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Sunday, May 1, 2011

Restoration Tips - 2

It’s been a little while since I did a blog entry to address a few more restoration tips, so I figured now might be a good time.

For this round, I have three tips that are intended to help with locating spot welds and making provisions in sheet metal patch panel flanges for spot welds.  Here goes!

Paint Pens:  Paint pens have many uses in car restoration and I use them often to:

·         Mark places that require trimming

·         Indicate where and how to bend flanges to fit

·         Mark spot weld locations before punching or drilling

·         Trace body features onto patch panels to locate spot welds along interior flanges

·         Marking step drills to easily identify when to stop drilling (e.g. a visual drill stop)

·         Marking stress cracks and other hard to see faults that require repair

I like the Uni brand of paint pens with a medium tip.  These are oil-based paint markers that mark well on just about any reasonably clean surface.  They can be found at art stores and on eBay fairly cheap and most are available in small packs of assorted colors.  As you look through the blog entries on this site, you will see many areas where I use these paint pens.  They’re handy and convenient and worth the small investment.  Give ‘em a try!
Here I have marked an area that required slight bending of a flange to get the fit I was looking for.

In this example, I use my white paint pen to outline the subframe and trans crossmember on the bottom of my new floor so I can accurately locate where each of the interior spot welds needs to go.

Marking areas that require trimming is also made easy with a good paint pen.

I also use paint pens to mark my step drills to help me avoid drilling too deep.  In this example, I paint the 3/8" band with a red paint pen which allows me to easily drill the 5/16" step for spot welds.

Step drills:  Step drills are excellent for drilling nice, round holes in sheet metal.  For drilling spot weld locations in interior flange locations on patch panels, etc., you just can’t beat a good step drill.  For restoration work, I prefer step drills with larger steps to help prevent accidentally drilling a hole oversized.

As when drilling holes with a standard drill bit, I like to drill a small pilot hole before using a step drill to ensure accurate hole location.  I also like to paint the step just above the size I want to drill to give me a quick and easy visual “drill-stop” reference so I know just how deep to go without drilling oversize (see paint pen tip above).

In normal circles, step drills can be a bit pricey, however I have found the step drill sets from Harbor Freight to be quite good and very inexpensive.  Often, I find a set of three step drill bits in a nice nylon pouch on sale at H.F. for about $10.  Can’t beat that.
Like with most drilling operations, a small pilot hole helps step drills start very easily in sheet metal without walking.

Step drill are particularly suited to sheet metal work and they drill very nice, round holes.

Pneumatic Punch:  Most restoration tool houses offer some sort of sheet metal punch and flange tool, but I have found most of them to be of minimal use as punches, mainly because they rarely punch holes much larger than 3/16”.  I mean, what the hell do you do with a 3/16” punched hole when you’re trying to plug weld a patch panel?
I spent quite a long time trying to find a serious pneumatic punch/flange tool that would smoke a clean 5/16” hole in a panel flange and still have the flange-forming features as well.  Fortunately, I found the perfect tool made by Astro Pneumatic Tool Company.  Their model 600PT8 pistol grip punch/flange tool is fantastic for punching beautiful 5/16” plug weld holes along panel flanges and the flanging feature has the power to make nicely formed flanges in almost any body sheet metal with ease.  Once you use one of these tools you will wonder how you ever got along without one.  Expect to spend about $85 to pick one up.  Check eBay and Amazon for sources.

The Astro Pneumatic 600PT8 punch/flange tool is priceless when it comes to plug weld hole formation. 

The punch head is very heavy duty and makes perfect 5/16" plug weld holes with little effort.


  1. That is all really useful info...I've never used a step drill or a paint pen while working on my car - I tend to get by with a Sharpie, but I think I will give both a try... Nice piece.

  2. I was a step drill doubter for years and then ended up with a set. Now I swear by 'em. And as a fellow Sharpie driver, I think you'll find a lot of use with the Uni paint pens. All the best!

  3. Thanks Sven. I was thinking about a paint pen. I used them in the Navy, I don't know why I didn't think of them earlier. My Sharpie keeps smudging.

  4. Paint pens are certainly more expensive than Sharpies, but worth the cost for reliable performance. And thanks for your Navy service!