Technical Tech Week - Hand-Punched Louvers with a Stone Chisel

There is actually some info about this already on the HAMB but I'm going to go step-by-step on how I do it and what not to do as you're going along.

First, some inspiration:

@HomemadeHardtop57 's decklid has the shape of louvers that fit right into the time period of the roadster I am building. I'm not sure how he did his but that's the shape we'll be going after.



Next up is @thunderbirdesq 's old roadster. This car and Andy's technique for hand-punching his louvers is what got me started. I've picked his brain on occasion. He fabbed his own punch, too. Mine, however, is something pretty much every guy could fab, welder or not with a range of different tools. Let's get into that, now.

 

I had a landscaping project a few years back that required a stone chisel. It's sat in my toolbox since the project was completed. It's a Dasco Pro 2-3/4" stone chisel. They range in price from $8-$15 and come in a variety of widths. They're hard and they'll last you as long as you need and beyond.

Like all chisels, this has a beveled edge and I've found that a straight edge works best.




So, before laying out the shape, I knocked down the bevel. Like I said, this could be done with all different tools. A hand-held grinding wheel would work, for sure.




I knocked down the edge afterward.




I found center and chose what type of depth I wanted. This happened to be about 1 cm (those 2 dots below center) so I put that on either side.


The arc is pretty much center. The site isn't allowing my vertical pictures. Just landscaping them for some reason.

Anyway, onto cutting.




Again, this can be done a bunch of different ways. I used the cutoff wheel.



After cutting off the corners I took the chisel over to the bench grinder and shaped it.



I traced it a couple times and would put a straight edge across the ends to see if it was a fairly equal shape. Once I got to a shape that was acceptable, I cleaned it up, i.e., I removed any sharp edges and made it smooth.

 

Oh, I don't want to step over this. I put a mark on the center of the punch. and hit it with ths grinder so there's an indentation. A marker or paint park will just wear away. It's on both sides. BUT, I try to pay attention and keep the punch facing the same way, always. so the louvers come out as similar as possible.

There's a lot of room for errors in hand-punching these. Unlike the consistency of a machine that pops the same louver time after time. You can mess these up, easily if you aren't attentive.




Now is a good time to say that the size of the louver is NOT 2-3/4" like the chisel. After shaping it, the punch is 2-5/8". I laid out the louvers accordingly.

Obviously this is a dirty old piece of scrap, which is good for practice or demonstration. It does have some drawbacks. Size is one. The amount of real estate around the sides of the scrap allow for the metal to deform much easier than a bigger piece. I practiced on a scrap Chevy hood and it was easier to focus on actually punching the louvers.

Note: if you need to louver something small, like license-plate sized. I suggest making a simple wood frame that pinches the perimeter of the work piece. I did it to a license plate (a buddy used it as a cover for his shed vent) and it worked like a charm.



I want to get this out there because there is a tendency to show highlight reel footage rather than reality. Like I said, if you don't pay attention or prepare well, it's going to come out poorly. Here are some things NOT to do.



Since I've been practicing I've learned a few things. You can drill holes at each side. I didn't here but if you're nervous about the cuts, I recommend it. Also, thin cutting wheels work best, for me. It looks the cleanest and clean-up is less. If you do use a drill, match it to the size of the cutoff wheel. Seeing the remnants of drilled holes looks shoddy.



The above cuts are even thicker than I usually use, now. Admittedly, I didn't want to fire up my compressor and use a different set-up. The kids were sleeping.

The ends of these cuts should get hit with a file or a hacksaw blade if you don't have a narrow file.



I'm holding the punch and trying to get a decent pic. Before hitting the punch I did square it up better.

You can tell how junky the left louvers are. We'll talk about those more in a bit.



(That's a glare on the punch, it's not oddly shaped like that. Believe me, I'm too OCD for that. )

This is the set-up I used. You don't need a shot bag. I have one so it's nice to use. But this is something that can be done on the cheap. I've read about guys banging out louvers on a pile of rags, out on the lawn, and/or fabbing a negative space to drive the louver into. I've seen these ranging in complexity from a piece of plywood with two strips of wood on either side leaving and "alley" to drive the punch into. When the metal hits the "floor" of the alley, they move to the next louver. Make sense?

Truthfully, the pile of rags could work out just as well if you take your time.

 

Cleaner, straighter cuts. you can see the end of the cuts, where there is material still left on the opposing side of the workpiece. Take a slim file or a hack saw blade and clean this up. It will result in a better louver.



Okay, now for some horrific looking louvers. This just shows you how skilled a guy like Andy is and how not being focused can result in hack work. I'm telling you now so there's NO EXCUSE. There are all sorts of problems here.

