Epifanes epoxy primer misery

[Avocet]

Oh dear, "D-Day" didn't go too well! After 5 years replacing Avocet's gelcoat, I thought I'd put some primer on. Being a cautious sort, I thought I'd just try the transom. Just as well I did! I'm using Epifanes epoxy primer. Armed with my Redtree foam rollers, a variety of Jenny brushes and a really expensive Omega brush, I mixed some up, with no thinners. Temperature at the boat is 20 degrees and humidity 44% (pretty good for West Cumbria)! Other than a bit more wind than I'd like, conditions were perfect.

Unfortunately, the paint seemed very thick and seemed to be drying almost instantly! I put some on with a roller, and it left that stippled effect that rollers do. I then tried tipping-off with the Jenny brush and it just dragged all the paint into lumps! I tried the Omega brush and that really wasn't much better. Then I tried the other half of the transom using the roller and just doing one "stripe" very quickly, then tipping-off with the Jenny brush within about 15 seconds of finishing the stripe. That was a bit better, but not much. I then tried thinning the paint to the maximum allowed. That improved things, but only to the point where it looked like it had been done with a toilet brush rather than a trowel! In the following photos, the 1st two were before the paint was thinned and leaving a minute or so between the roller first hitting the boat and starting the tipping-off. The 3rd one was with me tipping-off much sooner. The last couple were with the paint thinned. With the wind, I had been a bit worried about bugs in the paint, but even 10 minutes after finishing, it was dry enough for bugs not to stick to it!

What am I doing wrong?! The sides have a moulded ridge with a recess in it, so plenty of opportunity for runs. I daren't try those with this technique!

 

[oldsaltoz]

Well the temperature and humidity sounds ok, was it a sunny day ?
Any idea what the transom temperature might have been?

Roll and tip off is normally a two man job, perhaps two roller widths if it's a small roller, and a small small overlap to maintain a wet edge, tipping off starts when the roller just far enough away to get in and start tipping, by the time the first person has recharged the roller the second person has finished tipping off.

Thin coats give a better finish but it takes more time, your application looks way too thick, or is that the result of the brush dragging?

Thinning too muck will also reduce the gloss, you may have to experiment to find the optimum.

I have never used this product, but most epoxy primers do go off very fast, as it is only a primer have you considered spaying and a light sanding, then use the roll and tip for your final coat?

Good luck and fair winds.

 

[PaulJS]

Yet another post where I can't view the pictures!

I don't know if this applies to epoxy paints, and indeed this will certainly be totally irrelevant if they have no similarity to epoxy resins, however I recently read that if you mix epoxy resin and hardener in a tall narrow container it will start to harden much more quickly than in a wide shallow one.

Good luck getting a definitive answer though.

 

[PCUK]

You're going to have to sand it at some point so why worry at this stage?

 

[Caer Urfa]

Oh dear,. What am I doing wrong?! The sides have a moulded ridge with a recess in it, so plenty of opportunity for runs. I daren't try those with this technique!
QUOTE]

I have seen the problem before and also on International paints especially with two packs.

My opinion is for what it is worth is that you are applying it in 'to hot' conditions, 'to cold' is a well known problem but many do not realise 'to hot' is also a problem as indicated by the rapid 'going off' time, and you 'do not' need to sand it in between coats if they are applied within five days of each other.

NEVER mix the whole tin at once, only enough that you can apply in say 10 minutes at a time unless you have ideal application temperature conditions.

http://www.agl-marine.com/fiches/technique/epifanes/EPI DATA SHEETS/Epifanes Epoxy Primer.pdf

Suggest you wait until its about 12 deg C, with our Northern weather you should not wait long!

Mike

 

[TQA]

Did you use the brushing thinner?

It sounds like you may have used spray thinner.

http://www.budgetmarine.com/catalog.../Epifanes+Poly-Urethane+Thinners/product.aspx

 

[Keith 66]

I have used epifanes epoxy primer several times, it isnt easy to brush on & is probably better sprayed. I suspect that at 20 degrees air temperature the hull is nowhere near warm enough.
Make sure its hard before you sand it down as the cure may take a long time especially if the temperature falls off.
Likewise with the Epifanes two pack polyurethane, if its borderline temperature or very windy it isnt worth risking it going wrong not at the price the stuff is.
Damn good paints though!

 

[Avocet]

Thanks all. I got up extra early this morning and tried spraying the remainder of the tin that I'd opening to put on the transom. Air temperature was about 15 degrees this time. Can't accurately measure boat surface temperature, but the thermometer was resting on one of the cradle pads, so it would have been rpetty similar, I imagine. To be honest, the spraying wasn't much better! At first, it was coming out like pebbledash. I thinned it (I've got both brushing and spray thinner) and that made things better, but still not really the sort of finish that you could just put the topcoat on without rubbing down! Unfortunately, in quite a few places, it has formed pinholes and small, shallow craters. I'll try and get some photos later. I washed the topsides a few days ago with a garden hose and carwash brush, then this morning I wiped it down with acetone, then with some Awlgrip surface cleaner, and then with a tack rag. I was wondering whether the Awlgrip cleaner could have been the cause?

