Question about sealing wood parts

ScottAndrews

ScottAndrews

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I have received my full set of wood parts from @TomHom. They are really nice.

Given that my original wood parts did not fare very well over 50 years, I am wondering if it might not make sense to paint or seal these parts. One side will obviously be veneered, and then sealed with varnish, but what about the back sides, and the dash tray that gets covered in vinyl? Seems like sealing that with even something as simple as sanding sealer would help a lot with vapor penetration and subsequent de-lamination of the plywood.

Anyone have any thoughts or experience in this regard?
 
HB Chris said:
Unless windshield seal leaks you have nothing to worry about.
Click to expand...
My concern is that there is moisture in the air, and over temperature variations, that moisture will condense inside the car. This is what ultimately rots floor pans... happens more in these northern climes, I suppose. I had minor evidence of water intrusion, really only at the right hand edge of the dash, but the entire "tray" (the part under the cluster and the vinyl covered area on the right) was delaminated.

Since it is the lowest part of the assembly and it doesn't show, I may seal the tray with CPES. I am not certain what wood was used for the parts, and if it was not marine grade ply, it will delaminate. CPES will soak in and essentially bind the fibers inside the wood for quite a ways into the wood (especially the edges).

For the curved pieces and the door pieces, I think it is probably best to first veneer them, and then varnish them on all sides. Doing all sides also inhibits warping, since changes in humidity will cause the unsealed side to expand and contract with changes in humidity.

My core question was aimed at determining if anyone thought this was a bad idea, and if so, why?

As for finishing technique:
For my boat (which is all wood), I start with 50% thinned Epifanes varnish. That soaks in well and raises the grain. I then sand with 320 grit, and do another 50% thinned coat, sand again, and do a coat that is just thinned enough to brush well (full strength Epifanes is like heavy molasses), and then repeat until the grain is completely filed. My transom has 9 coats, and has lasted outside for 15 years with a couple of new coats every 4 years or so.

I learned early on that if you want a satin finish, you use full gloss varnish until the last couple of coats, since the matte finish is created by adding silicate flatteners to the varnish, and they will affect the clarity if you use a lot of coats. So you build up the coats with gloss, and then finish with satin (Epifanes calls it "rubbed effect").

The Art of Finishing Wood
 
I have a 1972, it never leaked, in fact did not go outside for 30 years, all the wood was completely de-laminated, like individual sheets of paper
I bought a new set from the guy in Hungary, the veneer looked new (is new), but the back side looked rather old
I put 2 coats of wood hardener on the back sides, figured it wouldn't hurt
 
IMHO, if the wood is out of the car, it doesn't hurt to seal the back side ... but i wouldn't take them out of the car just to put a sealer on them as @HB Chris is correct, as long as your windshield / window seals are good, you don't have much to worry about.
 
mark99 said:
well like I said, all the wood in my car was like loose leaf paper, and the car was never outside
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My car has been garaged for the past 20 years, and the lower tray of the dash was like yours. Sheets of paper thin wood.. all unattached from one another.

rsporsche said:
IMHO, if the wood is out of the car, it doesn't hurt to seal the back side ... but i wouldn't take them out of the car just to put a sealer on them as @HB Chris is correct, as long as your windshield / window seals are good, you don't have much to worry about.
Click to expand...
I agree. I would not remove the wood only to seal it.. To much work, and too much opportunity to do more damage than good!!

But, since a of mine is out of the car. I am going to seal it all.
 
The back shelf I remade from ply wood, the door and dash wood I bought redone, the dash shelf that is covered with vinyl I 'had' to keep, so I started at one end and epoxied all the layers back together
 
Devil’s advicate.

This was the hole in the kick panel underneath the dash on my parts car. Note you can see a good bit of the passenger front tire along with the car parked next to the e9.
IMG_2830.jpeg


This is the dashboard from the same car:
IMG_2831.jpeg


What is the key here? No water intrusion on the windshield seal whatsoever. The rest of the car was Swiss cheese.
 
Markos said:
Devil’s advicate.

This was the hole in the kick panel underneath the dash on my parts car. Note you can see a good bit of the passenger front tire along with the car parked next to the e9.
View attachment 222499

This is the dashboard from the same car:
View attachment 222500

What is the key here? No water intrusion on the windshield seal whatsoever. The rest of the car was Swiss cheese.
Click to expand...
luck of the draw...
 
ScottAndrews said:
My concern is that there is moisture in the air, and over temperature variations, that moisture will condense inside the car. This is what ultimately rots floor pans... happens more in these northern climes, I suppose. I had minor evidence of water intrusion, really only at the right hand edge of the dash, but the entire "tray" (the part under the cluster and the vinyl covered area on the right) was delaminated.

