Epoxy over paint?

[oldsparkey]

chucky,

what's been your bad experience on epoxy over or under oil based paint?

we put oil based paint over epoxy on our plywood boats with no problem

and i've put epoxy over oil based stain with no problem

Just going by what I have been told ,that the epoxy would not stick to the oil based paint. Sounded reasonable to me since epoxy will not stick to plastic and that is a oil based product. I guess the best way to say it is I like to err on the side of caution..... Last thing I want to do is to tell someone that is OK to do and have them destroy there boat and all the work they put into it , not mentioning the expense.
Personally ....... I Never have tried anything that is oil based , myself , since I like the natural finish on a boat and want the boat , not firewood. :lol: :lol: :lol:

All the folks I have purchased epoxy from always warn you not to get any oil , WD 40 or anything like it on the wood because it will make the epoxy dimple ( form a doughnut) when it his the oil.

If you and Friend Keith have done it , That I put faith in since you guy's know a lot more about this then I do. I am learning something new everyday.

Chuck.

 

[beekeeper]

My test may have to be expanded. I keep having "bright" ideas. My thoughts after what I have done so far and considering all the input are:
1. Epoxy over dry paint may develop bonding issues, but will have to be varnished for uv protection.
2. " " wet " may not " " " " " " " " " " " "
3. Epoxy mixed with water base paint is very hard, and shiny. May or may not need uv protection.
4. Water base paint over wet epoxy may be the best of 2 and 3.
5. If varnish or some other clear uv inhibitor could be mixed or applied over wet epoxy for a harder and better bond this would be great for a natural wood look.

All my bright ideas will probably suffer a black out. Just found a little information on Systems 3 epoxy SB-112. Anybody used it?

beekeeper

 

[seedtick]

I think that even though lubricating oils and oil based paint share the same terminology, they are in fact vastly different

Lubricating oils and water displacing oils (like WD-40) are designed to not evaporate but leave a thin film on the surface

Paint thinners, etc. are designed to evaporate and not leave an oily residue

a surface with an oily residue will cause problems no matter what the coating, oil based, water based, or epoxy

 

[Kayak Jack]

As I remember, Rustoleum products are fish oil based. They claimed, in the '50's, that fish oil penetrates deeper into existing rust than others. I can't vouch for that, but I know that I spray painted a '57 VW with it and it lasted over 5 years and was still in good shape when I sold it. NOTE: VW's were not made of wood in those days.

 

[beekeeper]

chucky,
we put oil based paint over epoxy on our plywood boats with no problem

and i've put epoxy over oil based stain with no problem

The epoxy paint from Interlux , Brightsides Teflon worked really well on the bottom of the canoe , one kayak and one pirogue in place of the graphite and epoxy mix.

If you leave the sides normal then it is nothing but a good epoxy coating , some sanding and varnish , if they get scratched ( and they will) then some more varnish makes them disappear.

Chuck.

Ok guys, I think y'all have the answers to my "bright" ideas but are holding back so you can have a good laugh at the amateur, ole beekeeper.

seedtick, You had no problems with the epoxy delaminating from the oil base paint? On making fishing lures, this seems to be the issue. May be a surface preparation problem more than a chemical one. I don't know.

Chuck, The Brightsides paint is a two part epoxy? Did it dry hard and shiny like epoxy resign? Does it have to be varnished for uv protection?

I wished I hadn't varnished the test boards that have the paint and epoxy mix. It would be interesting to know if it is uv resistant. The paint over wet epoxy holds the most promise for a hard, uv protected finished. I know, I know just "paint a couple of scrap boards."

beekeeper

 

[oldsparkey]

Chuck, The Brightsides paint is a two part epoxy? Did it dry hard and shiny like epoxy resign? Does it have to be varnished for uv protection?

beekeeper

The paint come pre mixed , it cures with air drying . The primer is separate and when it dries then the paint over it , the two of them will run about $70.00.
I only use it on the bottom so I can't answer your question about varnishing it. The wet area is protected from the sun or should be when paddling. The short time it is exposed to the sun during transport should not bother it.

One thing I know for sure , it stinks when using it , have plenty of ventilation when working with it. :lol:

Chuck.

 

[seedtick]

bee,

i've put oil based paint on epoxy, never put epoxy on any type of paint

not sure what you gain or what you're after by putting epoxy over paint

 

[Kayak Jack]

bee,...not sure what you gain or what you're after by putting epoxy over paint

Weight and cost both increase.

 

[beekeeper]

Chuck, The Brightsides paint is a two part epoxy? Did it dry hard and shiny like epoxy resign? Does it have to be varnished for uv protection?

beekeeper

The paint come pre mixed , it cures with air drying . The primer is separate and when it dries then the paint over it , the two of them will run about $70.00.
I only use it on the bottom so I can't answer your question about varnishing it. The wet area is protected from the sun or should be when paddling. The short time it is exposed to the sun during transport should not bother it.

One thing I know for sure , it stinks when using it , have plenty of ventilation when working with it. :lol:

Chuck.

