New Veneer Developing Wrinkles. Urgent Help Needed!!!

[FrankRoss]

I applied a beautiful maple veneer on the Concert Grand cabs, however the face on one cabinet and a side on the other have developed severe wrinkles!

I believe that I can pull the veneer off of the MDF without too much damage... does anyone have any advice for prepping the MDF for a second round of contact cement and veneer? Pulling back about 5 inches of the veneer, there's enough residual contact adhesive on the MDF that I don't know how to remove.

The good news is that I have enough un-used veneer left over to complete the project - if I can get rid of the glue (or smoothly even it out) from the cabinet!

[sqlkev]

http://www.stormpages.com/elfranche/.../photo104.html

[pinkmouse]

Yup, not enough pressure. You might well still be able to fix this if you can get enough pressure on the bulges. Do you have a J roller?

[elfranche]

You can dissolve contact cement with contact cement solvent, usually available where you got the glue.

However you can also use yellow glue with ease if you use weights and a J-roller.

[omni]

Frankross, There are a variety of approaches you can take to deal with this. Solvent was recommended in an earlier post, however it sounds as if you are working with a very thin, pure wood veneer and I would be dubious about using a solvent, as it may soak through the veneer and possibly stain it. In addition, solvent will invariably soak into your MDF, and no matter how dry it gets, may cause adhesion problems with new contact cement. It also may create an undesirable swelling or weaken your MDF, especially if you use too much......If you want to remove the dried contact cement from your MDF, I believe meticulous sanding of it with a high grit sandpaper is your answer, being careful not to create a concavity in your material, which would translate into a concave finished surface..... One approach may be to slice the wrinkles with a razor blade or X-acto knife lengthwise and then inject a fluid glue in, then use a roller to press the wrinkle down, then weight it down on a flat surface until it dries, then sand with a 400 or greater grit sandpaper to feather the seam. The way I would attempt to remove contact cement would be to tediously and meticulously sand it off with a high grit sand paper............but, if I was looking for a flawless surface, I would bite the bullet,..........rip off the bad veneer, sand the MDF clean of the contact cement and apply a new sheet using the dowel rod method, and not rush it. I work with contact cement and I screwed up an application of laminate on one of my boxes and fortunately it was repairable.......Once the surfaces touch, thats it man. You started another thread about wax paper and mentioned you had about a half inch extra on the edges.........Is there any way you can use a bit larger piece of veneer? Also you may want to consider the dowel rod method to apply your new veneer because it allows you to work in a more controlled manner, slowly, and not rushed, which will assure you of good contact, with the ability to give you good pressure on your cabinet and provide you the accuracy of placement........Nothing worse than misplacing veneer on your boxes when you use contact cement..............Respectfully......Omni ..........P.S. I would recommend a solvent based contact cement. There are waterbased contact cements out there, however, humidity creates a variety of adhesion problems. You live in Pennsylvania, and I am in Ohio, and the last few days here in Ohio were at 85% humidity, must have been similar in PA?

[poobah]

Can I guess??? You put oil stain over contact goop... and then finished with polyurethane?

Listen to very little spoken here...

Been there... send a PM if you like.

[elfranche]

Is there a problem with poly finish over oil stain?

[FrankRoss]

Thanks everyone, I do appreciate the feedback!

I keep a dehumidifier running all of the time so the enclosed room (with ventilation ducts and outward blowing fan) is really not that humid. After applying the adhesive to both surfaces with a 1/4" nap roller, let sit for 20 minutes, I used a straight 2X4 with a lot of force to "scrape" across the surface, working from the center out to the edges, to get a good bond. Everything went fine until I sprayed the MinWax polyeurothane and the wrinkles started to appear. No stain was used for this project (I wanted the natural look of Maple with a satin clear coat finish). I was shocked to say the least, that's the first time this has ever happened to me.

Btw, I used the traditional method of laying strips of 1 X 2 wood under the 10 mil paper-backed veneer (didn't use wax paper) to get it into position. The 1/4" extra was more than enough to work with (no problems with alignment).

I'm curious though, if I pull the veneer off, will the contact adhesive dry out over the course of a few days or a week, to make sanding easier? Or will it remain "rubbery"? Also, will it hurt to apply contact adhesive over the old contact adhesive if it's relatively flat, or is this asking for more problems?

[budwiser]

J-roller ? They never produce enough pressure for an excellent bond, his use of a 2x4 edge was a better choice because more pressure was applied from that small edge than you would ever get from a j-roller. One question, was this raw veneer or did it have a backing? I don't recall seeing this info. Raw would be more likely to let the Poly spray get thru and react with the contact cement. Paper back or some other type of backing that keeps the finish away from the cement is better. Did you use water based contact cement? Water based is less reliable. Spare the cement ,spoil the job. ALot of good articles on the net on veneering. Good Luck

[omni]

Frankross, It was cool to see you clarified your techniques, and it appears you have employed some good methods. How long did you wait to apply your poly finish after you applied the veneer? The scenario you describe in your last post is indicative, perhaps, of the solvents from the polyurethane seeping through your veneer to the contact adhesive, and loosening the bond.... My experience with adhesives has shown me to allow them to cure for a day or more, rendering them impervious to further treatment. In a case of spilled contact cement, I have observed that it does harden further over time. This should make sanding it off more predictable. I would not apply new contact adhesive over the old stuff until I removed as much as possible, and I would still stay away from a waterbased product, wait a few days after applying the new veneer to allow the adhesive to cure, then proceed with the poly spray with multiple light coats, instead of heavy coats. Light coats of the poly finish will provide less chance of its' solvents seeping through your veneer to the contact cement. The instructions on the can of contact cement may say that one can rejuvenate the adhesion of dried cement with the application of more cement, but I think there is only a short window of time for this to work. Even then, I believe this is a stretch. I hope you get through this hassle............Respectfully........Omni