Since it is the lowest part of the assembly and it doesn't show, I may seal the tray with CPES. I am not certain what wood was used for the parts, and if it was not marine grade ply, it will delaminate. CPES will soak in and essentially bind the fibers inside the wood for quite a ways into the wood (especially the edges).

For the curved pieces and the door pieces, I think it is probably best to first veneer them, and then varnish them on all sides. Doing all sides also inhibits warping, since changes in humidity will cause the unsealed side to expand and contract with changes in humidity.

My core question was aimed at determining if anyone thought this was a bad idea, and if so, why?

As for finishing technique:
For my boat (which is all wood), I start with 50% thinned Epifanes varnish. That soaks in well and raises the grain. I then sand with 320 grit, and do another 50% thinned coat, sand again, and do a coat that is just thinned enough to brush well (full strength Epifanes is like heavy molasses), and then repeat until the grain is completely filed. My transom has 9 coats, and has lasted outside for 15 years with a couple of new coats every 4 years or so.

I learned early on that if you want a satin finish, you use full gloss varnish until the last couple of coats, since the matte finish is created by adding silicate flatteners to the varnish, and they will affect the clarity if you use a lot of coats. So you build up the coats with gloss, and then finish with satin (Epifanes calls it "rubbed effect").

The Art of Finishing Wood
Click to expand...
IMHO, as a custom woodworker for 30+ years, Epifanes would be my go to for any laminated wood that's out of the car. Even if your car doesn't leak, temp variations/humidity/etc, will cause the wood to expand and contract many times over the years. All it takes is a little moisture to start the devils work. Even without the moisture, the old adhesives in the ply could still fail.. I use Epifanes on Yacht tables, too. similar to your description above, but about 15x the amounts. They ride around in the caribbean islands in the salt air and last for quite a bit of time. Epi would be overkill for this application, but most any decent varnish to seal the wood would be helpful. Just the Epifanes material for one table was about $1500, btw...yikes.
 
Been working with wood for decades.....I too believe temp swings are more detrimental to our car's wood and the goal is to maximize flexibility. I would not use epoxy as it is hard and inflexible, I reconstructed my dash using poly-based glue, both strong and flexible. Avoid any coatings that are super hard, like marine-based poly which is UV resistant but cracks with temp changes. Also the substrate for our dashes being multi-layer plywood has glue between the layers so any coating or oil will only penetrate so far. Bottom line is to keep it dry and avoid major temp swings.
 
Yep. Epifanes remains flexible, which is why it's on yachts..also on sailboats with masts that swell, twist, and bend. They have several products, but their stuff is overkill for a car interior...it wouldn't be bothered by temp changes or weather. For fun, here's my last job being delivered...brutal amount of work, but it'll take a ton of abuse.
TeakTable.jpg
 
StephenZ said:
Yep. Epifanes remains flexible, which is why it's on yachts..also on sailboats with masts that swell, twist, and bend. They have several products, but their stuff is overkill for a car interior...it wouldn't be bothered by temp changes or weather. For fun, here's my last job being delivered...brutal amount of work, but it'll take a ton of abuse.View attachment 222518
Click to expand...

That's cool! Interesting to see what people do
 
Mid-century tech animal hide glue, that's water soluble, that is fifty+ years old and crystallized, just doesn't hold up to the rigors of life in a metal-framed glass greenhouse.

I usually use a 2-3 X topcoat of polyurethane, and seal the edges and backside with at least 2 X sanding sealer...Wood hardener is also good for this if your wood is tired, but rotten is rotten.
 
StephenZ said:
Yep. Epifanes remains flexible, which is why it's on yachts..also on sailboats with masts that swell, twist, and bend. They have several products, but their stuff is overkill for a car interior...it wouldn't be bothered by temp changes or weather. For fun, here's my last job being delivered...brutal amount of work, but it'll take a ton of abuse.View attachment 222518
Click to expand...
Nice work on that table! I did the round bezel on the cabin hatch for the boat above, and thought that was a lot of work (and a lot of teak!!) That table must have $2K-$3K+ in teak alone...
 
ScottAndrews said:
Nice work on that table! I did the round bezel on the cabin hatch for the boat above, and thought that was a lot of work (and a lot of teak!!) That table must have $2K-$3K+ in teak alone...
Click to expand...
Thanks! The amount of work was staggering..partly because I work alone, but just brutal..Crazy as it sounds…the teak alone was almost $8k…
 
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