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Old 06-12-2003, 02:18 AM
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working up from bare metal...

hi guys, a number of questions...

my 74 Holden ute is now about halfway back to bare metal... and i'll be damned if i'll ever do this by hand again! straight to the sandblasters with my next project!!!


anyway...


a few questions:

1. can you use filler over the top of primer? is it possible but unadvised, impossible, stupid, fantastic, what?

2. so far my panel beating attempts have gone fairly well. the front right corner of the car had taken a tap by something, and was dented in a bit. with a $15 panel repair kit (crappy dollies and hammers) i've got it to within about 1/8 to 1/16th of an inch of where it should be, so i'm happy with that. however, the rear quarters (a very large panel as it's a ute, like an el camino) are pretty friendly... you know, they "wave" at you! whoever had this car before me had built up the filler to almost half an inch thick in places to hide that fact... i obviously would rather avoid that...

however, being that it such a large panel, i don't want to start tapping at the lows to bring them up, and the highs to take them down, and just end up stretching the bejeezus out of everything and ruining the lot! unfortunately i don't have an oxy setup so heat shrinking is not a possibility... any suggestions? i'd rather NOT find out the hard way...

i know i wanted to ask a couple of other things too but let's just start with that...

cheers,

col.
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Old 06-12-2003, 08:23 AM
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wondering if the guy who used to own your rig...used to own mine too.

If you can't afford an oxy rig, get a $20 MAP Gas setup from home depot (or a hardware store) and you can use that. I've had good success using it to heat stuff up on the sheetmetal.

I'm by no means experienced working on sheetmetal, but I figure you have to learn somehow. I can say without a doubt that the $15 hammer/dolly kits suck...if you can afford to pickup a couple of martin hammers and dolly's DO IT! Well worth the investment.

TO THE BEST OF MY UNDERSTANDING (my disclaimer for when Willys shows up and says I'm all wrong):

You should NOT tap on the "Lows" to bring them up and tap on the "HIGHS" to push them down. You should actually do the opposite...

You should use a hammer-off dolly. Put the dolly under the low spots, and bump the high spots down. Very difficult to do in a crowned panel...but that's the way you want to do it. Then Shrink if necessary...by heating up the "excess" metal and nailing it with a hammer.
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Old 06-12-2003, 11:50 AM
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sounds like that guy worked on my '68R/T too lol. whole left 1/4 panel is filled to 1/4 of bondo. I will be replacing panel from donor car, and id advise you to do so too. as far as bondo over primer is no-no unless you're working in chop shop he he..You can use putty though over your primers but not much, just skin coats..
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Old 06-12-2003, 11:57 AM
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you can however use filler over the top of Por-15.
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Old 06-13-2003, 03:50 AM
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thanks guys...

still looking for further comments on trying to straighten 'er up so fell free to drop in some more info iffn'ya got it! while my welding is pretty good, i'm reluctant to chop the whole panel out and weld in a new one given the huge size of it...

i may be able to borrow an oxy set off a guy i know, what's the procedure for shrinking then?

cheers,

col.
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Old 06-13-2003, 07:52 AM
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Basically what you want to do is heat up the metal, doing your best to confine the heat to only the area you want to shrink. Once it's heated up, you want to hit the heated spot with a shrinking hammer (generally has a round face). This will drag the surrounding metal inward toward the point of the blow. Of course now you have a low spot right? But the metal SHOULD BE thicker in this area (because you just shrunk it) now raise it up! You may have to repeat the process a few times if you want to do some serious shrinking. You can do this using a map-gas torch! It doesn't get AS hot as an Oxy rig, but it gets hot enough to turn sheetmetal red-hot.

Martin also makes a body dolly that has a bunch of raised serrations on it, that is used for shrinking. I think the mechanics of this dolly is a little different. You're basically "picking" at the metal from the backside, but limiting the depth of the blows. You're raising the metal so minutely, so the end-result is similar to shrinking (although I question if you are shrinking as in the above example).

http://www.eastwoodco.com/aspfiles/i...3.x=39&I3.y=28

There's also a hammer where the face "twists" when you strike a blow. I have no experience with this, but it seems like it would work.

It sounds like you and I are at about the same point in our projects. I'm currently stripping down my sheetmetal and knocking it out as I go. I recently picked up a bulls-eye pick, and man is that thing nice to have around. If you haven't already, pick up a copy of "The Key To Metal Bumping" available through Eastwoods (no I don't work for eastwoods and am not a shareholder).

I hope this helped you out at least a little
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Old 06-13-2003, 07:54 AM
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Wavy big flat panels are the toughest problem to solve. Actually Unstable, I am a compound curve expert - give me a bubble fender any day. I get REAL nervous when the metal flattens out.

All that being said, there are some things you can try without doing more damage. First thing is to determine where the high and low spots are. Is the high spot due to a panel being beaten inward in one spot or due to it being beaten outward? You need to shrink the spot that has been deformed. If that spot is a place that has been stretched by denting inward, you don't want to try to shrink the 'high' spots around it which are actually at the right level. You need to shrink the dent back out.

Once you have determined what the problem is, try this. If the dent is inward, you need to get a lot of access to the inside of the panel 'cause you need to do a little hammer and dolly work form that side. Find the peak of the dent and heat a quarter-sized spot red hot with a torch. This spot will expand even further due to thermal expansion and become a pronounced bubble. Immediately before it quits glowing pick up a hammer and dolly. Place the dolly behind the bubble and begin to tap the bubble flat by rapidly tapping from the outer edge of the spot spiraling toward the center. Don't pound the metal between the hammer and the dolly, the goal is to flatten the bubble. The dolly is there just to support the metal surrounding the hot bubble. Once flattened, you can quench the hot spot with a wet rag. Repeat your analysis of high and low spots and hot-spot shrinking until your panel is flat. This procedure will do an incredible amount of shrinking so go slowly. Once the panel is generally flat, there will probably be little puckers, particularly at the shrunk spots, but these can be massaged back out with some hammer-on-dolly stretching.

Sounds complicated and it admittedly does take some artistic talent but you can do a credible job. Don't expect perfect results your first attempt - guys apprentice at this for years before they become expert.

Last edited by willys36@aol.com; 06-13-2003 at 10:11 AM.
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Old 06-13-2003, 10:06 AM
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Looks like willys got the shrinking and streching taken care of.
But there isn`t any place to get to the inside of the quarter panel,
it is a big piece of sheet metal. I just finished replacing one, It took about 2 hours to get it aligned and tacked on pretty easy.
The only finish is at the door jamb and top post, a little around the tail light.

I think the whole thing is $295;00. Good Luck

Troy;
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Old 06-13-2003, 05:45 PM
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Autocol--Just came across a thread on the Hobart welding forum regarding using propane (or map) vice Acetylene. Apparently you can use the same regulator that is used on an Acetylene tank for propane...and it's suitable for heating, but not cutting. =)

http://www.hobartwelders.com/mboard/...&threadid=2013
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