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| Tips For Hand Sanding A Spruce Top http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10101&t=18342 |
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| Author: | Ron M. [ Sun Aug 10, 2008 11:23 am ] |
| Post subject: | Tips For Hand Sanding A Spruce Top |
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. |
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| Author: | Howard Klepper [ Sun Aug 10, 2008 11:30 am ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
A hard rubber automotive style block works for me. |
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| Author: | Mike_P [ Sun Aug 10, 2008 11:39 am ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
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... |
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| Author: | Sam Price [ Sun Aug 10, 2008 11:44 am ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
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... |
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| Author: | Hesh [ Sun Aug 10, 2008 11:46 am ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
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. |
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| Author: | Sam Price [ Sun Aug 10, 2008 11:47 am ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
Hesh wrote: LMI sells sheets of very hard, high density foam. It cuts easily with... a steak knife..... I'll have mine medium rare... 
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| Author: | Hesh [ Sun Aug 10, 2008 11:52 am ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
 Medium rare for me too Sammy!
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| Author: | Ron M. [ Sun Aug 10, 2008 12:53 pm ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
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. |
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| Author: | Martin Turner [ Mon Aug 11, 2008 4:47 am ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
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 |
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| Author: | Ron M. [ Tue Aug 12, 2008 11:12 am ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
Thanks Martin. Ron M. |
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| Author: | Howard Klepper [ Tue Aug 12, 2008 5:51 pm ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
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. |
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| Author: | Ron M. [ Tue Aug 12, 2008 6:28 pm ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
Thanks Howard for sharing those great tips. ron m. |
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| Author: | SniderMike [ Wed Aug 13, 2008 12:52 am ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
Howard Klepper wrote: Actually, I use a thin shellac coat after 180 and then resand with 220. Why do you do this, Howard? |
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| Author: | Martin Turner [ Wed Aug 13, 2008 6:26 am ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
SniderMike wrote: Howard Klepper wrote: Actually, I use a thin shellac coat after 180 and then resand with 220. Why do you do this, Howard? 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 |
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| Author: | SniderMike [ Wed Aug 13, 2008 11:38 am ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
kiwigeo wrote: SniderMike wrote: Howard Klepper wrote: Actually, I use a thin shellac coat after 180 and then resand with 220. Why do you do this, Howard? 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. |
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| Author: | Ron M. [ Wed Aug 13, 2008 8:02 pm ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
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. |
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| Author: | Martin Turner [ Wed Aug 13, 2008 9:21 pm ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
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 |
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| Author: | Ron M. [ Wed Aug 13, 2008 10:25 pm ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
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. |
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| Author: | WaddyThomson [ Thu Aug 14, 2008 10:05 am ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
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. |
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| Author: | Ron M. [ Thu Aug 14, 2008 10:46 am ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
Thanks Waddy for your help. Ron M. |
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| Author: | Ricardo [ Thu Aug 14, 2008 1:30 pm ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
Why try taking off the shellac from the top? Doesn't it need to be sealed before other finishes are applied? |
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| Author: | Michael Dale Payne [ Thu Aug 14, 2008 1:33 pm ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
Ricardo wrote: Why try taking off the shellac from the top? Doesn't it need to be sealed before other finishes are applied? The issue was they had not yet sanded to final 180-220 grit when they applied the shellac. |
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| Author: | Ron M. [ Thu Aug 14, 2008 1:41 pm ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
MichaelP wrote: Ricardo wrote: Why try taking off the shellac from the top? Doesn't it need to be sealed before other finishes are applied? 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. |
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| Author: | Howard Klepper [ Thu Aug 14, 2008 2:09 pm ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
SniderMike wrote: Howard Klepper wrote: Actually, I use a thin shellac coat after 180 and then resand with 220. Why do you do this, Howard? 1) raise grain 2) set up loose fibers 3) protect top while using colored fillers elsewhere |
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| Author: | Ron M. [ Thu Aug 14, 2008 3:08 pm ] |
| Post subject: | Re: Tips For Hand Sanding A Spruce Top |
WaddyT wrote: 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. 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. |
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