Repair And Restoration
TO ADD FORUM POST USE THE DISCUSSIONS TAB OR ADD NEW TOPIC IN THE SIDE BAR
Organizer:
- Organized by
-
-
Acetone Vapor Feasibility
-
Acetone Vapor Feasibility
I had a wild idea, and I would love to be talked off the ledge before I try it. I’ve seen some acetone vaporizers used in headlight repair, and the thought occurred to me that the concept could possibly work for blending poly finish with Ca (fill and finish) to lessen witness lines without sanding.
The idea would be to fill the finish chips as usual and scrape flush with a razor blade, then use the vaporizer to blend the edges before normal sanding and polishing.
Thoughts?
-
8 Replies
-
+1 interested in hearing about this. I know a few people have had some pretty successful techniques for poly touch-up repair but I’ve never mastered it. IIRC, Taylor guitars used to offer training on this at the higher tiers of their warranty repair program. I got through a couple levels of their training years ago but didn’t get around to finish repair, so maybe I’m wrong. I was under the impression that they would blend out the area of a ding with different sanding grits and create a bit of a concavity around the repair area, and this somehow made the witness lines on drop fills much less noticeable on poly.
Any further info on that technique or this acetone idea would be really interesting–maybe some of it already exists in a ding kings segment? I’m just beginning to navigate the site and haven’t seen it all.
-
Yes Brian, this part is correct: blend out the area of a ding with different sanding grits and create a bit of a concavity around the repair area, and this somehow made the witness lines on drop fills much less noticeable on poly.
But, we always sprayed a “spot” finish over the area to cap the CA. That’s the different grits idea, 600 grit on the outer edges to blend the new UV spot.
We would trough out the “ding” area to remove any vertical cracks in the finish. Much like the 2 edges of drywall go together before tapping and mud.
We couldn’t get a good repair just buffing a filled CA area, the CA was softer and would “sink” a little bit. It was also shinier, so the sheen didn’t match.
-
That’s one thing about fill n finish is the sheen is much better than the old glues. I did a repair on a PRS with the McFaddens we used to use at Breedlove and because the sheen was so close the layer line was there, but super duper subtle.
-
Good point, yes, I did a Fill&Finish on a PRS that turned out killer. Very compatible with whatever Poly they had on there.
-
-
-
You could totally try this.
One thing I might add is a lot of the witness line on a CA repair on poly is due to abrasions from prep.
I prep for CA repair just like I prep buffing, which is to say I sand through the grits down to 2000 grit. When I used to get wicked layer lines, I got a magnifier out and realized most of what the line was, was sanding marks form lower grits. What was happening was that when I was prepping out to buff, my abrading was just constantly revealing a fresh edge of deep marks. The polishing was just constantly, microly moving the edge back. When you prep down to 2000, that comes up to sheen with polish before the edge moves back. The layer lines can get really subtle.
-
Ian,
I get that. The repair that got me going on this was a Gibson j-150 which had been hit by a shoe. There was a lateral crack in the finish right along a grain line and to be honest I reglued the braces, put a little color on the exposed wood and then started right in with the fill-n-finish without sanding the surrounding area at all.
I used the tape over the razor blade method and then started stepping up sanding sticks from about 800 up to 2000. I’ve added 4f and rottenstone powders to my arsenal (which have been awesome) so I took it to a almost full gloss with that and then hit it with a light polish. The lines showed through and I always hate sanding on any finish any more than I have to.
I may try the acetone vapor (obviously on something else other than a good Gibson jumbo). And report back, I just wanted to see if anyone had ever gone down this path. I always end up trying to reinvent the wheel.
-
-
That is maybe a little far inside, but once on a larrivee I taped to a grain line and used fill n finish out the the binding. That layer line being on a grain line really obscured it.
For what it’s worth, from the pictures, it looks like you have already prosecuted an above average fix.
-
Log in to reply.