Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 09-01-2012, 09:15   #16
Registered User

Join Date: Nov 2011
Location: Columbia South Carolina, but moving to Portugal soon
Boat: Cavalier 39
Posts: 36
Re: Polishing linear polyurethane imperfections?

uI have two DA sanders, a Bosch, and a Ryobi, I believe. The rubber pad melted on the Ryobi and I replaed it with some harder rubber.

TWo more questions I have:
1. If it's polished will the shine last thte same amount of time or will it need to be repeatedly polished?
2. If instead of polishing it's sanded with 320 and thenrepainted how many coats would it need? Could 1 coat be enough?
__________________

__________________
Epicurean is offline   Reply With Quote
Old 09-01-2012, 09:46   #17
Resin Head
 
minaret's Avatar

Cruisers Forum Supporter

Join Date: Aug 2007
Location: Seattle WA
Boat: Nauticat
Posts: 7,201
Images: 52
Re: Polishing linear polyurethane imperfections?

Quote:
Originally Posted by Epicurean View Post
uI have two DA sanders, a Bosch, and a Ryobi, I believe. The rubber pad melted on the Ryobi and I replaed it with some harder rubber.

TWo more questions I have:
1. If it's polished will the shine last thte same amount of time or will it need to be repeatedly polished?
2. If instead of polishing it's sanded with 320 and thenrepainted how many coats would it need? Could 1 coat be enough?
1. With an acrylic like yours, it'll be fine. LPU not so much.

2. No. You need at least 2 coats, but you need to understand the painting technique involved. The first coat is very light, you are not trying to acheive flow on it. A very small amount of peel is expected. This is called a "tack" coat. You only need to wait for this coat to tack off, not cure. The tack coat should be so thin it is translucent. Wait about 1 hr for it to tack, when you can barely leave a fingerprint in the tape and no paint comes off on your finger it's ready. Then very carefully shoot a nice flow coat. Interthane 999 requires a WFT of 5.3 mils to acheive the desired DFT of 2-3 mils. It should be quite thin. Study and practice with the rig you intend to use. A wet mil gauge may help you learn while practicing. Often a third coat is required to provide coverage, but you won't need that as long as you reshoot the same color. Pot life at your temps can be as low as 2 hours, do not accelerate. For Interthane 999 you need fluid tip E and air cap 704 or 765 in your gun. I prefer the 704. Adjust fan and fluid tip volume carefully. Reduce with International GTA 713 about 10%-20%. This can make a huge difference in flow, play with the ratio when practicing. Do a search on painting and study on this site. Oh, and run pot pressure at 12.5 PSI, cap pressure technically needs to be 45 PSI but I run it up to 65-70 PSI. This causes extra material loss in the form of overspray, but provides a nicer peel free finish. It can only be done on a conventional rig generally, which may be illegal where you are. Those cap pressures may be illegal as well. Local law may require you to use HVLP systems. Hope this info is helpful and not too intimidating. This can be done by a novice, at least much better than your last attempt. It just requires careful study, practice, and planning. You are on the right path, but I wouldn't blame you if you found a pro to do it for you if you decide to reshoot. It can be intimidating and materials are so expensive. Good luck! Oh, and don't prep sand your topcoat with 320, you'll see the grit scratches through the new topcoat if you do, at least where you've hand sanded. Use 400 dry. And guide coat to make sure you have all of the peel out.
__________________

__________________
minaret is offline   Reply With Quote
Old 09-01-2012, 09:52   #18
Registered User
 
CharlieCobra's Avatar

Cruisers Forum Supporter

Join Date: Jun 2006
Location: PNW
Boat: Knutson K-35 Yawl "Oh Joy" - Mariner 31 Ketch "Kahagon" - K-40 "Seasmoke" - 30' Sloop "Baccus"
Posts: 1,290
Re: Polishing linear polyurethane imperfections?

Hmm, painted outdoors or someplace where a steady breeze was blowing I'm betting. Paint is funny. Cold airflow across it after spraying will cause massive orangepeel. Just think of it as goosebumps like ya get on yer arm on a cold, breezy day. That whole job needs taken down and re-shot but that's just me...
__________________
CharlieCobra is offline   Reply With Quote
Old 09-01-2012, 10:04   #19
Resin Head
 
minaret's Avatar

Cruisers Forum Supporter

Join Date: Aug 2007
Location: Seattle WA
Boat: Nauticat
Posts: 7,201
Images: 52
Re: Polishing linear polyurethane imperfections?

