Poxy Epoxy!!

[mickywillis]

What am I doing wrong?
I'm trying to epoxy coat the tiller off my Pageant and having poor success.
I stripped the tiller completely of the old finish by sanding.
I then mixed a BlueGee Epoxy A with its relevant hardener (2:1 ratio). Thoroughly mixed, the epoxy was painted on and left to dry. Air temp was about 11 degrees and I was doing the job in a dry workshop. About an hour later, I noticed drips on the underside of the tiller and the epoxy had not gone off. I left the tiller in the workshop overnight and the next morning, although the epoxy had gone off, there were runs all over the tiller and it had a very "tacky" feel when touched.
3 days later the tacky feeling was still present, so I stripped the lot off again and bought some West Epoxy with fast hardener.
After stripping and sanding, I fired up the workshop space heater to get the room and the tiller really warm (probably about 18-20 degrees) I mixed the resin with hardener (5:1 ratio as per instructions) and mixed thoroughly. this was then brush applied, not too thickly to the tiller and left. This was an hour or so and again I'm seeing the runs develop again!! Ive tried to brush them out but I don't think I can save it again.
Can anyone suggest what I may be doing wrong or what I can do to improve things?

 

[Danny Jo]

It's very difficult to get epoxy on thin enough with a brush. And if you are using it as a varnish base, you can't thicken it with filler. (As you probably know, you can't use epoxy as the finish because it is degraded by UV light.) I tend to slap on two or three coats, not getting too upset about the odd run if I cannot arrange for the work to be horintal, then tungsten-carbide-scrape and wet-sand the surface flat before varnishing.

 

[Amulet]

For Wests when coating you should use the hardner designed for coating (207 I think) in a 3 to 1 mix (I think). This makes it thinner and brushable. But are you doing my stunt of early poxying. A paraffin or gas heater? High humidity will result in the tacky finish you describe, so a heater which pumps out water vapour gives you no hope.

Good thing about poxy runs (assuming they go off as normal) is that you can sand them off. You don't have that horrible problem of solvent entrapment like with an alkyd finish.

But I'd advise against epoxy on your tiller. I'm a conventional varnish man. No matter how much you protect it, eventually UV causes the epoxy to come off in sheets. (At least in my inept hands.)

 

[oldsaltoz]

G'day Mick,

Two conditions are critical:

Temperature above 20*C.
Humidity below 73%.

If you need a thinner layer you can add up to 30% by volume Methylated Spirits to the mixed resin, thinning it will improve the penetration but you may need more layers.

To apply a thin coat of epoxy use a worked roller and tip off with a brush.

I hope this helps.

Avagoodweekend......

 

[Amulet]

I can get satisfactory curing down to 7 degrees C if the humidity is low. I seem to think that is the West guide for minimum temperature. I can get reasonably quick curing in the low teens.

 

[matelot]

your expectations are wrong - epoxy will take anything up to a day to harden off and a day or two more to cure properly. its not a paint that will dry in an hour or two. and because of that you will get runs. sure you can get hardeners that will cure a bit quicker, and warm workshops will speed things up too. but the process will never be like painting.

onew other thing that will help with the runs is to thicken the epoxy - West sell thickeners that become transparent. alternatively get some fine woven glass fabric and laminate.

if you get runs, wash the amine off the surface of the epoxy, dry it and then use a rotary sander. you cant leave the epoxy surface exposed to the light anyway so you have to paint afterwards either with two pack poly varnish or coloured paint.

 

[Amulet]

Wests recommend min temperature is 16 degrees C.
Gougeon Brothers book on the subject reports success at temperatures as low as 7 degrees. My experience is consistent with Gougeon brothers. (I have tried and failed at 5 degrees.)

207 hardner is supplied specifically for coating and I have not had good experience using the normal 205 when coating.

The problems of runs are a result of the coating being too viscous resulting in too thick a coat which then sags. Runny is better as it allows a thin coat.

Though I get adequate curing at an ambient temperature of 7 degrees, the resin will be too thick to apply at that temperature. You have to bring it into the house to warm up.
Gougeon Bros. say stand it in a bucket of warm water. Don't get it too hot otherwise it'll set in only a few minutes. It's also very effective to make sure the substrate is warm. With something like a tiller I'd bring it into the house to warm up before doing the job.

Curing at low temperature is slow and of course it takes a few days to reach its final hardness. Once it's basically set I would again bring it into a warm envionment to harden off if it's a small item. I stand it by the Aga. This causes some marital discord, but not as much as when I used to insist of doing the whole job in the house.

I have the impression that there's more of a risk of amide blush at low temperatures, which must be washed off before any subsequent coats of finish (more epoxy or UV protection).

For several seasons I did most of the varnish work using Wests to coat followed by a few coats of 2 part polyurethane for UV protection. It all gradually failed in an extremely ugly mess due to UV damage (more conscientious recoating might have prevented this).

I have now replaced all such coatings with conventional varnish (Epifanes) which looks great and is standing up much better. Each to his taste.

 

[steve28]

put the resin in a pan of hot water, then mix as usual, works every time for me.

 

[morgandlm]

I took the advice of Oldsaltoz and diluted West epoxy with meths. The thin solution then painted on very thin and soaked into the wood. Followed by many coats of Epifanes varnish. A good result.
Morgan

 

[dovekie]

I agree with the replies you've had. Epoxy just does not behave like paint - even two pot paint. Obviously there is the time taken to cure, but also plain epoxy has nothing to make it viscous (to stop runs) and virtually no surface tension (also helps stop runs). So you have to put on lots of coats, and then sand and polish back to get a shiny surface. Without wax in it (which "floats" to the surface) the surface will always feel tacky, but this goes with sanding and polishing. Without additives I think it has poor UV resistance too, so once you have the tiller gleaming, a cover is a good idea. The advantages are that it is very resistant to water ingress as long as the coat is inact, and is fairly hard so resistant to chips and scratches. Good luck.