Professionals and Amateurs Together

Glue Bleed-Thorough on a Vacuum Press


More often than not, when I remove a piece from a vacuum press, I get bleed-through of the glue (Titebond III) through figured cherry veneer (MDF substrate). It takes a lot of scaping to remove the glue. Any ideas on how to prevent or minimize this?— Steve Colello


Owain Harris replies: It’s possible that you are using too much glue. It’s an easy mistake to make. I apply the glue to just the substrate using an adhesive roller that applies the glue in a thin layer. I will typically make sure to get it a little thicker around the edges just to be safe. Figured wood in particular can be a real problem with bleed through as there is essentially exposed end-grain in places that just soaks up the glue.

I don’t think that Titebond III is a great choice. I find that the waterproof Titebonds II & III are a little less viscous than the original and therefore more prone to bleed through. I would consider using either Titebond I or better yet, Unibond One, which is a one part PVA glue especially formulated for veneering and lamination. If you are still having a problem, you could try using the original two-part Unibond 800 with a blocking additive that is designed specifically to prevent bleed through in figure woods.

Bruce Wedlock replies: You are using the wrong glue. UnibondOne or Titebond Cold Press are one-part veneer glues formulated to resist bleed-through.

Richard Oedel replies: Use a different glue, and a blocking additive. Depending on what you are trying to do, you might try Unibond 800, a two part adhesive which has a really hard glue-line, and a long open time to allow you to work with it. Or use UnibondOne which is a one-part glue that works well.

In both of these, they are formulated to not bleed through, but occasionally they do, in which case you can use a blocking additive. This blocks up the pores that allow the glue to travel from the glue side to the face side. It is not a perfect solution, but it works.

But first make sure you are not putting too much glue on the surfaces. I use a fuzzy an adhesive applicator roller from Wooster which you can buy at Home Depot. It spreads the perfect amount of glue but it works best if you roll it onto both surfaces. As always, test first.

Tags: Glue