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Highly figured redwood
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deadedith

Total Topics: 34
Total Posts: 165
I'm working on putting a finish on a redwood top. When I first acquired the wood, it was an impressive grains/inch count and wonderfully bookmatched

As I was prep sanding, I discovered to my pleasant surprise that there is quite a bit of figure in the wood, on all of the top except for the outer portions of the lower bout, where the grain is straight. It looked great.

I applied two coats of shellac and sanded pretty well. THEN I applied some Minwax Wipe-on Poly and let it dry. I just went back to sand a little and wipe on a second coat but discovered that the figuration had taken the poly unevenly, i.e., there are very shiney figured stripes and duller stripes. Looks ok in most light, but turn it the right angle and it looks - messy, I guess. Not good.

Suggestions? I've got all the time in the world to get this right, so lay it on me!! :-)

Thanks
Dave B

Apr 12, 10 | 3:56 pm
Ken C

Total Topics: 30
Total Posts: 554
Hi Dave,

I have never finished redwood, but cedar and many softwoods have a tough time taking stains consistently. As your shellac has a tint, it is acting a bit like a stain and may not have been evenly absorbed by the wood. When staining softwoods, I typically apply a coat of sanding sealer first. The wood won't absorb as much stain, but it will absorb it more evenly. Tinted shellac can be tough to work with as any sanding will vary the film thickness, resulting in lighter areas. My guess is this is your problem. You have to sand every square inch of the surface evenly or you'll end up with uneven areas. Also if you sand through the shellac and apply a different topcoat, it could get absorbed differently by the wood, creating blotchy areas. I have used shellac to tint red spruce tops, but I spray the shellac followed by about 6 topcoats prior to getting any sandpaper near the finish. This provides enough clear topcoats that I won't be removing any shellac when leveling, giving me a nice consistently tinted top.

I'd sand back down to wood for starters, and make sure you are down to wood everywhere. Any finish left on the surface will result in a blotchy area when you start building up finish again. Then if you think the unevenness was just a matter of the wood not absorbing the shellac evenly, I'd apply a coat or two of sanding sealer, then apply the shellac. After applying the shellac, check to see if the tint looks even. If it does, go ahead and apply several of your poly top coats. Once you have a good base built up, get your 400g or 600g paper out with a good sanding block and level the top. Monitor your progress carefully. If you start seeing any amber dust show up on your sandpaper, you are getting into the shellac layers, so stop.

I presume you are brushing as you are using wipe on poly. Make sure you lay down your shellac very carefully with the brush. You could end up with an unevenness just from brushing on the shellac thicker in some areas.

Good luck!

Ken

Apr 12, 10 | 7:52 pm
deadedith

Total Topics: 34
Total Posts: 165
I think you've put your finger on it. Thanks for the detailed response, Ken!
I'll keep you posted.
Dave B

Apr 12, 10 | 8:13 pm
Ken Hundley

Total Topics: 40
Total Posts: 2169
You might want to consider zinssers shellac sanding sealer only....I think on the otehr forum it was considerably more well liked than any shellac, including zinssers. The shellac sanding sealer is a different formulation than their shellac, and performs better. I have had great success using it as a sanding sealer, sanding back to wood, then building 4-6 coats with it as well. Gives a beautiful amber tone to whatever you are finishing, sands and levels quite nicely, and it sticks to everything, and everything sticks to it.

Apr 13, 10 | 9:01 am
deadedith

Total Topics: 34
Total Posts: 165
What do you all think about this : I just talked with the Minwax people, and they suggested I use the minwax sanding sealer that was developed for the minwax wipe-on poly. Their only qualification was that the wood must be uncontaminated.

Ken, Ken C, have you had any experience with their sanding sealer or could you take an educated guess whether their opinion is on the mark?

Is the zinsser seal coat and the zinsser shellac sanding sealer the same thing? Noone here in the Rogue valley seems to have heard of either. That includes the big box stores.

Thanks
Dave B

Apr 13, 10 | 12:32 pm
Ken C

Total Topics: 30
Total Posts: 554
Dave, I have used the Minwax sanding sealer, but I have not used their poly that I can recall. The basis for their recommendation is good as you noted Minwax developed the sealer for use with their poly. Are you looking for a tint or just a seal coat? If you are just looking for a seal coat, I'd suggest using Minwax's sanding sealer if you are going to use Minwax's poly. If you want to tint, you can investigate further Ken H's recommendation. I have used Zinsser amber shellac, but I haven't used their dewaxed shellac seal coat. I don't know if you can get the dewaxed stuff tinted or not.

Ken

Apr 13, 10 | 3:15 pm
deadedith

Total Topics: 34
Total Posts: 165
Thanks Ken. I'm not looking for tint, as the redwood and the figure within it are just right for my taste.

I believe I will try the minwax sanding sealer. Let me ask this though: What should that top look like the moment before I start wiping on the poly? Should I be looking at the top the way I want it to look, sans the topcoats?

I am pitiful in my finishing experience, but I don't see any reason this cannot turn out well.

Dave B


Apr 13, 10 | 3:45 pm
Ken C

Total Topics: 30
Total Posts: 554
Hi Dave,

When you brush on the sealer, the wood will darken as the sealer is absorbed by the wood. Once the sealer has cured, the redwood top should have a nice consistent color tone with no blotchiness. If the seal coats have done their job, adding your poly on top of the sealer coats should not darken the wood at all. If the wood darkens in an area or two as you apply the poly, those areas were not sealed properly and could likely remain visible after all your poly has been applied.

