Official Luthiers Forum!

Hello, I've been watching the forum for the past 6 months or so and have run into a problem I haven't seen addressed recently. But first I'd like to give some public thanks to the OLF sponsors I've dealt with over the past months.

RC Tonewoods: Ziricote and Pomele Bubinga b&s, Curly Redwood top
AC Woods: Padauk and Mad Rose b&s, mahog neck
Australian Tonewoods: beautiful curly Blackwood b&s
CTH Luthiery: Thicknessing jig - a well thought out design.
Stew Mac: tools, supplies and books.

Great customer service, top quality products, well packaged and promptly delivered.

Now my problem. I'm working on #4 - sitka top, padauk b&s from AC Woods, olivewood rosette, ebony binding- and I'm having trouble with the finish. Z-poxy base followed by Stew Mac's aerosol sanding sealer and lacquer, applied as directed with ~ a 2 week cure. The problem is the sealer is leaving a milky haze that's really noticeable on the ebony. I'm also having problems with adhesion. Last night I scored the finish for the neck joint and when I removed the blue tape the finish came with leaving a layer of soap like sanding sealer. Anyone have any ideas as to what I'm doing wrong? My followup question is, my shoulder is still sore from the 4 hours it took to rub out the finish, any recommendations for buffers?

Thanks for your time.

Bob K

Hi Bob, welcome to the OLF! Sorry i'm not much help with your question, i'm not there yet on my build but i'm sure someone will answer you shortly!

Good to have you here!

Serge

Sanding sealer is actually worse than just using finish alone .. I was using Mohawks lac based SS on a couple gutiars, adn had hte same thing happen. If you ready Understanding Finishes, I think by Dresdner, he says sanding sealers have stearates inthem, to aid the sandingness (new word there) of the stuff. Well stearates are milky looking arent they - just look at stearate coated sandpaper - as well, sanding selaer with the stearates is also softer than the harder finish coat lac you are using. I gave up on the stuff even though it made filling pores and flat sanding a breeze - its not worth it in the end - a slight knock on the guitar will produce a blush blister as the finish doesnt adhere to the sealer as well as it does to bare wood - go figure. My advice, ditch the SS. There may be other finishes where the SS is really a good thing, but I havent seen one with lac. I htink MArio had a similar prob, maybe a different finish, but he said a small knock and most of the finish pealed off in a single layer - OUCH.

One of my students is in the wet sand phase right now - the bottom line I told him is nothing comes for free at this stage - its all elbow grease.

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Serge, glad to be here.

Hesh, thanks for the info. Sounds like going forward I should skip the sealer. Maybe I'll get lucky and the finish that's on there will stick with further curing. Re the buffer, what are the advantages of an arbor and motor vs an all in one unit?

Thanks Tony, I had a nagging feeling as I was spraying the first coat that I didn't really need it. Are the vinyl sealers "required" under behlen and mcfadden's lacquer similar? I've been thinking about getting a spraygun, but the results of the stew mac aerosol seemed decent. And as Hesh says, it holds up.

Ditto on other comments,

I use Zpoxy only on B&S with the first coat a 50/50 mix, sand back down to the wood leaving just the pore fill, then follow the MichaelP suggestion I believe and mix a very thin 60/40 mix with DA to thin and coat the entire B&S area and don't sand back just to pop the grain and final seal. Top use one coat of dewaxed blonde shellac also thinned. From there finish, I have never used the aerasol spray over the Zpoxy and feel that may be causing the problems.

My 2 cents

Mike
White Oak, Texas

the main differences between the arbor/motor and all in one units is the cost of getting the wheels far enough apart and the rotational speed slow enough.

slow, wide all in one units cost $$$$$$$!!!!!! and weigh ###########, both in the too much category. the arbor/motor combos are much more affordable and moveable.

[quote]Hello, I've been watching the forum for the past 6 months or so [/quote]

Hi Bob!!! Welcome to the OLF! It felt like somebody was watching us!

   I've heard bad things about some sealers, but I'm no expert.

_________________
Billy Dean Thomas
Covina, CA

"Multi famam, conscientiam, pauci verentur."
(Many fear their reputation, few their conscience)

Thanks for all the help guys. I think Tony hit it on the head first. I went out this afternoon and tried the thumbnail test and got a white "blister" the size of a pencil eraser. I then tried the same test on the ebony headplate. I didn't put the sealer on it becasue of the discoloration problem. This time no blister and barely an indentation. Plus the headplate has only had 4 days of cure time. As for the Z-poxy prep, I think I've been diligent. Sanded to 400 and wiped with DA. I've been applying the last coat (unthinned) by hand, literally, and wiping with a cotton T. Next time I'll try a thinned coat instead. I never thought to follow with shellac. I spent the afternoon scraping, sanding and using thinner to remove the old finish and just put on another coat of Z-poxy to seal any residue I might have missed. I guess I know what I'm doing on the holiday, but at least I'll have a month or two to figure out the buffer situation.

Thanks again for all the help. It's great that those with more experience are willing to go out of their way to help others.

Bob K

Typically the milky hase is a sure sign of too thick of a single coat. The soapy sealer around the tape is likly sue to the solvent in the sealer drawing out the adhisve from the tape. this is always a danger if you apply a wet coat over making tape. If you use masking tape, keep your first two coats very dry coats and allow to dry full before next application. This will seal the edges of the tape and help prevent the solvent of later coats from drawing out the adhesive from the tape.