My favourite type of block is a hard rectangluar sponge which comes covered in wet/dry grit. The grit doesn't last, but the sponge then gets used to wrap the wet/dry paper around. The sponge is a nice size for the hand, and holds 1/3 of a standard sandpaper sheet wrapped round it, so there is little waste (scrooge is alive and well).
You can get rubber blocks too (some of them have slots in the ends to hold the paper), and I've heard of using Balsa wood as well. You need something which gives you a flat surface, but soft enough to conform to slight curves etc. Using a block makes for good feathered edges when sanding back filler etc too. The Balsa would have a problem when it's been bruised though – it won't bounce back to flat as well as rubber or sponge.
Using wet/dry is important - is allows the paper to be dipped every minute or so to remove the "dust" and this prevents scoring the body which happens with clogged dry paper. Frequent wetting means the paper lasts a long time too - no clogging, and so long as you don't touch bare metal too often it just keeps on cutting.
400 is more a finishing grade. I'd start with about 180-220 myself, and then go to 400, and them maybe a last rub with 600 or 800. The balsa wood is for doing curves I suppose.
I'd still be using the block on the flatter surfaces, but in all sanding a few small areas will need the paper wrapped round a finger etc to get into corners (the rain gutters for example).
Wiping the car down to remove wax and gress must be done BEFORE you start sanding. Acetone makes a good grease remover, but I suppose an engine degreaser would work too. And wear disposable rubber gloves so there is no chance any oils from (your) skin can get on the surface of the car.
Dave wrote -
I bought a sanding block -- about 2" wide and 8" long, with a handle and mechanism for holding the sand paper -- ideal for "block sanding" -- and a smaller block for smaller areas. I also bought a ream of emery paper of assorted grits (120 is the finest -- I'll have to get some finer stuff for the final sanding.
I HAVEN'T done a lot of body painting before, so you can be sure that I'm going to take this REAL slow. My plan is to take the black paint off, down to the original VW paint/primer, then block sand it from there with increasingly finer wet/dry paper.
Rob responded -
You may be better off just wet sanding and forget the grinder. Start with 140 or 180 grit to get most of the color coat off. I use a thick sheet of stiff rubber the size of a full sheet as a backing. It will produce an absolutely smooth surface on almost any contour.
Of course, the body shops have fancy air sanders, etc. that make ridiculously fast work of it
If the original top coat is in reasonable condition (might just be faded) there's no real need to remove it all back to metal (so long as the new stuff will cling well to the old enamel - compatible). You'll have to take your paint guys recommendations here I think -- since the final product will be in his hands.
His idea of using a rubber mat is good, but you have to be careful with a fully flexible mat like that that you don't end up with it cutting more directly under your fingers where the pressure is - would be OK if you can use the flat of your hand and work around and through each area rather than back and forth in the same place.
Miscellaneous Conversation
Rob wrote -
Under the car there are four large bolts at the front of the pan under the front door jamb (two each side). They compress the seal there, and hold the front of the pan in place. Two bolts wouldn't catch on the threads (seal not compressed enough) and I'll have to get a slightly longer bolt to start the threads so I can then use the correct length one next to it (they are close together), and once I get one correct-length bolt in place, I can replace the long bold with the correct length. The shafts of these bolts are a little rusty too, so I'll need to replace them soon, but will use the current bolts (suitably cleaned and greased) for now. Got the steering wheel partially re-mounted too, so I could move the car to the other side of the car-port.
It's odd really - on one side I was able to catch the threads, and once caught, they tighten a lot and compress the floor pan seal. But on the left side I just couldn't get the bolts to catch the captive nuts, yet the body is sitting on the pan evenly, and as far as I know the threads on these bolts are OK - but since its a new body I can't be absolutely sure. I'll just have to try a longer bolt to see if I can find the threads.
The holes had to be made manually in the floor pan seal before the body was dropped on it, and since they aren't exact it makes it harder since the seal now won't move with the weight of the body sitting on it.
I suspect it's just the floor pan seal holding the body and pan apart a fraction too much. The side I did get only just caught the threads, but once started I was able to pull the two together.
I just had a thought - I'll try putting upwards pressure there with the jack, and see if I can get the pan to compress the seal enough to catch the thread. I might try BOTH the jack and loosening the tightened side, and so how that goes.
I also knocked out a dent in the front boot lid, so it should now just need a little body-filler there now. That's off the new body, Bertie's wasn't salvagable. I also had a go at the badly dented original engine lid, but I don't think I can resurrect that. I don't have a lid off the white body, so I've seen a "4 slot" lid in a wreckers I can use if I can't get the correct "2 slot" lid (1300 73 standard beetle), so I may have to get that one.
And I got a little work done on that accident damage behind the right door. With a combination of slightly bent flat metal bars, and thin wood blocks to get in behind the interior metal lining (next to the rear seat) I was able to get into the restricted space and mostly straighten the panel. The bolt-line for the fender in that area had been distorted and was the hardest to fix (that crease line where the bolt-line starts makes the panel surprisingly rigid and it didn't want to straighten :-), but it's close enough now that I can fill in the small imperfections with body filler, and I think the fender will bolt up OK. There is some rust along the bolt line too, and a few pin-holes right through, but fortunately none around the captive nuts themselves, so wire brushing, rust converter and body filler there should have it looking good again. All the hammering dislodged the heavier rust and exposed the affected parts (dislodged the loose paint) so it should be a good fix when I hit it with the rust converter - no missing spots (I hope).
Dave wrote -
I took a penknife to a few little cracks in the bondo - Chipped off an area about 3" x 4" that had separated from the metal.
Last night I drilled out the three spot welds that attach the lower engine lid latch piece to the rear apron, then cleaned up the piece nicely with the wire brush attachment on my grinder. I'll bolt it onto the new fiberglass apron before I install the apron on the car.
Rob responded -
Any tips to drilling out spot welds? I'm not too experienced at that myself. Do you still have to break it free or does drilling the welds free the item fully?
Dave wrote -
I'm a poor one to ask -- I'm really making a mess if it. If the part you're removing is to be reused, I'm definitely not your man! :-) What I do is sand the area lightly, which sometimes (but not always) makes the spot welds show up more clearly (they're usually a little bit indented). The I give the weld a whack with a center punch to get the drill bit started, then just drill into it with a bit just a tad larger than the weld. I try to just drill through the outer piece, not all the way through, but I'm not always successful.
Dave wrote, regarding the holes in the top of the fenders where the turn signal assemblies used to be -
The paint shop is also going to remove the bondo from the holes that were left when the PO took the turn signals off the fenders and weld little circles in the top of the fenders to fill those holes. They will smooth all of the welds out so when it's painted it will look really good.
When I went over there they had one of the doors laid out on a table and a guy was working it over real good with a power (compressed air) sander. They are really doing a good job -- very professional. The car is going to look so very good! Definitely show quality.
Dave wrote, once the painting was finished -
I just returned from fetching all of the finished parts from the paint shop and stowing them in my friend's garage, setting on and covered with blankets. It took two trips in my little truck.
Downside -- they charged me $500 over the estimate for the body work, which I guess I can't begrudge them. They really did a lot.
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Last revised 20 August 2004.
