Ugly bubbles over shellac-treated cedar - Paint Talk - Professional Painting Contractors Forum
CLICK HERE AND JOIN OUR COMMUNITY TODAY, IT'S FREE!
Go Back   Paint Talk - Professional Painting Contractors Forum > Painting Forum > New Member Introductions

Like Tree2Likes
  • 1 Post By journeymanPainter
  • 1 Post By Jmayspaint
Reply
 
Thread Tools Display Modes
Old 05-30-2016, 09:26 AM   #1
Junior Member
 
Join Date: May 2016
Location: Houston, TX
Posts: 8
Rewards Points: 8
Thanks: 3
Thanked 0 Times in 0 Posts
View SidingJohn's Photo Album My Photos
Default Ugly bubbles over shellac-treated cedar

Opinions? Appreciated in advance. This is an oddball. I installed new cedar siding for a homeowner, and he asked to make it look natural. I gave him a few examples, and he fell in love with cedar that was simply coated with shellac - we are talking premixed shellac in denaturated alcohol sold at HomeDepot. So, I did the job and all is good. Then the usual - the owner's wife calls and says, "We changed our minds and now want to paint it light gray." OK, I go back and get paid for the second time to do the job (so far so good): I apply Killz (original oil based primer) over shellac-stained cedar and then wait half a day and then paint Resillience over it. Resillience is a tough exterior acrylic latex paint from Sherwin Williams. Looks great so far. Now, two days and a little sun later, bubbles everywhere. And not just bubbles, but bubbles where on the inner side Killz peals off! So, there shellac is where it was (on the wood), while Killz oil based primer and the exterior paint are holding together and blowing bubbles. In other words, bubbles form where there is poor contact between shellac and the oil-based primer... which is bizarre because Killz stick to just about anything. I checked - there are no leaks that could have caused this, and the cedar I installed was brand new.

There is a pattern to the bubbles - some boards seem to be affected much more than others. Under the bubbles - wood looks normal - no water or condensation. Truly a brain freeze situation. Granted, we are in Houston, where it is constantly hot and humid, but this Spring it's not that hot. Humid and wet - yes, but this cedar stock was not more moist than anything I installed at any point in the last 20 years. Opinions? Appreciated in advance.

Questions:
1. Is there an oil-based product that's better than Killz?
2. Who said there is anything wrong with painting over shellac treated cedar?
3. How do I fix the job? Is it even possible without stripping everything?

Last edited by SidingJohn; 05-30-2016 at 09:30 AM.. Reason: clarification
SidingJohn is offline   Reply With Quote

Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. PaintTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

Sponsored Links
Advertisement
 
Old 05-30-2016, 09:41 AM   #2
Senior Member
 
Delta Painting's Avatar
 
Join Date: Apr 2010
Location: Michigan
Posts: 1,530
Rewards Points: 192
Thanks: 4,514
Thanked 738 Times in 524 Posts
View Delta Painting's Photo Album My Photos
Default

Never use shellac outside to brittle for exterior use..
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Delta Painting is offline   Reply With Quote
The Following 3 Users Say Thank You to Delta Painting For This Useful Post:
lilpaintchic (05-30-2016), PRC (05-30-2016), ProWallGuy (05-30-2016)
Old 05-30-2016, 10:01 AM   #3
Save 2nd base!

 
ProWallGuy's Avatar
 
Join Date: Apr 2007
Location: St. Louis MO
Posts: 6,461
Rewards Points: 4,670
Thanks: 3,452
Thanked 4,395 Times in 1,920 Posts
View ProWallGuy's Photo Album My Photos
Default

I assume the Kilz dried too fast, and didn't penetrate/bond to the shellac. FYI, Kilz, is called Kilz for a reason, it is made to "kill" stains. It is not a good bonding primer.
An old school slow drying long oil would have worked much better.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.




