One glue up or two?

tvrgeek

Scott
Corporate Member
Making some veneered bits for my Triumph. Some flat, some curved. But complex cutouts that must have extremely good edge trim. My question is this: Should I laminate everything including the veneer in one step, or just the base, do the cutouts, then veneer and trim with a blade.
20200609_094353.jpg
 

creasman

Jim
Staff member
Corporate Member
A few questions first...
  • What technique do you plan to use to apply the veneer? Hammer veneer, vacuum press, clamps, ...?
  • Are you making a completely new base or reusing the existing one (i.e., just reapplying veneer)?
 

tvrgeek

Scott
Corporate Member
For this first one, I picked up one of the inflatable bags, as I figure it wil apply very even pressure. I have two layers of 5 mm ply in it right now to make a 10mm core. This first test I used Titebond, but I wil do one using poly resin. I was thinking of the resin for the cold-form layup for the curved instrument cluster. Concerned what the moisture from PVA will do for stability. Going in a car, it is a very hostile environment. Very hot, very cold, swings in humidity.

All new, moving stuff around ( Generic switches are a different size from the Lucas unobtanium) plus the old ones are de-laminating. When I get to the instrument cluster, it is curved, so that will be a vacuum bag. Just have not invested in it yet. Just started to make the female form. I have considered making both male and female and using the press. All new to me. Looks like the only way to get 1/16 slabs is to band-saw them but that leaves me with the grain all going in the same direction, which may not be bad.

The precision need comes from the gauges and some switches are half recessed, so the edge is visible. Glove box and AC vent pieced I will re-veneer as they are in good shape but have a convex face. Again vacuum.

I have not bought the vacuum stuff yet as I am debating buying a HVAC setup. I have to repair and test my AC in the Stag and need to do it before I put the dash back in and make it drive-able. I can justify a nicer pump if I need it for more than one thing. :)
 

creasman

Jim
Staff member
Corporate Member
For something like this I agree the vacuum bag is the best way to go. It's hard to get even pressure throughout using clamps. I haven't used my vacuum bag for anything with a curved surface but it works great on flat surfaces. It should work just as well for curves so long as they are gradual. Convex surfaces will be easier. Also, you'll need to support the curve with some sort of cradle so the piece doesn't get deformed or crushed when the vacuum is applied.

Where possible I recommend doing all the veneer first and then do the cut outs. Make the substrate bigger than you need and do all the cutting/trimming last. I don't think it matters whether you veneer in two steps (substrate first and then face second) or all in one. I'd probably do it in two steps to avoid wasting my veneer in case the substrate didn't come out quite right.

If you are reapplying veneer to an existing substrate that already has the cutouts, it will be tricky. Too much pressure and you'll pull the thin veneer right into the cutout and have cracks. I'd do a test pre-glue to gradually decrease the pressure to see what works. It won't take much to shape the veneer over the base and going full atmospheric pressure will likely deform it around any existing holes.

Sounds like a fun project. Keep us posted on the results.
 

Brian Patterson

New User
Bstrom
Will you make a template as well to edge trim the pieces with your router. This is great stuff you're doing - hope it looks OEM when you're done!
 

tvrgeek

Scott
Corporate Member
Old wood is de-laminating, so I can't reuse any of it. I did think of that for the cluster, but figured I woudl have better luck ( and more tries) if I learned to cold-mold in the first place.
Super, the answer I was looking for: veneer then cut.
Do not know how I am going to do the instrument cluster holes. The curve makes it hard. Router and jig, but to say that is the easy part. Main holes I think I should do from the back, then only have to do the recess from the front. I am gluing an MDF form of the curved cluster shape. Male side. Sure glad I got that new band saw! Close to OEM is the goal, just a little darker walnut. No kiddy racer stuff in this one, it is a touring car. My B ( for sale) is more the sports roadster.

Two hobbies is great as when I get frustrated on the car, I work on some furniture projects, and vice versa. Just finished staining a table to find a few scratches, so it has to sit to dry before I sand it out again. If I get bored, I need to paint the trim on the house.

