question on some paint stuff

[Bmarler]

I’d prime with zinsser (spelling?) or other solvent based primer. Just a light coat will do it.
It’ll help keep it from peeling or flaking.

 

[paulga]

Spray paint would not be my first choice for waterproofing wood. I would actually use epoxy to seal it and then paint over the epoxy to protect the epoxy from UV and to make it look nice.

I'm going to apply epoxy to a wood piece then primer and paint.

The epoxy I'm using is totalboat epoxy.

The epoxy gels in 40 minutes and cures in 4 hours at 72F. Can I apply primer in 4 hours without sanding, or should I wait 72 hours for the epoxy to fully cure, then sand and apply the primer?

 

[paulga]

I applied Totalboat epoxy to some wood pieces on Wednesday evening. After two days, one piece still feels a bit tacky, the other pieces have cured. The instruction says the epoxy cures in 5-8 hours. I also left a heater on nearby during the two days. I don't know why this particular piece didn't cure.
Next I'm going to sand and paint. For the tacky one I will probably paint without sanding first.

The top sides look good, eg, the block in the middle. But the sides touching the trash bag have lots of bubbles formed, where the epoxy coverage is not good. Is there a better release medium?

 

[Bmarler]

I typically do one side at a time. 24 hours apart.
Is it possible the tacky you feel is just amine blush? I know west system must be washed before sanding or recoating.

 

[paulga]

I typically do one side at a time. 24 hours apart.
Is it possible the tacky you feel is just amine blush? I know west system must be washed before sanding or recoating.

Thanks. i'm going to wash, light sand then reapply a coat of maybe thickened epoxy. is thickened epoxy better for the sealing application than unthickened?

the resin and catalyst may have degraded after being stored in the sundeck for almost a year

totalboat epoxy also has amine blush, it needs to be washed away before applying further coats of epoxy or paint

https://support.totalboat.com/hc/en-us/articles/360060521213-What-is-amine-blush-on-cured-epoxy-and-how-do-I-remove-it

 

[paulga]

I’d prime with zinsser (spelling?) or other solvent based primer. Just a light coat will do it.
It’ll help keep it from peeling or flaking.

How to paint it? A primer then a top coat, then the sealant 4200 essentially bonds just the top coat to the roof. If the top coat or the primer bubbles up, does the bond fail at once?

 

[Marco Flamingo]

Public Service Announcement: Don't keep spray cans aboard. Many paint cans (like Rust-Oleum) use propane or butane as the propellant. Both are heavier than air, as is toluene, a common highly flammable ingredient. Cans rust through easily or fall over and discharge. Rather than keeping them in a paint locker that vents overboard and/or running the bilge blower every time one goes aboard, just keep all spray cans in a shore locker. Not just paint, products like Pledge also have a butane/propane mix as the propellant.

 

[Bacchus]

When I use 2 part epoxy to coat & seal wood I use at least a 2 step process.
First coat is thinned resin w/o hardener ( to get better penetration being thinned and not curing quickly)
2nd coat is normal mix of 2 part epoxy with additional coats optional depending on exposure and level of seal desired.
I was taught this approach by an old friend that built cedar strip canoes and was his approach before covering with glass and epoxy to get the clear impermeable coating.

 

[Bmarler]

How to paint it? A primer then a top coat, then the sealant 4200 essentially bonds just the top coat to the roof. If the top coat or the primer bubbles up, does the bond fail at once?

depends on what you mean by bubbling. if it's just tiny bubbles from brushing it shouldn't be an issue. if it's bigger ones, you should have wiped it all off when still wet and tried again. if big bubbles have dried, sand smooth and try again. i forget what the project was, are you using 4200 to bond it to the overhead? not sure what you mean by "roof"

 

[paulga]

When I use 2 part epoxy to coat & seal wood I use at least a 2 step process.
First coat is thinned resin w/o hardener ( to get better penetration being thinned and not curing quickly)
2nd coat is normal mix of 2 part epoxy with additional coats optional depending on exposure and level of seal desired.
I was taught this approach by an old friend that built cedar strip canoes and was his approach before covering with glass and epoxy to get the clear impermeable coating.

depends on what you mean by bubbling. if it's just tiny bubbles from brushing it shouldn't be an issue. if it's bigger ones, you should have wiped it all off when still wet and tried again. if big bubbles have dried, sand smooth and try again. i forget what the project was, are you using 4200 to bond it to the overhead? not sure what you mean by "roof"

These blocks are used as bases for mounting backup cameras. I want to glue them to the corner areas of the sundeck rooftop.

