Best procedure for duplicating this dashboard panel in Proofgrade Walnut

Longtime listener, first time poster!

I have this plywood dashboard panel from a 1977 Fiat Spider:

I want to reconfigure the gauge cluster and reinstall it in my car with a new arrangement. Since the Glowforge doesn’t do precise 3D scanning/tracing of objects (I wish, I wish), what would you pros recommend as the best approach to getting a perfectly dimensioned Proofgrade panel sandwich I can mount as a replacement? I need the outside outline to be dead-on precise, as well as several of the left side gauge openings. I am going to redesign the right half in Illustrator.

Would it be something like:

  1. Place existing dashboard on top of a white sheet of paper and carefully trace the outline with a narrow felt tip pen in black?

  2. Do the same for the inside “cut” gauge openings I plan to keep?

  3. Trace the resulting drawing?

Can I count on the resulting tracing to render a cutout that’s exactly the same size if turned into a cut job?

Thanks much for the help, y’all.

As opposed to using a pen, I’d do a trace either with the :glowforge: or with a scanner (depending on overall dimensions places like Kinkos have large bed scanners)
Then physically measure and verify that the outside dimension matches. If one matches then the rest should be dead on as the relation won’t change
Place your art onto a 12x20 workspace in your design program and it will maintain that size when imported into the :glowforge:
Once you have your outside edge you can delete the holes you don’t want and then replace them with the new ones

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I think the scan on that would be difficult because it’s thick enough to throw some serious shadows, and that’s going to interfere with the Trace results.

Your idea of using a marker to trace it onto a flat heavy sheet of paper is going to get you the best accuracy. But I also agree that checking the measurements in Illustrator, smoothing out any Scanned results and tweaking it a little is going to be better. Do you have another Scanner that you can use to capture a digital scan of the paper with the ink hand tracing job? That would let you take it into AI and tweak it there.

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You could place the original on a gridded sheet (like graph paper) of known dimensions, take a photo, import in to Photoshop or Gimp, then do a lens correction on the result. Then resize the doc to the size of the original grid (hope that makes sense) then trace in Illustrator or Inkscape.

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Tracing and scanning (with a flatbed scanner) is very unlikely to get you a quality result without a lot of time spent tweaking it. I think it would be faster to measure it by hand and recreate in Inkscape. Cut it out in a heavy card stock and iterate until perfect.

This of course assumes you have already searched FIAT forums to find out if someone has already made a dimensioned drawing and have come up empty.

Also, have you considered sanding off the finish on the original and using the walnut veneer? That way if you’re still off by a fraction here or there the gauges will still fit in the holes without having to go to town with files and sandpaper.

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I would scan it on a flatbed or trace to paper and then scan that (but remember, the traced line isn’t the line you want to cut, you want to cut the inside edge of the trace).

You shouldn’t need to care about most of the interior dimensions, it’s just the outside edge that’s critical if you want it to fit back in the car. You do care about the screw holes, but if you can laze an accurate outline of the dash panel, you can lay the original over the new one and use the existing screw holes as a drill guide.

The circles for the instruments can be added “free hand” since their placement isn’t going to be super critical, since the instruments mount to the panel. All you need to do is measure the diameter of the hole and replicate it in about the same spot…

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Good idea @caribis2 - I did give the Fiat forums a cursory search but haven’t found a ready-to-go template.

The veneer idea is very interesting - but I want to save the original dash in case we want to revert to the original analog cluster. (This is for an EV conversion of said Fiat and is going to house a digital display for some battery charge, range, and other driver info - we want this info to display in the style of the original Veglia gauges and “poke through” the circular portals, and not look like some flatscreen tablet jammed into to the original dash.)

Sounds like my low-tech best bet is a really precise ink trace and then a cut on the inside edge of that trace, after tweaking it in Illustrator. And then prototype it in posterboard/card stock cuts until I’ve got it nailed. I’m thinking the final replacement panel will be two Proofgrade layers sandwiched and glued together to approximate the original’s strength and thickness. The old gauges are going to mount right back the way they did, so it needs similar strength. Plywood Walnut surface, 1/4" Draftboard backing?

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if you have access to a 3-in-1/multifunction printer, the sheet-feed function can be used to do scans that are longer than the bed of the scanner.

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Agree with lots of the others ideas. I re-did the dash on my 1986 Ski Nautique to be able to move some gauges around, and used illustrator to create the mock up. This was before I had a :glowforge:, so now I’d probably use draft board or similar to do a test run. Measuring by hand, I think, will get you better results than trying to scan that existing piece. Please post your results with pics!

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Thanks, I’ll definitely post before-and-afters…if I get to credible afters!

