I hate to be a pain

[mario515]

Let me first say thanks to all who have pitched in their advice and suggestions to not just me but to all the other novice builders who are building their first mando,, its a great thing,, I have learned much(mostly that I will never be a luthier, but its definatly been a fun/frustrating process.) Heres my question, is there a way I can be rid of this dull cloud that has engulfed my mando??(mostly around the sides). You know it was kinda bugging me so I tried a little wet sanding at 1500 but that seems to have made it worse and I was messing with it this morning(action problems/filing the nut down a tad) and I put some mineral spirit to it and it dont look half bad when its all wet and clean but as it dries the cloud slowly returns. I've done the swirlx and the scratchx but that doesent work. If there isnt an easy fix to it thats cool, I'm just not up for stripping it down again at the moment as I've done that twice already. Tnks again this joint is priceless(overstatement?) http://www.mandolincafe.net/iB_html/non-cgi/emoticons/mandosmiley.gif

[Dale Ludewig]

What's the finish? You say "engulfed your mando"- do you mean that the finish was dry and then, shall we say, days later this developed?

[Jim Rowland]

Mario,I'm sure you posted the type of finish you used somewhere,but I can't find it. It's important to know before offering any advice. From your description,it sounds as if you have moisture trapped in the finish. This is probably what Dale is getting at.
Jim

[Jim Rowland]

OK,I found your post naming the finish. Multiple coats of shellac. Wait til you hear from some others who know more about finishes than I. If you get no satisfaction,I'm going to tell you what I would try,as a last resort. Get it as smooth as you can with 320-400 grit paper. Shoot three coats of clear nitro,(Deft gloss in a spray can works fine,is cheap and available everywhere),wait ten to l4 days,level and polish. I can't guarantee any results,but it might work.
Jim

[mario515]

My apologies,, yes,, it is alcohol stain with shellac on top, I have posted about this before and I was sure I did what I was supposed to do,, but,,,maybe I didn"t. I put the stain on and let it dry then I sprayed a couple light coats of spray shellac,let that dry and then applied a few coats of shellac by hand. I didnt really notice the clouds until I was sanding in between coats and like I said, it seemed the more I sanded the worse it became,,Jim I thought appliying nitro on top of shellac was a no no? Dale no this clouding usually appeared when I tried to sand down between coats.

[Jim Rowland]

I've not had problems with nitro over shellac. Perhaps others have.
Jim

[Dale Ludewig]

You can put nitro over shellac. In fact, you can put almost anything over shellac. But, this sounds like trapped moisture. When it happens with lacquer, it's called "blushing", although there is no lovely woman involved. I suppose you could call it the same here. In any case, it sounds like trapped moisture. But- do not recoat with anything until this problem is resolved. You're only going to make the problem covered up with more finish. It will still be there.

With lacquer, you can sometimes do a light coat of lacquer with a fair amount of retarder in it, although I'm not a big fan of that process. You could try spraying, (no other way, sorry) a light coat of denatured alcohol over it and hope it opens up the finish enough to let the moisture out. Otherwise, if it were my problem, I'd consider using a hairdryer- or a VERY CAREFULLY used heat gun- the idea is to get the moisture to vaporize and escape the finish without ruining the finish. I've had remarkable results with this with some old furniture. I've also used it rarely on instruments, but I'm so careful about the moisture/lacquer problem that I always use retarder.
I don't know that much about how to deal with this problem with shellac. I don't know of a "retarder" for shellac. Were you applying the finish when it was humid? Likely, I would guess.
Also, were you spraying or brushing? You said the sides were the worst- to me that indicates brushing, because I would guess you started with the top and back, there was some "run-over, aka dripping," and then you did the sides and so the finish was thicker there, trapping the moisture because it took longer to dry. Man- I can get long winded, can't I?

Hopefully, Fletcher Brock will chime in here. He knows, from my experience, shellac finishes very intimately. Fletcher?

I hope this helps. But regardless, don't recoat with anything until you have this problem solved. You'll only compound the problem.

[mario515]

Thanks Dale, this is great Yes I was applying it in my basement when the temps decided to soar that week. It makes sense to me and I will see how it goes.

