Restoring An Exterior Wood Sign

Our exterior wood sign had aged badly in our damp environment. Discoloured with algae, warped and cracked it had clearly suffered from the damp, despite being decent old slow growth timber.

Once this piece of pine was flat. The crack probably wasn’t there when Michelle routed and carved our beautiful hand made exterior wood sign either.

Let’s get the sign down and do what we can for restoration. We clearly need protection from weather, and I am keen to make the lettering stand out a bit more too.

First we sanded the sign with a random orbital sander and 120 grit paper. The discolouration went deeper than that. Refinishing needs more effort than I was prepared to do by hand on the edges.

We rerouted the edge using the correct profile bit (a cove ) in a Ryobi palm router (also known as laminate trimmers sometimes). Simple; nice clean edges and the original look and feel of the hand made exterior wood sign restored.

As the discolouration of the faces was rather deep, we used the random orbital sander from 40 grit down to 400 grit. This left the faces pretty nice, with odd patches of discolouration where damage to the timber had allowed deeper discolouration.

We used a small hand held rotary tool with a rotary wire brush to clean out the hand carved lettering that made our external wood sign say something useful.

Finally we addressed the last few bits of discolouration on our external wood sign, as far as possible, by a three hour bath in a gallon of water which had a mug of bleach added to it. We submerged the sign in the bleach bath, and then dried it in the conservatory over four days.

The finish was probably as good as when new now. So – How do we keep it this good when we put our sign back outside, and how do we make the letters more readable?

I lined an old biscuit tin with plastic to make a bath to immerse the end grain of the sign into during treatment. This tin did not have soldered edges, if it did though it would have been liquid tight without lining.

We can immerse the whole end grain of the sign with only a few hundred ml of CPES. The tin now makes a handy drip and recollection tray whilst painting the faces and edges of the exterior wooden sign.

I used a small bottle of 120ml capacity to measure identical amounts of part A and Part B CPES into the lined biscuit tin. We stirred the Clear Penetrating Epoxy Sealer with the disposable brush to mix the it in the tin.

With the exterior wood end grain immersed in the bath of CPES, the chip brush is used to paint the faces and edges of the sign.

The sign was left immersed into the bath for fifteen minutes on one end and the faces were painted.

This was repeated on the other end grain, and the faces repainted again.

I repeated that process one more full time (half an hour of immersion on the end grain, and four coats at 15 minute intervals on the faces and edges) .

Notice how well the Clear Penetrating Epoxy Sealer has bought out the grain.

The exterior wooden sign is then removed and hung up to dry.

A second coat will be done later when the majority of the solvents have evaporated. We determine solvent evaporation by smelling the end grain area.

We removed unused CPES from the bath and put it back into a closed bottle and stored in a cold dark place. This slows down the setting of the CPES. The CPES should still be usable to apply our second coat once the solvents have evaporated from our exterior wooden sign.

Two coats applied and dried to the touch (overnight) as before, the sign is starting to look nice now.

The warped sign made us fill the words on the sign one at a time. I set the word ‘Lodge’ level on a flat surface, and clamped it down. Clamps held it down onto plastic spacers that levelled it on my work surface.

I score Irwin Quick Grip clamps very highly indeed by the way, as they are fast simple and very reliable.

To ensure accurate mixes I use kitchen scales to weigh the two components of the Smiths Layup and Laminating epoxy that I used.

I could have used any epoxy resin with a set time of a half hour or greater here instead of layup and laminating.

We decided on black lettering for a classical look, and added a small amount from one of our epoxy colouring kits.

I mixed 22 grams of epoxy for each word on our sign. This was more than enough, but means that the colouring is very consistent.

I used a disposable pipette to carefully fill the letters to level. The resin is liquid so it will flow and settle.

Once the resin has settled the levels can be adjusted by adding or removing resin with the pipette.

If you don’t have a steady hand then I suggest you find someone who does here. It is an awful job clearing epoxy resin off if you spill any, particularly if you don’t have clean up solvent to hand.

Use a blowtorch or a lighter to burst any bubbles that rise to the surface of the resin. The localised heating will also thin the resin and assist it to flow and level faster. I used this lighter for about 4 seconds per letter to burst the bubbles here.

The nearly finished wood sign is now ready to have some UV protection applied to it. It already looks far better than it did when it was new, let alone a week ago when the restoration started.

Firstly I flattened the CPES with some fine wire wool. CPES is very much easier to use to fill grain, and prime timber with than thinned varnish. Furthermore it sands far easier too. It’s deep penetration enhances the natural grain of the timber whilst priming it perfectly.

That it also makes your varnish finish last many times longer is really the cherry on the top. This is a trick much used by the wooden boat fraternity.

The sign is then washed and dried to remove sanding residues before we proceed any further.

Before applying top coats we now apply a final thin coat of Smiths Clear penetrating Epoxy Sealer (CPES) to the exterior wood sign.

This will make our top coats stick as chemical bonds will form between the top coat and the still curing CPES. I will apply the top coats tomorrow.

I applied the CPES with a rag to save wasting a brush. We only want a thin film as the wood is already saturated with CPES.

Then I hung the exterior wooden sign up to dry for a few hours. The applied film was thin enough that it was solvent smell free then.

We applied a single coat of Sadolin Superdec paint which is microporous to the back of the exterior wood sign, and let it dry overnight.

Microporous paints work very well indeed over Clear Penetrating Epoxy Sealer, as it is also microporous.

I apply the first of 5 coats of Epifanes High UV gloss varnish by brush.

Wrapping the brush in cling film was a mistake, as the Epifanes was hardening and the brush required significant cleaning. The brush was cleaned in white spirits after every application following this discovery.

I sand the Epifanes after every coat has dried (24 hours) to ensure that the coats adhere perfectly together. Use 400 grit sandpaper or finer. Alternatively fine wire wool can be used.

I apply another coat of black microporous paint to the back of the sign and it is deemed fit for purpose.

The finished sign is mounted on our gates once more. The finish is quite magnificent – shiny flat surface with wonderful grain.

This is June 2019. I decide I don’t like the blackboard on top of the sign – so that will get moved.

Future maintenance of the sign will be logged here, as will the ageing of the finish. A photographic library will develop.

The end grain of the sign looks pretty fabulous and weatherproof as well. This was Spring 2019 when this sign was initilly restored.