Wednesday, February 29, 2012

Hofner Colorama II restoration project (part 18) - rescuing a ruined finish

Well, it happens. You have a lovely finish on your guitar and then you drop it, chip it, scratch it, or whatever. In my case I got a bit overly energetic while polishing it and this happened:



It probably didn’t help that the lacquer hadn’t completely cured so was still a little bit soft. I’m sure there’s a term for this, but I can’t for the life of me remember what it is. The long and sort of it is that I friction burned it, causing the lacquer to melt and shift.

First things first, I decide to scrape off the raised lacquer with one of my favourite new tools, the razor blade:



This leaves us with the following:



Next, I carefully sand away any remaining effects left by the original melting using 400 grit paper wrapped around a wine bottle cork:



This leaves us with this (you know that expression about things getting worse before they get better?)



Next, we go over it with 600 grit paper, again wrapped around a cork (800 grit would be better if you can get your hands on some):



Leaving us with the following:



Now I decide to go with wet sanding (you could do this on the earlier stages if you wish too), using 1200 grit paper:



Now it’s starting to not look so scary:



And lastly, as far as sandpaper’s concerned, I wet sand it with 2000 grit sandpaper:



Leaving us with this:



Luckily I had enough lacquer on there that even after all the sanding, I never broke through to the paint. Had I done so, I’d need to do a bit of painting/lacquering and a little bit more sanding to get to this stage, but it would still be perfectly do-able.

Finally, it’s a case of using the rubbing compound to get the shine back (being a little less zealous this time around):



And the final result. It’s almost like it never happened:

Thursday, February 9, 2012

Hofner Colorama II restoration project (part 17) - finishing the paint job

Back in this post (http://diystrat.blogspot.com/2011/11/hofner-colorama-ii-restoration-project_30.html), we applied some initial coats of paint (two complete rattle cans, in fact) to our vintage Hofner Colorama II and left it to dry for a few weeks. This is how it looked after that:



The whole body was then wet sanded with 400 grit paper wrapped around a rubber sanding block.



This left us with a clear view of any imperfections that were either small divots that were missed at the time of filling, or where the filler didn’t stay in place during pre-paint-application sanding.



Rather than applying hundreds of coats of paint until these were filled in, they were spot-filled instead. To do this, we sprayed some of the red paint from the same rattle can into the rattle can lid, left it to thicken up for 10 minutes or so, and then applied it with a small paint brush (the paint brush can be cleaned afterwards with mineral spirits (turps) and live to see another day).



The filled-in areas were then sanded back again.



After this, another full rattle can of paint was applied and after waiting a couple more weeks, any remaining imperfections (much fewer than before) were again drop-filled:


However, this time they were carefully scraped flat with a razor blade:



The whole body was again wet sanded back with 400 grit paper as before, and was now ready to receive lacquer/clear-coat. About two and a half rattle cans were applied and thankfully there were no runs:



The guitar was then left a full month and this is how it looked after that:



To remove the “orange peel”, the guitar was again wet sanded with 400 grit sandpaper wrapped around a rubber sanding block:



Getting there:


Done:



After that, it was wet sanded with 600 grit paper, again wrapped around a sanding block, and making sure to sand in a different direction to the 400 grit paper. This is to make sure no marks left by the 400 grit paper were missed.



Then the next available grit was used (in my case 1200 grit [something like 900 grit would be preferable as an in-between grit, but I just couldn't locate any at the time]), again changing the sanding direction:



Followed yet again by the next available grit, which in my case was 2000 grit (again not ideal to jump grits this quickly, but sometimes you just have to work with what’s available):



Finally rubbing compound was rubbed in with a clean, fairly soft rag and the finish was polished up by hand:



Leaving us with this:



The camera flash is really showing the micro-scratches left by the rubbing compound in this photo, but to the naked eye they're not very visible at all. I'm going to wait another month or two before finally polishing them out, since it's become evident that the lacquer is still a bit too soft (more on that in the next post).