# Duralux not curing



## Sthomp (Apr 20, 2015)

Can someone tell me where I went wrong and where to go from here. Sanded and primed with self etching primer and rolled two coats going on 3 weeks ago. Painted in my shop with a dehumidifier going and 18 hours between coats (rolled it). It's rained for the past 3 weeks but ontop of that my house is heavily wooded so even with sun it wouldn't do much good. At this pointed I can chip the paint with my fingernail. Options at this point?


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## Sthomp (Apr 20, 2015)

Marine Enamel not aluminum boat green.


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## poxyPonce (Aug 17, 2015)

I think I'm having the same problem. 
I washed/de-greased, sanded, wash/de-greased, etched with 50/50 white vinegar/water and dried well.
I spray primed with well mixed Duralux Zinc-Like primer M739 and dried for 24 hours. 
I sprayed on two coats of well mixed Duralux Duck Boat Drab M691, 24 hours between coats.

Just as the instructions call for. 

It's cured for a few days now in my garage with fan running. 
We've had little rain, so not as humid as Sthomp describes. 

It looks good, BUT I can scratch it with my finger nails as pictured. 
Not the finish I would expect on a jon boat. 
I started sanding and the color comes right off. 

Any ideas on where I went wrong???


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## Johnny (Aug 17, 2015)

Sthomp and poxyPonce - welcome aboard !!
could ya'll give us an idea of what part of the country you are in ?
you seem to have similar problems.

First of all, I would ask if you started with bare aluminum all over the hulls
or only partial bare spots with existing coatings here and there ?
also, a fan in a closed room only keeps the air moving, (IMO), it does nothing to adjust the humidity level.
A dehumidifier definitely reduces the humidity.
The only thing I can just guess at is something went wrong in the first two or three steps.
If the bare aluminum was sanded down to a smooth 320 or 400 grit surface, the primer had nothing
to hold on to - creating the first weak spot in a series of failures. Like peeling an onion.
So, #1 question: when you scratch the paint with your fingernail, what comes off ??
you have three (3) layers.... primer, paint, and another layer of paint.
Try to explain again, of your first steps taken. . . . 
there are many people here that eat, breathe and dream paints. So the more accurate information
you provide will help. If you call the paint store, they will ask you the same questions.


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## poxyPonce (Aug 17, 2015)

Thanks for the reply Johnny. 

Here's some background:

I'm about 50 miles west of Chicago. The weather has not been all too bad for us, we've had some high temps the last few days, but the rains from earlier in the summer dried up in the last few weeks and we've had what I'll call typical Chicago August humidity for last week with decent winds so it been somewhat comfortable without needing to fire up the AC. (At least comfortable for me without the AC.) It's nothing like the hot and humid in the South where I'm reading success stories with Duralux. 

This is a '91 Lowe 14' Delta John. The previous paint was not too bad to start with. The hull bottom was pretty well scratch up and sanding smooth did get some of it to bare metal. There we a lot of stickers on the hull sides so I used stripper to get those and all the glue off before hitting these areas completely with a stainless cup brush. This took these areas down to bare metal. I then pad and hand sanded the entire boat at 80-120 grit, exposing more bare metal as well. All places where the OEM coating was still in tack were exceptionally solid. 

I've done plenty of fiberglass and wood boats before, not aluminum. I've read just about every post here as well as several other forums on painting these jon boats, and I got pretty comfortable with the Duralux product. I figured that since I heard all the talk on not needing primer I'd give it a shot. Since I could get it though Home Depot I went that way, with 'ship to store' saving me the cost of shipping direct. I like the M691 Duck Boat Drab color over the other Duralux greens and decided to go with that one at $34 a gallon rather than the M736 Aluminum Boat Green or others at $75/gal. I figured they were the same formulation, just a different shade and that Home Depot was just jacking up the price for the Aluminum Boat Green as more people bought it. 

When the M691 arrived I was disappointed to read the label calling for use of M739 Duralux Zinc Chromate Like Primer on any bare spots and figured there might be a formula difference. I don't know this for sure though. If anyone out there reading this has a can of M736 Aluminum Boat Green around, could they please check the label and advise if it calls for priming with M739 on bare spots?? I went ahead and ordered the M739 through Do It Best and got on with it when it arrived. ($15/qt and another $15 for shipping.)

I scrubbed well using Zep Purple de-greaser and rinsed, rinsed, rinsed, and blew dry. I etched for about 30 minutes keeping a mix of 50/50 white vinegar/water wet, then rinsed, rinsed and rinsed again, blowing dry. 

I've been spraying in the evenings when the temps and humidity die down. Again, around Chicago we don't see nearly what the guys in the South do... The Zinc Like primer shot on very well with a 1.5 tip at about 35 lbs and I was actually impressed with it. I dusted with it as recommended, second shooting a little more where the bare metal was after I finished the first dusting over the whole outer hull. 

I have a plastic spray booth set up in the garage and the fan is in the window to blow out, circulating air and exhaust. I don't think a $200 60 pt. basement dehumidifier will do much for this garage space and I'm not spending on anything more just to paint this boat. It is hot in there and I know the humidity does come into play. Call it about 100 degrees at 80% humidity, peak.

After letting the primer sit for about 24 hours I sprayed the first layer of M691. The manufacturer's label does not recommend thinning, but if you desire they recommend no more than 16:1 their own thinner or Xylene. I went ahead and did not thin as that is the initial recommendation. I found it rather thick to shoot with the 1.5 tip. It was difficult to get and even spray, seeming 'spurty'. They recommend two full coats, so I shot these 24 hours apart. It has sat in the garage for the last two days and that's were I was when I posted this morning.... 

