First repair would love to hear pro feedback... Question on finishing???

[J45joe]

Hi Folks,

My first post here.  Leveraged lots of internet info from here, acousticguitar forum and youtube, along with personal correspondence to do my first repair on my j45 with a 13 year old crack. Figured it was about time to fix it :)

Enjoy :)

https://docs.google.com/document/d/1QsIy-ku0B3mDKIuyqZdiDHlLDHBw5_n...

As for my question,  the finish is still cracked.  should I do anything to "seal" the finish?  If so, is there anything I should do other than drop fill and sand?  Any magic tricks that I should do?

Thanks

Joe

[jbbancroft]

It’s going to be nearly impossible to make the cracked lacquer disappear. A simple sealer I use is thin superglue applied to the crack. It is easy to build up and level with the adjacent finish. 

As long as the crack is glued and cleated, if needed, then it’s not necessary to seal the crack. You can seal with either shellac or Lacquer if you want it sealed, but will take more time to build up and level as compared to super glue. Or, you can just apply a sealer coat and forget about building it up level with the adjacent finish.

Jim

[J45joe]

Thanks Jim. The crack is glued tight.  Good to know that sealing it is not necessary and only a cosmetic thing.  If I decide to go for it and run a thin line of thin ca glue, would I still need to sand and buff?  I also saw another post talking about using retarder to melt the crack.  It seems like overkill to buy a quart of that stuff if it’s only cosmetic.  Would you agree?

thanks again

Joe

[jbbancroft]

If you just apply a thin layer of superglue you won’t need to level and buff as you won’t be building up the finish. Shellac and lacquer will also work as a sealer. You will only need to build up the cracked finish if you are trying to make it look better, which doesn’t always work.

Jim

[jbbancroft]

If you just apply a thin layer of superglue you won’t need to level and buff as you won’t be building up the finish. Shellac and lacquer will also work as a sealer. You will only need to build up the cracked finish if you are trying to make it look better, which doesn’t always work.

Jim

[J45joe]

Thank you Jim!  Appreciate your help!

Joe

[Mark McLean]

What you need to know about the finish repair is illustrated by Guru Frank here:

http://www.frets.com/FretsPages/Luthier/Technique/Finish/Lacquer/Dr...

Don’t miss the link to razor blade scraping:

http://www.frets.com/FretsPages/Luthier/Technique/Finish/RazorScrap...

You can use CA glue as your filler, or nitrocellulose lacquer as Frank does.  But the technique for levelling, sanding, polishing and buffing is the important bit.  

Guru Dan imparts some useful tips here:

https://m.youtube.com/watch?feature=emb_rel_end&v=rTVScFJoe24

Finally, if you want to see it again, Guru Robbie also has a demo here:

https://m.youtube.com/watch?v=oCc-rK6REmg

Welcome to the cult

Novice Mark

[J45joe]

Hi Mark

This is a fascinating world of restoration and repair :)

Thanks for all of the links.  Lots of options!

The razor blade technique has made me start thinking of all sorts of finish repairs around the house!

Did you guys ever see this video that uses retarder to melt the crack? It seems like magic.  

https://youtu.be/FISY9I6pQdQ

since I only need a few inches,  would this suitable?  
https://www.umpretail.com/products/tamiya-40ml-lacquer-retarder

Lastly, I saw someone use clear nail polish on another site.  That scares the bells out of me but we have that problem n the house so.....

Since I glued the wood, it’s so tight now that you have to be right up on it to see it...

Thanks

Joe

[Greg Mirken]

If the goal is to make it as unobtrusive as possible, the best thing to do is stop now. Using lacquer or CA to seal it, which might then require wet sanding and buffing, is going to make a small crack into a large area that looks like a brand new finish [or worse]. I might take a 000 brush and a tiny amount of tinted lacquer to it, but I have decades of experience with this sort of thing. I would still avoid buffing.

[J45joe]

Thanks Greg!!! I don’t want to make things into a nightmare.  Appreciate the advice

Joe