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Step-by-Step Guide to Restoring an Old Window Frame

DIY: Make Your Own Reusable Coffee Cup Sleeve With a Glue Gun

Do you need to restore an old window frame? Look no further: our step-by-step guide will help you harness your sanding skills to get the job done. Put your knowledge on wood sanding and sanding tools to the test with some home improvements.


Before you start sanding, check the wood for soft spots.

Step 1: Inspect the Wood for Rot

Before you start sanding, you’ll want to check your window frame for wood rot, a fungus that eats away wood. Wood rot can compromise the structure of the frame. First up, remove the frame from its hinges and lay it on your workbench. This is the easiest way to get to work. Using the sharp, pointed tool known as an awl, start tracing along the edges and crevices of the wood. Make sure to check for soft spots, which signify wood rot. Anywhere the awl easily pierces the surface of the wood – bingo, you’ve found rot!

Sanding preparations: getting rid of wood rot and old paint with a triangle scraper.

Step 2: Remove Wood Rot and Old Paint

Before you can clean out the wood rot, first remove old paint from the window frame. You can easily do this using a triangle paint scraper. Scrape over the whole frame with the tool until you’ve removed all the loose paint. The paint should flake away with ease. Don’t worry if the surface isn’t smooth – we’ll get to the sanding later on. Now you can start cleaning out the rot. Using the pointed side of the scraper (or the awl), scrape out the rot you found in step 1. This is the first stage of rot removal – we’ll guide you through a more thorough cleaning in the next step.

Sanding preparations: removing any old, damaged and damp wood with a Dremel router bit.

Step 3: Thoroughly Remove Damaged Wood

Thoroughly removing rot helps to ensure the structural integrity of your frame and prevents future rot from developing. Before you pick up your Dremel Multi-Tool, put on your safety gloves, goggles, earmuffs and dust mask. Attach Router Bit 6,4 mm (640) to the Multi-Tool. Start at a low RPM (rotations per minute) – such as 10.000 or 15.000 – and begin to rout the places you scraped away in step 2. Don’t apply pressure and move slowly. Rout away all wood rot and don’t worry about roughness: the sanding will smooth everything out. Check out How to Avoid Failures While Sanding for more tips like these.

Sanding routed areas using a Dremel Flap wheel.

Step 4: Sanding the Routed Parts

After routing, it’s time to start sanding the wood. Insert the Flap wheel 4,8 mm (504) into your Dremel Multi-Tool. This time, you can set the RPM a little higher than you do when routing – say around 20.000. Keep your safety gear on, and start sanding the surface of the wood. Focus on sanding the holes created by the removal of the wood rot. Keep sanding until the edges of the routed holes are smooth and ready to be filled.

After sanding the wood, fill holes with an epoxy filler.

Step 5: Patch Up the Holes With Filler

The goal now is to patch up all the holes and restore the frame’s uniform surface. Two-component epoxy filler is great for this because it hardens well and it’s water-resistant. Start with the base filler on your pallet knife and add a squeeze or two of the second component. Using another pallet knife, mix them together until the filler is consistent in both colour and texture. Press it into any holes or gaps, filling one at a time. Wipe away any excess filler with the side of the pallet knife and let the filler dry. Don’t worry about getting it perfectly smooth – you’ll be sanding soon.

Sanding the hard-to-reach places with a Dremel sanding band.

Step 6: Sanding the Frame

The next step is to prepare the frame for painting by sanding it. Wearing your safety equipment, start with an orbital sanding tool. This way, you can sand all the top surfaces at once. Then switch to your Dremel Multi-Tool and attach the Sanding Band 120 grit (432) . Starting with a low RPM and light pressure, begin in the hard-to-reach places, such as corners and edges. Pay attention to the areas with filler, ensuring a smooth transition between filler and wood. You don’t need to remove all of the old paint – the goal is a smooth, splinter-free surface that’s ready for paint.

After sanding, clean the window frame with a degreaser.

Step 7: Wipe Down the Frame

Now that you’ve used a sanding tool to smooth the frame, it will be quite dusty. Grab your dust mask and use a bristle brush to remove most of the surface dust. You could also use a vacuum cleaner for this part. Next up, fill a small bowl with a mix of water and degreaser – the degreaser packaging should have instructions for the correct ratio. Dip a dry cloth into the mixture and rub down the window frame first, before cleaning the glass. Finally, ensure your work surface is dust-free so your paint job is perfect.

Taping the window frame so the paint stays off the glass.

Step 8: Tape Around the Frame’s Edges

No matter how confident you are in your painting ability, taping up the glass ensures a neat finish. Top tip: use a strong, good quality tape so it doesn’t leave adhesive behind when you remove it later. Is your frame made up of lots of small windows, like ours? Simply tape over the wood using one long piece of tape. Then use a packing knife to neatly slice away the tape that’s covering the cross-sections of wood you’ll need to paint. See the video at the top of this page to learn exactly how.

Painting the window frame with a mini roller brush.

Step 9: Paint the Sanded Window Frame

Good job! You’ve reached the very last step in the restoration of your window frame. Give the paint a good stir and then start by painting all the tricky edges with a small brush. A brush is also handy for the frame’s sides. Next, use a roller brush for the flat topsides. For the best result, paint two thin layers, letting one layer dry before the next. When the final layer has dried, remove the tape. Before doing so, score the edges with the packing knife to cut through any dried paint and ensure clean removal. Finally, attach your frame to the window and admire your handiwork!


An old window frame

Safety gloves

Safety glasses

Dust mask

Ear protection


Triangle paint scraper

Router Bit (HSS) 6,4 mm (640)

Dremel Multi-Tool

Flap wheel 4,8 mm (504)

2-component filler

Filling knives

Random orbit sander + 120 grit sanding paper

EZ SpeedClic Sanding Mandrel (SC407)

Sanding Bands 13 mm grit 120 (432)



Piece of dry cloth

Small bowl or bucket with water

Painter’s tape

Packing knife

Paint suitable for outdoor use


Small foam paint roller

Paint tray

A few pieces of scrap wood