epoxy and varnish, which one first

[colvic987]

I am about to start to recoat a bit of wood i have been meaning to recoat for years, finally getting around to it, as it now needs it before its too late.

The question is which is first, varnish then epoxy, or epoxy then varnish, any tricks of the trade etc.

I have tried this in the past on smaller bits of wood, but not to a satisfactory finish, whats the best way to get this done to a satisfactory eye pleasing result.

The bit of wood is marine ply of 18mm, which has been previously coated, 10 years ago, of unknown coating. it looks very dark and shiny, and very hardwearing coating.

any tips gratefully recieved, as this is an unknown mystifying area for me, all this varnish makes a awb owner shudder.

 

[simonfraser]

have you tried Sikkens cetol marine wood-oil varnish ?
dead simple to put on bare wood, easy to repatch.

epoxy needs exelent preperation and has to go on first. why varnish on top ???

 

[colvic987]

someone told me to epoxy then varnish, but have had no experience of this, ref the sikkens have used the teak cetol, on outboard holder and has been an excellent coating, and with no flaking you have with varnish.

Would varnishing then epoxy be more suitable solution.

Looking for a very hardwearing coating and not a skikkens type for the wood as its used as seat/step. looking to replicate what is already on wood.

 

[oldsaltoz]

Epoxy is not at all UV stable so if you plan to apply any, first sand and clean then epoxy coat first and this fully cure 24 + hours, it should be so hard you can no mark with your thumb nail.

The varnish used over an epoxy MUST have a high UV screen rating or you will see it flake away.

Hope this helps.

Done properly it will last for years.

 

[Lakesailor]

Expoxy on varnish would have no benefit as it would rely entirely on the mechaical bond the varnish had on the wood. Also (as well as the UV issue Oldsaltoz mentions) epoxy finish is not guaranteed to be the best whereas you can choose a varnish to provide exactly the finish you want, the epoxy doing all the hard, protective work.

Varnish over epoxy (click on image)

​

 

[colvic987]

Hi lakesailor, really nice pics of your heron, have admired the pics of heron in secret harbour, which you have posted in past threads, what sort of varnish did you use for the finish.

i have been trawling the chandlery sites, and have noticed one and two pack varnishes, do you know what the difference is between the packs and which are the hardest wearing in the way of uv stability.

a very mystifying process all of this varnishing etc, any sites which cover the processes and types of varnish.


i had used blakes favourite varnish in the past, still have a full tin, is it any good for the use i am looking at. (seems to flake quite quickly)

 

[xtiffer]

Carefully strip back to bare wood and then use
3 coats of Wood Impreg 120 ( a clear epoxy primer)
followed by 5 coats of a good 2 pack polyurethane varnish
such as Seatop PU360UVR.
The end result will look like 20 coats of Epifanes.
For ordering see http://www.mcmc-uk.com/order.html
Cheers,
Chris

 

[Weekend Yachtsman]

Epoxy first, to protect the wood. Let it cure thoroughly, as someone says above.

Then varnish, to keep the UV off the epoxy.

One word of caution - DON'T USE ACETONE at any stage. It makes the epoxy sticky (even if well set) and stops the varnish from drying properly. Stick to the correct thinners for the varnish you're using. I use Epifanes, about seven or eight coats with the first one 50% thinned, then 25%, then full strength. Comments as above re thinners. Get a decent brush. And all will be well.

btw LakeSailor is that really a Heron dinghy? It sure looks like the one I built in my Dad's garage circa 1963. Was it built from a Bell kit? Wonderful little boats but boy were they heavy. Those frames! All those screws! But we had fun with it back in the day.

 

[Lakesailor]

Definitely a Heron. Click on the pic to see a small web site of the boat.

Colvic987: It's International Schooner varnish. A one pack tung-oil based varnish. Quite soft, but the epoxy takes care of the protection aspect. It also sinks as it drys so the epoxy needs to be ultra smooth.

 

[lw395]

Did you find any issues with the varnish taking a long time to harden?
I've recently had International varnish take a long time (>1 week, in this warm weather) and still been a bit sticky.
Some vague advice I've had, third hand is that polyurethane varnish is a better bet over epoxy. One suggestion was to use epoxy, then poly, plus a final coat of trad varnish for the best gloss.
Apparently, not all epoxy is the same, likewise not all varnishes are the same so different combinations might be a problem.

