make wood harder

How to Harden Wood: 4 Different Techniques for Beginners

Whether it is rotten or too old – you don’t have to get rid of it. A piece of wood can always be restored and put into work again. But you’ll have to learn how to harden wood first.

Hardening offers the chance to use this wood for structures as well as fixing stuff later. And sure enough, hardening will also make it last longer.

But this process is not easy. Hardening wood requires effort and time. If you follow this guide, however, you will reduce the time and effort exponentially.

So, are you eager to learn how to buff up that old wood at home? Then keep scrolling!

Why Should You Harden Wood?

There are various reasons why someone would want to make the wood harder. Here are some of them:

  • To re-use a piece of wood that is well-preserved but a little soft
  • To give life back to a rotten wood board or object
  • To recover wood exposed to an excess of moisture
  • To finish a woodworking project without buying new wood
  • To increase the durability of a wooden object
  • To make a piece of wood more resilient and robust

Here are just the main advantages you get from hardening a piece of wood. Yet, remember that some parts of wood can be irrecoverable.

If the wood looks rotten to the point that it breaks away too easily, has animals living on it, or simply smells awful – then you may not be able to recover it.

For any other piece of wood that is just a little softened or rotten up – there’s a high chance you can still harden it.

How to Strengthen Wood in 4 Techniques?

We wanted to give you the easiest and most effective ways of hardening wood. So, we came up with 4 methods that will make it possible in little time and with little effort – so any beginner can harden wood following our instructions.

Here are the methods we’re talking about–

Technique 1: Hardening Wood with Fire

fire harden wood

The oldest and most popular method is to harden wood with fire. It is a simple yet effective way to get even the softest piece of wood a little harder, so you can eventually use it for whatever you want.

This process is all about using the heat from the fire to get rid of the humidity of the wood. At the same time, the heat strengthens the wood grain and makes the rotten parts solidify.

But it is not as easy as it seems. Without the right precautions and taking the wrong steps, it is easy to burn the wood, damage it, or just burn yourself.

Don’t worry, though. Here’s a small guide on how to make it happen without causing any mess:

  1. First, prepare a fire pit, kiln, or a small hole in the ground with fire – it should be open so you can operate the wood.
  2. Pour charcoal and firewood inside. Then ignite them. Let the flames grow enough, so they produce decent heat. Keep pouring charcoal and firewood until the flame stabilizes.
  3. Once the flames are stabilized and at least 6-inches high – then you can start holding the pieces of wood over the fire. You should keep them at no less than 3 inches apart from the flames to prevent any burn on the wood or yourself.
  4. While the food is over the flames, you should move it around every few seconds. Don’t let it absorb heat for more than 1 minute to prevent any over-heating or burn.
  5. Watch how the wood dries up and gets rid of the moisture. The more moisture the piece of timber secretes, the harder it will get.
  6. Touch the part you’re heating up to see whether it got harder. If it did, and it looks dry enough, then you can take the piece of wood away from the heat. Let it cool for at least 5 minutes and check.
  7. The piece of wood should be more rigid and more robust now. If not, you will have to place it on the heat once again for a couple of minutes.

We recommend using fire-retardant gauntlets and an object to hold the piece of wood separately from your hands (e.g., a metal tube or a grill).

Technique 2: Hardening Wood with Epoxy

Another way to harden soft wood is to use epoxy. Yes, this is another popular way to do so, and it is way safer and easier than heating up with fire.

The whole function of epoxy resin is to strengthen the surface and to make sure all the interior wood fibers stay put. This solidifies the wood entirely and makes it possible to use the piece for almost anything.

If you’re a beginner and don’t want to waste time starting a fire, or just don’t want to put yourself at risk of burns – then using epoxy would be an excellent alternative.

These are the steps you need to take:

  1. Clean the piece of wood you want to harden. Make sure the surface and any crevice or hollow portion are spotless. From debris to dust, get rid of everything so you can apply the epoxy properly.
  2. Then find a strengthening epoxy ideal for the job. There are various kinds to go for, and all of them offer different strengths. You go for whatever feels perfect for your needs – yet the strongest ones are always the best choice.
  3. Once you have the epoxy, prepare the mixture. Remember to follow the instructions on the epoxy package or bottle. Usually, it’s only water and epoxy. Stir the epoxy well enough until you get a thick mixture.
  4. After preparing the epoxy resin, then you can start applying it. We recommend using an old paintbrush or old soft-bristle brush. Pour some of the mixtures on the wood surface and spread it. Make sure the whole mix stays even on the surface. Don’t hesitate to pour as much as needed.
  5. In case the wood is too soft or too thick, you should drill a hole in the middle and pour some epoxy in. This will harden the wood from the inside, sometimes delivering even better results.
  6. By now, the whole surface and/or interior of the piece of wood should be filled with epoxy. You should now wait at least 3 hours for the epoxy to strengthen a little. Then, you will need to apply a second layer on the surface. If the interior can handle a little more epoxy, then pour some as well.
  7. If the piece of wood is going to be used for something that will be exposed to moisture or other elements, we recommend adding at least 3 layers of epoxy. That will harden it up enough for your needs.
  8. Now that you’ve applied several layers and there’s nothing else to add – then you’ll need to let the wood piece dry up. Typically, epoxy takes about 3 days to cure completely. Place it in a dry and cool area for faster straightening. After a few days, you’ll receive a hardened piece of wood.

