Don Silsbe Posted July 3, 2022 Report Posted July 3, 2022 I just finished modifications to my Two Paw8, including painting her with Devthane 374 2- part polyurethane. It came out a horrible mess. I’m hoping that someone can tell me what went wrong. I mixed the paint 4:1, and allowed it 20 minutes induction time. I then added 20% thinner (Awlgrip reducer). I used a mini velour roller and a 3” Corona Urethaner brush to tip it off. Halfway through the process, I even added about 15% more reducer, to make up for evaporation. It’s hot and humid, here in the Carolinas— 90+ degrees and about 80% humidity. But it never laid down. The brush marks are horrible. I had simply rolled the first coat, and did not tip. The orange peel was so bad, I sanded and tipped the final coat. “Final” is the operative. We leave for a 4-week vacation in 7 days. There is no time to amend my sinful ways. I will be using her as-is, and putting my shame on display to the world. What did I do wrong? I need a mentor to begin spraying these boats. That’s what they deserve. Am I stuck with this until then? Quote
PadrePoint Posted July 3, 2022 Report Posted July 3, 2022 How ‘bout: “I think the brush marks are kinda pretty.” Hey, I’m tryin’. Quote
Kennneee Posted July 4, 2022 Report Posted July 4, 2022 Don- Are you sure you have the correct thinner? It is clearly drying to quickly. I am no expert but have done a bit of painting with LP. The hardest thing is not to overwork it when applying. It seems like magic to me if do a light tip and let the brush marks shrink up. Maybe enjoy your trip and try again in the Fall when the temps are cooler. 1 Quote
Nick C Posted July 4, 2022 Report Posted July 4, 2022 I am also not an expert but I agree with Kennneee that things are moving too fast. I have had similar experience and also the one where it seems like magic. Remember, the largest area you have shown us is only visible to the fish and the rest easily passes the 10-foot rule. That’s what I keep telling myself about my boat(s). Quote
Don Silsbe Posted July 4, 2022 Author Report Posted July 4, 2022 B&B recommends the Awlgrip thinner. I had a quart of N333, which I used on the interior and first coat. About the same performance, except the interior was better. I think it was the heat and maybe humidity. Quote
Mark Rendelman hull 24 Posted July 4, 2022 Report Posted July 4, 2022 Don i know what your going thru but I think I found the best solution for me iam painting my cs with devthane 379 using 379/359h hardner I believe it’s close to the Same two part as 374 both are 2 part epoxy I tried acetone as a thinner it’s to fast in warm weather I got ahold of the paint dealer he said that I should use devoe t17 thinner this is made specifically for devthane paints to slow down the flash off time to allow the paint to flow out I thin x 20% or a count of 5 or 6 count dripping off the paint stick, also I have the best results with a solvent proof foam roller and then tipping it still is not without some brush marks but it seems to give the best results hope this will lead to some peace of mind by the way you will have to sand the hull down so as to remove the brush marks already there 400 grit wet/dry should do the trick quick enough and give good bite for the new paint. ps as much as I tried you can not do this in one coat let the paint cure at least 3days before sanding should give really good coverage 3coats 1 Quote
PeterP Posted July 10, 2022 Report Posted July 10, 2022 Don, I have always used Devoe polyurethane (379) and believe you me - I sympathize . Bear in mind that polyurethanes are moisture and temperature activated. In summer it can be a trial. Spraying always worked the best for me because it goes on fast and even. It may help to get your gear set up the night before ( including lights) and then get up at four in the morning, throw your paint together and go at it. If you use HVLP sprayer you may need to run your hose through bucket of ice to keep the air hose cool. The turbine has a tendency to heat up the air supply causing the paint to flash set and you'll get a nice orange peel or powder coat effect. Good luck PeterP Quote
