Repainting Two Part Urethane

[jpendoley]

I am getting ready to repaint my topsides and had a question for the group. My old P365 topsides were painted with Interlux Perfection-only one white coat was applied and that was probably ten years ago. Paint job was not great in that the patches that were filled are visible through the single coat of paint that was applied, but the hull is fair-it just should have had more finish coats.. Since I acquired the boat, it has earned some nicks and gouges, but has held up pretty well. I want to repair the new scratches and nicks with epoxy (VC Watertite) sand, prime and repaint with with Epiphanes two part urethane -same color white again. Just ordered the paint, primer and reducer. my question is can I use acetone as the dewaxer/degreaser or must I buy their proprietary, over the rain bow fibreglass prep product? Seems like an overcomplication given the hull was painted with a two part urethane in the past. Would acetone suffice?

[coopec43]

Sorry! Can't help you. Might pay to be careful though (just read this)


https://www.interlux.com/en/ca/suppo...nknown-coating

[tkeithlu]

If you've got just the one coat in the way, consider sanding it off and starting over, without the issue of solvent incompatibility.

If the only issue is degreasing, soap and water will do a pretty good job, where a solvent will dissolve the grease and then evaporate, leaving the grease residue behind.

[Jammer]

The fiberglass prep products are designed to remove remnants of mold release wax and amine blush, so they do not solve a problem that you have.


Here's the thing though. When you buy a jug of acetone at the home center, you don't know what's in it. Oh, sure, it's 98%+ acetone. But what's in that last ~2%?


Better to use whatever reducer Epiphanes recommends as any impurities will not interfere with the bond.

[capt jgw]

Acetone is not a very good solvent for that anyway. It evaporates too fast leaving whatever you're trying to remove on the surface. I prefer to read the ingredients on the paint can and use whatever solvent is in the paint, often it's xylene. Evaporates slower, allowing you to wipe with a clean rag while still wet, and since there's already some in the paint you know it's compatible. But as said above, since you don't (or shouldn't) have mold release wax to remove, a strong soap mixture and thorough water rinse will probably do as well.
If previous repairs are showing through the existing paint, it's probably not the film thickness at fault. It's poor surface prep. Prep is the key and hardest part of any paint job, and moreso with LP paints. LP paints are so shiny that any imperfection shows through and more coats can make it worse. The surface must be perfectly dead flat smooth before the finish costs are applied. That's what sanding primers are for.

[Sailshabby]

Originally Posted by Jammer

Oh, sure, it's 98%+ acetone. But what's in that last ~2%?

Flavoring… 😉

[George DuBose]

I use Epifanes two component paint over Awlgrip. I just sand the original paint, wipe it carefully down with a dozen tack cloths and then apply the Epifanes.

I use two component foam rollers, changing them a couple of times. I tried mohair and it left a stipple and I didn't want to start "rolling and tipping" as I was alone.

If you recoat the first coat after 24 hours, you don't have to sand the first coat at all.

...and if you are careful to avoid holidays and runs, the paint job can look great. I used the 854 color, a dark blue and it looks great from 3 meters.

[Cheechako]

IF you are talking minor blemishes which show in the high gloss, you may want to use a "high build" primer to make it better than your original paint job was.

[Squanderbucks]

They key to any paint job is surface prep ( sanding). If you sand it all using 220 as the “final” grit all you need to do is wash it down with soap free water, let it dry and wipe it down in sections that you are ready to paint immediately with denatured alcohol. Give it a few minutes to dry, wipe with a tack cloth and paint away.

If you want it a little glossier final sand before painting and in between coats with 3M scotchbrite pads.

[Nord Sal]

I had a similar question about interlux 202 fiberglass solvent wash and used Google to find a thread on another boating bulletin board where someone from the deduced it was a blend of three common solvents. I remember xylene and naptha being named but not the third. I don't recall the proportions of the blend.

I just bought the interlux. It was $39.99/quart at that large national retailer, Worst Marine but $21 bucks a short walk away at local supplier Admiral Ship Supply in Port Townsend WA.

[jmschmidt]

Jumping through your "you-know-what" just to please the manufactures of their very expensive, time consuming and frustration-fatigue inducing products along with their preaching that you absolute need to buy only their solvents, primers, paint, and nonskid material or or hardware store material will eat a hole in the bottom of your boat and it will sink is BS.

Hopefully the newly developed one-part paints will assign these products to the ash bin of history, like nailing copper sheets to bottom of the hull and make the life of the DIYer, if not easy, at least less frustrating.

[Reefmagnet]

Use what the car guys use to clean for painting - wax and grease remover. Acetone flashes off too quick. I'd also consider an epoxy primer/undercoat too as this acts as a barrier between the old and new top coats and, more importantly, it also has high pigmentation that will prevent minor discolouration of the old coat showing through on the finished job.


As always, test on an inconspicuous location first to make sure the new coatings are compatible with the existing.

[billgewater]

Paint jobs on decks etc. usually require "repairs" due to high traffic areas, dropped winch handles etc. So on my tub, as I wanted to protect my deck substrate, I used epoxy primers (two or three coats) and then applied "recoatable" polyurethanes. You need to ask around for this product as it is not the usual stuff. It allows me to touch up every ten years or so, or do a complete paint job. Preparation involves fixing any dings, using epoxies, then a good wash down with soapy water and a good rinse. Then the new topcoat is applied.No full sanding jobs, no nasty solvents.
I am currently using 2 part Dulux Luxathane HPX (in Aus.) but I have used other brands. They all seem to be compatible with each other as well. Dulux provide a non skid additive grit that is added to the paint where needed.
Industrial recoatable polyurethanes are not a designated "marine" paint so are (generally) more affordable.

My hull painting is a little radical. I hate sanding so I decided to bite the bullet and not aim for a mirror smooth finish on my 16 m hull. I looked around the building industry and noted that recoatable gloss exterior acrylics (single part, not the stuff used on cars) come generally with a 20 year warranty. They don't fade as a general rule. My current hull has 30 year old paint and it washes up well. It has one problem and that is that it can be easily damaged. It can also get a mould that looks a bit ordinary but disappears with one application of 30 second mould removing spray. A light brush with broom and just hose it off. Clean up paint with water.
I apply the acrylic with a roller and get a glossy "orange peel" surface but on a large boat this is irrelevant. AND IT'S REALLY REALLY CHEAP! Folk often comment how bright the white hull looks.
However, it would not afford the water proofing ability of polyurethanes.

[s/v Jedi]

Just do what the pro’s do:

https://www.youtube.com/watch?v=KmW9_eDKXdQ

[Methersgate]

Very interesting thread.

Topsides were professionally painted with Awlgrip “Sunfast Red” in 2012. Boat now looks like this:



Something must be done!