I have been doing lots of blocking over the past few weeks but still cant get to where I want to be.
We are all looking for that super straight panel, right!
I have noticed that on my final blocking rounds, P320 & P600 wet, I am blocking small dips out of the guide coat but when I look down the panel they are still there?
For a guide coat I use an over reduced 5:1 black base coat, is there any other way to see these very small dints? I feel like painting the job direct gloss black then blocking that out to see where I am at.
After your final stage of blocking you can wet the panel down with solvent based wax and grease remover to get a good look for straightness. If you're having trouble removing ripples try using a stiff, straight, flat block. I have two boards that are bare aluminum that work really well and also plexiglass blocks and sticks that cut out the finest imperfections. Keep your sandpaper one thickness-don't fold/double the paper. PSA paper works best the velcro styles have too much cushion and clamp on paper will often wrinkle. If your block is as flat as glass your work will end up as flat as glass. Guidecoat will show you what each of your blocks is doing. A super flat and straight block with 600 grit will cut the minor ripples out before paint. The longer the wobble the longer the board needed for correction. Most blocks and boards aren't perfectly straight when new and need some tuning before use, I've seen many people fight with warped blocks and boards never realizing what the problem is.
Painting the car with singlestage black for a straightness check is sometimes done but definately not necessary if you get the blocking proceedure down.
I have been doing lots of blocking over the past few weeks but still cant get to where I want to be.
We are all looking for that super straight panel, right!
I have noticed that on my final blocking rounds, P320 & P600 wet, I am blocking small dips out of the guide coat but when I look down the panel they are still there?
For a guide coat I use an over reduced 5:1 black base coat, is there any other way to see these very small dints? I feel like painting the job direct gloss black then blocking that out to see where I am at.
Like Bad Bob points out you can use a longer straight block, to help bridge the gap between high spots.
I'd actually bet it's more a combination of block size and blocking technique.
X-Patterns are best, straight back and forth usually doesn't do the job.
The Main technique problem I see is that people apply too much pressure on the panel when blocking, to the point of moving the car and/or metal - that won't do it, you need to let the block and the sandpaper do the work for you not your muscles!
If you want something straight IMHO you have to paint it 2x minimum.
You can block, wipe with Wax and Grease remover to sight the panel all day long, but you won't see waves, ripples really well until it gets some paint on it.
The paint job acts as a good guide coat to block-wet-sand imperfections once it sets up. The 1st Paint also will help with the inevitable skrinkage from body work and sanding.
Sanding pattern depends a lot on the shape of the panel, but when I start the blocking process down the side of the car I usually make my first cuts lengthwise. This establishes the straightness related to the length of the panel-the sightline. After the first cuts have been made lengthwise there will be flatspots when feeling the panel vertically-these get removed by changing to an x pattern. It's also important to keep the pattern consistant and work the whole panel from one end to the other and back untill the guidecoat is gone. Hope this makes sense, it's more scultping than anything.
If you want a truely straight panel you need to start
sanding with a coarse grit, the coarser grit, the flatter it gets.
I'll start sanding primer with 180 or coarser if it needs
to be absolutely straight. imp:
As I posted on SPI, Just because the block is new does not mean it's flat.
ALWAYS check it on a good,flat surface. I use an old glass front door off a cabinet thats 1/4" thick glass and framed,stick on some 80gt PSA roll paper and true them up. i recently bought a new Dura Block 24" long board that was WAY off,Returned it and the other new one was even worse than mine. Finally got a 3rd and it'swas really close. So Beware....
If you've got three coats of clear on her I'd try dryblocking it with 320 grit with a perfectly flat block, the gloss will provide the guidecoat. Then give it a final round with 600 grit and go to paint.
For blocking I've been using some extra wood drawer guides, and sawing them down to the length I need. (shorter for curved areas, longer for straight panels)
They work pretty good. They are a "T" profile, and if you turn them upside down the edges are slightly rounded off.
I actually prefer them to the durablocks now. I have cut pieces from 1" long through to 12"
I will give it a final block P320 & P600 & try not to break through.