AmosSwogger Posted July 10, 2022 Report Posted July 10, 2022 Letting it sit 20 minutes after mixing is unnecessary in my opinion. This may be allowing too much thinner to evaporate. Quote
Mike Vacanti Posted July 10, 2022 Report Posted July 10, 2022 3 hours ago, AmosSwogger said: Letting it sit 20 minutes after mixing is unnecessary in my opinion. This may be allowing too much thinner to evaporate. The 20 minute induction time is before the thinner is added and is explicitly called for by the manufacturer. 2 Quote
Hirilonde Posted July 11, 2022 Report Posted July 11, 2022 When I have to use epoxy in really hot weather, I place the cans/jugs in a water/ice bath before mixing. This at least gives me a head start. It may be a bit thick in the cold state, but warms very quickly as I spread it out. I don't know if some variation on this cooling idea would help. Another thought is to become 2 people, one to roll and one to tip. 1 1 Quote
Mark Rendelman hull 24 Posted July 11, 2022 Report Posted July 11, 2022 If you check with the manufacture just about every paint has a retarder to slow down flash in warm weather Quote
Dnjost Posted July 11, 2022 Report Posted July 11, 2022 check out Alan’s video of glassing his 20 mk III build. exactly as you said, one to pour, one to spread. Find a friend who enjoys getting messy. provide beer afterwards . Quote
Don Silsbe Posted July 13, 2022 Author Report Posted July 13, 2022 On 7/10/2022 at 3:24 PM, Mike Vacanti said: The 20 minute induction time is before the thinner is added and is explicitly called for by the manufacturer. I added the thinner after the induction time at a 20% rate. I added about 10% more halfway through the process. I used Awlgrip’s thinner product, because Alan said that it produced better results than Devoe’s thinner. I wish someone would teach me how to spray these boats… 1 Quote
Jknight611 Posted July 15, 2022 Report Posted July 15, 2022 Just like to add, Awlgrip has several types of reducers, looks like the reducer flashed before the flow. I have had reasonable success with Awlgrip T-0005. A quick buz with the DA sander and it is called “an extended primer coat” BTW, Carol has been sick so I haven’t been to the Flinders in almost 2 weeks, it currently is in a marina in Madisonville La, plan to post some pictures without it under sail…..well directionally drifting. Either it is 50kts or 1.2 kts here mid summer! Quote
Jknight611 Posted July 15, 2022 Report Posted July 15, 2022 And if you want to spray, 3M Accuspray MK2 is an awesome gun, just painted a motorcycle and it looks (rather immodestly) great. Shame it isn’t my bike…. 1 Quote
Don Silsbe Posted July 16, 2022 Author Report Posted July 16, 2022 I think T-0005 is what I used. Quote
Don Silsbe Posted May 19, 2023 Author Report Posted May 19, 2023 OK, boys and girls, I have repented for past sins. I believe my mistake was not paying attention the the evaporation of my thinner. I think the paint simply got too thick for the final coat. To quote Peter Noone, “Second verse, same as the first!” Today, Two Bits got sanded down to a smooth surface. This afternoon, I dabbed gray primer where needed. That’ll get a second coat tonight. Tomorrow calls for fair weather. (Meaning, I’ll fair any holes and spots that look needy.) By then, my rollers will have arrived. Monday and Tuesday are booked, so maybe Wednesday is the big day to roll on a couple of thin coats of blue. Let’s do this! Get this— I put on a long sleeved tee shirt and bibbed overalls to do the sanding. Then, I put on my respirator and gloves, rolled up my sleeves, and got to work. Rolled up my sleeves??? Doh! Quote
Don Silsbe Posted May 24, 2023 Author Report Posted May 24, 2023 Today’s the day. I will apply three coats without sanding in-between. I will allow each coat to dry, but re-coat as soon as possible, while the poly is still green. I will be generous with the T-0031 reducer, thinning to around 20%. I’m adding the thinner just before use. I have some 4”, 3/16” nap rollers that I got for the job. They were recommended by a professional shipwright from Wisconsin (on YouTube, Boatworkstoday). The temps are not supposed to go above the mid-70’s. Fingers crossed! Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.