Dashboard restoration

[nthomas1]

Just started on my winter project.  The previous owner of my S2 had rather clumsily fitted a tripmaster to the dashboard.  After removal it left holes and some separation of the plywood layers underneath.  After researching earlier forum posts I've acquired a sheet of iron-on mahogany veneer (from Veneers Online) and a surgical scalpel and blades.  For just over £16 the veneer sheet is big enough to do 4 dashboards with a piece left over for me to practice with!

******** Amendment added in March 2021.  After five years the veneer on my dash has lifted (bubbled) a few millimetres in a couple of places.  In retrospect I don’t think the adhesive that is on the back of the iron-on veneer is entirely suitable for long term application and associated temperature variations.  If I were doing the job again I’d use plain veneer (without the self-adhesive backing) and  apply an appropriate glue and then clamp the dashboard while the glue is drying. Many apologies to anybody who has followed my advice (which was based on information I took in good faith from somebody else's blog), and has encountered similar issues.**********

[simonandjuliet]

Nice, are you going to iron on top of existing , or remove the original ?

I suspect it depends on the thickness of the new veneer ??

[chriswgawne]

If you run into problems, I am fairly sure I  have got a pretty good one available in Sunningdale.
Good luck with the restoration.
Regards
Chris

[D5177_55A]

If you’ve got ply layer separation, I’d be tempted to get some wood glue and soak as much of the loose bits with glue, wrap the dash in plastic bags/greaseproof paper, then press it for a few days under books or other such weighty stuff. Maybe use some cut-down dowelling to fill the drilled holes rather than wood filler. Sand down the dash edges that are visible through the layers of ply i.e: on the main cut out, 2 large dials, 3 mini gauge holes an the warning strip slot before you apply the veneer. I wouldn’t use any paper courser than 150 grade. And after you’ve ironed on the veneer, keep changing the scalpel blades after cutting say one edge”s worth; it might seem wasteful but the new veneer is a lot tougher than you might think and the blades will dull easily. Finish off the edge of the veneer with glass paper.

[nthomas1]

Thank you gents.

Simon - I plan to lightly sand the existing veneer and apply the new directly on top.  With the adhesive backing it's about 1mm thick.  The adhesive is ridged so after heating/melting I'd expect the incremental dashboard thickness to be only about 0.6mm.

******* Amendment added in March 2021: See comment in opening paragraph about plain versus iron-on veneer***********

Chris - thanks for the offer.  Good to know I have a Plan B if (when?) I screw it up!

Stephen - thanks for the tips.  I've fixed some of the gaps using pieces that fell away when I removed the dash from the car. See pics below.  
I'll see if the dowel suggestion will work for the surface holes but am wary of any further drilling in case I damage the plywood underneath.  I may just use wood filler, but do it in 3 or 4 layers with a couple of days to dry between each.  I think that would protect against shrinkage and give me a smooth surface for the new veneer.  I have a question about cutting out the apertures.  One approach is to pierce through from above and, with the knife held perpendicular to the surface, try to follow the shape of the cutout underneath.  An alternative would be to cut out the shape from underneath leaving a small overlap all round.  Then trim the surplus from above, or sand it away.  Any thoughts?

[nthomas1]

This is the delamination that I was fixing in the last couple of pictures.

[Richard Fridd]

This reminds me of when years ago, I bought some veneer from an eastend warehouse full of the stuff on more than one floor. I should have taken a camera. 

[frankxhv773t]

The approach from the front or the back is an interesting question. Whichever you choose don't try to cut to the final line straight off. start with a rough hole well inside your intended end point and work your way to the edge gradually. The finer the final cut is the more likely the blade is to follow the perfect line. I think the danger with working from the front is a lack of support for the pressure of the knife whereas from the back there might be a danger of the edge splitting away along the grain. Perhaps doing the rough cuts from the back and then the last millimetre or two from the front would work best.

[DavidLaver]

I've very little experience of veneer so this is 100pct "a question" rather than "a suggestion"...

Is there any merit in something like a hole saw or forstner bit or even a fret saw to clear the majority of the excess?

Any advice for what to cut on / into?   A bit of MDF or is a "cutting mat" worth finding?

[davidwheeler]

I would think a hole saw would tear it as it is so thin.   A careful fretsaw with a fine tooth blade should be OK and then a very sharp knife - or perhaps a sanding cylinder in a Dremel?

[D5177_55A]

Whenever I’ve done any dashes, I’ve always cut out the apertures with 25mm (1") of veneer remaining around the edges of each aperture just to make sure that the heat actually melted the glue to the aperture edges. Then I would cut from the rear until there’s about 2mm excess veneer left. Keep changing those blades! Then I hold the dash vertically, balance one end on my shoulder, carve off small slivers looking along the aperture until the veneer almost level with the ply, then use superfine sandpaper/Aluminium Oxide paper wrapped round some form of edge (file, small block of wood) to get it down level with the ply. If you’re going to use a saw it would ideally need to be very fine toothed (20tpi). Those pics you posted look like the ply is very ”dry”.

[nthomas1]

Thanks for all the tips so far.  I've got enough left-over veneer that I can practice sticking it down to see how good a bond I get, and can then practice cutting it.  After the practice sessions (and assuming I don't give up at that stage!) I intend to place the dashboard upside down on a cutting mat and cut the apertures from behind to within a few millimetres using a surgical scalpel and plenty of blades, then cut the excess from above by shaving it away, again with fresh blades.  I'll use fine sandpaper to finish off the edges.  I will report on progress.

[nthomas1]

I've cut two rough outlines and have placed them under some heavy books to uncurl ahead of ironing one of them in place. The lower one does fit. The picture makes it look too short!!

[frankxhv773t]

I tend to cut against something reasonably hard because it's important not to let the veneer distort downwards during the cut. A cutting mat is useful to have but in this case a piece of old plywood should work perfectly well.

[nthomas1]

Good point Frank.  There's probably enough give in a cutting mat to allow the veneer to pull away from the surface of the underlying plywood.  I'll use a wooden board instead.