Outdoor veneer adhesive and finish questions.

[Flyinfool]

I was reading with great interest the thread https://www.hobby-machinist.com/threads/adhesive-for-veneer.113979/
It has inspired me to look further into fixing the front door on my house.
On the current door the original factory applied veneer is peeling and needs to be replaced. My application is a bit different than the other thread but there has been good info on what might work for me on this application that is outdoors.
It will see temps from -30°F to +110°F, and get rained and snowed on, at least it is on the north side of the house so it will only get early morning and late afternoon direct sunlight during the summer.

The plan is to take the door off the hinges and remove all of the original veneer and as much of the old glue as possible. Probably by first scraping to get the big loose parts off and then sanding using a DA and/or belt sander starting with 80 grit and working my up until it is a smooth solid surface.

Currently the outside of the door is painted with an outdoor paint and the inside is clear varnish. The edges are also painted the same as the exterior. I would like to sand the edges down to bare wood and have a clear finish on both inside and outside of the door. If I go clear finish then I can use a nice looking veneer like maybe Birds Eye Maple The inside looks great and I do not plan on refinishing it at all.

From what I have been reading, there is no clear exterior finish will hold up long term other than paint. If I go paint again then I can use some cheap veneer shut to get back to a smooth surface for the paint.

So the questions are.....

1. Best adhesive for this outdoor application?

2. Is there a cheap dirty way of making a vacuum bag around this door?

3. best finish system will hold up the longest outdoors and be reasonably easy to refinish down the road as required?

 

[Eddyde]

I would use an epoxy like West Systems. A vacuum bag would be the best way to clamp it.

 

[VicHobbyGuy]

So the questions are.....

1. Best adhesive for this outdoor application?

2. Is there a cheap dirty way of making a vacuum bag around this door?

3. best finish system will hold up the longest outdoors and be reasonably easy to refinish down the road as required?

I've done some vacuum bagging of both flat items and curved things like guitar sides.
Epoxy works well, but it can be pulled through pores in the veneers (I was using sawn veneers, thin sliced veneers would be worse). So you need to plan on using epoxy as a sealer coat on the outside, to 'even out' the color, since you will be varnishing the surface.
It's easy to make a bag for vacuum pressing. Heavy duty vapor barrier plastic and plastic vapor barrier tape on three sides of the rectangle, tape the open end after sliding the bag over the work. Places that sell vacuum bagging supplies can provide the valve to attach to the bag to your vacuum pump - I never had any luck with using a vacuum cleaner (instead of a pump) for this work and you run the risk of burning out the motor in a shop-vac as they use air cooling (so I am told). You'll need breather materials - it's a whole new area to explore, and a door-size project is a big thing to start on.

My inclination would be to sand smooth the outside of the door and use epoxy with thickener (silica or microballoons) or even Bondo to fill any cracks. Then re-paint with good quality primer and exterior paint. You can still buy oil-based marine paints.

 

[borges1]

So the questions are.....

1. Best adhesive for this outdoor application?

2. Is there a cheap dirty way of making a vacuum bag around this door?

3. best finish system will hold up the longest outdoors and be reasonably easy to refinish down the road as required?

1. Epoxy. West system has been mentioned and what is available here. I use it all the time on exterior doors and have had no glue failures.
2. Heavy garbage bags and duct tape also work. Borrow a vacuum pump from someone. Venturi systems for a compressor can also be had pretty cheap. But if you can borrow a self-regulating vacuum pump it will make the whole process a lot easier. You will have to bag overnight/many hours if you use epoxy. Putting a space heater under the door and blankets over it will help it cure a lot faster.
3. No clearcoats i have tried hold up. that includes marine varnishes of all sorts, 2k UV stabilized exterior coatings, etc. nothing holds up over years. I dunno what they put on cars, but someone should sell it for doors. Any high quality exterior paint will do. Its a wooden door, it will need maintenance.

My inclination would be to sand smooth the outside of the door and use epoxy will thickener (silica or microballoons) or even Bondo to fill any cracks. Then re-paint with good quality primer and exterior paint.