Quote:
Originally Posted by CharlieCobra View Post
Hmm, painted outdoors or someplace where a steady breeze was blowing I'm betting. Paint is funny. Cold airflow across it after spraying will cause massive orangepeel. Just think of it as goosebumps like ya get on yer arm on a cold, breezy day. That whole job needs taken down and re-shot but that's just me...

The OP is in malaysia, his average temps are very high. I doubt it was cold air, just a novice on the trigger. Though any wind never helps. He is shooting in an outdoor shed, from the pics. Probably didn't reduce either. Airflow can't cause peel, it can only prevent flow from occuring. The peel still has to be put there by the applicator.
__________________
minaret is offline   Reply With Quote
Old 09-01-2012, 12:49   #20
Registered User
 
CharlieCobra's Avatar

Cruisers Forum Supporter

Join Date: Jun 2006
Location: PNW
Boat: Knutson K-35 Yawl "Oh Joy" - Mariner 31 Ketch "Kahagon" - K-40 "Seasmoke" - 30' Sloop "Baccus"
Posts: 1,290
Re: Polishing linear polyurethane imperfections?

Eh, I've seen this happen with cold air in my shop. I've watched perfectly smooth paint peel up with a draft. However, in high temps, it's likely pilot error exasperated by too fast of a set up time. Better application and some retarder would help.
__________________
CharlieCobra is offline   Reply With Quote
Old 09-01-2012, 17:07   #21
Registered User

Join Date: Nov 2011
Location: Columbia South Carolina, but moving to Portugal soon
Boat: Cavalier 39
Posts: 36
Re: Polishing linear polyurethane imperfections?

Since I painted the cockpit and it turned out good I know that it's just my inexperience that is the problem. There were really ideal conditions; no wind and temp in the high 80's. I understand much of what minaret said but some of it I'll have to look up. Here, in Malaysia, nothing is illegal (except eating pork) but also much isn't available. I'm virtually certain it's not possible for me to change fluid tips or air caps. I haven't seen a Devilbiss gun but the guns here do work. I can only get 320 grit sanding discs, nothing finer. So, if I respray the hull (hopefully find someone) what can I do? Stop at 320 or block rub (dry) with 400? I ran the pressure into the pot at 65 psi (I hope in a metric country the guage isn't in Pascals or newton's per meter) but don't know how to tell what it comes out at. I read the wrong pressure can cause orange peel. You guys who are experts understand or have a feel for this but it's still a mystery to me. Anyway, I certainly appreciate all the response and will read some more to try to understand how to spray.
__________________
Epicurean is offline   Reply With Quote
Old 09-01-2012, 17:31   #22
Resin Head
 
minaret's Avatar

Cruisers Forum Supporter

Join Date: Aug 2007
Location: Seattle WA
Boat: Nauticat
Posts: 7,201
Images: 52
Re: Polishing linear polyurethane imperfections?

Quote:
Originally Posted by Epicurean View Post
Since I painted the cockpit and it turned out good I know that it's just my inexperience that is the problem. There were really ideal conditions; no wind and temp in the high 80's. I understand much of what minaret said but some of it I'll have to look up. Here, in Malaysia, nothing is illegal (except eating pork) but also much isn't available. I'm virtually certain it's not possible for me to change fluid tips or air caps. I haven't seen a Devilbiss gun but the guns here do work. I can only get 320 grit sanding discs, nothing finer. So, if I respray the hull (hopefully find someone) what can I do? Stop at 320 or block rub (dry) with 400? I ran the pressure into the pot at 65 psi (I hope in a metric country the guage isn't in Pascals or newton's per meter) but don't know how to tell what it comes out at. I read the wrong pressure can cause orange peel. You guys who are experts understand or have a feel for this but it's still a mystery to me. Anyway, I certainly appreciate all the response and will read some more to try to understand how to spray.
It is a big learning curve for a complete novice. Be careful, most pressure pots will explode if over pressurized. 65 psi is getting there. When the bottom of you're pot turns inside out, it's a sign! Pot pressure should be 12.5 psi, no more. Tip pressure, or the pressure coming out of the air cap is different. I'm guessing this is what you mean and you are using a siphon feed gun, not a pressure pot. A pressure pot will have an extra regulator on the pot itself. If it is a pressure pot rig which you cranked up that high, it certainly would explain the peel! If all you can get is 320, prep with that. You'll probably be perfectly happy. It just wouldn't fly at my pro yard, but we do megayachts and need a perfect finish for what we charge. A little 320 scratch barely printing through will still be 100 times better than what you have now. Sounds like it's definitely a reshoot for you, unless you want to import everything you need. If it helps the tip size you need is 0.33-0.45 mm or 13-18 thousandths, depending on your measuring system. The right fluid tip and air cap make a big difference.
__________________
minaret is offline   Reply With Quote
Old 10-01-2012, 08:00   #23
Registered User

