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Hey all. I've been hard at this commission for a month now and it needs to be delivered in a week. I used tru oil for it's speed of application and simple application method, but as the description says, I forgot to mask for the bridge and fingerboard extension. I plan on still scraping, but fear with an oil finish, I'm not going to get good adhesion when gluing, do to TO penetrating/oily properties. Anyone have an suggestions how I might be able to get a solid adhesion. A little careful swab with alcohol after scraping maybe? Superglue? Epoxy? If the bridge is a permanent bond, I'm much less worried about that than I am it popping off. I can always rout off the bridge if for any reason it needs to be removed in the future. I think I'm going to just scrape and use LMI glue for the fingerboard extension. Any input would be much appreciated!

I'd probably duplicate the finish on an off cut from the same top and experiment with various removal methods. Routing followed by scraping and small sanding blocks would be the first thing I'd try. You could also glue a block of your bridge material afterwards and see how easy it is to pop off.

Better to have a late delivery than take a chance on the glue job.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Contrary to popular belief, oil finishes do not penetrate and soak in to wood, especially the long grain.
Maybe the end grain can a little, with the softwoods, but nowhere you shoulkd be scraping is going to be end grain (unless you have SEVERE runout), so you should be fine, especially with tru oil which hardens and scrapes clean away.
I wouldn't be afraid, but you can make offcuts anyway.

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Old growth, shmold growth!

Thanks Terence. I've been building a finish over the last couple days on my top off-cuts. I'll be doing some testing in the next couple of days.

That's a relief to hear! I'll continue with my tests, but am breathing a little easier now.

I thought people might be interested in my test results. A disclaimer: The epoxy is about 5 years old and has sat the last couple of years without caps, but it was handy. The LMI Glue was a brand new bottle just opened, the Titebond is a couple months old, and the super glue about a month (medium viscosity from Stewmac). Also I applied straight TO to my test piece without a coat of the sealer TO first as I did on my actual top. The regular TO is thinned a bit more than the sealer so I think it soaked in more on my first few coats. I also didn't apply and wipe off as I did on my actual guitar, I just applied thin coats and let sit for a few hours 2 coats a day, and a total of 3 days. It did seem to absorb quite a bit on my first coat, but I was also surprised how much seemed to scrap off. I didn't scrape down real deep, just until it seemed like it was clean bare wood underneath. All pieces aside from the super glue came off relatively easily. I glued all at the same time and let sit for 3 hours, then clamped the small pieces of rosewood in a vice and pulled. I'm going to go ahead with the gluing and use superglue, and in the event that the bridge ever needs to be removed, I'll rout it off and make a new one. A much better option than having it pop off in my opinion. Thanks Terence and theguitarwhisperer for your input.

Mitch

Those glues need 24 hours to fully cure.

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Pat

I'll give it another go and allow to dry for another night and use a newer set of epoxy as well. I still have quite a bit of finished scrap left.