ProWallGuy is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 05-30-2016, 10:29 AM   #4
Senior Member
 
straight_lines's Avatar
 
Join Date: Oct 2007
Location: Wilmington, N.C.
Posts: 7,822
Rewards Points: 1,574
Thanks: 5,686
Thanked 5,172 Times in 2,981 Posts
View straight_lines's Photo Album My Photos
Send a message via Yahoo to straight_lines
Default

Shellac is for spot priming exterior usage only. The bubbles could be a sign of trapped moisture or solvents escaping the oil primer.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



Primer makes everything better...
straight_lines is offline   Reply With Quote
The Following 2 Users Say Thank You to straight_lines For This Useful Post:
lilpaintchic (05-30-2016), PRC (05-30-2016)
Old 05-30-2016, 11:35 AM   #5
Senior Member
 
Join Date: Aug 2012
Posts: 2,033
Thanks: 340
Thanked 1,053 Times in 684 Posts
View MikeCalifornia's Photo Album My Photos
Default

Ouch, you used two interior products on the outside? What could possibly go wrong. Maybe blame SW for the bubbling.

Didn't I see Houston got more rain in one day than an entire century or something just a few months ago? Hmmm I would say its a little wet on those boards. Did you check with a moisture meter?
MikeCalifornia is online now   Reply With Quote
The Following User Says Thank You to MikeCalifornia For This Useful Post:
lilpaintchic (05-30-2016)
Old 05-30-2016, 03:39 PM   #6
Senior Member
 
lilpaintchic's Avatar
 
Join Date: Jul 2014
Location: Blue Marble, Earth
Posts: 4,010
Rewards Points: 5,006
Thanks: 3,702
Thanked 1,897 Times in 1,217 Posts
View lilpaintchic's Photo Album My Photos
Default

Call a painter. ju$t my opinion. when ya find yourself in a hole, STOP DIGGING!
You're moving way too fa$t with the wrong product$. Ye$, it can be fixed. Ye$,you're $crewed. if your going to do it yourself-- buy LOT$ of $andpaper.

Last edited by lilpaintchic; 05-30-2016 at 03:50 PM..
lilpaintchic is offline   Reply With Quote
Old 05-30-2016, 09:15 PM   #7
Junior Member
 
Join Date: May 2016
Location: Houston, TX
Posts: 8
Rewards Points: 8
Thanks: 3
Thanked 0 Times in 0 Posts
View SidingJohn's Photo Album My Photos
Default

Quote:
Originally Posted by Delta Painting View Post
Never use shellac outside to brittle for exterior use..
Agree that this wasn't the best idea, thought I've done it before. It does a nice job of preserving wood's natural beauty.
SidingJohn is offline   Reply With Quote
Old 05-30-2016, 09:18 PM   #8
Junior Member
 
Join Date: May 2016
Location: Houston, TX
Posts: 8
Rewards Points: 8
Thanks: 3
Thanked 0 Times in 0 Posts
View SidingJohn's Photo Album My Photos
Default

Quote:
Originally Posted by ProWallGuy View Post
I assume the Kilz dried too fast, and didn't penetrate/bond to the shellac. FYI, Kilz, is called Kilz for a reason, it is made to "kill" stains. It is not a good bonding primer.
An old school slow drying long oil would have worked much better.
I confess I've used (and likely overused Killz). The original Killz - in my defense - says "for interior and exterior use" on the can. The issue we are not mentioning here is this: painting cedar means possibly getting stains from knots... unless you use a strong antistain agent. Agree?
SidingJohn is offline   Reply With Quote
Old 05-30-2016, 09:20 PM   #9
Junior Member
 
Join Date: May 2016
Location: Houston, TX
Posts: 8
Rewards Points: 8
Thanks: 3
Thanked 0 Times in 0 Posts
View SidingJohn's Photo Album My Photos
Default