Join Date: Nov 2011
Location: Columbia South Carolina, but moving to Portugal soon
Boat: Cavalier 39
Posts: 36
Re: Polishing linear polyurethane imperfections?

OK I'm convinced to respray. It's just too difficult to get the things needed to sand and polish. It could be done here but it's a lot of work and wouldn't come out as well, I feel. Also, a first rate paint job will likely be downgraded after a short time by collisions with dinghys, etc. It was very interesting to get all this advice from some very knowledgeable people. Thanks
__________________
Epicurean is offline   Reply With Quote
Old 12-01-2012, 01:37   #24
Senior Cruiser

Cruisers Forum Supporter

Join Date: Feb 2011
Location: Hood River, OR
Boat: Farrier, F-44SC, performance cruising cat
Posts: 148
Re: Polishing linear polyurethane imperfections?

Quote:
Originally Posted by cat man do View Post
I prefer NON marine specific urethanes like ameron coatings or Jotun

Far more affordable than awlgrip and sterling and tough enough for mining equipment and oilrigs, so certainly good enough for boats

Have seen them used on boats for over 20 years, easily buff able and re-coatable
Those paints may be cost effective, but it comes at a cost:

5/30/2001: U.S. Reaches Settlement of Cleanup Costs at Ainsworth Paint and Chemical Superfund Site in Baltimore
__________________
vientoman is offline   Reply With Quote
Old 12-01-2012, 04:50   #25
Registered User
 
cat man do's Avatar

Join Date: Aug 2006
Location: Brisbane Australia [until the boats launched]
Boat: 50ft powercat, light,long and low powered
Posts: 4,409
Images: 36
Re: Polishing linear polyurethane imperfections?

Quote:
Originally Posted by Epicurean View Post
Here, in Malaysia, nothing is illegal (except eating pork) but also much isn't available.
Never had an issue finding and eating pork in Malaysia, mainly in more Chinese areas, but it is available
Malaysian cuisine - Wikipedia, the free encyclopedia



Quote:
So, if I respray the hull (hopefully find someone) what can I do? Stop at 320 or block rub (dry) with 400?
The image below is my last boat being blown
That was dry sanded with 180 as have the majority of boats I have had any say in.

__________________
"Money can't buy you happiness but it can buy you a yacht large enough to pull up right alongside it"...............David Lee Roth
Long Distance Motorboat Cruising It Is Possible on a Small Budget
cat man do is offline   Reply With Quote
Old 12-01-2012, 04:51   #26
Registered User
 
cat man do's Avatar

Join Date: Aug 2006
Location: Brisbane Australia [until the boats launched]
Boat: 50ft powercat, light,long and low powered
Posts: 4,409
Images: 36
Re: Polishing linear polyurethane imperfections?

Quote:
Originally Posted by vientoman View Post
Those paints may be cost effective, but it comes at a cost:
That has nothing to do with the paints performance.
__________________
"Money can't buy you happiness but it can buy you a yacht large enough to pull up right alongside it"...............David Lee Roth
Long Distance Motorboat Cruising It Is Possible on a Small Budget
cat man do is offline   Reply With Quote
Old 12-01-2012, 07:43   #27
Resin Head
 
minaret's Avatar

Cruisers Forum Supporter

Join Date: Aug 2007
Location: Seattle WA
Boat: Nauticat
Posts: 7,201
Images: 52
Re: Polishing linear polyurethane imperfections?