I haven't used Minwax's wipe on poly, but I have used General Finishes wipe on finishes quite a bit. Those finishes build up fairly well and can be leveled and buffed. In fact that was my finish of choice prior to getting into water based spraying a couple of years ago. I presume the Minwax works similarly.

Take your time with the finishing. The biggest mistake most people make is rushing through the finishing stages. Make sure you sand well with a good sanding block prior to applying finish as these finishes are so thin they won't hide any imperfections. Be very careful leveling your finish around the edges. One careless swipe with some sandpaper along an edge can remove all your finish. I typically won't even level the edges until I am all done applying finish. And then, I'll use 800g paper just to make sure I don't sand through.

Good luck!

Ken

Apr 14, 10 | 5:09 am
deadedith

Total Topics: 34
Total Posts: 165
Hi KenC - okay, I'll do it, but it's all on YOU! :-)
Just kidding of course, I'm glad for the directions and advice.
Thank you.
Dave B

Apr 14, 10 | 5:54 am
deadedith

Total Topics: 34
Total Posts: 165
Some pix before I start sealing and such. Naturally the pix suck but they give a general idea. The sides have a coat of wipe-on poly, I still have to build more finish on them.
Dave B







Apr 14, 10 | 10:17 am
Ken Hundley

Total Topics: 40
Total Posts: 2169
NICE! I love the end graft and triangle in the top! Very cool. The top looks very warm and rich as well. Can't wait to see this and hear it finished!

I have not used any minwax products on a guitar, so I cannot speak from experience. The black guitar I am building was tinted in the sanding sealer coats, and it worked great, though did slow the drying a bit. I first did two coats of clear sealer. Then, 6-8 coats of black, light sanding every 3rd. After that, I have used tru-oil. Looks good so far. I'll get pics up on it in the next few weeks.

Apr 14, 10 | 2:27 pm
Ken Hundley

Total Topics: 40
Total Posts: 2169
Oh, and zinssers shellac and shellac sanding sealer are definitely different. I read somewhere that someone actually successfully french polished with the sanding sealer, but couldn't with the shellac. I bet it is not as hard as the "hard" shellac sold by LMI though.

Apr 14, 10 | 2:30 pm
Ken Hundley

Total Topics: 40
Total Posts: 2169
Here's Frank Ford's review of the stuff...thats what I was trying to remember:

http://www.frets.com/FRETSPages/Luthier/ProductReviews/Materials/Zinsser/zinsser.html

Apr 14, 10 | 2:39 pm
deadedith

Total Topics: 34
Total Posts: 165
I ended up wiping on a very thin coat of minwax sanding sealer - using a cotton ball wrapped in old tee shirt material, and it worked great. I'll get some pix when I get time.
DaveB

Apr 14, 10 | 5:19 pm
Ken C

Total Topics: 30
Total Posts: 554
Dave,

Glad to hear you have a nice even colored base now!

Ken

Apr 14, 10 | 5:42 pm
deadedith

Total Topics: 34
Total Posts: 165
Here' s part of a letter I sent to Ken Cierp this morning:

Yo Ken -
The minwax sanding sealer/minwax wipe-on poly works very well, I am pleased with the results on the redwood top especially.

Things that make it successful: (taking for granted that the prep work is as perfect as one can make it): I WIPED on the sealer in a very thin coat, using a ball of cotton wrapped in old t-shirt material. When that was dry - 2 hours was plenty - I sanded with 600 then I started applying the wipe on with the same type of application, but rubbing in circles, as per instructions from the minwax guys. The coats have to be very thin for it to work. Then after maybe 10 minutes of drying I held the guitar in all sorts of angles and lights to see where the poly was over/under applied; using a folded up blue shop towel (I love them so much :-) ) I lightly and in straight lines would pick off the over applied areas using long strokes that went from top of guitar to the bottom. When it all looked even, I let it dry another 2 hours. The first two coats took some blue towel time; subsequent coats just flow on nicely without much attention at all.

So, just an FYI. Your comment about using the same brand system surely paid off here; I first used another brand's sanding sealer and it just did not work.

To the Forumites : there's a bit of a learning curve, but the results look very good and I will send pics soon.

Dave B

Apr 16, 10 | 10:21 am
Ken C

Total Topics: 30
Total Posts: 554
Fantastic news, Dave! Glad to hear you found a process that is working for you. If you want that piano type finish, I would build up enough coats that you can level with your sanding block to get the surface nice and level while still having finish on the guitar. I would then build the finish up from there until you get enough that you have enough for one final leveling and buffing. If you don't want to sand and buff, I found that the General Finishes wipe on finish I used in the past would level pretty well on its own and would leave a decent gloss. Not as perfect as sanding and buffing, but still pretty nice.

Look forward to seeing the results when you are done.

Ken


Apr 16, 10 | 5:02 pm
deadedith

Total Topics: 34
Total Posts: 165
Thanks KenC, for the info and encouragement.

I have finally put my finish preferences into a formula: I'm looking for 'glow' rather than shine. Does that make sense? Don't get me wrong - I am wowed by the piano-like finishes, and have doubts that I could ever produce one - but a subtle shine on real warm wood is what I am aiming for (and not getting yet, alas).

Dave B

Apr 16, 10 | 5:35 pm



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