What I found this morning is that I could easily scratch the drab color away revealing a whitish/gray color with my fingernail. The surface was not smooth, rather somewhat 'spurty' textured. This was the case everywhere on the hull, not just where stickers may have been, bare metal or the OEM's coating was, or even on the new aluminum diamond plate I installed -wire brushed, washed and etched prior to painting. 

A few passes with 80 grit and the color was gone, revealing a hard white/grayish surface. The dust would chalk up, not gum, and I'd have to slap the paper often. I hand sanded at 80 and followed up with a medium sanding sponge to get the whole surface to this grayish hard surface. If I sanded too much I could get to the yellow layer which is the Zinc Like primer. The rivet heads obviously took the brunt of the sanding and are now exposed as bare. Rinsing with water revealed the color M691 should provide as present when wet, when dry it reverts to the grayish/green chalky color. The surface is hard and I cannot scratch it with my fingernail any further.... 

I think in trying to get to the 'two full coats' I may have sprayed too much on. I used half a gallon in the two coats un-thinned and think that for the temp/humidity it may have been too thick. 

As I still have half a gallon of M691 left what I think I'm going to do is thin it at 16:1 Xylene and see if it sprays any smoother. If not, thin more till it does. 

I think I need to wash again as there's quite a bit of dust about. 

I think I'll get a spray can of Rust-Oleum self-etching primer and re-prime the rivets and other places where this morning's sanding exposed bare metal again and let it dry till tomorrow. 

Then tomorrow evening shoot a thin coat of the thinned M691 to see it revives the color over the whole hull.
If so, shoot the rest of the hull exterior with thinned M691, trying to use up the half gallon in three more spray coats 24 hours apart. I think I'll move the boat out of the garage into the sun in the morning as well to let it bake in the sun through the day too. 

Any other ideas/advice I'd like to hear. 

Thanks Again....


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## Johnny (Aug 17, 2015)

wow - it seems like you know what you are doing.

I can only "theorize" as to the air application method.
With everything considered, humidity and temperature may not be a factor.
I have "heard" about atomization or vehicle separation when a product is sprayed on.
basically meaning, the fluid was too thick, thus getting the spurting.
Not the proper ratio of vehicle (like varnish) and color with the thinner.
So when the fluid leaves the nozzle, it is mixed with the air, when it falls to the surface,
it is already on its way to hitting that thin line of air drying - not "curing", but drying.
This will prevent the applied fluid to settle for a minute or two to really get bonded to the surface.
example: automotive paint. You have the base coat, then a reducer then a thinner. All must be
mixed in the correct ratio in order to work. If the spray gun is held too far away from the surface,
this effect will happen just as you experienced. And must be sanded down and repainted. (from experience).
So I can only guess that your paint was too thick for the atmospheric conditions
and also, the spray gun was too far away from the surface.

If you can, sand down a portion of your boat bottom. Maybe 2x3ft.
Use the suggested thinner and hold your spray gun a little closer to your surface, about 12-14"
Then, paint with a paint brush or roller, the same size area and let it dry 24 hours 
and do the scratch test again. A full wet coat, either sprayed or brushed should work as it should.


I have never sprayed Duralux so I don't know the specs as to the film thickness or air pressure.
If either test is not to your expectations, call the Duralux Technical office.
OR, call them first for the correct film thickness and air pressure.
I will be spraying a wood boat tomorrow with Rust-Oleum Filler Primer. 
My temps are mid 90s and the humidity is there as well. Everything is WET around here.
I can only hope that it will cure before the afternoon rains begin.

OH - if you are going to reprime the rivets with self etching primer, this could lead to
more problems down the road. If S.E. Primer is applied to existing paint, it "may" tunnel
or migrate under the existing paint creating an avenue for corrosion. your call.

Please keep us posted as to any of your testing.


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## poxyPonce (Aug 17, 2015)

Thanks Johnny, 
While washing the boat and prepping for the next round that's what I'm thinking. 
There was separation between pigment and reducer during spraying.
Funny thing is I had to dial the width down all the way and move in close to actually get coverage. 
Even better, when I went to clean the gun, the air cap was seized to the fluid nozzle and both unscrewed together. 
It seemed heavy on pigment in the set when they separated. 

What I seem to now have is a well primed hull, close to the color I want it (when wet).
Based on all that I've read, highest probability for satisfaction seems to come from roll and tip. 
I think it's better for me to go this way with the remaining half gallon rather than mess around further. 
I'm already a week behind. 

I'm open to any other feedback...

Thanks Again...


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## Johnny (Aug 17, 2015)

Roll and Tip is for SPEED painting....... are you in a hurry ???
I have painted 3 story homes in the 5,000 square foot range with the
Spray and Roll and Roll and Tip methods. Hurry up and get it done.
I find painting very enjoyable and relaxing. I painted my 14' V hull with
a 3" brush with a glass of Ice Tea and in the shade. That is my kinda day.
You have more control over your "wet edge" just by being careful, using the right 
amount of thinner for the circumstances at hand and it is done before you know it.
Also, with a little care, you will have just as a slick finish as if you had sprayed it - without the mess.
You are not painting a 800,000 gallon water tank - you are painting a small BOAT.
So many people overthink this part of their project and make it harder than it has to be.

a day outside might be good for what you have put down. Not necessarily baking in the sun,
just outside in the fresh air .........

Keep us posted


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