Dang it missed a couple high spots

R

robking

Promoted Users
Hey folks, I blatantly missed a couple high spots on the cowl and could use some advice on best way to address 'em.

Pics below, circled the two high spots that are right in front of the wiper hole. No way to get behind them really. Two ways I thought of:

1. Clean a little more back to metal and just lightly touch them with shrinking disk.
2. Weld a couple of studs nearby and pull up while tapping down

That area doesn't have a lot of support due to vents nearby so it's easy to push it down.

I think it might have been this way from the factory but I'd like to clean it up if I can safely. It also seems like a bad place to have very much filler.

Advice greatly appreciated!

PXL_20240619_235603924~2.jpg


Side view

PXL_20240619_235615871.jpg
 
If it's not low in-between those two spots and the highs are not outrageously high, this is a good time to use the pick end of a body hammer. Lightly tap the highs. No need to have anything behind it. Very lightly to start. Check your progress often. The blunter the pick end of the body hammer the safer. If you aren't making much progress then a shrinking disc would work well. If you don't have one you can use a phenolic backing pad if you have one, or you can use the backside of a grinding disc. Dont quench or blow air on the spots, let them cool naturally.
 
Chris_Hamilton said:
If it's not low in-between those two spots and the highs are not outrageously high, this is a good time to use the pick end of a body hammer. Lightly tap the highs. No need to have anything behind it. Very lightly to start. Check your progress often. The blunter the pick end of the body hammer the safer. If you aren't making much progress then a shrinking disc would work well. If you don't have one you can use a phenolic backing pad if you have one, or you can use the backside of a grinding disc. Dont quench or blow air on the spots, let them cool naturally.
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Thanks Chris, I have a hammer that should fit the bill, I'll try that lightly only. I have a set of Wrays metal shrinking discs, good suggestion on the not quenching. I've found they work well, sometimes too well. Not quenching seems like it would allow you to sneak up on flat slower.

Using a straight edge and comparing to the other side, I'd guess that high spot is between 1/32 and 1/16.
 
The homemade ones I listed won't mar the metal. I have a set of WS's as well and I think they would be real aggressive in your situation. If you use them just touch the spot for a second or so. Sneak up on it.
 
Chris_Hamilton said:
If you aren't making much progress then a shrinking disc would work well. If you don't have one you can use a phenolic backing pad if you have one, or you can use the backside of a grinding disc. Dont quench or blow air on the spots, let them cool naturally.
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Please excuse the question but where would i find a phenolic backing pad? I have only seen phenolic tube's used in house paint style rollers used with strong solvents. What type of grinding disk if you don't mind?
 
Kawickrice said:
Please excuse the question but where would i find a phenolic backing pad? I have only seen phenolic tube's used in house paint style rollers used with strong solvents. What type of grinding disk if you don't mind?
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They come with the little air grinders that take 5" pads. You can get them individually as well. As for grinding discs just the backside of a worn 5, 6, or 9" inch stiff grinding disc.

Link to phenolic backing pads (click on images to see examples)

Link to example of the disc. You of course would use the backside of the disc.
 
Just to add only do any of the above if you can noticeably feel the highs with your hand. It may just be a case of normal highs poking through when sanding. If that's the case you don't want to put a shrinking disc on there or tap it.
 
Chris_Hamilton said:
Just to add only do any of the above if you can noticeably feel the highs with your hand. It may just be a case of normal highs poking through when sanding. If that's the case you don't want to put a shrinking disc on there or tap it.
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You can feel them for sure.
 
DanMcG said:
Are you planning on addressing the lows too?
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Yep. Thought is after getting those high spots addressed I'll hit it with two more layers of epoxy and block. Whatever lows are left will get a hopefully thin smear of rage ultra before final layer of epoxy.
 
Not sure what you are working on or how high those spots are but for small high spots I have used a 2 in right angle grinder with a 36 grit disc to remove the high spot.
 
RayH said:
Not sure what you are working on or how high those spots are but for small high spots I have used a 2 in right angle grinder with a 36 grit disc to remove the high spot.
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This is a 68 Dodge so metal's not thin but not exactly a tank either.

I took a minute to give the highs some taps and they have layed down pretty well. I've got some couple day old epoxy in good shape, think I'm gonna clean it up and lay some more on it.
 
RayH said:
Not sure what you are working on or how high those spots are but for small high spots I have used a 2 in right angle grinder with a 36 grit disc to remove the high spot.
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No. No. No. That is terrible advice. You are thinning the panel unnecessarily doing that. And what if someone takes that advice, starts grinding and still has a high area after grinding. How to fix it now? You aren't fixing or addressing the issue doing that It's like filling a deep dent with filler instead of working it out.
 
RayH said:
Chris, I guess my suggestion was taken the wrong way. I just give a couple of quick light passes.
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No problem Ray. :) Wasn't trying to chastise you but any sort of grinding off of a high is a bad idea. Much better to work it out and address whatever the issue is.
 
I think if any material removal is part of the repair plan, tapping along with some sanding with 80 on a hard block can help, more to indicate exactly where tapping is needed than any serious material removal, but the 80 will smooth metal just slightly. I'm not really any great metal guy but that has always worked okay for me. Altering the direction of sanding between rounds of tapping can help indicate progress.
 
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