Sealing End Grain with Glue – a Good or Bad Idea?

If you have the habit of not properly prepping your project, then the end grain must be one of those problematic areas. Often, you’ll finish sanding your project and everything will look amazing, however, once you apply the finish your project will suddenly look like it’s made of two different kinds of wood.

This is usually because the end grain soaked up too much stain or finish and it started appearing to be a much darker color. You can usually get away with this because the end grain is usually on a different face and shadows can play tricks on even someone with a keen eye. However, you need to take extra care of areas like stile door frames or the top of rails where end grain issues are more obvious.

End checking is another problematic area when dealing with wood. After finishing your project, you’ll find cracks along the growth rings of wood. A long-standing question for so long has been whether gluing end grains can ensure a consistent color after finishing a project and whether it can prevent end-checking. This article will look at all the ways to solve these issues and whether gluing really works.

End Checking in Wood

End checking is the process where wood begins to separate at its growth rings. Checking of end grain happens when wood loses moisture faster than the rest of the wood. As a result, the end grain will shrink faster than the rest of the wood.

This uneven shrinkage will result in stress that will crack the end grain. Wet wood will usually check if you bring it to your dry woodworking shop without sealing it. Sealing with glue will slow down or even stop moisture loss from the end grains.

Other Tips to Prevent End Checking

  • Check the moisture content of wood using a moisture meter.
  • For wood with high moisture, stack it on stickers. Ensure to leave a 0.25″ gap between the boards for proper airflow.
  • Wrap the end grains with plastic to prevent moisture loss.
  • You could also allow the wood some time to naturally dry in a cool environment before bringing it to your woodworking shop to make furniture.

Sanding to Ensure Consistent Color of your Project

As the end grain usually soaks up more finish than the face grain, sanding is the most direct solution. This needs to be done before applying the stain or finish. Sanding the end grain to a higher grit will limit the absorption of stain or finish hence ensuring its color is lighter and closely matching the face grain. Sanding also removes rough spots and seals pores that usually allow moisture to penetrate end grains.

The procedure to sand wood is simple. Just draw a pencil line on the end grain. With 60-grit sandpaper, rub continuously against the end grain in the direction of the grain until the pencil line is gone. After this repeat the procedure with 80 grit, 120 grit, and 180 grit sandpaper. It is important to work your way from the lowest to the highest grit. You can use a vacuum cleaner to remove the sawdust.

To seal end grains well with sanding, ensure you sand side grains to one lower grit than the end and edge grains. For example, if you sand the side grain to 220 then the end grain needs to be 320 and if the side grain is 150 then the end grain is 220. Sanding the end grain to one higher grit will ensure that the finish soaks up less finish.

The main challenge with sanding the end grain is that it doesn’t sand easily, and it is quite tedious.

Is Gluing a Better Alternative to Sanding?

Sanding some woods to a high grit will usually do the trick but sometimes you may just be a little too lazy and you may not want to do extra sanding. So, what do you do? Simply gluing the end grain will work wonders. Gluing also seals the pores thereby limiting the absorption of stain and ensuring a consistent color for your project.

How to Apply Glue to End Grain

  1. Remember to always seal the end grain of wood immediately after cutting it. You can use PVA or Elmer’s All-Glue.
  2. Using a brush, lightly spread the glue onto the surface.
  3. Start off with the end grain first in case you don’t get to it first and end up forgetting about it.
  4. Then you can apply the glue onto the face grain. This will prevent the wood from splitting, and you can achieve a more uniform finish on your project.

Waterproof Glue to Seal End Grain

Have you ever noticed that outdoor furniture rots at the end grains most? Due to the thirsty nature of end grains, they tend to soak up water and become perfect breeding grounds for fungi. Exposed end grain areas like the ends of the legs, therefore, tend to rot a lot.

Glue is a perfect way to protect end grains from rotting. Simply drizzle a small amount of glue onto the end grain and let it soak for about five minutes and wipe off the excess. Repeat the procedure an hour later to guarantee that the end grain is properly sealed.

Other Methods to Seal End Grain

Below are other methods that can be used to seal end grains:

1) Sanding with High Grit Sandpaper

Excessive sanding will usually clog wood pores and thus reduce the stain and finish absorption. This is because, with a high sandpaper grit, extremely fine dust is produced that can clog wood pores. As the pores of the piece will be clogged, less finish will be absorbed into the end grain, and it will therefore match the other parts of the piece.

2) Pre-Seal with Shellac

Zinsser’s Shellac Sealcoat simply prevents the wood pores from absorbing the finish or stain. You can use a small paintbrush to apply the shellac to ensure it only gets on the end grain. You must then give it an hour to dry.

It is important to select Zinsser’s Shellac Sealcoat as it is wax-free. Other shellacs may contain wax which will limit the adherence capability of different finishes.

3) Apply Wood Conditioner

The advantage of wood conditioner over all the other methods is there’s no wait time before you can apply the stain. You can easily apply any finish almost immediately after the application of a wood conditioner. Even if it may not be dry, the wood conditioner would dilute the finish and reduce absorption.

Types of Glue to Seal End Grains

There are different types of glue on the market that can be used for sealing end grains. PVA and Elmer’s glue are the most common types of glue that are used.

1) PVA

PVA sealant is used for a wide range of jobs. It can be an adhesive, a primer, a dust proofer, and a bonding agent. PVA can also be used to seal end grains. When sealing end grains with PVA, apply a thin layer on a wooden surface as a sealer before applying a finish.

PVA is usually mixed with water in a 1:4 ratio. Using a brush, you’ll spread out the mixture onto the end grain making sure to work it well into any crevices. Ensure you allow the coat to dry before applying a finish.

2) Elmer’s glue

Elmer’s glue is also great for end grain sealing. Titebond wood glue is chemically like Elmer’s glue. It is flexible but harder to sand. Normal wood glue isn’t 100% waterproof and may not completely hold back water like sealing compounds like wax. The best alternative to wood glue is ANCHORSEAL. It is thinner than wood glue and therefore lasts for a long.

Final words

Sealing the end grain is especially important for outdoor furniture. The bottoms of legs for example must be sealed as they are continuously in contact with water. The top and bottom edges of other outdoor furniture like doors don’t have to have end grains sealed as they’re not exposed to water a lot. A door, for example, will dry off quickly if it becomes wet.

You can give the end grains of these parts the same treatment as the rest of the door. If the door absorbs a lot of finish, you can add an extra coat or two.

Glue works by sealing the pores of wood thus preventing moisture loss which could lead to checking. At the same time, it limits the quick absorption of stains at the end grains thus ensuring a consistent color along the end grain and face grain.

PVA and Elmer’s glue can be used to seal end grains. Other methods to seal end grain include sanding, pre-sealing with Shellac, and applying wood conditioner. There are many other methods to seal end grains. Regardless of which solution you end up using, the end grain should be properly sanded after the sealer dries. You’ll end up with amazing results.