Tru oil is not hardening / curing in one spot

[ThatCluelessGerman]

Hey folks,

so I've been tru oiling my kit for what feels like and eternity... More than 4 weeks or so... 99% of the guitar is cured and hard and looks fine, but there is one (deep) spot where it is just not curing. It stays like jelly and can't be sanded or polished (of course).

I don't know what I could do there. I've been trying to fill with pumice powder and tru oil, but what worked fine on most of the burl veneer, doesn't work there.
I have no idea how to proceed. It must have been 2 or 3 weeks since I added the last coat of tru oil, so it should be sufficient to harden out, no?

The spot that stays jelly like just doesn't change. As I tried to slightly sand it today, a big chunk of jelly just ripped out and now I'm back to square one, a hole that doesn't want to be filled.
Any advice?

Thank you!

[Simon Barden]

I'd clean it out, and see if what remains dries. Either there's something wring with the tru oil, or there's a chemical reaction going on stopping it setting. Have you tried it without the pumice powder? There may be something in that that's not just pumice.

I keep getting areas on my spraying that just bubble up for no apparent reason. It's very frustrating but there must be something there that's causing it, even if it's only a very small impurity that acts as a catalyst.

[ThatCluelessGerman]

Thanks Simon, that's what I just did. How long should I wait to see if it dries? It's way beyond 25°C here in our flat, so it SHOULD cure pretty quickly? So if it didn't harden until tomorrow, safe to say there is a problem in this spot, right? The tru oil should be fine, it's just 2-3 weeks old and worked fine on other areas...

I have tried without the pumice first, and found the advice with the pumice while doing research. So the pumice isn't the problem, but it's also not the solution I hoped for...

The problematic area is where the veneer was chipped and has been reglued (by the factory), so does that mean the tru oil is probably not liking the glue? Is there anything that could be done to fix it? Or do I have to live with it?

[Simon Barden]

It's probably the glue. Not sure what could fix it now.

[Simon Barden]

Maybe try and cover the area up with a layer of some thin CA/superglue? You'd need to get all the non-drying bits of tru oil off the spot first.

If you've been thinning the tru oil at all, then try wiping the tru oil off with a cloth soaked in that. Then wait until all that remains is hard, then a layer of CA (which should dry clear if left), then tru oil over that for colour/tint.

[ThatCluelessGerman]

That sounds like it's worth a try, thank you.

[Simon Barden]

For future projects it may be worth investigating Solarez 'I can't believe it's not lacquer' products. Grain filler and top clear coat. It cures with UV in a minute or two, so is very quick to use and sands easily. No solvents, so can be used indoors , then hold it out the window on a bright day and it will set (or you can use a UV lamp if it's a dull day). No days or weeks waiting for it to harden.

I've just bough some of the grain filler on Amazon and ordered the lacquer. It's expensive as they don't seem to have an UK or EU importer who stocks it, so it normally comes shipped from the US, which more than doubles the US price. But for your situation, the cost may well be worth it.

[ThatCluelessGerman]

Good idea, I have heard of this product before. I have an UV exposure unit so this wouldn't be a problem. For the next project, I have some PUR I want to try together with oil based stains, but I'm really interested in the Solaris stuff for the build after the next (Don't tell my husband I'm hiding two kits in the closet...)

[Simon Barden]

They have places in the UK & EU that sell their UV curing resins for surfboards and fishing rods and the like, but not the general finishing products. Which is a shame.

[JohnH]

(Don't tell my husband I'm hiding two kits in the closet...)

Ha ha ha, glad to see it's not just me