They are brushed thickened epoxy, then sanded and sprayed a thick coat of oil based primer. Does it still require a final coat?

 

[Bmarler]

I see. I’d let them dry thoroughly, then sand smooth and top coat with a good glossy paint. No need to top coat the side that is glued to the overhead.
It’s all about how nice you want them to look. A coat of smooth glossy paint is easier to clean and maintain than a primer coat, and just looks more finished.

 

[paulga]

I see. I’d let them dry thoroughly, then sand smooth and top coat with a good glossy paint. No need to top coat the side that is glued to the overhead.
It’s all about how nice you want them to look. A coat of smooth glossy paint is easier to clean and maintain than a primer coat, and just looks more finished.

If I put them in the sundeck and leave the heater on, do they dry thoroughly after 7 days?

 

[Bmarler]

If I put them in the sundeck and leave the heater on, do they dry thoroughly after 7 days?

That should do it, but it also depends on humidity. If they don’t sand well and the paint balls up you can try wet sanding. I always use sanding blocks, even on small parts. It keeps the surface flat. Sand the flat surfaces with a block, then use your paper without the block to get the corners. After wet sanding, be sure to dry thoroughly before top coating.

 

[paulga]

That should do it, but it also depends on humidity. If they don’t sand well and the paint balls up you can try wet sanding. I always use sanding blocks, even on small parts. It keeps the surface flat. Sand the flat surfaces with a block, then use your paper without the block to get the corners. After wet sanding, be sure to dry thoroughly before top coating.

Sanding manually feels slow. I always use a multi tool with a sanding attachment to speed up the process. Is multi tool great for this purpose?

 

[Bmarler]

I don’t use a multi tool for sanding. I like the control of a sanding block. I did auto body work for decades though, and hand sanding is fast for me because I choose my materials carefully.
You’re certainly welcome to choose whatever method you want, I’m sure a multi tool will sand it. I’d be careful not to gouge it with an edge.

 

[paulga]

I don’t use a multi tool for sanding. I like the control of a sanding block. I did auto body work for decades though, and hand sanding is fast for me because I choose my materials carefully.
You’re certainly welcome to choose whatever method you want, I’m sure a multi tool will sand it. I’d be careful not to gouge it with an edge.

for the final coat, is the Protective Enamel Gloss White Spray Paint good?

All the paints in my storage have gone bad.

 

[Bmarler]

it'll work. it's not what i would use, but it should be fine for what you're doing. give it plenty of time to cure. one part paints, aerosol cans especially, take ages to come to full hardness. when you can press a thumbnail into it and not leave a dent it's cured.
most people can't wait that long though, so use your own judgement.
another tip. put something underneath those parts so the edges aren't sitting on your plastic sheet. keeps the edges nicer.

 

[paulga]

it'll work. it's not what i would use, but it should be fine for what you're doing. give it plenty of time to cure. one part paints, aerosol cans especially, take ages to come to full hardness. when you can press a thumbnail into it and not leave a dent it's cured.
most people can't wait that long though, so use your own judgement.
another tip. put something underneath those parts so the edges aren't sitting on your plastic sheet. keeps the edges nicer.

Thanks. It seems the final coating requires another 7+ days wait. Any faster curing options?

Is the adhesion b/t the primer coat and the epoxy coat going to be as strong as 4200 bonds to the primer by that time?

 

[Bmarler]

Thanks. It seems the final coating requires another 7+ days wait. Any faster curing options?

Is the adhesion b/t the primer coat and the epoxy coat going to be as strong as 4200 bonds to the primer by that time?

you can speed up the cure with infrared lights if you have some. just don't get things too hot, or run them unattended.
as far as adhesion goes, i'd only be guessing, but for camera mounts i think you'll be fine.