[Jim Rowland]

Dale's advice is good. I am inexperienced with shellac,except to use it as a base coat. On nitro,blush is often relieved by a medium light sanding which liberates some or all of the moisture underlying the top coat. I hope you'll let us know how all this turns out for you. Best of luck.
Jim

[Jim Garber]

I had this problem with my vintage Gibson. I would be very careful with the heat gun and the hair dryer. My expert luthier fixed it for me and I believe that he did very careful controlled and monitored heating with a desk lamp and 60 watt bulb.

Jim

[devilsbox]

Should you wet sand shellac? I am no expert, but I thought water and shellac were a bad combo. Remember those ugly white rings left on furniture from wet glasses etc.? The hair dryer idea might work. Good Luck!!

[Yonkle]

Been there, done that! I had some blushing on 2 of my mandolins, from spraying when it was too humid. It turned to a "milky" looking haze in some areas of the mandolin. I just took some 400 grit and carefully flat sanded the whole body again (keeping fingers X not to break through) After getting a good flat sand, sprayed again (when it was dry outside) and it was crystal clear, then re-buffed ect.
I had this happen with lacquer and also with shellac. With the shellac, as soon as I saw it going milky, I rushed the poor mando into the house, where it was warm, hung it in the closet and pointed a fan at it, from about 10 feet away. As the shellac dried, the "milky" went away, took about 15 min and it was clear or blond. If I saw any sign of blushing after it dried, I just flat sanded the area, and went on with the next coat, (on a dry sunny day) Good Luck JD
SEE PHOTOS (GOOD EXAMPLE OF BLUSHING) These are my #1 and #2 mandolins. I refinished both of them 2 years later (after I got better at it)

1st photo: Lacquer finish, SEE Blushing in Neck Area, above the Button!

[Yonkle]

Two years later,with me being a bit better at finish.
Sunburst, with a Blond Shellac Finish. Clean as a whistle!
Viva La Differ'ance! No?
Sometimes I even amaze myself!

[Bill Snyder]

Should you wet sand shellac? I am no expert, but I thought water and shellac were a bad combo. Remember those ugly white rings left on furniture from wet glasses etc.?
I have wet sanded my shellac finished instruments with no problems, just did not go overboard with the water and did not let water stand on the finish.
I am not sure how to remove the blush. If you try spraying the alcohol on the instrument as suggested make sure it is a quick, light spritz or you could end up stripping the instrument again whether you intend to or not. I speak from experience about that. #http://www.mandolincafe.net/iB_html/non-cgi/emoticons/tounge.gif

[labraid]

Sounds like a problem of finishing in an area that is too humid and not warm enough... When you use a spray can, the spray at the very exit of the nozzle is cooled substantially, much as the innards of an air conditioner function. This instantly condenses some of the humidity in the air (more humid obviously makes more condensation) which then mixes with your spray, and when the environment is too cool it can't evaporate fast enough, hence your problem. Wait for a nice warm afternoon in the upstairs garage perhaps..

[kvk]

So what's the trick to getting the environment right if you are a typical hobbyist relegated to a damp basement during an humid eastcoast summer? Wait till the heat comes on in November to do your finishing??? Leave a whole bunch of incandscent lights on before your finishing session???

Maybe turing both the heat and A/C on at the same time would do it; just don't let the wife see the utility bill http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

[Yonkle]

[QUOTE]Quote (devilsbox @ June 19 2005, 22:27)
Should you wet sand shellac? I am no expert, but I thought water and shellac were a bad combo. Remember those ugly white rings left on furniture from wet glasses etc.?

I wet sand shellac, but I use very little water and just a touch of mineral oil or olive oil for a lubracant. I used to use dishsoap, but it leaves and film and you can't see the scratch's leaving while sanding. You have to sand and wipe. Also leaves dry scum in small areas between the binding and wood. Oil works much better, I wipe it off right away too, don't want to leave it standing on the shellac. Very fine scratches I use McGuires #10. Or I use the (french polish) type method rubbing alcohol and olive oil into the shellac and burnish the scratchs out. This can be deadly if you don't know how to do it, take pratice, I finish my #2mandolin entirely this method (F.P.) and find that wet sanding and McGuires is much more easy and safe. JD