Jump to content

Sign in to follow this  
timbo2

Quick tipping off question - updated

Recommended Posts


If you want to spray LPU paint (perfection is a LPU) you must use a forced air respirator. When atomized, LPU paint is very toxic. When brushing it you can get away with using an organic filter mask.

What makes solvent based LPUs so toxic is isocyanates (on top of all the solvents). Organic vapors cartridge respirators remove most solvent fumes but do absolutely nothing to filter out isocyanates. Yes, sprayed is much more dangerous, but even brushed the isocyanates are there and only breathing supplied air is really safe. Draw your own line on safety, but I won't touch solvent based LPUs with a 10 foot pole without supplied air.

Share this post


Link to post
Share on other sites

I second the suggestions to use a 2 part. i painted my 17 with devoe devthane 389 sold by pettit. you can get it in white and i sucessfully tinted it with black evercoat colorant from west marine (did NOT test any other colors) and with graphite powder to get grey and white. i did all my reducing with awlgrips brushing reducer (0031 i think). if you use graphite powder make sure you mix well and use a filter to get the chunks out before you try to roll or spray it but i didnt have any problems. i did all priming with awlgrip 545 over epoxy sanded to 80 grit and whiped clean with denatured alcohol. I rolled and brushed the inside and sprayed the outside. only thing i dont like about the devoe us the mix ratio 9:1. alexseal is a nice 2:1 and you can get colors but i was going a durable economic finish an i was really happy with the result.

I'm not sure a primer is really necessary If you don't like sanding And your not too fussed about a perfect finish. i dont believe that the topcoat will stick any better to epoxy primer sanded to 80 grit than to well cured epoxy sanded to 80 grit. in fact i didnt bother to prime my rudder or ruddder cheeks and they came out great.

my 2 cents

Share this post


Link to post
Share on other sites

As I understand it, most automotive paints are LPUs. Is there anything......other than the cost........that would prevent a guy from taking his boat to an auto shop and having them spray it with one of the modern automotive paints? That stuff is flexible, durable and nearly bomb proof. Not only that, but most shops are highly skilled in both the chemistry and application methods. Those guys could give you almost any color and degree of gloss finish you want.

Share this post


Link to post
Share on other sites

That's all I used on our race boats - auto paint. Centuri enamel with gloss additive kicker, iso-hardener paints from PPG, and my fav = lacquer. A touch of flex additive in lacquer and it was tough.

Share this post


Link to post
Share on other sites

Most of the auto paints now are not a gloss. They depend on the top coat for that. I sprayed the top and hood of a couple of vehicles last year.

The top coat is a high gloss and most have a 10 minute respray time.. The base coat is even quicker.

The mast on Tehani (wooden) was sprayed with 4 coats of auto top coat 4 years ago and is still flawless. However it has no U/V screen in it, so the wood has bleached underneath.

Big drawback to auto paints is they are quite costly- roughly 50 a quart (about the same as Imron or Awlgrip) and MUST be sprayed due to the rapid dry time.

But sure- you could take the boat to a paint shop and have it done. Get a quote first, or be sitting down when you get the bill :rolleyes:

post-1126-0-80739400-1350655614_thumb.jpg

post-1126-0-73772100-1350655638_thumb.jpg

Share this post


Link to post
Share on other sites

true. Auto paints went to base + clear years ago. Bummer. And an auto paint shop is no guarantee of a great job. Rear bumper on Milady's PT was replaced and painted a couple years ago after a goober did vehicular sodomy on her car. Clear coat is blistering and peeling. Shop warranty = 90 days - so sad, to bad.

Share this post


Link to post
Share on other sites

That's a buddy of mines store, in fact I'm doing some product durability testing for him now. He's been an epoxy formulator for about 20 years and the site, though a bit clunky has a lot of information on it. It's worth cutting and pasting the information and placing it in a text file for better access.

Share this post


Link to post
Share on other sites

Brighsides was some of the worst stuff I've used. Several local boat people recommended it, but I think it sprays better, humidity and temperature has to be just perfect for proper application. A friend demonstrated in his house, with a sample, and it turned out much better then doing in heat and humidity. In the summer in Georgia there was a 3 hour window mid day, where the humidity dew point dropped low enough to apply perfectly.

The two-part interlux epoxy primer worked great. If you use an Interlux product from West Marine, use someone's Port Supply Account and by the 1.5 or 2 gallon paint kits (Saves most money, but limits you to one color).

Having now used the Petite 1-part easy poxy, I enjoyed putting it on, and can change anything I don't like like or gets messed up in usage easily later. Color changes or differences are also relatively cheap, easy to get ahold of.

