Wood glue can be a godsend when you want to avoid nails or screws in exposed areas, but it can get confusing over whether you should stain your wood before gluing it or just glue over already finished wood.
Wood glue will not stick properly to stained wood. As a general rule, you should use wood glue only on bare wood. It is not recommended to use wood glue on stained wood because it will not create a strong joint. Sand the surfaces you plan on gluing up down to the bare wood first.
Wood glue always works best on bare wood because it seeps into the wood’s pores during the bonding process. Let’s learn more about how wood glue bonds and the best way to make it work.
At our Cucamonga Woodworking live online workshops we discuss bend and steaming wood at about the 5 minute mark of this video. You can also check out our other past workshops on Youtube Here(Link to Cucamonga Woodworking)
Using Wood Glue on Stained Wood
When wood is stained, its pores are filled in with the stain. This means the glue can’t get into the pores anymore, greatly reducing the glue’s surface area to attach to. This then reduces the strength of the hold.
While it is not impossible to get a reasonably powerful bond even if your wood was stained where you glued it together, it’s not advisable to try this. It’s a virtual certainty that whatever strength that join has, it won’t be nearly as strong as if you had glued bare wood together.
A good glue joint can be stronger than even nails or screws, but one weakened by having the stain between the glue and the bare wood can sometimes be knocked apart with just a good hit.
How to proceed with gluing wood depends on what situation you are in. If you’re working with bare wood, you have a choice about whether to stain before or after gluing. If you modify an existing product already finished with stain, you should prepare the area you need to glue to make sure your bond holds.
Can I Stain After Gluing?
You can glue first and stain afterward. However, you need to make sure you completely remove all the excess glue from the wood before staining, or the stain will be noticeably lighter where the glue residue remains. This is because the glue will block the stain, and it won’t penetrate those areas.
How Can I Remove Excess Glue?
You can remove “squeeze out” glue in a few ways:
- Wipe off glue before drying
- Scrape off glue after it skims over
- Scrape off glue after it dries
Most experts recommend wiping off glue before drying. This can be done with a wet cloth or towel. You’ll never get all the excess glue off from any of these approaches, so you should sand off whatever remains.
Steven Ramsey, who operates the site Woodworking for Mere Mortals, has a useful video on handling wood glue. He advises you to apply some mineral spirits to the area to reveal any remaining leftover glue after sanding so you can see if you need to sand further.
Can I Still Stain My Wood Before Gluing?
You can stain your wood before gluing if you prefer, and many professionals like to pre-stain. But wait, didn’t we say you shouldn’t apply glue over stained wood? The idea here is to avoid staining the areas you are going to be gluing.
Here’s how you can stain your wood before gluing:
- Apply masking or painter’s tape over the areas you plan to apply glue.
- Apply an even coat of stain on the wood.
- Remove the tape and let the piece dry.
- Glue the parts together and clamp for several hours.
Michael Dresdner of Woodworker’s Journal recommends setting the tape about 1/16 of an inch inside the glue area to allow the stain to cover just inside the joint. This will ensure you get an even coat on all exposed areas while still having enough bare wood to create a strong bond.
When Should You Stain Before Gluing?
It may make more sense to stain before you assemble the wood parts of your project in some situations. We’ll cover a few of these reasons below.
When You Have Contrasting Parts
Your project may use contrasting colors as part of its visual appeal. It can be challenging to apply differing stain colors to parts joined together in your project without getting the wrong color onto the wrong parts.
When Access Will Become Difficult Later
Staining your project before it is fully assembled can often prove to be far easier and cleaner. In cases where parts like spindles will be spaced closely together, it may be difficult to stain them after they are already in place.
Interiors of things like bookshelves or cabinets may be easier to reach when still exposed. This doesn’t necessarily mean staining each part before joining them but could just be considering staining while partially assembled.
When Parts Are Designed to Move Or Shift
If your project has pieces designed to shift for flexibility or move as part of their function, then some of their surfaces will not be exposed all the time. Staining these before gluing then becomes a necessity to avoid exposing unfinished surfaces when revealed through movement.
How Can I Remove Stain from Wood Where I Need to Glue It?
If you have a finished item, like old furniture, and need to glue something to it, you could try sanding down the area where you need to glue to get a better bond. This can be tricky if the area is small or narrow. Also, stain and other finishing coats can gum up your sandpaper. But this might be your only viable option based on the area you are working with.
Alternatively, you could try using a heat gun to soften the finish and then scrape it off. Another option would be to apply a stain removing solution, like mineral spirits, on the area, and then wipe it clean.
Other Options to Connect Stained Wood Pieces Without Wood Glue
Fortunately, you have alternatives to wood glue for working with stained wood. Epoxy resin can be a suitable option for gluing over the wood stain. Epoxy resin is a specialized form of adhesive that comes in two separate compounds that, when mixed, form a powerful bond with many materials, including wood.
If you decide to go this route, do some checking to see that it will work with the stain you will apply it to, as epoxy resin doesn’t work well with some oil-based wood stains. You also need to be aware that it takes longer to set than wood glue.
Another possible alternative to wood glue is construction adhesive. Again, you will want to check how it does against different wood stains before using it. It would be best if you also learned about the properties of the different variants it comes in, including flexibility and color (many are not transparent when they dry).
Wood Glue Works Best on Bare Wood
All things being equal, wood glue is the one adhesive designed for woodworking. It is the easiest to work with and creates a potent bond. But as stated earlier, avoid using it on stained surfaces. Use it wisely, and you’ll be building durable woodworking products that will withstand the test of time.
Do you have a favorite way to attached stained wood after it’s been sealed? Or, do you have a favorite way to keep stain off of certain spots when staining so you can glue it later?
I include a link to my favorite finish products if you are interested in what I’m learning to use. (Link Here)
