Cruisers Forum
 


Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 30-05-2020, 18:39   #1
Registered User

Join Date: May 2014
Location: USA
Boat: 41' yawl
Posts: 1,187
Teak turning grey while sanding

Hello,

I've got some hefty pieces of varnished teak that were beautifully honey-colored, like you could eat them.

For various reasons unrelated to the finish it had to be taken down to bare wood (quick pass with a heat gun and sharp, flat blade scraper) and at this point it still looked nice and golden.

Now while sanding to prepare for a new finish I'm finding some spots are appearing to turn from gold to dark grey. Like, the opposite of what you imagine when sanding.

There's no caulk seam nearby that I'm pulling shmutz from, I've tried hand-sanding with a block instead of the RO, different grits, etc, but it keeps happening as i make my way through these pieces regardless.

I'm wondering if the wood is actually _deeply_ greyed in these sections and a previous owner "bleached" it before varnishing last time? This would explain an outer layer of honey colored teak followed by darker stuff underneath. If that's the case, perhaps I should do the same?
chris95040 is offline   Reply With Quote
Old 31-05-2020, 02:22   #2
Registered User

Join Date: Dec 2009
Location: Australia
Boat: BUILT!!! Roberts Mauritius 43ft
Posts: 3,908
Re: Teak turning grey while sanding

Sorry, I can't help.

Are you sure the teak hasn't been coated with something like Sikkens Cetol?


Sikkens Cetol Marine Wood-Oil Varnish Natural Teak 946ml ...
www.whitworths.com.au › sikkens-cetol-marine-wood-oil-varnish-nat...
Sikkens Cetol Marine with Next Wave UV-absorbing technology is a protective, translucent and breathable wood finish for use above the waterline on interior and exterior woods. Suitable for all hardwoods, particularly teak. Wipe clean and recoat without sandin


Have you done some googling (or duckduckgo)?

"As the teak must be fully dry in order to sand it, you should leave it in a dry place for around twenty-four hours. Use only fine-grit sandpaper when sanding teak. Teak is a hardwood that reacts well to weather conditions. It has a fine grain, so sand in the direction that the grain is going.Jun 22, 2010"

How to Sand Teak Wood | DoItYourself.com

coopec43 is offline   Reply With Quote
Old 31-05-2020, 02:27   #3
Registered User
 
Captn_Black's Avatar

Join Date: Jan 2009
Location: Cabo Verde
Boat: Bruce Roberts Spray, 36' Steel Junk-Rigged Schooner
Posts: 1,245
Images: 26
Re: Teak turning grey while sanding

Quote:
Originally Posted by chris95040 View Post
Hello,

I've got some hefty pieces of varnished teak that were beautifully honey-colored, like you could eat them.

For various reasons unrelated to the finish it had to be taken down to bare wood (quick pass with a heat gun and sharp, flat blade scraper) and at this point it still looked nice and golden.

Now while sanding to prepare for a new finish I'm finding some spots are appearing to turn from gold to dark grey. Like, the opposite of what you imagine when sanding.

There's no caulk seam nearby that I'm pulling shmutz from, I've tried hand-sanding with a block instead of the RO, different grits, etc, but it keeps happening as i make my way through these pieces regardless.

I'm wondering if the wood is actually _deeply_ greyed in these sections and a previous owner "bleached" it before varnishing last time? This would explain an outer layer of honey colored teak followed by darker stuff underneath. If that's the case, perhaps I should do the same?
Try phosphoric acid (rust cleaner). Brings out the colour really well. A 50/50 mix should do the job.
__________________
"Civilized men are more discourteous than savages because they know they can be impolite without having their skulls split, as a general thing." Robert E. Howard
Captn_Black is offline   Reply With Quote
Old 31-05-2020, 02:33   #4
Registered User

Join Date: Dec 2009
Location: Australia
Boat: BUILT!!! Roberts Mauritius 43ft
Posts: 3,908
Re: Teak turning grey while sanding

Anything here?



https://assets.cdn.thewebconsole.com...uide-small.pdf
coopec43 is offline   Reply With Quote
Old 31-05-2020, 02:44   #5
Registered User
 
Captn_Black's Avatar

Join Date: Jan 2009
Location: Cabo Verde
Boat: Bruce Roberts Spray, 36' Steel Junk-Rigged Schooner
Posts: 1,245
Images: 26
Re: Teak turning grey while sanding

