[T2] Cleaning the van/prepping for paint - underside - a bit long winded

Bob Pratt ka1dza at verizon.net
Mon Jun 3 17:49:11 MST 2013


Has anyone considered rhino skin for undercoating?

I'm 75% done with the parts replacement and painting on the beetle. THEN I can get back to the Westy!!

Bob Pratt

Owned by a 78 Westy and a 74 Super Beetle



Bob Pratt

On Jun 3, 2013, at 5:41 PM, Joe Average <joeaverage at frontiernet.net> wrote:

> So I'm working on our '78 Westy. It's revealed a few details I'd like to share with everyone.
> 
> First - inspect your outer seat belt mounting bolts. They amount to the sheet metal floor of the van with a small plate about 1/8" thick spot welded to the bottom of the floor. To the bottom of this is a nut spot welded in place. My plates were in fair condition but the sheet metal floor above it was rotting out. Obviously in a crash when my seat belts might be called upon to save my hide, this might not be good. Especially if a guy (like me) needs to lose a few pounds.
> 
> I bounced around on the web and saw that replacement panels are available but I'm making mine. For darn near free. I made a replacement underside plates out of 1/8" or 3/16" steel with the edges rolled over for strength. Mine looks very much like the original. Just used a sheet metal break to do the bending. I think it could be done in a bench vice too.
> 
> Am undecided whether I'll weld the end of this underside plate to the rear bulkhead at the back of the fender well. The factory did not and I wonder if the engineers wanted the sheet metal to distort in a crash and absorb some of the crash forces. The spot welds don't look to be structural - just to hold the plate against the floor. Might have been a great place to put seam sealer to prevent the rust...
> 
> Looking around the web I saw people making plates to put under the floor when installing seat belts into antique cars out of 1/4" plate with a nut welded to it. The problem I saw was the sharp corners they left on the plates. Wonder if that would cut and weaken the floor steel during a crash and risk a tear-out?
> 
> Anyhow - I marked the center of the bolt hole with a magic marker cross beyond the welding zone. I cut out the floor around the seatbelt mounting point and made a patch. Will do some plug welds through the patch into the underside plate I made after welding a big nut to the bottom of that. Will seam weld the patch into place.
> 
> Tools: MIG welder, angle grinder. I'm using a mix of cheap air tools and an electric 4.5" grinder. My 220V MIG is a pretty good one but the metals in question are so thin, any welder down to the entry level import welder would probably work just fine if the operator a decent welder.
> 
> ALSO - I'm cleaning out the fender well of all the undercoating to inspect for rust. The ends of the rocker panels behind the front wheels are rotted out but the rockers themselves are fine. Not too many more miles and there would be complicated repairs needed which could spread to the bottom of the 'B' pillar and I don't want to get into that. Fix it right now so it doesn't need to be fixed later. Brush on rust converter and weld through zinc paint everywhere is the goal. Stop the rust.
> 
> The undercoating was hiding some rot around the rocker end and maybe contributing to it. I also noticed surface rust under the undercoating in the top corner behind the seatbelt bolt. No damage yet but the undercoating was not doing it's job. Also noticed surface rust at the front of the fender well below the back of the step. The undercoating had let go there too. Was also a blister in the undercoating forward of the shock absorber. All in all, my Westy is very solid though.
> 
> I HIGHLY recommend removing that undercoating mess. At least with paint you'll be able to see where the rot might be setting in. Or at least remove the old and renew the undercoating.
> 
> How to get that mess removed was fun. Am about 95% done now. This was not without risk based on my methods - so don't do this in the garage and put your home at risk. I torched the undercoating with a propane torch. Made it crispy, burned a little, stunk badly, and then I was able to wire brush it out/off in dry flakes. Scrape off the melted/hot mess with a wooden paint stick. A plastic putty knife melts. A metal one just ruins the paint which might still be a good foundation for the new paint.
> 
> Again that 4.5" electric grinder with a knotted wire wheel did most of the work - even on the tar I did not make crispy. Am also removing the seam sealer b/c I found a few places where it too had let go and surface rust was developing. Despite the mess and the torch - the paint under the undercoating never got hot enough to blister or fall apart.
> 
> Here is where a lift or rotisserie would be really, really nice. Don't burn down your bus, garage or house. Be careful!
> 
> In the places where the big grinder wouldn't reach - I tried my little 2" air grinder (90-degree) with a Scotchbrite pad or a sanding disc. Neither was a good solution - both simply loaded up with tar.
> 
> The fix for that detail seems to be the same $25 two inch 90-degree air grinder coupled with a 1" knotted wire brush from the local hardware store. It was $10.
> 
> When that wire brush is coupled with a drill, it turns too slowly (maybe 2000 rpm) to get much work done by my measure. Maybe other folks have more patience than I do! ;) However when spun at 20K RPM, it TEARS through anything but can still be used in such a way that the base factory paint is not completely removed . Fortunately I lucked out and bought a wire brush that was rated for 20K RPM too. Wear eye protection of course. The cheaper non-knotted 1" wire brush was rated at some speed lower than the better brush. Was half the price too.
> 
> Along the way I also tried a plastic long bristle brush supposedly for removing undercoating and it frankly was $10 wasted. I'd love to try it's 3M cousin which makes big promises. my purchase was of a no-name brush. Despite the 20K RPM of the little air grinders - my two 90-degree air grinders don't have enough torque to push against the surface being cleaned very hard. Partly b/c the undercoating it pretty hard now - not soft like it might be if it was 20 years newer.
> 
> After everything is cleaned up, a few wipes with a cloth and lacquer thinner makes the original factory paint look like new but it is rough enough to have some "tooth" so the new paint will stick. This is where the little Scotchbrite pads shine so to speak. Add some tooth to the paint anywhere and everywhere.
> 
> So what remains is new seam sealer, steel patches welded in and then multiple coats of paint. No undercoating will be put back on my bus. Will probably use something like Rustoleum brushed on. Multiple coats of primer and black paint. If it doesn't hold up it'll be easy to sand it back off and I'll try something more serious. I was considering "stone guard" paint as used on the exterior rocker panels of some brands of vehicles. It's tough stuff but again - it might disguise rust until the rust is quite advanced. Any thoughts anyone?
> 
> I also bought the seam sealer/caulking at lunchtime from a Mom 'N Pop auto paint store. It is a urethane sealer/adhesive. Was $14 per caulking tube.
> 
> I'm leaving out all the brands tools/supplies b/c in the past I got a stern finger pointed at me over this sort of thing. P-mail me for that info if you want.
> 
> Chris in TN
> '78 VW Westy 2.7L complaining of a cool breeze in one of it's wheel wells
> '65 Beetle 2.0L ever patiently awaiting some TLC
> '97 VW Cabrio feeling neglected
> '99 CR-V AWD EX at 252K and keeps on ticking...
> Brenderup 1205S
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