Looking for a good gutter man and a painter. I should not be on ladders any more.
 

tvrgeek

Scott
Corporate Member
What I learned today:
Poly resin worked great to laminate the ply layers, but was a disaster with the veneer. Bleed through and it did not stick well. Guess it is no surprise being walnut. Back to PVA.

Had a thought, should I be wiping the walnut down with lacquer thinner before glue up? I was also thinking, with the oils problems in Walnut, maybe I should pick a different wood for such a hostile environment.

Much cleaner cut on the BS with veneer up.

More to learn tomorrow. Time to finish shape the mold for the curved dash. Still not sure what wood to use for the core.
 

JohnnyR

John
Corporate Member
I'd strongly recommend hide glue. Given that you're New at this, you can peel off the veneer if you make a mistake. Bleed thru would not be a problem. Also walnut doesn't really have an oil problem. You can also slow down the open time by adding salt.
 

JohnnyR

John
Corporate Member
Another concern, if the gauges are under mounted and you're rounding over the wood, make sure you won't go through the veneer layer or use more layers of walnut. If you're not trying to make it look like OEM , you might try a layer of walnut over maple veneer so when you round over you'll have a tiny strip of white around the gauge.
 

tvrgeek

Scott
Corporate Member
Gauges are recessed about 3/16 inch. The round-over is small. Triumph just painted the edge. Getting it really clean with no splinters is my main concern. I thought about several layers of veneer for just what you point out. Not sure how thin I can slice it as I thought about just making it up from walnut. Not sure my band sawing skills are up to it yet, though the new saw is. 1/42 inch veneer is flexible, but seems difficult in other ways. I would like to find some about twice that.

So the walnut oils are not a problem? Good to know. Something I read or was told years ago.

Hide glue in a car? Temps of 130 plus, variations in humidity? Not sure about that. I assume the original was urea-formaldehyde and even it can give up in a car. Plus, don't you know the difference between a British roadster with the top up and one with the top down? If its down, the carpet dries out quicker. I was going to order some of that newer thicker PVA said to be designed for veneer, though heat, springback, and creep worry me, so maybe a urea based glue. Searching found this:

Ultra-CAT™ Powdered Urea Resin Veneer Glue: $13.50 - $86.90

I also found Spruce Aircraft sells 1/16 thick plywood. Might just be a good core material for the instrument cluster. The two layers of 5 mm from Home Despot will work out OK for the flat pieces.
 

tvrgeek

Scott
Corporate Member
Thanks for that site. Reading their lit, they point me to their "pre-cat" for what I need to do, but the X-press looks handy for inside work.

Noticing a lot of shelf life warnings. Darn, I need to actually plan ahead? What fun is that!
 

tvrgeek

Scott
Corporate Member
Ultra-Cat seems to be sold out in small pails, so I ordered some Weldwood which happens to be 1/3 the price. ( Amazon prime shipping has saved me tons of bucks! Enough to learn with. Added in a nice silicone glue roller. Ordered a down cut router bit.
 

tvrgeek

Scott
Corporate Member
OK, digging in deeper. Is there a preferred filler for under the veneer? I need to fix around some cutouts on the glove box. I was thinking Bondo as it is tougher than most wood fillers. I was also thinking JB weld as it is really strong and I can machine it more accurately. Where some of the damage is, it is likely to get knocked again.

How very correct on PVA. I used a heat gun and just pealed the coin tray veneer off. Wrong stuff to use.

I wonder, really short setup, but thicker super glues may have some use for the parts that I have to re-veneer that are thin edges , not flat, so a vacuum press would cause chipping and issues on the edges. The center HVAC piece is basically a square about 1/2 inch wide rim. Outside edges will be viable. I could make a plug to support the edges, but that would be a lot of work.
 

tvrgeek

Scott
Corporate Member
Here is the piece. Reading around the WEB, one thought was super glue. I have some very firm foam I use for tail light gaskets that could apply pressure but not sink in deep enough to bend the edges. Or would I do better making a piece of blue foam as a flush recess for the part? Easy to carve out and open cell so I think it woudl hold up to vacuum.
 

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