Super Glue wood finish. Help scaly white marks in Finish

[Damage8]

Hi, I am new to woodworking and this forum and need some expert help. Sorry if this is a bit long.

I recently made a laminated wood solid body electric guitar from multiple off cuts of hardwood (all done by hand) and I needed a clear grain filler and finish, so decided to try super glue. I have however hit a few problems.

As the grain was very open and deep, I applied lots of coats of thick viscosity glue to the guitar until the grain appeared to be filled ~ 10 coats. I then wet sanded it back to 220 and continued to apply multiple coats of thin glue after this. But I didn’t sand the surface back between each subsequent coat and I am now left with a scaly white marks in the finish. I think this is due to either the surface being uneven prior to applying the next coat or putting the next coat on without allowing the previous one to fully dry - so the rubbing in disturbed to previous layer. If someone could tell me what I did wrong, it would help a lot.

So, my questions are:
1) Is there a way to remove the white marks within the finish wood? I have tried sanded them out but they are too deep (even with 60 grit and many hours of sanding) and the finish is too hard. I have tried using super glue de-bonder, which worked a little. It tends to leave patches where it removes all the finish back to the raw wood and strips the finish out of the gain making it un-level again (reversing the grain filling). Its also difficult to remove as it dries fast.

2) How do I get rid of the white residue left by the sanding slurry? It goes away when wet and returns when it dries – tried water, acetone, alcohol (mentholated spirits) and brushing. Will something like applying wax or polish keep it looking wet and stop the white returning? All the pickup and control cavities etc are full of it. It is not effecting the smooth areas only little indents in the wood.

Any help you can give would be appreciated. As I have been trying to fix this for weeks.

 

[profchris]

I've regularly used CA (superglue) for local fills on acoustic instruments. The white, scaly bits are essentially air bubbles - the CA cures by absorbing moisture from the atmosphere, and if it absorbs too much too fast that creates heat, which creates bubbles.

There's no way I know of to fix this by applying something over the top.

For the future, what you have to do is, after each coat, remove any white scaly deposits by scraping (or sanding, but scraping is quicker and less messy. Once you get back to a smooth whitish surface you're fine for the next coat as all be bubbles are gone. I think that thick CA might be part of your problem - it takes longer to cure through, which gives time for it to heat up and foam. I use thin CA in small tubes from the pound shop.

For this guitar, if you have white marks in only a few places you could scrape those back locally until the white marks are gone - something like single-sided razor blade is good. Then build back up with CA, scraping or sanding between coats.

If there are white marks everywhere, scrape back to good CA and then build up with more CA until you get a flat finish.

 

[thetyreman]

I'd just scrape off the finish and start again from scratch, sounds like there's no way of fixing that.

 

[Damage8]

Thank you for your help. I now know how to avoid it in the future.

For this one, I have managed to remove the areas with a razor blade on the front and it now looks good.

The back is really bad though and the white appears to be in one of the early coats. Do you happen to know a quick way to remove super glue from the wood? Nail varnish remover (acetone) doesn't touch it, sanding and even a razor is taking hours - managed to do about 1 square inch in 2 hours. De-bonder just reactivates the glue for a few seconds, but it is difficult to remove the result, as it turns into a sticky rubber like gel.

Thank you again for any help.

 

[profchris]

A proper cabinet scraper (hand, not a Stanley/Record). This is a piece of steel maybe 4 inches X 2 inches. Once you've read up how to sharpen it (for this purpose a burr made by a stone would be enough, no need to burnish), you hold the edges and push it across the surface with your thumbs. This shaves a 3 inch wide strip, and you might take the back down to good CA in just 5 or 10 mins.

If you have a hand plane and the back is flat, you could even plane the finish off - CA sets to acrylic plastic, which is quite soft.