I'm sorry but I'm not clear about the paint. I thought if it was an epoxy paint a hardener would have to be added,or is it uv curred?

bee,

I've put oil based paint on epoxy, never put epoxy on any type of paint

not sure what you gain or what you're after by putting epoxy over paint

My mistake. I misread. You said epoxy over oil based stain. I feel like, because my lack of communication skills,[ I'm going in circles with this post and my ideas. What i am trying to do is have a finish that is harder and more scuff resistant than paint, or varnish over epoxy. I know epoxy over paint is much harder than paint over epoxy from my bait making experience. I never had any problems with delamination or yellowing, but some makers have. My suspicions after mixing water based paint and epoxy, is that the bonding question may be eliminated. If epoxy applied over wet paint or varnish will work, it will be a beautiful finish.

bee,...not sure what you gain or what you're after by putting epoxy over paint

Weight and cost both increase.

My boat is fiber glassed and painted, so I don't understand how the weight and cost will increase. If the wet paint and wet epoxy works it will probably take less of each. A differance in our thought process might be I'm not considering the process of fiber glassing. I'm thinking in terms of chine log construction that wouldn't require glassing.

beekeeper

 

[Kayak Jack]

Right on. I don't use chine logs or paint. I do use epoxy and fiberglass. Less cost, less work, less weight, more strength. Other than that, almost no advantages.

 

[bg64vw]

Just curious, I don't know the first thing about boat building but would the off the shelf truck bed liner (Rhino Liner????) you buy at Autozone work on the front of the boat. Not the whole bottom, Im sure it would add considerable weight and the rough surface add considerable resistance. However the front might be protected from banging into rocks.

 

[Kayak Jack]

Bug,

I think you may be way over rating what rocks will do to you. First off, river rocks are usually worn smooth. IE: they have few to no sharp edges to gouge and cut. Secondly, after your first layer of epoxy in the glass on the bottom, the next three layers of it should be enriched with powdered graphite (or some other additive) to make it HARD.

I regularly run up on rocks if I have to with disregard about damage. Every season or two, sand it down some and add a coat of epoxy with graphite.

 

[beekeeper]

Right on. I don't use chine logs or paint. I do use epoxy and fiberglass. Less cost, less work, less weight, more strength. Other than that, almost no advantages.

Paint and epoxy can be common to either method of building. Which one is applied first, if wet or dry would make no difference in weight or cost. If your wood unpainted suits you, that's great. I chose to paint mine because it was not pretty. Even your preferred method of building and finishing could benefit from a finish that the uv protection didn't have to be redone because it scratched, rubbed, or wore off.
I am not saying any thing I've proposed or thought of is best or will work, only putting them out there. "You got to go to know." So, I guess I'm going.

beekeeper

 

[beekeeper]

The test expands:

Top two square boards and the triangle one are painted with epoxy tinted with latex paint. The bottom two boards are wet epoxy painted over with latex.
I plan to do a scratch/scuff test soon. The U.V. queston will take time, but what's time to a board.

beekeeper

 

[beekeeper]

Ran the scratch/scuff test. Very scientific, accurate, and conclusive. I'm sure. :wink:
Pulled the boards over concrete 10' with weight on each:

The results:

Can not get the picture to rotate. I hope I get the boards labeled correctly.
Top left = Varnish only
Middle top = 2 coats paint dry/1 coat epoxy dry/ varnish
Right top = 2 coats paint dry/top coat varnish

Left 2ed. row = epoxy tinted with paint dry/no varnish
Middle 2ed. row = epoxy over wet paint/varnished
Right 2ed. row = epoxy tinted with paint/varnish

Bottom right = wet epoxy with 2 coats of paint

beekeeper

 

[Kayak Jack]

And your Observations, Conclusions, & Recommendations are?........

 

[beekeeper]

And your Observations, Conclusions, & Recommendations are?........

Observations:
1. 2 coats of paint only is very scratch/scuff resistant, and can be a viable option.
2. 2 coats of paint over wet epoxy did better than paint over dry epoxy.
3. the epoxy tinted with paint and the epoxy over dry paint seemed (looked) to not do as well.

Conclusions:
1. My skiff is finished with only 2 coats of paint. I feel better about its chances of surviving regular usage. A practical
and inexpensive finish.
2. Tinted epoxy (paint or pigments) has potential to be a hard and pretty finish. U.V. protection may be a factor.
3. 2 coats of paint over wet epoxy may be the best choice. The epoxy saturates the wood to protect and it bonds to the
paint. The paint resist abrasions and offers u.v. protection.
4. Epoxy and latex paint bond well together if applied befor drying.
5. All these conclusions are from visual observations. I have no way to measure the actual depth of the scratches.

Recommendation:
1. Get a scrap piece of board and try it befor useing any of these ideas.


beekeeper

 

[Kayak Jack]

Good job, Beekeeper. Nice work.


You get an "Atta boy!" and a gold star. Also, you get to go to the head of the line to leave school today.

 

[beekeeper]

2 coats paint/varnish:

Varnish only:

Epoxy over dry paint/varnish:

Epoxy tinted with paint/varnish

Epoxy over wet paint:

Epoxy tinted with paint/no varnish

I failed to take close up of paint over wet epoxy. I will try to post latter time. It is lower right inthis picture:

beekeeper

 

[keith]

I say, dont drag your boat over concrete. If you do, dont turn the boat over and look at it or just repaint it and go on down the river. later keith