Quote:
Originally Posted by straight_lines View Post
Shellac is for spot priming exterior usage only. The bubbles could be a sign of trapped moisture or solvents escaping the oil primer.
I was tempted to think this... but shellac separated from the bubble (the bubble is made of kills and the paint, and shellac is intact on the wood. Still, you're probably right about the moisture IMO.
SidingJohn is offline   Reply With Quote
Old 05-30-2016, 09:24 PM   #10
Junior Member
 
Join Date: May 2016
Location: Houston, TX
Posts: 8
Rewards Points: 8
Thanks: 3
Thanked 0 Times in 0 Posts
View SidingJohn's Photo Album My Photos
Default

Quote:
Originally Posted by MikeCalifornia View Post
Ouch, you used two interior products on the outside? What could possibly go wrong. Maybe blame SW for the bubbling.

Didn't I see Houston got more rain in one day than an entire century or something just a few months ago? Hmmm I would say its a little wet on those boards. Did you check with a moisture meter?
One good reason to hate H-town is the weather. It makes all exterior work harder... I'd even say painful. Granted, shellac may or may not belong outside, but the original Killz is clearly labeled as "interior/exterior", and, as I may have mentioned in a reply to someone else here, it is pretty important to use " something" under the paint to ensure that cedar knots don't come through the paint and don't become stains. What's your opinion on preventing cedar stains? (with or without shellac)
SidingJohn is offline   Reply With Quote
Old 05-30-2016, 10:10 PM   #11
Senior Member
 
journeymanPainter's Avatar
 
Join Date: Feb 2014
Location: Vancouver(surrounding area) BC
Posts: 2,926
Rewards Points: 686
Thanks: 3,276
Thanked 1,656 Times in 1,065 Posts
View journeymanPainter's Photo Album My Photos
Default

Quote:
Originally Posted by SidingJohn View Post
One good reason to hate H-town is the weather. It makes all exterior work harder... I'd even say painful. Granted, shellac may or may not belong outside, but the original Killz is clearly labeled as "interior/exterior", and, as I may have mentioned in a reply to someone else here, it is pretty important to use " something" under the paint to ensure that cedar knots don't come through the paint and don't become stains. What's your opinion on preventing cedar stains? (with or without shellac)
I don't trust any product on an exterior that says interior/exterior
SidingJohn likes this.
journeymanPainter is offline   Reply With Quote
The Following User Says Thank You to journeymanPainter For This Useful Post:
SidingJohn (05-30-2016)
Old 05-30-2016, 10:25 PM   #12
Senior Member
 
Jmayspaint's Avatar
 
Join Date: Mar 2013
Location: East TN
Posts: 4,253
Rewards Points: 14
Thanks: 1,875
Thanked 3,731 Times in 1,918 Posts
View Jmayspaint's Photo Album My Photos
Default

Quote:
Originally Posted by SidingJohn View Post
One good reason to hate H-town is the weather. It makes all exterior work harder... I'd even say painful. Granted, shellac may or may not belong outside, but the original Killz is clearly labeled as "interior/exterior", and, as I may have mentioned in a reply to someone else here, it is pretty important to use " something" under the paint to ensure that cedar knots don't come through the paint and don't become stains. What's your opinion on preventing cedar stains? (with or without shellac)


There are several lines of Kilz of course, and we don't know which one the OP used.

As far as the original Kilz primer though, I always though it was interior only. As per this spec sheet;

http://www.kilz.com/MCContent/MC_Pro...nal_CE_TDS.pdf

Slow drying (long oil) ext oil primers are what I've always thought was idea to stop tannin bleed on woods like cedar. Short oils suited for ext use, like Coverstain, can work also but don't tend to hold up as well in the long term due to lessened penetration.