If you’re curious, the project is generally doing what these guys did (in fact we’re using their motor+battery kit):

:oncoming_automobile: :zap:

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The best way to handle this is to take a photo from a ways out and directly over it to minimize paralex. Then import the photo into Fusion 360 as a canvas. From there you can precisely calibrate and trace for the perfect fit.
I’ve done this for several projects and it works great. A bit of work but great results.

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A couple ideas here. Gluing two layers of anything into a sandwich induces sideways slipping that is near impossible to avoid. A solution is to use alignment pins that go through both pieces. This is very easy to do with a glowforge. However, this mars the top piece where the alignment pin comes through. One solution is to engrave the pin hole only partway through the backside of the top piece. Another solution is to sand the alignment pin flush and then use veneer (I really don’t have a veneer fixation) over the entire dash piece. Another option for this particular project is to use cylinders through those gauge holes for alignment. Just remove them before the glue sets.:grin:

As for materials to use, the proofgrade plywood comes pre-finished, which means you are trying to bond two finished surfaces (most likely polyurethane.) I would consider using an unfinished walnut plywood. Rockler carries it as does my local Menards. If you are going to go the veneer route you can use a birch plywood. As birch plywood doesn’t use a MDF core it will be stronger. I haven’t seen a FIAT spider, Triumph or Spitfire in over twenty years, but IIRC they’re only about eight inches tall not including the windscreen. So if the maximum width of that dash is in the eight-inch range, another option is to use a birch plywood backer and then a solid piece of 1/8 or 1/16 solid walnut. There are plenty of online resources for solid walnut in widths of at least 8 inches (IIRC even wider.) Using a solid top layer lets you go to town sanding, which will make the finish you apply look soooo much better.

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I know this is heresy in the GF world, but perhaps you might get better results using the original as a router template using a trim bit. You would have an exact replica of the outside, but could alter the inside cutouts as necessary.

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The sandwiching trouble makes sense - but the four mounting holes that the existing grommets sit in (and which screw into the backplate in the dash itself) should act as alignment pins pretty well. So this would work the same way as your cylinder-through-gauge-opening suggestion, I think.

If I go buy unfinished plywood, dumb question perhaps – I assume the Glowforge can’t cut it cleanly beyond a certain thickness? (And that’s why Proofgrade materials are sized the way they are.) I need to measure the current dash plywood’s thickness and match that as closely as possible with the sandwich, otherwise my replacement panel won’t be flush.

Yeah, this sounds really good! Wish I had a router already to experiment with. And I’m perhaps trying too hard to optimize this task to work with the Glowforge, although it sure seems appropriate.

As long as you have cylinders the exact size they’ll do fine. I’ve only used rubber grommets before and obviously they don’t have the rigidity needed for the task.

The thicker the material the more noticeable the kerf. Also, not burning the $&^&% out of thick material can be problematic. But you can find non-proofgrade plywood in similar thicknesses. The 3/16" (sold as 1/4") Birch ply I buy from Menards cuts very well. I’ve only seen the non-proofgrade walnut plywood sold as 1/4", but that is probably a generous measurement.

A perfect fit and finish?!?!? Why are you trying to murder the soul of your FIAT? :smirk:

I figured that would be an issue, but they sell very thin spacers/washers.

Heh! I’ve already gotten grief from the Fiat community for going EV, so at this point I’m just doubling down. :grimacing:

Thanks for the additional advice perspective. Will shoot for the 3/16" ply as my backer and go from there. :sandwich:

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Just a thought but MDF is not something I would trust outside over the long term. Theoretically the interior of the vehicle is not outdoors, but the life goes through pretty extreme conditions when people are not in it. High temperatures, high humidity , and perhaps freezing temps as well, as well as fumes of various kinds, from cleaners to aroma hangers etc.

My first preference would be solid walnut. The Glowforge will not cut just any half-inch wood, but walnut is on the list of those it will. Making it in two layers has the advantage of helping against warping but not the reason that you could not cut it.

If I was to want a walnut veneer I would definitely avoid the MDF and go with something like Baltic Birch or aircraft grade that will be strong and stand up to environmental issues usually 5 or more layers all real wood and thus extremely tough against any warp or breaking up. I would not want to cut that at more than 3/8 thick as they would char a lot more than Walnut.

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If you’re going to go with veneer, put it on a substrate that’s “weatherproof” like Acrylic. You don’t need to glue veneer just to wood. :slight_smile:

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@cynd11’s or @dwardio is a great way to go. This is a great skill to for making parts for existing objects. One uses 2D and the other uses 3D.

And you can always just use a vector drawing program to make the outline from measured dimensions on the part. Often the scanning thing isn’t worth the trouble for correcting the scan. You can draw it by the time you get through manipulating the image.

The measurements can be exact. For the curves. You just need to understand the radius that is part of the design. Tracing on a grid paper will help immensely. Then measuring your instruments to get the circles exact.

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