Damaging Your Finish

[BlindBo]

I learned a valuable, but, painful lesson yesterday. I have a relatively small shop. Even though I have a good dust collecting system, almost all of my dust generating equipment is on mobile carts. I usually roll those outside to minimize as much dust as possible, weather permitting. I also live in the Deep South where summer temps and high humidity create all sorts of challenges. One that I hadn’t considered enough is the swarms of mosquitoes 95 degrees and 90% humidity create.
This time of the year I have to bathe in Deet before working outside. Yesterday I was buffing a beautiful sunburst OM for my grandson. When I finished and brought it into the shop for the night, I found anywhere I had held it against my arms, the finish was seriously damaged. I was so discouraged, I just turned off the lights and locked the shop door. Ended up spending the day today repairing the finish and getting ready to start the buffing all over tomorrow.

A lesson learned the hard way. My new procedure involves minimizing deet usage, wash your hands really well, put on a clean long sleeve shirt and use latex gloves when handling a finished guitar (or raw wood when building). From time to time I’ve had spots appear (oh, about the size of a finger or thumb print😫) that will not accept lacquer w/o bubbling up. I usually wipe everything with NAPTHa followed by tack cloth before spraying. But, apparently, even NAPTHA doesn’t evaporate deet deposits.

I hope none of you ever have to suffer the effects of deet on lacquer! Going forward, anytime the deet is required, I’ll be dressed like I’m handling nuclear fuel! Hope this helps someone.

[Kevin Sjostrand]

That is a tough lesson to be learned. We've had bad mosquitoes here in past summers, this year not as bad.
But i have in the past used repellent on my arms and back of my hands and I seem to recall it causing me some issues with finishing.. I think denatured alcohol worked well to clean the wood surface. Can't recall for sure though.

Duck hunters ruin finishes on their duck calls using Deet.

[BlindBo]

Found this on ChatGBT:

If you’re looking for a mosquito repellent that won’t damage or react with lacquered surfaces (like furniture, guitars, pianos, etc.), you need something that doesn’t contain DEET.

DEET is an effective repellent, but it can soften, dull, or even dissolve lacquer, plastics, and certain finishes.

✅ Safe alternatives for use around lacquered surfaces:
• Picaridin (a.k.a. Icaridin) – Often marketed as being “gear safe.” Won’t harm lacquer, plastics, or synthetic fabrics. Brands: Sawyer Picaridin, Natrapel, Ranger Ready.
• Oil of Lemon Eucalyptus (OLE) – A natural option that doesn’t melt finishes. Brands: Repel Lemon Eucalyptus, Murphy’s Naturals.
• IR3535 – Gentle on materials and skin (used in Avon Skin-So-Soft Bug Guard).

❌ Avoid:
• DEET sprays or lotions (they’re known to damage lacquer, some plastics, and even eyeglass coatings).

[BlindBo]

I found the Murphy’s OLE on Amazon (along with several others) and it’s on the way. It’s not cheap, but, neither are our guitars. 💰
My situation got a little worse this morning. While building the OM, I decided to refret my favorite guitar. It’s a Brazilian, OO-45 I built several yeas ago. I decided to rebuff and polish it while having the equipment out for the OM project. Last night I put the final wax on it and polished it this morning. Damn if it didn’t have three or four damaged spots on the top too. This effort is turning into a ”Tar Baby” project, I just can’t get my hands loose!😂 Not sure you can see them in this picture, but they are around the edges near the end block,

IMG_2155.jpeg

So, I now have two guitar finishes to repair. Since the deet came in contact with the surface, I’m hoping I can sand it smooth w/o burning through the Tobacco Brown, clean the spots and repolish. I’ll report back.

Today I’m getting anything containing deet the hell out of my shop!😥

[Stray Feathers]

As a lifelong birder and former dealer in binoculars and telescopes, I've had lots of experience with deet removing black paint from older binoculars. Newer ones mostly have rubber-like finishes and I have seen what I think is perishing from deet , but I suspect some of these newer coatings may be tested for deet resistance. One company refinished my spotting scope for me at no charge, because I think they realized their coating was being damaged. Bottom line is to be aware of the risks with deet! Bruce W.

[BlindBo]

I am pleased to report success (not a word I often get to use!😂). Spent the day working on the OM damage. First step was gently wet sanding the spots with 400 grit. Surprisingly, I was able to level the spots with no burn through or having to add any lacquer. After that I went through the 5 grits of Super Assilex. So far, so good.
Then back to the buffing wheels with 4 grades of rouge. Finished by polishing with 2 grades of polish and finishing with McGuiar’s #9 Swirl Remover. I still need to apply and polish with wax tomorrow. Best I can tell (of course I’m 85-90% blind😵‍💫) the repair worked. Tomorrow, it’s a repeat on the 00-45. I’m exhausted!😴🍺

IMG_2162.jpeg

BTW, this is a short scale 0M-28 with Bloodwood back & sides, veneer, fretboard, and bridge. The neck is a 3 piece maple with a Bloodwood center strip and the back is 3 piece with a maple inset. The top is red spruce.

IMG_2163.jpeg

The kit came from John Hall. He really makes a great kit.

[TEETERFAN]

Great recovery! I marked up a lacquer finish one time after I wiped my hands off with lacquer thinner. My hands felt dry, but enough remained in my skin to mar the lacquer. I now wait a few minutes before I take a chance. Additionally, I try to clean my hands with acetone now. It evaporates much faster and is relatively low in toxicity. If I was smart, I would take care to keep my paws clean.
Anyway, the sunburst looks so nice and the 3 piece back is beautiful.
That’s one tasty looking instrument!

[BlindBo]

Thanks so much. It’s turning out really nice. Leveled and crowned the frets this afternoon and will apply the wax tonight.
After what I’ve been through this week, anytime I’m using lacquer thinner, I’m washing up and putting on gloves before handling anything finished.