Remember that epoxy is not the healthiest product out there. It can produce fumes and may even be somewhat toxic. That’s why we recommend working on a ventilated area and use a safety mask plus safety gauntlets when handling the mixture. This will be enough to harden the wood with epoxy safely.

Technique 3: Hardening Wood with Polycryl

apply the epoxy properly
hardening wood

Also known as a wood fortifier or stabilizer, Polycryl is one of the best chemical products you can use to strengthen the wood.

In contrast with other products, Polycryl has the sole function of strengthening wood from the surface. And what makes it such an excellent choice is how affordable it is and how effortlessly you can use it. On top of that, Polycryl is ultra-safe.

So, if you’re a beginner woodworker or someone who has little to no experience with this type of process – Polycryl can be an excellent choice.

Here’s how to harden wood with it:

  1. Find a Polycryl fortifier. We recommend concentrated versions for the best experience and strength. Sure enough, you will need to dilute it before application.
  2. Once you have the Polycryl, follow the instruction to prepare it. Most of the time, you will only need to mix it with water, and that's it. Stir until it gets thick enough to apply smoothly.
  3. Before you apply the Polycryl, remember to clean the entire wood surface. Get rid of any dust or dirt particle to prevent any issue later. This will also make the wood look better and give a more even surface.
  4. You may use an old paintbrush, applicator brush, or a soft-brittle brush. Whatever you find, make sure it’s something you can eventually get rid of. Then start applying on the surface, slowly and gently, but making sure it is even.
  5. Polycryl usually only goes on the soft areas. But you can apply it on the entire surface of the wood if you want. If the piece of wood is too large, you can pour the whole bowl or bottle of polycryl over it and then brush it to even up the surface. Remember to protect floors and walls if doing so.
  6. After applying the Polycryl, you will need to let the piece of wood dry for several hours. It is recommended to find a dry and cool place for the wood to dry up. Let it dry for about 5 hours.
  7. Check the piece of wood after letting it dry. If the piece is not hard enough for your needs, then you can apply one or two more layers of Polycryl.
  8. Once you have the piece hard enough for your needs, then you’ll have to apply a finish layer. We recommend a varnish or lacquer. This will protect the wood from further damage and keep the Polycryl working for longer.

While Polycryl is not necessarily unsafe, we still heavily advise you to use gloves.

Technique 4: Hardening Wood with Wood Hardener

The easiest and most effective way to strengthen wood is to use a wood hardener. In contrast with Polycryl, most wood hardeners are not water-soluble, so they are usually more rigid and reliable in the long run.

However, wood hardeners mostly work in pieces of wood that are too old. If they’re rotten or too soft already, then a wood hardener won’t work well.

Overall, though, they’re pretty useful. By penetrating the wood grain, wood hardeners provide the perfect hardening effect to make wood usable again.

Here’s how to apply wood hardener:

  1. Prepare the piece of wood you want to strengthen. Cut and chop away pieces that you don’t want on the wood. Then get rid of dust and debris. Use a putty or carving knife if necessary. Before applying, the whole surface of the wood should be clean, dry, and free of oil or grease.
  2. Then grab the can of wood hardener. In some cases, it could come in bottles or packages. To prepare it, you may just need to stir or shake it, and that will be enough. Then you can proceed to spray it on the entire surface you want to strengthen, spread it with an old paintbrush.
  3. Let the first layer dry up for 1 to 2 hours. Then you can proceed to apply the second layer the same way. Pour or spray the product on the wood surface, and then spread.
  4. In case you want the wood to be shining and super smooth, then we recommend applying at least 5 layers of wood hardener. That will not only make it super strong but also better-looking.
  5. After the last layer, let the entire piece dry for 5 to 12 hours. And after that, you can always paint the surface or add a protective coat.

While wood hardener is typically safe, you may still want to protect yourself using safety gloves. Also, try to work in a ventilated area, so the smell doesn’t bother you. That will be enough to apply it safely and with ease.

Tips to Keep Your Wood Hard

After hardening wood, you’ll want the piece to stay that way for long. In most cases, you’ll have to take a few extra steps for that.

Here are some of the things you can do to keep the wood hard after strengthening it:

Apply a Protective Coat

There’s nothing more protective for wood than a coat of stain, polyurethane, lacquer, varnish, or even just paint.

This keeps further moisture from entering the piece of wood and decreases the likelihood of the already-dry and strong wood from softening in the long term.

