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I need some tips for sanding my flat spruce top. I attempted to hand sand it with a rubber sanding block, but It seems that It's not the best sanding material for sanding spruce.

What kind of sanding block do you use, and what kind of paper? Also what grits do you start and end with? Thanks for your help.

Ron M.

A hard rubber automotive style block works for me.

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

what I've done for trying to create a very flat surface is to use contact cement to glue a piece of cork onto a wooden block and then wrap/staple sand paper to it...the size of the block being determined by how wide I feel I need a 'flat' surface and also to efficiently use the sand paper...

I've found for soft woods that using fine sandpaper to start with is dang near required unless you want to spend a lot of time removing sand paper scratches (which of course is removing thickness) from the growth ring part of the wood....many times I start off with 180 grit and go finer past that for a finished surface...yeah, it may take more time but may also take less when one takes into account the effort required to remove deep scratches caused by 80 and even 120 grit...

Hand held rubber sanding block...

Initial 180 grit (remember that the top would have been sanded & planed to thickness before)..this removes any dings during the build process.

Then with a damp cloth, I wipe the wood to make the grain stand, wait until the wood is totally dry, then use a series of 220-400 grit until the final damp cloth application yields no standing grain, and the wood feels smooth to the touch.

Make sure you have sanded evenly across the wood, you don't want any overly sanded thin spots in the wrong places...

LMI sells sheets of very hard, high density foam. It cuts easily with a band saw or a steak knife..... It's about 1/2" thick and makes great sanding blocks for contoured surfaces since it will conform with pressure.

Before using a Festool ROS I used one of these blocks with first 120 3M Gold and then 240 3M Gold.

I'll have mine medium rare...

Medium rare for me too Sammy!

Thanks everyone for the sanding tips, It's appreciated.

I brushed on a coat of shellac to protect the top, should i use denatured alcohol to remove it, or should It sand off easily?

Ron M.

Ron,

I also put on a protective coat of shellac sealer on my tops. I sand it off but I make sure theres not too much build up of dust and shellac on the sandpaper which can sometimes scratch the spruce. I run a cabinet scraper over the sandpaper at regular intervals to clear any buildup.

Cheers Martin

Thanks Martin.
Ron M.

Since I thickness sand with 80 grit, that's where I start on finish sanding. I find there is no benefit from going any finer than 220. Actually, I use a thin shellac coat after 180 and then resand with 220.

Eugene Clark used to talk about how going too fine with the sanding packs dust into the grain and causes the wood to lose clarity. He would stop at something like 120 on his tops. I think he also sanded cross grain--again, he said the wood had more visual clarity. You can do that if you are careful and do the last grit with the grain. I don't do the cross grain hand sanding part, but power sanding with an ROS is sanding in all directions.

Change paper often and don't press too hard. If you have heard the myth about used paper giving a finer surface, fugheddaboudit. Sandpaper is a cutting tool; it leaves a worse surface when dull, and there's more chance for a clump of grains to form and gouge as it wears.

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Thanks Howard for sharing those great tips.

ron m.

Why do you do this, Howard?

_________________
Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

I do it to keep the top clean while fitting bindings and working on other parts of the body. Shellacing the top also helps with getting a clean cut in spruce when cutting binding and rosette channels.

Cheers Martin

Gotcha. I do that as well. For some reason, late last night after watching the Olympics for far too long, I was thinking this was part of Howard's sanding ritual, and the shellac was immediately sanded off.

_________________
Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

I'm having a heck of a time removing the protective coat of shellac from my spruce top. I'm sanding with 120 grit, and I still haven't gotten it all off yet. I'm trying not to over sand, and I haven't as of yet. I also tried to break the shellac down by wiping It with denatured alcohol. Any suggestions, or should i just keep sanding?

To avoid this problem in the future i'm trying to figure out what I did wrong, If anything.

1. I used a 2 lb. cut of shellac, is that too thick?
Is a 1 lb. cut better for a protective coat?

2. The shellac has been on the top for over 2 weeks, is that too long?

Thanks for any suggestions.

Ron m.

Ron,

2lb cut is probablly a bit on the heavy side. I use a shellac sanding sealer which looks like its about a 1lb cut or even less. If youve got old shellac thats too old for french polishing you can cut it down with alcohol and use it as a sanding sealer.

Two weeks isnt too long. My guitars take months to build and often the sealer is on the top for six month or more.

Taking back 2lb cut might take a while but just keep at it. If its on really thick you could try removing most of it with a cabinet scraper and then finish off with sandpaper. As Ive already noted keep the sandpaper cleared so you dont build up shellac on same and scratch or dent the top.

Cheers Martin

Hi Martin,
Thanks for your reply. i suspected that the 2 lb. cut was a little on the thick side once i attempted to sand it off and it didn't sand off easily . I will attempt to get the rest off tomorrow. Thanks for all your help.

Ron M.

Alcohol will dissolve it. It makes a bit of a mess, but you can get a lot off with the alcohol. Let it dry over night, and sand the bit that's left. It won't be much.

_________________
Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Thanks Waddy for your help.

Ron M.

Why try taking off the shellac from the top? Doesn't it need to be sealed before other finishes are applied?

_________________
A higher purpose for wood.
Rich Smith
Issaquah, WA

The issue was they had not yet sanded to final 180-220 grit when they applied the shellac.

That's correct, thanks Michael.

Ricardo, I applied the shellac to protect the spruce from the dark walnut dust during sanding, and from getting dirty, Thanks just the same.

1) raise grain
2) set up loose fibers
3) protect top while using colored fillers elsewhere

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

I applied some denatured alcohol last night and thought it didn't do much, however, i noticed today that it sanded off easier with 120 grit. I won't make the mistake of applying a heavy cut of shellac again. Thanks to all for your contributions.

Ron M.