Quote:
Originally Posted by cat man do View Post
Never had an issue finding and eating pork in Malaysia, mainly in more Chinese areas, but it is available
Malaysian cuisine - Wikipedia, the free encyclopedia





The image below is my last boat being blown
That was dry sanded with 180 as have the majority of boats I have had any say in.


That's hilarious, spraying in the dirt! Definitely amateur hour. Newspaper for masking not even taped down, one good gust of wind and it's in the paint. Funniest painting pic I've seen in years.
__________________
minaret is offline   Reply With Quote
Old 12-01-2012, 10:42   #28
Senior Cruiser
 
bstreep's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: San Antonio, TX/Port Aransas, TX
Boat: 1990 Macintosh 47, "Merlin"
Posts: 2,274
Re: Polishing linear polyurethane imperfections?

Quote:
Originally Posted by minaret View Post
That's hilarious, spraying in the dirt! Definitely amateur hour. Newspaper for masking not even taped down, one good gust of wind and it's in the paint. Funniest painting pic I've seen in years.
Who cares? The dirt is has probably been dampened, and if there's no wind, there's no wind.

Not everyone wants/needs a professional job. Buddy of mine had his 40' trawler painted to the tune of $60K - which included completely stripping the boat. It's been a year. And the old hardware still stains the new paint.
__________________
Bill Streep
San Antonio/Port Aransas, TX
bstreep is offline   Reply With Quote
Old 12-01-2012, 12:55   #29
Resin Head
 
minaret's Avatar

Cruisers Forum Supporter

Join Date: Aug 2007
Location: Seattle WA
Boat: Nauticat
Posts: 7,201
Images: 52
Re: Polishing linear polyurethane imperfections?

Quote:
Originally Posted by bstreep View Post
Who cares? The dirt is has probably been dampened, and if there's no wind, there's no wind.

Not everyone wants/needs a professional job. Buddy of mine had his 40' trawler painted to the tune of $60K - which included completely stripping the boat. It's been a year. And the old hardware still stains the new paint.
How about the neighbors boat 3 feet away with no masking on it? How respectful is that, trashing someone elses boat out of sheer laziness or lack of know-how? Not to mention the cars parked right there. Here it wouldn't even be legal to do that, ground wet or not, and it doesn't look wet. Prepping for topcoat with 180 is just beyond ameteurish, any study would tell you that's a terrible idea. And so is shooting a boat that's not even blocked on bare dirt and masked with newspaper. Sorry but thems the facts. Next time tell your buddy to come see us, we usually do a 40' trawler for about half that.
Attached Images
      
__________________
minaret is offline   Reply With Quote
Old 12-01-2012, 13:59   #30
Registered User
 
cat man do's Avatar

Join Date: Aug 2006
Location: Brisbane Australia [until the boats launched]
Boat: 50ft powercat, light,long and low powered
Posts: 4,409
Images: 36
Re: Polishing linear polyurethane imperfections?

Quote:
Originally Posted by minaret View Post
That's hilarious, spraying in the dirt! Definitely amateur hour. Newspaper for masking not even taped down, one good gust of wind and it's in the paint. Funniest painting pic I've seen in years.
Laugh all you like but countless thousands of boats sprayed the same way around the world with not an issue.
The overspray cant tell if it is landing on free newspaper or purchased plastic.
and the proof is in the pudding with the 180 prep.
No sanding marks can be seen if you put on more that one layer of paint.

Oh, and paint job for this vessel cost less than $500 in labour and about the same in primer and topcoat, no runs, no dirt, no stuck paper.

My building and spraying sheds cost $0.00 a week in rent, how about yours?
__________________

__________________
"Money can't buy you happiness but it can buy you a yacht large enough to pull up right alongside it"...............David Lee Roth
Long Distance Motorboat Cruising It Is Possible on a Small Budget
cat man do is offline   Reply With Quote
Reply

Tags
polyurethane

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Help Needed with Raymarine Linear Drive - Urgent ! Pete the Cat Marine Electronics 17 24-04-2015 11:24
For Sale: Raymarine Type 1 Linear Drive - $500 funjohnson Classifieds Archive 9 29-11-2011 07:15
Fuel Filter / Polishing Setup steve_roach Engines and Propulsion Systems 2 02-08-2011 07:55



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 05:22.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.