A couple more questions:

1. Does anyone think there will be a problem using brushing thinner to wash the spray gun out?

2. The advice on the leaflets is to dry sand, rather than wet. Does anyone know why that is? Dry sanding just clogs the paper very quickly and is pretty messy. I'd much rather wet sand!

 

[oldsaltoz]

Oh dear,. What am I doing wrong?! The sides have a moulded ridge with a recess in it, so plenty of opportunity for runs. I daren't try those with this technique!
QUOTE]

I have seen the problem before and also on International paints especially with two packs.

My opinion is for what it is worth is that you are applying it in 'to hot' conditions, 'to cold' is a well known problem but many do not realise 'to hot' is also a problem as indicated by the rapid 'going off' time, and you 'do not' need to sand it in between coats if they are applied within five days of each other.

Suggest you wait until its about 12 deg C, with our Northern weather you should not wait long!

Mike

G'day Mike,
We are talking about an Epoxy Primer only here, the only thing likely to effect it is humidity firt and temperature second.

I live in the tropical area or Queensland in Oz and getting a day with less that 30 *c is not common, humidity can also be in the mid 90's.

As this product is mostly applied below the water line there is plenty of shade, failing that rigging some shade is no major task.

I have never has a problem spraying epoxy primer, I apply 3 coats, the first just a mist, the second a mid depth and the final a full coat.

I also like to put another mist coat the next day after sanding and cleaning, then apply the top coat as soon as it's mixed and stood for 10 minutes to start the reaction process before spraying.

I would never any epoxy of any brand at or near 12*c, or above 73% humidity, also I ensure all applications finish with enough time to surface before any temperature changes.

All the above means we start spraying around 0930 and stop around 1430.
I also run the compressed air supply through an Ice Box and then a water trap to ensure the air is as dry as possible for the spray gun.

In this particular case, if I were Avocet I would buy or borrow a cheap spray gun with number 2 tip hole and spay the area then sand and wash beroe tip and rolling the top coat, hopefully a polyurethane based one.

Good luck and fair winds.

 

[oldsaltoz]

I was wondering whether the Awlgrip cleaner could have been the cause?

A couple more questions:

1. Does anyone think there will be a problem using brushing thinner to wash the spray gun out?

2. The advice on the leaflets is to dry sand, rather than wet. Does anyone know why that is? Dry sanding just clogs the paper very quickly and is pretty messy. I'd much rather wet sand!

Not sure about the Awlgrip and a possible reaction, but it might have.

Brushing thinner should be fine to wash out out with but make sure with a final rinse in Acetone.

Wet sanding might fill the small pin holes, but a good blat of water as you go before it dries should help, I have wet sanded epoxy primer and blasted with a pressure cleaner, no problems.

You can van expect more pin holes when using an epoxy primer, I have tried every trick in book to eliminate them but still get a few. Beacuse the stuff dries so fast it's no problem to walk round and use a small brush to fill them then sand off about 30 minuted later, this last but is best done dry though as as it's only very small spots it's no bother.

Good luck and fair winds.

 

[Avocet]

Thanks Oldsaltoz. That's generated a few more questions, if I may?

1. In your reply to Mike, you mention a "mist coat". I guess this is just a very thin coat? When I try that, the surface looks very rough - almost dusty, rather than painted. Is it supposed to? Also, how long after applying the mist coat do you apply the next one? I'm keen to try this, as the pinholes seem to be worst where the primer is thickest.

2. How soon after applying this lot would you wet sand? Today has been really hot (for here!) mid-to-high 20s! We've got an East wind too, so it's much drier than usual. It's currently 4.30 PM and the temperature is 26 degrees in the shade, the humidity 33%. The temperature is still likely to be 20 degrees by about 20.30 tonight, (remember it won't be dark until gone 10PM!) and I don't anticipate it dropping much below 11 or 12 during the night. Humidity will increase though, but didn't get much above 70% last night. It was applied by 09.00 this morning and feels dry now - though I can still mark it with a fingernail.

3. I very much like the idea of wet sanding with 320 grit and then presure washing, followed by an overnight drying out period and then a wash with acetone immediately before trying to touch-in the pinholes. Can't believe they can be dry-sanded 30 minutes later though? Is that at 30 degrees C?

