Clear for redgum recommendation?

[Canoath]

I've got this small slab that I was asked to refinish. It was weathered, all grey and I set about sanding it back and it came out really well. I wet it down and man that made the grain pop. Then, once dry, I used Cabots exterior marine polyurethane clear and the timber was so dark that even in the sun it was too hard to see the black contrast of the number. I left it for a while but it never lightened up so I brushed a heap of turps on to remove as much as I could

I've sanded it back again to grain that's not as light as it was before and now I'm ready to coat again. Any recommendations as to what clear will work without darkening the grain too much? I've used that cabots stuff on tas oak, merbau and meranti before without issue, but no go for this particular bit of redgum.

This is what it looked like after final sanding


First bit of clear going on looked promising but it went darker


I don't have a pic of the front that shows how dark it got but this is the rear after turps was used to wash the clear away.

[Arron]

Its going dark because its basically endgrain.

Any oil or poly applied direct to endgrain will darken it.

You need to seal the endgrain. Old soultions for sealing include shellac and well-thinned pva. Im not sure which is best for redgum.

Another thing which helps is to sand to a very fine finish.

Arron

[Cliff Rogers]

I like the colour of the timber, I'd paint the channel white & use the oil on the rest to highlight the timber.

[Canoath]

Geez, it sounds obvious in hindsight but I never even contemplated it being end grain. Thanks Arron, that explains too why some areas, particularly the sapwood, soaked up the non thinned polyurethane like a sponge. I've never seen this stuff do that before on such a big area, but typically I've only used it on face/edge grain. Now I think that by using turps to wash it off, I've inadvertently thinned the uncured product allowing it to move further into the grain and is why I haven't been able to sand it to be as light in colour as that very first picture. Looks like I'll have to throw a 40grit belt on the sander and start all over. This photo shows how dark it is still despite another sanding earlier today. Originally I finished at 240 and now 320 but still too dark.



Hi Cliff, even whilst the slab was at its lightest with the light red colouring I thought about making the number lighter. Rather than paint I've got a load of vic ash off cuts, shavings and dust to shove in that wobbly "2". I dunno, this little job was supposed to be a one day effort.

[Canoath]

A little update. I sanded twice to get to a lighter colour and it came up well, close to what the original pic was. The pic in the last post was after the first sand but I neglected to take another photo. I tried a PVA/water mix to try and seal the grain, then proceeded to add vic ash dust to the "2", and made a paste with the PVA/water mix. Didn't really look good by this morning. It hadn't set so I scraped it all out and gave another light sand of 240 then 320 and no doubt disrupted the PVA seal.

Sorry but I'm becoming impatient. I rubbed in beeswax assisted with a lpg torch, then scraped and buffed with cotton rag and gum turps. Took a while but once excess was removed and no hint of the rag leaving marks it came up really nice. Darker but not blackened like the polyurethane left it. Further to this I rubbed some Scandinavian oil. It looked really nice. Still dark but I'm happy with it. Unfortunately I only took one photo of the wax going on, none post oil application.



Next I decided to go high gloss all black on the number 2 to get the most contrast with the dark timber. So I grated some charcoal on a surform file and mixed it with pour on gloss. I think the result is nice. The only downside is because of the overflow of the epoxy, I had to use acetone on a rag to carefully wipe away extra epoxy away from the boundary of the "2". Fearing the acetone may have affected the beeswax and oil finish on the natural timber I gave the whole lot a wipe with acetone so whatever if the acetone has taken away some of the finish, at least the whole lot may be evenly affected.

It's going to take a while for the "2" to harden so I probably won't do anything for a few days. I'll probably put more Scandinavian oil on but I don't know yet. I think the slab will go under a North facing verandah so I'm not sure if a UV finish is required. The pour on gloss won't last in the sun that's for sure. I should've epoxied the whole lot then spar varnished but anyway, I'll let the gloss cure and give it some more thought.