Store It Properly

The way you store wood has a significant impact on how hard it stays over time. Especially if you’re stacking several planks and/or pieces together instead of using it, then you need to make sure they’re properly stored.

Here are a few points to consider:

  • Store them in a dry yet breathable place possible
  • The place should also be cold and vapor-free
  • Never place heavy stuff over strengthened wood
  • Wrap the wood with protective fabric in winter or in moisty areas
  • Keep the wood away from sun exposure (especially if it isn’t coated)

This should be enough to keep the wood strong even after years.

Dry the Wood

Drying wood is almost the perfect extra step to keep the wood strong and free of any warping or softening.

The main advantage is that drying gets rid of the internal moisture. That’s enough to prevent any soft part or further humidity from causing damage in the long term. And sure, it keeps the wood dry for long.

Still, be sure to dry the lumber just enough so it gets rid of moisture. But if you dry it too much, it may eventually split or crack.

Seal the Wood Ends

Another excellent way to keep wood strong is to seal all the parts that let moisture go in. If you see a small portion of wood with exposed grain, then that’s an area to fill.

You can use anything from epoxy to tung oil, linseed oil, and much more. This will prevent even the smallest drop of moisture from getting inside and softening the piece. Also, it prevents bugs and bacteria from rotting the wood.

So, if you want to keep the wood plank hard, make sure it has no exposed area without a sealant coat.

Frequently Asked Questions

By now, you should be aware of the best practices to make wood stronger. But you may still hold a few doubts about the whole activity. Here are some questions with their respective answers that may help you out:

1. Will the Wood Stay Strong After Hardening It?

Ans: It is not easy to say, but you should get at least 1 more year of hardness. In case the wood was not too soft before you strengthened it, then it can last up to 5 years or more. But if the wood was rotting or very soft before hardening it, you may get about 2 years of extra lifespan in the best-case scenario.

2. Is it Possible to Strengthen Any Type of Wood?

Ans: Most softwoods and hardwoods can be hardened. The only ones that we don’t recommend strengthening are human-made woods like laminated timber, fibreboard, particleboard, and soft plywood. Once they rot or soften up, they are almost irrecoverable.

3. Should I Harden a Broken Piece of Wood?

Ans: It doesn’t matter if it is broken, cracked, or split – if you can use the wood later, then you should harden it. Remember to seal the broken, cracked, or split areas, so moisture doesn't get through after strengthening it.

4. Can I Use Strengthened Wood to Set UP a House or Cabin Structure?

Ans:  Yes, as long as the wood wasn’t rotten or fragile before hardening it, then it’s totally possible. But still, try to use the plank or piece of wood in a place that doesn’t make it withstand too much weight.

Final Thoughts

harden wood as a beginner

If you got this far into the article, it means you should know how to harden wood as a beginner. So, there’s no more time to waste.

With our small tips and guide plus the extra information in this article, hardening any piece of wood will be a piece of cake. Just remember to follow all our advice to the letter, and you won’t have a single issue.

So, what are you waiting for? Start strengthening that wood now!


13 thoughts on “How to Harden Wood: 4 Different Techniques for Beginners”

  1. Awesome! I’ve been looking for a source that mentions fire hardening wood. Do you know from experience or has this been passed down? ACM – 03/11/21

  2. Thanks for the article. I want to strengthen a small part of a window sill and a small area on a painted floor. In both cases, do I need to get rid of the painted finish before using the wood hardener? Thanks.

  3. I’m making a table for my daughter with a wood mosaic top. It’s made of small pine, poplar and maple rectangles glued and pinned to a plywood substrate. The table is to be an apartment sized kitchen table.
    Can I use a polycryl before stain and top coat without causing problems with that final finish?

  4. phillip mcintosh

    Hello I am currently restoring a plywood dinghy I have quite large patches where when tapped the sound changes I have read several places including yours that hardener does not work very well my three questions are.
    1 Are there any detrimental reasons why I Shouldn’t
    2. would applying epoxy over the top help in spreading the weight around and ultimately prolonging the life for a little longer before a foot goes through the hull.
    3.How well will the new varnish bond to this surface.

    1. 1. I don’t think it would cause any harm to the wood if you use any of the hardening techniques.
      2. Yes, applying epoxy would help in distrbuting the weight.
      3. Varnish will bond well to the surface.

  5. I am having to replace four 6×6 rough-hewn cedar posts where the bottoms have rotted out. I want to apply Minwax wood hardener to the bottom ends and maybe 6 inches up from the bottom. What is the best way to do it?

  6. Is it possible to use one of these techniques on a large sunflower stalk? I have a culled mammoth with about a 2″ diameter that I’m hoping to repurpose into a hiking staff.

  7. Jennifer Howland

    I have a kitchen table that was built out of rather soft wood, which has allowed numerous scratches all through the table. I’m curious on how to go about hardening the table. Would I sand down its current finish and then apply the epoxy and then refinish, or would I sand and reapply the finish, and top with the epoxy?

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top