Quote:
Originally Posted by coopec43 View Post
There it says not to use phosphoric acid. But the bottle I have says that a 50/50 mix is good for teak. Could be based on marketing rather than science. Either way, you need a thorough rinsing with water after 15-20 minutes. I have used it with good results. Doesn't damage paint or sealants etc.
__________________
"Civilized men are more discourteous than savages because they know they can be impolite without having their skulls split, as a general thing." Robert E. Howard
Captn_Black is offline   Reply With Quote
Old 31-05-2020, 02:49   #6
Registered User
 
danstanford's Avatar

Join Date: Nov 2010
Location: Peterborough, Ontario
Boat: J/88
Posts: 802
Re: Teak turning grey while sanding

The freshly sanded wood has lost the oil inherent in teak. Wait a bit and the oil will come back into the wood and give it the nice honey colour you expect. I vividly remember the first time I bought some very valuable teak for a customer and ran it through the planer....grey and ugly. To be honest I don't remember how long it took to bring back the colour but I bet in 24 hours you will see it most of the way back to a color you like.
Dan
__________________
Never attribute to malice what can be explained away by stupidity.
danstanford is offline   Reply With Quote
Old 31-05-2020, 04:33   #7
Registered User

Join Date: May 2014
Location: USA
Boat: 41' yawl
Posts: 1,187
Re: Teak turning grey while sanding

Quote:
Originally Posted by danstanford View Post
The freshly sanded wood has lost the oil inherent in teak. Wait a bit and the oil will come back into the wood and give it the nice honey colour you expect. I vividly remember the first time I bought some very valuable teak for a customer and ran it through the planer....grey and ugly. To be honest I don't remember how long it took to bring back the colour but I bet in 24 hours you will see it most of the way back to a color you like.
Dan


Interesting- Iíve sanded an awful lot of teak and havenít encountered this, for example my ancient deck planks after being reworked sanded to a beautiful (albeit temporary) gold color.

Iíll try waiting a bit more but itís already been 48 hours...

After reading more about these teak brightener products (never looked closely because old salts told me to stay away!) Iím starting to think my original theory is likely - this teak had its surface brightened before its last varnish job, and now Iím sanding through that brightened surface.
chris95040 is offline   Reply With Quote
Old 31-05-2020, 09:13   #8
Registered User
 
Scaramanga F25's Avatar

Join Date: Mar 2015
Posts: 971
Re: Teak turning grey while sanding

Are you certain it is "teak". Many look likes in the industry.
Scaramanga F25 is offline   Reply With Quote
Old 31-05-2020, 15:03   #9
Registered User

Join Date: Sep 2016
Location: Melbourne
Boat: Palm Beach 50
Posts: 1
Re: Teak turning grey while sanding

In support of Dan... I'm going with teak losing its oil when sanding. Heat from an orbital, belt or linear sander dries teak oil. It can look grey or brown and will need to sit exposed to air for even a week or two before cleaning and perhaps brightening prior to application of a coating. If sealed while grey, it will stay dull. Nige.
coolnige is offline   Reply With Quote
Old 31-05-2020, 15:37   #10
Registered User
 
Cheechako's Avatar

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,601
Re: Teak turning grey while sanding

Maybe you used too much heat. Seems weird. I've never had teak grey from sanding heat.
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 01-06-2020, 14:19   #11
Registered User

Join Date: Jan 2010
Location: San Francisco East Bay Area
Boat: Mariner 36
Posts: 50
Re: Teak turning grey while sanding

Try Nu-Teak, it would great on my teak that had teak oil on it. Cleaned the teak with no sanding. Good Luck.
Sailor George is offline   Reply With Quote
Reply

Tags
sanding, teak

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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
Sanding Teak Slats SqPeg Construction, Maintenance & Refit 3 05-11-2015 13:09
Sanding teak SqPeg OpenCPN 2 01-11-2015 19:17
Sanding with a Vacuum or Tarping and Sanding Without? Yeti Construction, Maintenance & Refit 30 28-04-2015 15:10
Sanding Teak Deck Black Diamond Construction, Maintenance & Refit 6 15-04-2013 04:39
Sanding Teak motion30 Construction, Maintenance & Refit 10 08-10-2010 07:28

Advertise Here


All times are GMT -7. The time now is 14:10.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.