This is what i would do also. Re-veneering a door is a big project for not much gain. especially if you are just going to paint it. Did the sand/epoxy/sand/paint to mine after the second clearcoat failure.

 

[MikeInOr]

I just installed a new fiberglass door and used Rustolrum Top Side paint which is made for above the water parts of boats.

I have never seen any clear coat that holds up to the elements.

If you can handle repainting you might consider filling in the bad veneer with Bondo body filler then painting over the exterior.

 

[woodchucker]

vac bag can be made as stated using 6mil or heavier plastic. fold it over, then use stringy caulk to close the bag all around (you know that caulk that unrolls and has a few strands that you pull apart), then fold over and tape. use a shop vac to get the air out, and if you have a proper pump continue with that.

So for the glue, if you go epoxy you can thicken it with west thickener, I'll get a number later when I go downstairs. just use a little so it will not soak through the veneer.
you can also go for weldbond contact cement, you only get one chance with that.


I have a gast vac pump so for this size, I would use the vac to get started and then connect the gast, which can run 24x7 for days. I don't use a reservoir.

 

[woodchucker]

its 410 microlite fairing filler.
you would mix it in after mixing the epoxy, and you are looking for it to be less setup than peanut butter. Peanut butter is too thick.. it won't glue.
you want it to be on the slightly runny side so that there is still glue and it's less like a filler.

btw, you may want to start with 60 grit, and work through to 150.. 80 might fill up real quickly.

 

[Flyinfool]

3. No clearcoats i have tried hold up. that includes marine varnishes of all sorts, 2k UV stabilized exterior coatings, etc. nothing holds up over years. I dunno what they put on cars, but someone should sell it for doors. Any high quality exterior paint will do. Its a wooden door, it will need maintenance.

I did refinish a deer hunting rifle about 20 years ago using automotive clear coat. After 20 years of beating through brush in all kinds of weather it still looks the same as the day after I finished it. Granted that is not the same as living outdoors.

 

[Larry$]

Veneering a door facing the elements is a very short time solution.
I've never met a clear finish that will stand up to the sun over time.
The best glue is Resorcinol phenol formaldehyde (RF). Totally water proof, stands heat (can be boiled and will not fail.) Is not subject to creep. Is NOT gap filling! It is a resin and powder that need to be accurately mixed by weight. Once spread it needs to be quickly clamped.
Epoxy will work but becomes weak when heated (sun on door!)
There is a water proof Titebond but it is also heat sensitive.
Contact cement is a total NO.
Best alternative, buy a fiberglass door.

 

[Flyinfool]

The problem with just buying a fiberglass or steel door, is that this house was built in the 1800's. NOTHING is a standard size, plumb or square. The wood door I now have was easy to cut to fit the opening. To go to a fiberglass or steel door I would have tear out and rebuild the whole door frame and wall to make it a standard size and shape. With modern windows and doors the hole in the wall is framed so that a window or door unit can be dropped in. In this house the wall studs are literally also the door frame. The door is already only a 30 inch door. If I were to drop in a pre-hung into that opening I would be down to a 28" x 78" door opening. None of my furniture or appliances would ever go in or out again.
I had a few places come out to give me quotes to put in a fairly plain Jane door, nothing fancy. The cheapest price was $3500 because of the extensive work needed to rebuild the wall to accept a modern door. When I replaced the back door with a pre-hung steel door I had to rebuild the wall and floor to accept a standard door size.

The veneered door that is there now I installed 40 years ago. I am now old if I can rebuild it to last half that long it will outlive me and then not my problem.
I seem to be taking that view on a lot of things, it does not need to be the best, it just needs to outlive me and the wife.

The reason I was thinking of veneer was that I really like the look of natural wood. It sounds like there is no good finish for natural wood outdoors unless I was to refinish every couple of years. I may have to go back to just a painted finish. Although The idea of trying an automotive 2K clear coat does sound interesting. It did work great on my wood rifle stock. As I mentioned earlier this is a north facing door so it does not see much direct sun.