For my final block last time I used a 7" Snap On rubber block, the type that has the little spikes in the ends to grip the wet & dry. I think today I will lay it on some glass to see if it is true before I use it.
Jim said it all in my opinion. Use as coarse of paper you can get away with. Coarser paper CUTS the panel flat. Coarser paper CUTS with less pressure. Use NEW, SHARP, QUALITY paper, and throw it away often. DO NOT use the wrap around into the nails. You can't even buy non-adhesive paper any more can you? Use adhesive paper and make sure the block is true.
Well guys, I have blocked it the best I can without breaking through the clear. I am going to re paint it again this Sunday. Fingers crossed, I hope I have nailed them ripples.
Painted my project. There are still a few shallows in the doors & I just cant get them blocked out arrrrrr!
The car looks mint when you are a few feet away but when you back off 20 feets or so there are some slight shallows in the doors. I dont know where to go at this point, I dont really want to start basing it all up again.
Could I re clear UC35 then block them out of that? I am so disapointed
If you want a truely straight panel you need to start
sanding with a coarse grit, the coarser grit, the flatter it gets.
I'll start sanding primer with 180 or coarser if it needs
to be absolutely straight. imp:
This is correct, you will not do mush straighting with anything finer than 400G
We start blocking with 36G and progressively get finer.
We have approximately 200 different blocks of all shapes and stiffness, and they all get used.
This is one of the hardest thing to teach. It is not easy.
Some of my favorites, our called "Dura Block". I know they can be bought at Eastwood, among other places.
It is not all about the "block", it has a lot to do with technique.
The biggest problem I see others doing, is sanding with to fine a sand paper. Also trying to straightening a panel with primer. It starts so much sooner.
We also make a lot of our own.
When you are blocking, try and visulize, the shape. If it, if it's round, you have to have a block that will create that shape. If it has high crown, it can't be a flat block.
Good blocking is an art form. It will take practice. A guide coat will also help you see you way through it. As you are blocking, know that every stroke is aimed at making it better. Not just rubbing sand paper on it.
I have built show winners since 1969, yes I know I was born about the time of dirt.
Check out our web site, the web address is on my profile. (can not advertise ). we do some crazy stuff. One of our current projects is 2003 Caddie, changed from front drive to rear wheel drive and a 572 big block.
Any time time you need good honest advice, from someone that does it every day, contact me.
Good luck, keep practicing.
Dave Tallant Hot Rods KC MO
I finally lost it with the panels I was trying to get super straight. I applied spray poly over the base & clears to re block & wrinkled the lot. So in a moody fit & the fact that I had to da sand all the soft paint off, I decided to bare metal the panels!
This is where I was shocked. One of my panel guys who first started the doors & was supposed to tap up the metal & apply first skim had left 2 dents about 6" round & 1/2" deep. these had caused a huge high spot between the dents & proberbly the reason I could not get them straight. Every time I baked the primers etc off the panel shape seamed tp change. I blocked them panels lots of times & must of spent 20hrs plus.
I have since let the guy go. I dont have time or the money to waste on lazy panel men. I am now re doing the doors myself from scratch, pin pulling the dents & re working the metal.
One question guys: when starting from bare steel do I use a body file to check the panel progress or should I epoxy it & block with p36 to check the highs & lows?
I dont usually do metalwork, I mainly prep & paint, oh & organise my daily bodyshop schedules.
Let me get this straight(no pun intended) You couldn't get the panel straight,sprayed primer on it,it wrinkled,you stripped the panel then you got mad and fired your bodyman? Now you need to redo it and get it straighter than you had it before but your a painter not a bodyman? seems like by firing your bodyman you cut off your nose despite your face. Best of luck to you.
I hear what you are saying but I have more than one panel man & I aint paying dummies to do half the job when they should have tapped it up straight in the first place!
You have to trust your staff to do the job right. When you find a bad apple in the cart out it goes!
I have not cut my nose off to spite my face, I have unearthed a bad un!
I have to be able to trust people, ask any bodyshop owner.
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