I have mentioned the cutting issues (on the three left) but there's also hammering issues. You need to hammer straight. It's not the end of the world if you don't but you will have some extra work to do. The three louvers on the right show different issues. One is hammered off-center, the center one is pretty clean and the furthest right, I didn't hammer fully. All things that can be adjusted/fixed. The louvers to the left, they would draw someones eyes right away even if they were surrounded by a hundred perfectly hammered louvers.



See what I mean? Bottom three have issues. The top haven't been worked on, yet.

 

Paint is something that wouldn't happen so fast and any paint prep would have gotten rid of the burs and sharp edges. Which I highly suggest. My roadster decklid won't have any. The fact that I'm bringing it up is so that it's mentioned and out there.

Really, I just sprayed these to show shape and what a little extra metal work can do.



That top louver has a bit of a deflection that my larger practice pieces didn't have. I didn't see it until now. I would go back and straighten it out.



That's pretty much it as far as directions and tech. I'm not 100% proficient, yet. But I'm confident that I could bang out 50 louvers on an old gowjob and have it look respectable and completely match the era and level of build.

Thanks for looking. Any questions feel free to ask.

 

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Spacing, I forgot to talk about that. I chose 1-1/4" on this project. The louvers that are hand-punched by ThunderbirdEsq, below, are 3" wide and 1" separated.

I'm going to continue to practice as well as change spacing to see what I like best before going at my decklid.

 

Doesn't get more traditional than that.
Great instructions, tips, and photos.
I would suggest these three things though.
1. Lock the door before starting.
2. Turn off the phone.
3. Enjoy a cold one AFTER you are done.

 

Great tech article. I'm gonna try that. Thanks

 

Thanks for pointing out the techniques Brent!

 

Very cool!

 

Yeah, I couldn't be drinking beer while doing this on my car. Haha.

Thanks, fellas. It was fun doing it.

 

When I first read the title, I thought 'Stone chisel??!! Is somebody going Fred Flintstone on us??!!' but after reading it, this is great tech!

 

Low Buck Tools in SoCal sells round top louver dies. Dave Williams 951-735-7848
I have them and they work great.

 

This is for their louver press, no? I don't have a louver press and new, precise, modern louvers would look way out of place on my roadster with all its wear and tear.

 

I have to try this Thank you Tech week is Great !!! Jim

 

Interesting that you would choose 1 1/4 as your spacing, Brent. The most widespread press/die is the Goodtimes one (Zapato has one that I use) and they are exactly that spacing.....
My pal Beaver Bob made a wooden buck for his hood side louvers and clamped/pressed a set. easy to do with a corking tool and a great result as well. Ferrari even did them like this in the early days.
Lots of good ideas to be had. Tech Week rules.....

 

Neat. I would love to say there was some great reason behind it but that was the width of my straight edge. Haha. I do think that spacing would look pretty good with my project. I want to try a little further spacing (but more of them) and see the look with that.

 

Here's where a lot of guys start out, an article from Car Craft 1955. It's more involved/time consuming and from reading and talking to a few folks it's not a very desirable process. After all the labor, they end up abandoning using guide pins and such. Those pins are probably the equivalent to training wheels. A hand-chiseled wood buck is neat, too, but you can get away without that - as well. Especially if you invest the time practicing rather than chiseling.

 

Yeahhhh buddy !!!

 

I gotta admit I like the domed look of the louvers. HRP

 

Ditto what he said! Great tech

 

For me to vote for it, a tech week has to be more than cool, it has to be something I am actually likely to use. I am pretty much down to this one, and the exhaust tubing layout deal. I really want to try this.

 

Thanks for writing that, George. I appreciate it. And, I agree. I actually really like @Rich B. 's embossing thread, too. When I was thinking about doing this post, I kept thinking this is really something anyone can do. I think the only limitations are for those that are not patient. If you rush or cut corners it's going to suck, which is true for anything.

Thanks a lot, fellas. I really appreciate it.

As well, I hope someone posts up their results after trying this. And, I'll put pics of my decklid up once it's knocked out. It'll be during this fall season, for sure.

 

Great tech, how about a small plasma cutter, using a long fence to make the slits ? They would be uniform and a snap to do.

 

Geez Marty, You're so smart. I can see I'm going to have to buy a plasma cutter. I wanted one anyway.

 

If I had one it certainly would be the most likely option.

My problem is, whenit comes to bigger ticket items like that, I almost always don't buy the smaller/less expensive option.

 

Cool stuff Brent!

 

This is great because it reminds me of work I see on some of the lakes cars from back in the day. You know that guys were doing hand work like that with what they had and it all looked pretty cool.
They just come out so perfectly imperfect (a good thing).
Thanks for sharing