Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 07-08-2014, 11:31   #1
Registered User

Join Date: Nov 2013
Location: Belgium
Boat: One-off Baron von Hoevell, 29ft steel classic
Posts: 334
Sandpaper Marks Visible in Endproduct?

Hi there,

I'm putting a whole new paint system on my cabinroof, and parts of it had to be sanded by hand with 60 grit sandpaper. This of course led to some nasty sandpaper scratches that are pretty deep. My concern is they will show in the end product, but I'm not at all sure and sanding the whole thing again with 220grit as recommended by the paintcompany is a ****ton of work... I've also tested a section with a spraypaint can I had at hand. After the first layer the marks were still visible, but after a second pass they were gone.

So here's what I'll be putting on as the new paint system: two layers of primer, two or three layers of finish paint and a last (extra durable) layer with anti-skid in it. Before anybody jumps on that last bit, the non-skid will be in patches, so it won't cover all imperfections .

Watcha reckon'?


Sent from my iPad using Cruisers Sailing Forum
__________________

__________________
Orchidius is offline   Reply With Quote
Old 07-08-2014, 11:35   #2
Registered User

Join Date: Sep 2012
Posts: 4,948
Re: Sandpaper marks visible in end product?

I recon that you will see the scratches. The paint prep is 90% of what makes a decent paint job, now is not the time to avoid the work.
__________________

__________________
robert sailor is online now   Reply With Quote
Old 07-08-2014, 11:42   #3
Registered User
 
Mark1977's Avatar

Join Date: Oct 2010
Location: Halifax, N.S Canada
Boat: Tanzer 26, Walk22
Posts: 930
Re: Sandpaper marks visible in end product?

Quote:
Originally Posted by robert sailor View Post
I recon that you will see the scratches. The paint prep is 90% of what makes a decent paint job, now is not the time to avoid the work.
+ 1..
__________________
Just the guy that runs the boat.
Mark1977 is offline   Reply With Quote
Old 07-08-2014, 11:49   #4
Registered User

Join Date: Nov 2013
Location: Belgium
Boat: One-off Baron von Hoevell, 29ft steel classic
Posts: 334
Re: Sandpaper marks visible in end product?

Is that speaking out of experience or the general knowledge that it's best to put in a little extra prep then to redo the whole thing?

The latter is obvious, and I'll take that route if I have to. But experience also teaches me that I tend to be overly perfectionistic, and in this case that would cost me the remainder of my summer holiday with half the refit still to do...


Sent from my iPad using Cruisers Sailing Forum
__________________
Orchidius is offline   Reply With Quote
Old 07-08-2014, 12:03   #5
Registered User
 
Bluemansailor's Avatar

Join Date: Aug 2011
Location: Philly
Boat: Nassau 34
Posts: 203
Re: Sandpaper marks visible in end product?

60 grit is pretty course grit- only way to get rid of the scratches now is A LOT OF HARD WORK- 80 grit, 120 grit, 150 grit then finally 220 grit.

Sorry but like everyone said prep work is 90% of the work, It shows in the end.
__________________
Sailor - kayaker - woodturner - Photographer.
http://www.etsy.com/shop/FORMSFROMWOOD
http://www.sailblogs.com/member/kodachrome/
Bluemansailor is offline   Reply With Quote
Old 07-08-2014, 12:41   #6
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,363
Re: Sandpaper Marks Visible in Endproduct?

High build primer.
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 07-08-2014, 12:52   #7
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
Re: Sandpaper Marks Visible in Endproduct?

I would use paintmaker's recommendation as a baseline.

b.
__________________
barnakiel is offline   Reply With Quote
Old 07-08-2014, 13:48   #8
֍֎֍֎֍֎֍֎֍֎

Cruisers Forum Supporter

Join Date: Apr 2006
Posts: 13,042
Re: Sandpaper Marks Visible in Endproduct?

Phrase it another way:

Follow the paint maker's advice, relying on the fact that they don't sell sandpaper and they don't want to make using their product any harder than it has to be. A ton of work.

Or, don't follow their advice. And then it will be four or five times as much work to get a lot of expensive primer and paint ground all the way back down again before you have to redo the whole paint job again.

Hmmmm.....What to do, what to do....

Buy a couple of good small power sanding tools perhaps?
__________________
hellosailor is offline   Reply With Quote
Old 07-08-2014, 14:08   #9
Registered User

Join Date: May 2010
Posts: 666
Re: Sandpaper Marks Visible in Endproduct?

