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No Interlux Pre-Kote over epoxy?

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Gentlemen,

As I set here at work obsessing about the paint job I will be attempting when I get back to land, I may have a problem. I bought Interlux Pre-Kote and Brightsides to paint the boat with and while going over the data sheet, I found this on the last page:

Compatibility/Substrates - Apply to clean, dry, properly prepared surfaces only. Do not apply over clear epoxy such as Epiglass Epoxy. For epoxy resin, use Epoxy Primekote Y404 as primer following proper preparation to the epoxy resin

Ugggghhhh.....

I have, I know read about many people using it over epoxy, is Interlux worrying about the epoxy blush? Is it "that will not work, buy the more expensive stuff" ploy? I have already bought the Pre-Kote and would not like having to buy another gallon of 100 dollar primer, plus I wanted the high build aspect as well, the boat is pretty fair but I wanted "smooth as a women's lower back" surface and from what I've read the Epoxy Primekote 404 is not very high build. Dont want to screw anything up at this point so close to the finish line.

Please advise

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What about a first coat with the Epoxy Primekote and then Pre-Kote on top for sandablety- new word! 

 

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This is an issue that the paint manufactures are starting to catch up with. Apparently they've had comments about their alkyd base not sticking well to epoxy and indeed some alkyds do have issues with epoxy, though it's been a crap shoot as to which these might be. I've avoid this for some time using nothing but epoxy primers, but those of you that are going to use an alkyd primer, do some test samples first, to insure it's not one of the alkyds that has problems with epoxy.

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I have run into this issue on a build many years ago. I used a one-part primer (West Marine store brand) over WEST epoxy and it never cured. I ended up sanding all the primer off and then applied Interlux 404/414 2-part epoxy primer (now called Epoxy Primekote). The Primekote cured just fine and sanded very nicely. I thought it was a reasonably high-build primer. The Primekote is also very tough. If I were painting a new build I'd certainly use the Primekote. One warning, the fumes from the Primekote are pretty noxious. Be sure to use a good organic respirator.

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I have had good luck with PreCoat and Brightsides over well cleaned and scuffed epoxy.  Your resutls could be different. I just painted ROSIE’s hull with ALEXSEAL and need to paint a black boot stripe.  Don’t want to buy another quart of the 2 part stuff just for the stripe and will go the BRIGHSIDES route.  I will let you know if there are any problems but, I don’t expect any.  

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The epoxy I coated over was SYSTEM 3. It doesn’t blush like WEST so that could explain the differnence between my and Mike's result.

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I'm pretty sure it's not blush that causes the issue. I scrupulously cleaned the cured epoxy before applying the primer but it still never dried. I've read explanations for the problem but can't explain it myself. 

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Sounds like I made a 100 dollar mistake, not the first and Im sure not to be the last. 

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Kennneee is right, what you already have may work just fine. Just don't paint the whole boat to test it out.

 

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First off, all epoxies blush, even the ones that say they don't. Simply put, if it's a BPA molecule (Bisphenol A), like most marine epoxies are, it's going to blush, unless you have perfict environmental condisions in the shop, which most builders don't have. I have an A/C'd shop now and I can get non-blushing epoxies to cure without a blush, but I still don't trust that some surface contamination hasn't occurred, so I still wash freshly epoxied surfaces, just in case. This is a result of having blush ruin and force a redo on several projects.

 

Some, not all, nor even most alkyd paints, will have a problem with fresh epoxy coatings. Most of us have a mental note about which brands and formulations have this issue, so don't use these products over fresh goo (like Rustolum marine topcoat for example). It doesn't mater if the surface was washed or not, it's a chemical reaction that occurs as the epoxy finishes it final curing process, which can take a few weeks in some cases. Most are painting before the goo is actually fully cured, so this problem comes up. This said, I've never heard of a fully cured epoxy having this issue, but I'll bet it still can occur on fully cured epoxy.

 

I'm glad to see some of the paint manufactures are recognizing this and making cautions about it. PrimeCoat works well and being an epoxy doesn't have this issue, so if using single part Interlux paint, use the PrimeCoat or possibly an other epoxy primer.