Share this post


Link to post
Share on other sites

I have used International Perfection on my boat and the one before it. The stuff aint cheap but put on properly you can hardly tell the difference from a spray job, and its tough. My last boat was built in 2007 and after 3 years of abuse... beach launching, dive tanks and fish blood it still scrubbed up as good as new every time. I was bloody impressed. Hence the reason for using it again on my Ocracoke.

There is a few things I have leant about it the hard way though. Put on atleast 2 undercoats. The stuff sands back beautifully but in doing so you are also rubbing back your base coat so you end up exposing glass if you go to hard. External corners are the worst. As for the top coats, I use a foam roller...which puts the paint on thinner than a brush but alot less chance of drips and runs. The finish coats are super glossy....like you could shave in the reflection, the first coat is easy because the undercoat is a dull white so you can see where you are going. The second top coat is very hard to see the wet edge, even after you have rubbed it down with 320 grit. Also 2nd coat must be applied within a couple of days max of first coat as 1st coat hardens so much the 2nd wont stick properly. I found this out the hard way a few years ago.... It was like trying to put paint onto a greased piece of glass. All this info is on the back of the tin.

Like I said if done right the results are impressive and very hard wearing. The stuff aint designed to be sprayed as thinning it will deminish the gloss levels but care taken with some rollers and a brush and you will have a top notch job. Its worth the money.

Share this post


Link to post
Share on other sites

Thanks for all the imput, guys. Sounds like 2 part LPU is a good way to go for this beginner boat painter. I'll update with some pictures in a few weeks when I've painted it.

Tim

Share this post


Link to post
Share on other sites

The latest formulations of single part polyurethanes are rivaling the LPU's, at much lower cost and considerably easier application. I've had good success with Britesides and the other usual suspects, including an AwlGrip single part polyurethane. As you'd expect, it's all about prep and not trying to do more then the conditions will permit.

Share this post


Link to post
Share on other sites

More paint questions?

The two photos are from my Spindrift. It was painted with 3 coats of System 3 water based LPU, the last coat with the hardener included, over two coats of their "water based" epoxy primer. From a gloss and appearance standpoint, it has held up well. But I've found it to be somewhat fragile. These scuff places are where the boat rubbed on the launch ramp or some other piece of submerged concrete. In both cases, I didn't think it was a hard hit or anything, just the normal contact you might see with a boat of this type when it is pulled ashore.

Anyway, is this typical for most epoxy coated plywood boats regardless of paint or would an LPU hold up better?

I don't have much experience with these beyond this boat. I have used aluminum boats and canoes on shallow float streams and they get scratched some, but nothing major. Same with the injection molded plastic canoes most of the commercial outfits have gone to. They hit bottom all the time and shrug it off. If I tried the same thing with this boat, there wouldn't be any paint at all left on the bottom.

post-303-0-05094100-1352666639_thumb.jpg

post-303-0-53299700-1352666670_thumb.jpg

Share this post


Link to post
Share on other sites

I've found you shouldn't skip the hardener with the WR-LPU's. The hardener is cyanoacetate (well sort of) and it hardens the film quite a bit. I've also found you need more then just a few coats, for a durable surface. Did you notice how thin it seemed when you applied it? Your eyes where not deceiving you, it's thin, so a minimum of 3 coats just for good coverage, 4 if you want enough film thickness to be reasonably durable. Lastly, what kind of sand paper did you use? I discovered that the water borne coatings don't like "Fre-Cut" papers. They use some sort of animal fat on the paper, to make it non-clogging. This prevents the film from getting a good grip on the surface. I've seen (personally) huge sheets of cured paint pulled up (3'x4' pieces!) while removing taped off areas. It took me a while to figure this out and was a costly mistake on my part (had to strip and repaint a whole boat) in the process. I now only use aluminum oxide or zirconium papers and am very careful to insure the surface is clean.

Share this post


Link to post
Share on other sites

I may have succumbed to their suggestion that all you needed the hardener for was the last coat. With the hardener, you can re-coat within 24 hours or so........without it, up to a week or so. My recollection was I put on 4 coats, but only the last one had the hardener. I did it that way because I knew I wouldn't be able to put on all the coats at the same time. Lesson learned would be to reserve that job for a time when you can put them all down at once.

As I recall, I also sanded between the 2nd, 3rd and 4th coats. Wet sanded with 320 grit or so 3M wet/dry paper. I went that fine because anything more than that struck me as taking off what I just put on. It is rather thin.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  


Supporting Members

Don't see ads and make messing-about.com possible! Become a Supporting Member - only $12 for the next year. Pay by PayPal or credit card.




×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.