it to dry either. 

[MyMopar]

When I'm done with the primer's and its a nice car...I'll spray the base color and block that too to see how the body is looking. A bonus is, especially with dark colors is you can put some water on it and see how the lines or flatness came out.
 

Such a simple idea and I never thought of it.  After spending thousands of dollars on parts, chroming, etc... what is an extra $200 or so in paint if that. 
Let me ask you this, do you just block it with a 400 grit or do you go higher?  Do you sand it all back done to primer or if the body is just right and the stars are shining on you, wipe up and spray?

[67Vette427]

You got the guide coat question answered correctly. Its a must on Corvettes ( fiberglass ).

When I spray on the base color I won't sand all the way through it. I've already got everything flat or if I didn't this is where  I catch it. It may go through in a couple areas but I'll use a 600 or even a 400 on it. Its just a easy method to see how flat everything looks. Plus, it make your base have a little more color.

Hope all this helps! 

[Mark 12:30]

 

[Plum6Pak]

This is an interesting discussion, is any of this wet sanding?

[67Vette427]

I wet sand all primer coats and later coats. If you don't wet sand it the material builds too fast in your paper. Get yourself a nice small bucket and move it along with you as you go. Sometimes I'll even put a squirt of dishwashing soap in the water to help make the sanding a little easier.

He's a picture of my cuda hood. I did this hood a couple months back. I was moving some heavy things down in the garage and dropped some stuff on the hood that dented it pretty good. Here is how it looks now. I've got the hood off the car right now. I've built a new engine that's going in it this week.

This is a PPG Base and clear...2 stage... I had to color match the base to the car with tinting.

[Bullitt-]

67Vette, Thats slikern OWL POO  Where did you learn this stuff?

[67Vette427]

LOL Thanks.. you should have seen the dent near the hood pin.. I almost cried when that happened.

I just never liked some of the jobs people did on my cars and I use to race and wreck so many I just watched and learned. I did the 67 Vette too and you can't even feel the black stripe and pin stripe on the hood   

[Bullitt-]

Nice work. I am planning on doing the whole enchilada to my Chally, just getting started but have VERY little experience
. Would you be interested in giving us a step by step tutorial of what you do & what to NOT do?