 

With paints getting as sophisticated as they are now, lots of things can screw with the cure. I had an issue with a "non-clogging" sand paper once. I primed, then sanded normally, but the top coat didn't stick. I did dry normally, but peeled off in huge sheets of cured paint film. After some investigation, I found the sand paper's non-clogging feature was done with animal fats, which left a residue on the surface the paint didn't bond too. Pissed me off, as I used $300 a gallon paint and had to strip every thing and do it again, for a customer that wasn't in the mood to wait. 

 

It's things like this, that force painters to stick with stuff they know, rarely varying from established products and procedures.

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I use 2 primers over epoxy.  For System 3 lpu I use their 2 part primer.  For any and all solvent based paints I use Awlgrip 545.  Both dry quickly, sand easily with med. fine paper until for 24-48 hours and then get really hard.  I put too much effort into my boats to take chances.

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I used Prekote and Brightside over MAS epoxy and it worked fine. I waited about 3 weeks, so the cure had probably run its course. 

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Think I will just buy a gallon of Interlux 404, West Marine has a match the price thing going on, and the store in town has some. The boat has been sitting for 3 weeks at this point ( I go home tomorrow) but I still will be putting some epoxy here and there when I get back and do not want to wait another couple of weeks, I only have 3 off as it is. 

Thank you all for your imput 

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Let me start with Interlux 2 part primer is AMAZING, tough as nails, and goes on well though stinky. Brightsides is ok, but you have to have a perfect dew point for application for best results, when I lived in Georgia we had a small window every afternoon. This was applied over epoxy that had been sanded with 80 grit and was just fine.

 

Most of my recent experience on restoring boats and some new builds has been using Petite EzPoxy. It's pennies on the dollar compared to high end two parts, applies well over west system, system 3, B&B epoxy, and even bare or bare wood with oils (old motorboat). Buildup is high and sanding is VERY easy. The Petite reps say Interlux or Petite two part primer is fine if your worried about a tough coat on outside of boat, followed by one part Ezpoxy color of your choice..

 

West marine one part paints are made by Petite as well, but are more limited on colors. My favorite thing with the Ezpoxy is ease of sanding, and ease of touch up due to wear and tear. Also, the one part primer/paint stays good for a long time, and if needed to make it flow better it it's gotten old add a little bit of Xylene.

 

For boat bottoms that aren't staying in the water I'm a fan of Graphite epoxy mix, wet sanded for final coat. I didn't use to think that could make a difference, but doing blades and bottom with that added noticeable speed. I have in past talked to Interlux reps about the Teflon bottom paint, but its made to inhibit sea life a little bit, and while slippery they agreed that graphite epoxy mix is better, and more bang for your buck. 

 

Quick notes to think about:

1) Spend time with high power light, and some epoxy with easily sandible filler before you paint. A little filling and fairing will save you money on redoing paint coats later. Use a light colored marker to circle where you need to fill and touch up.

2) Brushes: Jen manufacturing, poly brush, foam brush, dense foam, plastic stifner (Wal-Mart and homedepot cheap foam brush packs do not have the stiffeners).
3) Roller: Wooster 1/8 foam roller is perfect for most paints, and tipping afterwords.
4) Tape: 3m crape tape, or smooth. This is perfect for doing small turns, a little more pricey but worth it.
5) Sanding: 3m roll sand paper, foam hand sander.. Even through duck works not cheapest, but hand sanding is not hard for final stuff, and will make it perfect. I will NEVER use a power sander for finishing on a personal boat again, except for initial sand on epoxy maybe.
6) Paint colors: Marshall cove paint Bainbridge, next to Petite this is amazing paint, and you can send in a color sample and they can mix! Fire engine red, beautiful teal, you name it they can do it. A little but more pricey then Petite but worth it for final coats for custom color.

7) Skinning: Keeping varnish/paint from skinning in can use Bloxegen. Usually for one part I just add and mix well a little Xylene.

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Hey ecgosett-- tell me about the epoxy/graphite mix.  Is that also the final finish?  What's the purpose-- abrasion?  Does the graphite protect the epoxy from UV degradation?  I'm thinking about building a nesting dinghy.  If it helps protect against abrasion (sliding in and out of my sprayed-in bedliner), then that's the bottom for me.

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