4. Good plan with the ice box on the air line. I have a very old Hydrovane compressor and was worried about oil contamination int he air lines. I flushed them out with Acetone the other night, so I'm wondering if that might have been the cause of my small craters? I must admit, I thought I'd purged them sufficiently. I've bought a good quality DeVilbiss filter / dryer and have run about 30' of copper pipe going uphill from the receiver before it gets to the filter. That said, I'm using a very long airline because the boat is a good 30' from the garage, so I'm also wondering if the pressure at the gun is much lower than what the regulator is set to. I might try to measure that later, because more pressure seemed to make it better.

 

[oldsaltoz]

Thanks Oldsaltoz. That's generated a few more questions, if I may?

1. In your reply to Mike, you mention a "mist coat". I guess this is just a very thin coat? When I try that, the surface looks very rough - almost dusty, rather than painted. Is it supposed to?
Try keeping the gun a little closer when mist spraying.
Also, how long after applying the mist coat do you apply the next one?
Your set up should give you access right around the boat, the second coat goes over the mist coat, no waiting, the same for the final coat.
Only mix enough for the pot you are using, some brands need to stand after mixing to allow a reaction tostart, check the manufacturers notes.
2. How soon after applying this lot would you wet sand?
The next day and only after the finger nail test.
Today has been really hot (for here!) mid-to-high 20s! We've got an East wind too, so it's much drier than usual. It's currently 4.30 PM and the temperature is 26 degrees in the shade, the humidity 33%. The temperature is still likely to be 20 degrees by about 20.30 tonight, (remember it won't be dark until gone 10PM!) and I don't anticipate it dropping much below 11 or 12 during the night. Humidity will increase though, but didn't get much above 70% last night. It was applied by 09.00 this morning and feels dry now - though I can still mark it with a fingernail.

3. I very much like the idea of wet sanding with 320 grit and then pressure washing, followed by an overnight drying out period and then a wash with acetone immediately before trying to touch-in the pinholes. Can't believe they can be dry-sanded 30 minutes later though? Is that at 30 degrees C?

4. Good plan with the ice box on the air line. I have a very old Hydrovane compressor and was worried about oil contamination in the air lines. I flushed them out with Acetone the other night, so I'm wondering if that might have been the cause of my small craters? I must admit, I thought I'd purged them sufficiently. I've bought a good quality DeVilbiss filter / dryer and have run about 30' of copper pipe going uphill from the receiver before it gets to the filter. That said, I'm using a very long airline because the boat is a good 30' from the garage, so I'm also wondering if the pressure at the gun is much lower than what the regulator is set to. I might try to measure that later, because more pressure seemed to make it better.

I run the compressor around 60 PSI and sand with 200 grit torture board.


Good luck and fair winds

 

[Avocet]

That's done it! That you SO much!

I did the other side today - got up early, so 15 degrees and about 75% humidity. Tried the mist coat with the gun closer and higher air pressure and it worked MUCH better. I wouldn't quite go as far as to say this side could be topcoated straight away, but at least the finish is such that I can get annoyed about bugs getting stuck in it. Only 3 bugs, so not too bad. On the other side I probably wouldn't have noticed the bugs and they could hide behind the lumps in the paint! Still got some pinholes though, but none of the odd craters.

You mention 200 grit (I'm going to conveniently forget the mention of the torture board!). Is 200 grit OK for the sanding before the topcoat? Don't the scratches show through?

ALso, when I sand this down again, I'm bound to go through to the brown microballoons underneath, in places. In fact, this primer doesn't seem very opaque in general, so even the lightest sanding will have slightly darker areas beginning to show through. Is that OK, or should they be re-primed?

 

[oldsaltoz]

That's done it! That you SO much!

I did the other side today - got up early, so 15 degrees and about 75% humidity. Tried the mist coat with the gun closer and higher air pressure and it worked MUCH better. I wouldn't quite go as far as to say this side could be topcoated straight away, but at least the finish is such that I can get annoyed about bugs getting stuck in it. Only 3 bugs, so not too bad. On the other side I probably wouldn't have noticed the bugs and they could hide behind the lumps in the paint! Still got some pinholes though, but none of the odd craters.

You mention 200 grit (I'm going to conveniently forget the mention of the torture board!). Is 200 grit OK for the sanding before the topcoat? Don't the scratches show through?

I start with 200 grit as the finish after all 3 coats are down has a slight orange peel effect, the 200 removes with no fuss, I then use a 300 to to remove the last of the peel and finish with wet and dry.

Also, when I sand this down again, I'm bound to go through to the brown microballoons underneath, in places. In fact, this primer doesn't seem very opaque in general, so even the lightest sanding will have slightly darker areas beginning to show through. Is that OK, or should they be re-primed?

You should only be sanding the final coat, not the progressive coats, this stuff will cure enough between runs and not exposed long enough to pick up too many bugs between coats, this is why access should be set up for all areas, so you can spray almost non stop.

Avoid spraying any area that has the sun shining on it, the primer will flash dry, a simple sheet to provide shade is fine, just leave it up long enough for the hull to cool down.

Good luck and fair winds.