Experience. Never use 60. Work your way through the grits. You will find that you'll spend much less time on each grit than your initial scouring. Power tools help. Hand sand along the grain of wood and along the most likely sight line of gel . Paint is only microns thick and is only as good as was what you lay it it onto.
I recall the lads of Nice. Working on their antique fishing boats, sanding, sanding. The shared bottle of Jack seemed to make the time fly for them
__________________
dlymn is offline   Reply With Quote
Old 07-08-2014, 14:13   #10
sitting on the dock of the bay

Join Date: Mar 2006
Posts: 1,513
Images: 6
Send a message via Yahoo to gonesail
Re: Sandpaper Marks Visible in Endproduct?

start with 150 and go to 220 .. sanding is fun .. sand until you cannot sand anymore .. then it will be ready to paint
__________________
sometimes the things that may or may not be true are the things a man needs to believe in the most.
gonesail is offline   Reply With Quote
Old 07-08-2014, 14:15   #11
Writing Full-Time Since 2014
 
thinwater's Avatar

Join Date: Nov 2008
Location: Deale, MD
Boat: PDQ Altair, 32/34
Posts: 4,337
Re: Sandpaper Marks Visible in Endproduct?

Buy an electric sander. Use a Multimaster in the tight spots. There should be little hand work.

And work your way though the grits. It won't take that long on each and 150 is probably enough with that paint schedule.

And don't use 60 in the future. I ONLY use that for very rough work on FRP with a disk sander. 120 should be the workhorse even for rough stuff.
__________________
Gear Testing--Engineering--Sailing

Writing full-time since 2014.
Bookstore:http://sail-delmarva.blogspot.com/20...ook-store.html
thinwater is offline   Reply With Quote
Old 07-08-2014, 14:27   #12
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,051
Re: Sandpaper Marks Visible in Endproduct?

Quote:
Originally Posted by Cheechako View Post
High build primer.

which is nothing more than talcum powder in regular primer, but if you want to fill scratches, that is exactly what it is made for
__________________
a64pilot is offline   Reply With Quote
Old 07-08-2014, 15:29   #13
Registered User

Join Date: Jan 2010
Location: Port Ludlow Wa
Boat: Makela,Ingrid38,Idora
Posts: 1,973
Re: Sandpaper Marks Visible in Endproduct?

You can think about wet sanding, might go a bit quicker and reduce the dust.
__________________
IdoraKeeper is offline   Reply With Quote
Old 07-08-2014, 16:21   #14
Neo
Registered User
 
Neo's Avatar

Join Date: Dec 2009
Location: Salem, MA
Boat: Pearson 31
Posts: 535
Re: Sandpaper Marks Visible in Endproduct?

I just refinished the bow portion of my deck (replaced rotted core). I sanded down to fiberglass with 80 grit and some limited 60 grit. I would suggested starting with an epoxy barrier coat before priming and painting. I used two coats over 80 grit sanding, and no visible scratches remained. I followed with 2 coats of primekote and 3 coats of interlux perfection with 120 - 220 grit sanding in between coats. There is no way 80 grit scratches will show through that, in my very humble and unprofessional opinion. Bubbles are the real problem.

It is my understanding that the fine grit is more about creating better bonding of the paint to the previous coat.

Epoxy barrier coat. Probably get the same result with high build primer, as Cheechako said. If you can still see scratches after the barrier coat, then sand your little heart out.
__________________
Neo
Neo is offline   Reply With Quote
Old 07-08-2014, 16:35   #15
Registered User

Join Date: Feb 2013
Location: WY / Currently in Hayes VA on the Chesapeake
Boat: Ocean Alexander, Ocean 44
Posts: 922
Re: Sandpaper Marks Visible in Endproduct?

I just made the error of thinking high build primer would fill 80 grit scratches. Sand to at least 120 grit before wasting that expensive paint.
__________________

__________________
darylat8750 is offline   Reply With Quote
Reply

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
Stearated sandpaper and interprotect Ian R Construction, Maintenance & Refit 5 20-12-2013 15:23
GPS & Sandpaper tanksalot General Sailing Forum 5 23-05-2011 07:55
No Waypoints Visible After Importing GPX in OpenCPN Roel Smidt OpenCPN 37 29-03-2010 01:45
Sanding Wood before Varnish - What Grit Sandpaper ? Beersmith Construction, Maintenance & Refit 17 09-02-2010 20:43
Images/photos not visible undrsol Forum Tech Support & Site Help 3 31-08-2007 12:38



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 05:31.


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.