Classic Car Dash - Burl Veneer Finishing

[John TenEyck]

Rather than polyurethane I would look at something like GF's Exterior 450 product. It's a water based acrylic made for exterior applications, so it will handle the expansion/contraction likely to occur.

John

[David Hawxhurst]

check with delta lavatories (in FL) they make some pretty good 2k urethanes. i currently use the following 2k from them and it does have a uv protection.

53C032423 / 95C000307

CLEAR GLOSS HIGH SOLIDS UV INHIBITED URETHANE

TECHNICAL DATA SHEET

DESCRIPTION: A high performance fast drying , two component Clear Acrylic Urethane especially formulated to provide a high gloss, tough, durable, non-yellowing clear finish for a variety of wood, plastic and metal substrates. This coating has been identified as part of a Polyurethane System that meets the National Fire Prevention Association Life Safety Code, NFPA No. 101 Class A rating. See a separately available information sheet regarding the test methods used to determine the Surface Burning Characteristics of this finish. Some outstanding features of this product include:
￢ Suitable for use in both interior and exterior applications.
￢ Fast lacquer like dry-helps prevent dirt pick-up and speeds finishing steps.
￢ Contains UV inhibitors to protect film and inhibit color change in substrate.
￢ Resistant to many normal household chemicals including weak acids, alkalies and gasoline.
￢ Excellent gloss, clarity, and gloss retention on exterior exposure.
￢ Retains 85+(60o) gloss after 1000 hours QUV(B bulbs) exposure.
￢ May be used as a high build finish although normal coats should be applied to prevent solvent entrapment.

TECHNICAL DATA (Catalyzed mixture):
Viscosity: 20 - 22 seconds #4 Ford Cup Weight/Gallon: 7.8 + 0.2 lbs.
Weight Solids: 37.4 + 2.0% Volume Solids: 30.7 + 2.0%
Spread rate: Recommended spread rate is from 250 to 500 sq.ft./gallon.

MIXING INSTRUCTION: Mix 8 parts by volume of 53C032423 Clear Urethane Enamel with 1 part by volume of 95C000307 Exterior Urethane Catalyst. Stir very well; but no induction time is needed. Reduce this mix to application viscosity with 02T016944 Urethane Reducer, usually about 9:1 by volume for spray application. This reducer is also recommended for clean-up. Pot Life: Greater than 8 hours at 80° - 90°F.

DRY TIME AND RECOATABILITY: For best performance, use this coating self-sealed. It may be recoated anytime after the solvent has evaporated from a previous coat, and within the same day. Do not apply excessively heavy coats, especially in extremely humid conditions. Before starting full production, it is recommended that test parts be finished using the planned shop finishing schedule to assure successful use and test for wrinkling or lifting. Full film properties will develop in seven to ten days. Finish can be buffed out within 2 to 3 days.

CAUTIONS: Consult with a Delta Laboratories' representative for other compatible products which can be used with this system. See a separately available Material Safety Data Sheet (MSDS) for information regarding proper storage, handling, safe use and disposal of this product.

[Simon Roodt]

OK. So it's been some time since I've posted here. Dashbaord will experience some minimal flexing and definitely exposure to sunlight. So the proposed finish schedule is ....
1. Seal Coat - a number of coats of "dewaxed" shellac, with sanding in between with 400 or 600 grit
2. Grain/Pore Filling - pore filler (tinted slightly darker than final finish) followed by 600 grit sanding
3. Finishing - I'm a bit stuck here ... and need advice on my options ...
a. 2K Polyurethane Finish - probably susceptible to UV unless one can get good UV resistent 2K?
b. Oil based Varnish - made with alkyd or phenolic resin and a drying oil (tung or linseed). As far a I understand these will be tough so some risk of crack/craze but since minimal flexing is expected this may be low risk. Better UV resistance.
c. A good quality MARINE VARNISH with UV protection and some flexibility, but being softer, maybe not possibly to achieve really polished finish.

Any comments or suggestions on this.