Sent from my iPhone using Tapatalk
SidingJohn likes this.
Jmayspaint is offline   Reply With Quote
The Following 2 Users Say Thank You to Jmayspaint For This Useful Post:
journeymanPainter (05-30-2016), SidingJohn (05-30-2016)
Old 05-30-2016, 10:28 PM   #13
Junior Member
 
Join Date: May 2016
Location: Houston, TX
Posts: 8
Rewards Points: 8
Thanks: 3
Thanked 0 Times in 0 Posts
View SidingJohn's Photo Album My Photos
Default

JourneyManPainter - This is a good point. I never thought about this. I guess it's like, when someone says, "we can sell you any kind of car as long as you sign right here"... it probably means that they just really want to sell you a car. On a related point: I noticed that Killz isn't as popular in some states; I see less of it in the Northeast and in California, for instance. But in Texas very few jobs go without Killz. Its side benefit is that it kill(z) and prevents mold, which in Texas is like scorching sun and rain. That said, Killz here is like a panacea, historically speaking. Where are you located? (did you say Vancouver? No problems there with mold I bet) What's your exposure to the Original (oil-based) Killz (in the white gallon can) professionally? And most importantly, what would you use locally as the go-to product for your "hardcore priming" jobs?

Last edited by SidingJohn; 05-30-2016 at 11:06 PM.. Reason: clarificcation
SidingJohn is offline   Reply With Quote
Old 05-30-2016, 10:33 PM   #14
Senior Member
 
Jmayspaint's Avatar
 
Join Date: Mar 2013
Location: East TN
Posts: 4,253
Rewards Points: 14
Thanks: 1,875
Thanked 3,731 Times in 1,918 Posts
View Jmayspaint's Photo Album My Photos
Default

Aside from being brittle, the main reason shellac isn't suited for exterior use is it forms a vapor barrier. Unlike regular exterior acrylic or oil primers, a shellac film is non permeable. This is the quality that makes it so good for sealing in smoke, urine, or other residues on interior surfaces. Vapor cannot penetrate it.

Conversely, this quality makes it a bad choice for exterior priming where the substrate must inevitably absorb and release moisture vapor as atmospheric conditions change. Spot priming is ok because your not creating a continuos non permeable film over the surface and moisture can still escape around the sealed spots.

A full shellac prime on an exterior wood surface can be disastrous. I've experienced this myself many years ago, and recounted it here in the past.


Sent from my iPhone using Tapatalk
Jmayspaint is offline   Reply With Quote
The Following User Says Thank You to Jmayspaint For This Useful Post:
SidingJohn (05-30-2016)
Old 05-30-2016, 10:51 PM   #15
Junior Member
 
Join Date: May 2016
Location: Houston, TX
Posts: 8
Rewards Points: 8
Thanks: 3
Thanked 0 Times in 0 Posts
View SidingJohn's Photo Album My Photos
Default Sounds like bulls eye

Jmayspaint - it seems that you have experienced a more-or-less the same scenario as mine. I obviously didn't use shellac as a primer... but it ended up being exactly that - a primer that was coated with Killz first and with a non-oil paint second. That said, your vapor barrier reference is convincing, and it appears that this is exactly what I have suffered: I had stock fully covered with shellac, and then I painted over it..,,,, that said, Killz or no Killz, it can act weird... however, let me ask you. Let's say you were approached by a customer who said "I have a wall covered with cedar that was treated with shellac... can you please paint it for me using this exterior moisture-barrier Resillience paint from Sherwin Williams?" And if not, what would you recommend to change the appearance of this wall to a painted wall... apart from reinstalling new cedar siding stock?
SidingJohn is offline   Reply With Quote
Reply

Tags
bubbles, shellac, sherwin williams

Thread Tools
Display Modes

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
Options for refinishing shellac finish on interior windows Pierson Painting Surface Preparation and Application 10 01-24-2016 02:50 PM


All times are GMT -4. The time now is 09:40 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Our Pro Sites Network
ContractorTalk.com | DrywallTalk.com | ElectricianTalk.com | HVACSite.com | PlumbingZone.com | RoofingTalk.com