Suggestions for water proofing large christmas ornaments?

[barrysumpter]

Last year I made some yard ornaments for christmas.
A sleigh with santa and some reindeer.

It was too late for christmas last year but I'm ready now to get them sorted for this year.

The templates were made of 18mm mdf.
And used to make another set from 18mm ply.

Any suggestions for water proofing the them to keep them from being damage from the ridiculous Australia weather?

And thoughts on this:
https://www.bunnings.com.au/zinsser-...paint_p1560190

Or maybe:
1 White under coat.
2 White weather proof outdoor house paint overcoats.

Thanks in advance.

[woodPixel]

Perhaps just use any outdoor paint thats made for windows, eaves.. pergolas?

If some standard paint can offer 20 years protection, a few months in the rain/heat wont affect it.

https://www.bunnings.com.au/our-rang...paint/exterior

As for MDF, it's fine. I have a test piece that's been outside for 2 years now and it hasn't weetbix-ed yet! The edges haven't been sealed or anything. Its been incredibly resilient.

[barrysumpter]

Think I went with the Taubmans Sun Proof.
Best price of course was the 4 Liters.
x 3 for no reason other than saving heaps of money.
Yeouch!

Many thanks.

[barrysumpter]

Its raining and I want to get going:

Under the heading: How to Apply
Sun Proof | Taubmans

I had my veranda guide rails paint bubble up.
I do remember it was humid.
And outside.

But how humid is too humid?

With my large Christmas yard ornaments:
Painting some under cover in he garage and others under a carport exposed to outside.
I've already applied the under coat yesterday. When it was NOT humid at all.

Should I wait or is there and exact humidity % I can gauge?


Interesting:

Optimal vs. Acceptable Humidity Levels
Optimal relative humidity (RH) levels for exterior painting, says Karl Crowder of Crowder Painting from Colorado Springs, Colorado, tend to be in the 40-50% range or lower.

Levels of 70% or greater will "drastically slow drying and curing," but again will not prevent you from painting.

Painting above an RH level of 85% is strongly not recommended. The paint will remain gummy and gel-like until the RH lowers to an acceptable level long enough for the paint to solidify.

However, because the paint has not been allowed to "level" properly, the texture will remain wavy and otherwise unacceptable.

"Painting above an RH level of 85% is strongly not recommended. "
Currently 86% in Glen Iris, vic.
Crap!

[barrysumpter]

Another year and another set of reindeer.

I could have sworn I applied some sort of filler to the MDF before the undercoat.
grrrr

[barrysumpter]

https://www.bunnings.com.au/diy-advi...w-to-paint-mdf

Modification mine. Added a few details and remove "oil-based" paint.

Step 1. Sand the MDF

The first step to prepare MDF for painting is to sand it. Sand the surface and edges using an orbital sander with 180 grit sandpaper. Wipe away as much dust as you can with a dry cloth. Then use a damp cloth to make sure all the dust is removed. Wear the appropriate safety equipment when sanding.

Step 2. Apply the first undercoat/primer

Use a normal wood undercoat. Quick drying(?). Not a special MDF primer.
Put a drop sheet down and place the MDF on the saw horses. Stir the undercoat thoroughly, then pour it out into a paint tray. Using a paint roller, evenly apply the undercoat across the MDF. Paint the edges using a paintbrush or roller. Let it dry.

Step 2b. Lightly sand down the first undercoat. Using 120 grade sand paper. Very light sanding pressure.

Especially the edges. As they are very porous and the grains will stand up after the first coat.
Use a fine grit sandpaper. And remove the dust using a dry cloth.
Again, Wear the appropriate safety equipment when sanding.

Step 3. Apply the second undercoat

A thin layer to fill the end grain and provide a perfect base for the top coat.

Apply the second undercoat and let it dry.

Step 3b. IF NEEDED, Lightly sand down the edges that have the second undercoat.
Yet again, Wear the appropriate safety equipment when sanding.

Step 4. Paint the MDF

It’s time to paint the MDF. Use the roller to apply the first coat of paint to the surface and edges.
Let it dry

Step 4b. Lightly sand down the second undercoat.
Final reminder, Wear the appropriate safety equipment when sanding.

Step 5. Paint the MDF with a second coat
Apply the second coat of paint.

Step 6. Job done

Once the second coat has dried your project is complete and ready to use.