Shellac under contact cement

[Clif Liliedahl]

I'm refacing 45 yr old faceframe cabinets. I want to apply 20 mil Cherry Veneer over the shellac-covered end panels (3/4" plywood). DAP tells me not to use contact cement on the shellac. (Wax content prevents good adhesion) Is there another way, or do I have to strip the shellac?

Second part of the question - Is there a similar adhesion problem for the Pressure Sensitive Adhesive (PSA) of the type used on 24" x 96" Cherry Veneer rolls sold by Rocker et al.

I chose this forum because of the shellac finish. Pls forgive me if this is the wrong forum, but thanks for any replies.

[Kim Spence]

I'm not an expert in Contact Cement, but if its the wax in the shellac that is the concern, simply apply a sealer coat of dewaxed shellac over the existing shellac.

[Steve Schoene]

The PSA adhesive would probably be a better bet over the shellacked surface. Be sure the panels are seriously clean and that the shellac is in good condition.

[Steven Wilson]

Clean the panels, scuff sand, apply a coat of dewaxed shellac.

[Clif Liliedahl]

Thanks for that suggestion.
Do you know what the long term results might be? That is, might there be any sort of chemical reaction between the shellac and the adhesive that would cause the bond to break after 4-5 or 10 years?

I'm hoping that we are still in this old house for a few more years, so I'm trying to avoid kitchen cabinet problems in my twilight years.

Thanks again.:confused:

[glenn bradley]

Thanks for that suggestion.
Do you know what the long term results might be? That is, might there be any sort of chemical reaction between the shellac and the adhesive that would cause the bond to break after 4-5 or 10 years?

I'm hoping that we are still in this old house for a few more years, so I'm trying to avoid kitchen cabinet problems in my twilight years.

Thanks again.:confused:

I don't know about a chemical reaction but your adhesive manufacturer would be able to tell you. Just remember, whatever you are using, you are adhering to the film of the shellac. I don't think you'll have any problem with a properly prepared surface (no wax). I have used dewaxed shellac as a prep for surfaces not friendly to adhesives. No problems.

[Clif Liliedahl]

My cabinet refacing plans revolve around "Refacing Cabinets" by Herrick Kimball (1997). He uses contact cement, and says "The worst way to apply veneer is to put it directly on unfinished wood."

My quandry is that DAP, the mfg. of Weldwood Contact Cement says "None of our construction adhesives will bond well to a surface with any foreign material (wax, paint, primer, sealer, or any form of a coat.) We can only guarantee the usage of our products on a hard surface. Contact Cements are categorized as construction adhesives. This applies to them as well."

Experience is the best teacher.

Does anyone want to weigh in on this? I'm stuck, as I'm puzzled over these two diametrically opposed positions.

Should I strip the shellac so that the CC goes over bare wood, or, cover the shellac with Sealcoat (unwaxed shellac), and then use CC.
The veneer is a 20 mil paper backed cherry.
Will a product like Flex-Pro or Better Bond be better than CC?

Thanks so much to who responded to my previous queries.

[Kent Novick]

Clif -

I refaced my cabinets last year and read that same book. I'm not very knowledgeable on some of the limitations of contact cement, but it is widely used in refacing, which would mean that it is used over finished surfaces. The psa veneers are definitely designed to be used over finished surfaces.
Personally, I used the psa veneers without contact cement and they worked out great. Scuff sand the surface and clean it well. If you want some extra insurance, you could use some hi-strength aerosol adhesive.

Regarding the shellac, while standard shellac may be an issue for adhesives because of the wax content, would additional coats of dewaxed help solve the problem? Since shellac dissolves into previous layers, wouldn't the dewaxed just "combine" with the waxed and not "cover" it?

[Steven Wilson]

Regarding the shellac, while standard shellac may be an issue for adhesives because of the wax content, would additional coats of dewaxed help solve the problem? Since shellac dissolves into previous layers, wouldn't the dewaxed just "combine" with the waxed and not "cover" it?

Once shellac has cured, fresh coats of shellac won't disolve very far into the previous surface and if you apply a dewaxed shellac over an old waxed shellac surface you won't have very much wax in the new surface (maybe a little but not much). If you apply one spit coat, let it dry and then apply another coat you will be good.

[Rich Engelhardt]

Hello Clif,
Well, by coincidence, I happened to have some ~ 45 year old trim work that was finished with shellac.
Today, I was gluing some bead board using DAP Weldwood Contact Cement - the original formula - the one in the red can.

Since the trim was scrap, I decided to see what would happen.

The MEK in the CC ate the shellac off all the way down to the wood.

I also had a sliding door - same vintage that had a couple of coats of paint over the original shellac finish - that I was using as a work surface.

The CC ate that up too.

I believe I'd stick with DAP's advice to not use the CC - at least the original formula and/or the gel over a previously coated surface.

[Howard Acheson]

Solvent based contact cement can not be used on top of shellac. The solvents will easily dissolve or soften shellac.

However, you may be able to use a waterbased contact cement if you first isolate the old shellac from the contact cement. First I would apply a coat of Zinnser SealCoat which is a dewaxed shellac. Give that a try and see how it works.

[Clif Liliedahl]

1. I could adhere the paper backed veneer (already bought, stained and varnished) to 1/4" plywood, using CC (water based or solvent based, whichever), and fasten the plywood to the existing end panels with tiny brads.
2. Or, I think I can order cherry veneer plywood panels and do the same thing. Maybe they come with PSA as well.
3. Or, I can make solid cherry wood end panels to match the doors (simple flat panel shaker style), and fasten those to the cabinet end panels with screws and cover the screw holes with dowels. That's my last choice, due to the additional expense and because of inadequate clearance between the existing end panels and the kitchen door.

Whichever I choose, my problem will be where the vertical edges meet with the face frame. I'm not exactly sure how to handle the seam to avoid it looking like - well, I want it as invisible as possible. I guess a little trial and error will be in order.

Thanks for all the tips so far, and for any more that may follow.