128-Shellac Under Polyurethane

A quick simple test to see if polyurethane will adhere to waxed shellac.

Category:

Howto & Style

Tags:

• woodworking
• finishing
• shellac
• polyurethane

[EdgerHumphrey]

The guy at the paint shop hands me a quart of shellac and a quart of poly to treat my stained t&g. Says "this is what you need". Great. He should know. That's all he does. I get home. Read the labels and it tells me the exact opposite. Chit. I think maybe someone on the youtube tested this out. Sure enough. Many thanks to you woodwisperer.

[TheWoodWhisperer]

@EdgerHumphrey Glad to help. But make sure you test first. My little experiment here didn't really prove much. Just raised more questions. :)

[EdgerHumphrey]

@TheWoodWhisperer I just thought it was great that someone actually took the time to test it and share the results. A fine job you did of it. But after careful consideration I opted to skip the shellac and just use several coats of poly. I treated the cedar with a pre-stain conditioner before staining so shellac would be overkill. I'm still waiting for the stain to settle so if this is a bad idea I'm all eyes.

[TheWoodWhisperer]

@EdgerHumphrey I think you'll be fine with the poly only. Always simplify the process whenever possible.

[boostz32]

Hey Marc, Great video as always but what are your thoughts on using this waxed shellac under Lacquer? Thanks

[TheWoodWhisperer]

@boostz32 Personally I think its probably. But ultimately, its probably not worth the risk. Although I made this video to challenge the assumptions out there, when it comes to finishing my furniture, its not a place where I'm going to take a needless risk. So honestly, I only stock up on dewaxed shellac just to make sure I never have a problem. So unless you have a particular need/reason to use waxy shellad, I'd play it safe and go dewaxed.

[cyberyiyo]

This is nice. But I have an idea. Could you cover up HVLP? Like pros and cons, if shellac / poly can be reduced and sprayed on and if so, if lacquer thinner or mineral spirit should be used to reduce and if it has any effect on the wood etc... I hate brushes and i'm sure there are more people like me out there. Thanks for all the vids, they are great.

[TheWhitetailrancher]

Ive used shellac both waxed and dewaxed under both std and water based poly for 35 years. only time i have ever seen adherence issues is when the sealer coat has been applied improperly meaning to thick. it seems that it actually does matter if the material is over sanded as well with the tighter grained woods such as rock maple etc. then after time AND significant indirect sunlight, peeling of the poly occurs.

simply not sanding the sealer coat seems to reduce exposure to peeling too!

[jrovang]

I scratch test would be interesting, e.g.: Car keys, rough bottom of a plate

[TheWoodWhisperer]

@boyzwithboardz Should be just fine. And it should definitely help your poly build faster.

[boyzwithboardz]

Hi Marc. Do you see any issue using shellac under water based poly? I make a bunch of cornhole boards and am thinking that a coat of shellac could save a few coats of poly. As usual thanks for all the videos!