 

[LittleShip]

In the States they have a product which is called CPES (Clear Penetrating Epoxy Solution) it is basically a thinner epoxy.

The method used is to brush on a couple of coats of CPES wet on wet and before the solution is dry put a coat of varnish on and allow to dry.

This gives the varnish a very strong hold on the epoxy as it bonds to the curing surface and the epoxy holds onto the wood. I have seen the results of this method (stunning) and I am assured that it will last much longer than just varnish.

Tom

 

[Lakesailor]

Did you find any issues with the varnish taking a long time to harden?
I've recently had International varnish take a long time (>1 week, in this warm weather) and still been a bit sticky.

Yes. It took 3 weeks to harden properly, but I was restoring the boat in the garage and time wasn't an issue.
The gloss was so much better than the finish I got on the floorboards and thwarts, on which I used polyurethane, for it's harder surface.

 

[Lakesailor]

If you are doing a clinker built boat or something that has movement and won't suit epoxy this Universal Clear Primer is fantastic.

 

[lw395]

I think International have discontinued UCP.
Buy it if you see it!
Their varnish range is now a joke, all new names, completely out of synch with the sales info at my local chandlers. Also so many different flavours, you decide exactly what you want, then find there isn't any!

Now I'm wondering if I want gloss or satin for my dinghy, confused as to whether satin is as UV resistant.

 

[jpcarter30]

Would this process of epoxy+varnish apply to the wood on deck and around the guardrail too?

 

[Pasarell]

Epoxy and varnish

As said above epoxy first then varnish. Epoxy protects the wood and varnish gives UV protection to varnish and the finish you want.
Wood will need to be very clean with all old coating removed which may mean you damage the wood so think seriously about this.
Apply suitable epoxy of your choice and allow to cure thoroughly (LW395 this may be why your varnish is not curing). Lightly abrade surface of epoxy, taking care not to allow any surface contamination such as greasy fingers, and apply varnish of choice. Polyurethane varnish will give much better adhesion than alkyd or acrylic varnishes. Polyurethane can be single or 2 pack but may not give the finish you want - PU has a more plasticky appearance than alkyd.
Personally I would be very cautious about applying epoxy given what you say about provious unknown coating. The system you want is best applied to new wood but can make a lot of problems on old, previously coated wood

 

[Woodlouse]

Epoxy will never give you a nice varnish like finish. If you are using epoxy as a base coat then I'd go all out with 2 part varnishes as well.

If I was using one part varnish then I wouldn't use the epoxy.

What no one has asked is how are you preparing this bit of wood? If you are not stripping it down to bare then there is no point in using epoxy or 2 part varnishes as you don't know what was used before.

 

[oldsaltoz]

It's worth pointing out that you can thin epoxy with Methylated Sprits by adding up 30% by weight or volume.

This will help penetration and should be applied wet on wet with a final coat of resin with no thinning.

This should then be be left to fully cure and harden, only then should it be sanded and cleaned to remove dust and any other contamination caused by handling, a wipe with Acetone is good provided it's done quickly and left to fully dry before further coating.

Most important is the varnish UV rating, this can not be over stressed, the higher the better.

Little tip:
Sometimes you may notice tiny bubbles of trapped air in you varnish soon after you apply it and it's still wet.

A small heat amount of heat from a small gas flame or even heat gun will remove them, but be sure not to apply the heat too long, or the heat will cause the timber to gas out and make things worse.

Avagoodweekend......
.

 

[colvic987]

Epoxy will never give you a nice varnish like finish. If you are using epoxy as a base coat then I'd go all out with 2 part varnishes as well.

If I was using one part varnish then I wouldn't use the epoxy.

What no one has asked is how are you preparing this bit of wood? If you are not stripping it down to bare then there is no point in using epoxy or 2 part varnishes as you don't know what was used before.

From all the advice i have received here, i decided to remove all the old coating and start again with bare wood, as i feel it will be the only way of getting a good coating and pleasing result.

 

[xtiffer]

Some vague advice I've had, third hand is that polyurethane varnish is a better bet over epoxy. One suggestion was to use epoxy, then poly, plus a final coat of trad varnish for the best gloss.
Apparently, not all epoxy is the same, likewise not all varnishes are the same so different combinations might be a problem.

See my post #8
Cheers,
Chris