Help with Clear Coat Problem

[mturi]

I was helping a high school student build a backgammon board for his senior project and disaster struck in the 11th hour. Here is an explanation.

We painted the game surface in three layers to account for the dark, light and the board colors. I used a repositionable contact paper to overlay the triangles as I painted each layer. This worked very well. When the surface was finished, we sprayed the game surface with multiple coats of a clear gloss. The next day I covered the entire game surface with the same contact paper to protect the surface while we completed the outer frame, hardware, etc. When everything was done and we unveiled the game board and to our horror, more than half of the clear coat came with it. The entire surface had blotches of glossy and flat spots all over and the glossy spots had very visible edges. I felt terrible for this kid because of what happened and didn't know what to do so we decided to recoat with clear paint to make the surface look uniform and glossy. The edges of the original gloss layer was completely visible and it did not look great. We worked very hard for several weekends and it all went to crap in a matter of minutes.

This may have been caused by cool temps while painting or not completely dry before covering with the contact paper. Either way, my question is...what is the best way to correct this? I have a few last resort ideas but was hoping someone has advice from past experience.

The game surface is a lamination of hardboard and oak plywood to make the inner and outer surfaces. This is all surrounded by a border of oak hardwood to make the frame and box.

Sorry for such a long post and thanks for any help you can offer.

Mark

 

[boxxmaker]

I am not sure what type of finish you used,but I believe that you may have to go back to square one an start over,but you may be able to sand the clearcoat back down to the base paint,then redo it.It is almost impossable to analize it without seeing it.I painted cars for about 30 yrs and used a lot of clearcoat an there's no way to repair this without it showing up.If you have to do it over,check an see what the drying time is required,before putting tape over it.You said you used contact paper,if its what I think your talking about,that stuff will pull the skin off a hog (SORRY) They have tape that is made just for what you used the contact paper for and it won't leave any marks on the finish.Wish I could have given you a miracle cure for your problem,but I hope this helps you out.
Ken

 

[mturi]

Sanding and starting over was one of my last resorts but it will be much more difficult now that the entire box is assembled. Just an FYI, the contact paper I used is "repositionable" and does not adhere like the contact paper you mentioned. That's why it worked so well while painting the triangles on the board. It worked better than painters tape with no edge bleed and removed with no residue or marking. Thanks for your reply.

 

[boxxmaker]

Sorry about the missunderstandin about the contact paper,but I actually thought you were talking about something besides that sticky stuff :embaresse
Sure hope you get it squared away without havin to redo it.
Ken

 

[Matt Schnurbusch]

Mark,

I am of no use on this, other than to say, it may be helpful to those with more experience to know exactly what products were used.

I hope you can come to a relatively painless resolution.

 

[BobN]

Without knowing what materials or type of paint you used it's hard to determine exactly what happen. But here's my guess - the clear coat didn't stick to the paint under it, the base coat (color coat) should have been sanded with 360 or 400 grit sandpaper before putting down the clear coat. The sanding would have rough up the surface enough for the clear coat to stick.

Only way I know to fix it is to sand all the clear off and start over.

Bob

 

[Howard Acheson]

A number of folks have asked a very relevant and important question: What paint did you use? How long did you let it dry before over coating?

I can't think of the finish that I would apply a any type of contact paper or material to unless it have fully dried for a month or more. No finish is fully cured overnight and while curing it will off-gas and interact with anything on it.

At this point, I can't think of a way to recover except to strip off all the finish and then go through the process again.

 

[mturi]

We used Valspar enamel spray paint for the colors and Rustoleum clear gloss for the top coat. I only let the clear gloss dry for about 10 hours before covering it with the repositionable contact paper because the student was misinformed on the due date. We thought we had another week but instead had less than 24 hours. I suspect it was not long enough and I did not sand the finished surface before the clear coat. A lesson learned in many ways.

Could I have used a spray shellac over the painted surface as another option? Not sure this would have helped or is even an option over paint.

Thanks

 

[nelsone]

Rattle can lacquer like Deft would have worked for what I understand you are describing. Nice thing about lacquer is it dries quickly!

 

[TracyP]

Rattle can lacquer like Deft would have worked for what I understand you are describing. Nice thing about lacquer is it dries quickly!

