Is Glue Bleed-Through Preventable?

Is Glue Bleed-Through Preventable?

Glue bleed-through on veneered doors frustrates virtually all finishers and prefinishers.  They apply several remedies, some before staining, some after:  sanding, blacklight inspection, seal coats, and touchup.  But these remedies often fail to catch all of the spots. And the cost of prepping these raw doors at the prefinishing stage adds too much to the cost of an economy, production door.  Another problem is origin.  Most stile and rail doors sold in the U.S. originate in China, making quality standards and communication more difficult to maintain.

Glue bleed-through on a stile & rail door

Glue bleed-through on a stile & rail door

What is glue bleed-through?
Glue seeps through the pores of the veneer, then dries at the veneer’s surface.  Almost invisible on a raw door, it shows up as lighter spots after staining.  Then, it’s often too late to remedy.

How can we prevent it?
Let’s speculate on potential remedies at the manufacturing level.  First, bleed-through occurs more often in open grain species, such as oak, requiring special consideration.  Second, it’s affected by the quantity and application of the glue.  CP Adhesives wrote, “The major cause [for bleed-through] is a heavy glue spread.  By minimizing the spread, you can lessen the bleed through.”  Veneer Systems advises matching the spread to the specie.

“Be aware of the thickness of your veneer and relative porosity of the species you’re working with, and adjust the spread accordingly.  In many instances, a thin spread coupled with mandatory open assembly time (perhaps up to 10 minutes) will be necessary to prevent excessive bleed-through. … Remember, it’s not only the amount of glue, but also how consistently it was applied…”

CP also suggested a filled adhesive for clogging the pores of the wood.  Good remedies from experienced vendors.

Are these remedies practical for the manufacturer?
We assume that production door manufacturers know these remedies.  It’s in their best interests to ship doors without glue bleed-through.  And, to be fair, production manufacturing requires different techniques than the project work related to these glue vendors.  But CP Adhesives and Veneer Systems offer sound advice if manufacturers can apply them to their production lines.  A bit more time, money, and inspection during manufacturing produces more sales and profit later.

Have you tried to remove a glue bleed-through spot?  Were you successful?  If you are in the millwork industry, how often do you see this problem?

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