I received this question in episode 5 of the Ask Brian Boggs Show:
I’ve seen people clean up pva glue in so many different ways – it seems like if even a small amount penetrates the wood, there will be some blotching during the finishing, especially if stain is involved. What’s the best technique? Let it sit and gel, or meticulously clean up with water? (soaking up water immediately with dry toilet paper seems to help keep the watery glue from soaking in… thanks! – Patrick
Patrick, what I like to do if using PVA glues is to get at least one coat of finish on the wood in order to saturate fibers and minimize the wood’s ability to soak up the glue. Alternatively, wetting the surface of the wood before glue application helps keep the glue from penetrating. When I use PVA glue, I wash with water immediately after assembly. I am not afraid of using a lot of water. Use enough water to not leave a wet edge because you want the entire surface of the piece to be soaked. By doing this, you will not have a line where glue-water ends and the clean wood starts. If you don’t get all glue off it will leave stains. By using a lot of water you will essentially dilute the glue in order to have a thin and uniform enough layer of glue that will not show up very much. However, I have never succeeded in getting all glue off in the first washing. I will wash, dry and wash again and I have not found that the water does any damage to the wood, and we use a lot of water. Wood doesn’t soak in water that deep. Make sure to wait until the next day to start finishing it (applying finish). This will give the piece time to dry out completely. It will make it a lot easier if you can completely finish the pieces before assembly if that is practical for that design.
I actually use to do that with all my chairs. In fact, I would do the final coat of wax on the parts before I even drilled holes for the legs. That is a bit risky but the glue just fell off. I had no issue with glue staining at all. How I did this was kind of extreme and actually proved to be more time-consuming. Attempting to handle all the parts carefully through several applications of finish proved to be tricky. Applying some finish, at least one coat is a big help.
1 thought on “How To Prevent PVA Glue From Staining Wood”
Good question and good answer, you really did explained it well.