I love lacquer finishes. I too, like you like it because it dries so quick and polishes, buffs, so easy to the desired shine.

 

[Howard Acheson]

You must be very careful over coating finishes from different manufacturers unless you are sure that the chemicals are compatible. It's particularly a potential problem with spray can finishes if that's what you used. For example lacquer very poorly interacts with oil based finishes and will frequently not be happy over shellac as lacquer thinners contain alcohol. With the exception of waterborne acrylics, clear finishes generally have some amount of an amber cast which can affect to overall color of the item.

Finally, oil based and waterborne finishes take 3-4 weeks to fully cure and develop full adhesion and protective qualities. Treat them gently during the curing period and don't put anything on top of them.

For the future, it is always a good practice to go through the whole finishing process on scrap material to determine how it will look and how different finishes interact with each other.

 

[mturi]

Thank you for all your replies. We are going to sand it and start over. :5sigh:

 

[mturi]

I like that idea and will try the lacquer after we start over.

Thanks

 

[TedAS]

Mark
As Howard said it may be in your best interest to test the compatability between the paint and the lacquer top coat on some scrap. You don't want a repeat.

Ted

 

[mturi]

I agree and believe I learned my lesson. I guess the good thing is I won't have to protect the surface once I redo everything because the rest of the work is already done. Once I spray the clear lacquer, I will let it dry and it should be complete.

Any recommendations on how many coats of a clear lacquer top coat considering the game board will have lots of surface activity such as rolling dice and moving game pieces?

Thanks

 

[boxxmaker]

AS many as you want,just make sure you have a dust free place to spray,cause any dust you paint over will magnify under the top coats.I put 30 coats on a 55 chev.with candy apple base coat.Took two months two do,but looked like you could walk into it.:gar-Bi:gar-Bi:gar-Bi

 

[cpowell]

You must be very careful over coating finishes from different manufacturers unless you are sure that the chemicals are compatible. It's particularly a potential problem with spray can finishes if that's what you used. For example lacquer very poorly interacts with oil based finishes and will frequently not be happy over shellac as lacquer thinners contain alcohol. With the exception of waterborne acrylics, clear finishes generally have some amount of an amber cast which can affect to overall color of the item.

Howard - the warning about lacquer over shellac got my attention. I've used NC lacquer over dewaxed shellac with nary a problem. Was I just lucky?

Chuck

 

[Howard Acheson]

Howard - the warning about lacquer over shellac got my attention. I've used NC lacquer over dewaxed shellac with nary a problem. Was I just lucky?

Chuck

"Lacquer Thinner" is a not a standard product. By that I mean that each manufacturer has their own brew. How lacquer thinner reacts with other finishes is dependent on what chemicals the manufacture used. One of the chemicals used in almost all lacquer thinner is alcohol. Depending on which alcohol and how much is used, the lacquer thinners interaction with shellac will differ.

I too, have applied NC lacquer over shellac with no problems but, I've also has some big screw ups. The screw ups were almost always with brushing lacquer. Spraying was less of a problem. I always test when applying lacquer over any non-lacquer undercoat.

 

[cpowell]

"Lacquer Thinner" is a not a standard product. By that I mean that each manufacturer has their own brew. How lacquer thinner reacts with other finishes is dependent on what chemicals the manufacture used. One of the chemicals used in almost all lacquer thinner is alcohol. Depending on which alcohol and how much is used, the lacquer thinners interaction with shellac will differ.

I too, have applied NC lacquer over shellac with no problems but, I've also has some big screw ups. The screw ups were almost always with brushing lacquer. Spraying was less of a problem. I always test when applying lacquer over any non-lacquer undercoat.

Thanks for clarifying. I've only used NC lacquer over shellac. I just picked up a can of Deft brushing lacquer and got some Deft lacquer sanding sealer to seal the pigment stain. I'll spray both the sealer and lacquer. The pigment stain is home brewed, pigment in a mineral spirits carrier...no BLO/dryer. I have used straight lacquer over this several times without incident but wanted a seal coat or two before sanding.

I used wipe on poly on the previous piece and was pleased with the results but it took a week to finish.

I would like to try mixing the pigment in lacquer some day. Have read that it works okay and that would save me several hours per project. Just need to take the time and experiment on scraps.



Chuck