Sanding Issues

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John Reid
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Joined: Fri Aug 03, 2012 3:48 pm

Sanding Issues

Post by John Reid »

Could use some help. I just glued on a maple heel cap on a mahogany neck. I sanded the maple heel cap pretty much flush with the heel, but as I got closer, I was sanding the mahogany. Here I started to get nervous. I was using 120, then 220, 320, but I’m worried I might be doing bad things with the mahogany. It seems to look worse than when I started, which I think one can see in the pictures.

Should I keep going, or take a different approach, or what? Any sanding tips or other suggestions?

Thanks.
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tippie53
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Re: Sanding Issues

Post by tippie53 »

you look like your still sanding glue and from what I can see you have a lot of sanding to do. I think you will be fine
once you get it closer to final shape.
I sand to 220 so don't go too fine you need to let a little tooth for the finish to hold on to.
Also I don't use Stew Mac necks I find LMI and Andy Birko necks much better
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
AluminumTop
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Re: Sanding Issues

Post by AluminumTop »

2 Cents, Looks like a soft to hard wood transition, try a contoured back-up block. I had this same problem on surfboards with a foam-to-redwood or balsa transition, hard-to-soft. Might try doing the maple sanding first, then blend to softwood.
I get the contoured stiff rubber foam sanding blocks from the autobody supply shop.
John Reid
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Joined: Fri Aug 03, 2012 3:48 pm

Re: Sanding Issues

Post by John Reid »

Ok, thanks so much for the advice on the sanding. I’ll keep at it with 220 and try a rubber sanding “block”, too.

All in all, the neck is going well. I made maple inlays that went in well and manufactured a maple headstock veneer that went on well. Fingerboard is registered on the neck, but needs its width shaped to the neck. I’m not too far away from gluing the fingerboard on, then fretting.
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tippie53
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Re: Sanding Issues

Post by tippie53 »

great point on sanding blocks I use Cork and pipe insulation on plywood , and at the dollar store they sell large erasers your hands never sand to plane like a good block
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
Kevin Sjostrand
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Re: Sanding Issues

Post by Kevin Sjostrand »

John you might try scraping with a razor blade instead of sanding that area. I do that a lot on those differing wood transitions....soft to hard wood. Also it cleans up the hog nicely in those side grain areas like that.
John Reid
Posts: 28
Joined: Fri Aug 03, 2012 3:48 pm

Re: Sanding Issues

Post by John Reid »

Could use some input.

I’m working on the finish. My approach is to use filler then Tru Oil

I’m putting Aqua Coat on the rosewood back. A few times I’ve taken one step forward and three steps backward.

For example, after putting several coats of filler on, I thought it looked splotchy. So, I sanded all the oil and filler off, and re-sanded the whole back. I think that helped, but now I’m back again putting on the filler, and I don’t know how thick to put it on and how many coats to use. Watching YouTube videos, I see most people putting on 2 or 3 thin coats. At least one person put on a really thick first coat, (which wasn’t on a guitar).

The picture here shows the back with 4 coats of Aqua Coat. I rub it on with gloved fingers and scrape it pretty thin along the grain with a credit card. After drying, I go over it with 400 grit and 0000 steel wool, then wipe with naphtha.

I think you can clearly still see the dips in the grain in the photo.

Should I keep filling until I get a flat surface?
Am I done filling and will the Tru Oil smooth it out?
Should I do a thick coat of filler before Tru Oil?

Would appreciate input!

Thanks.
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tippie53
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Re: Sanding Issues

Post by tippie53 »

did you use a sealer first?
you need to do that on oily woods
if you didn't use a sealer sand the back and sides with 180 grit and no finer apply shellac as that is a good universal sealer then apply aqua coat as directed , seal and then apply tru oil that should help a great deal
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
John Reid
Posts: 28
Joined: Fri Aug 03, 2012 3:48 pm

Re: Sanding Issues

Post by John Reid »

Nope, I didn't do that.

Will do!

Thanks.

Back to the drawing board....
John Reid
Posts: 28
Joined: Fri Aug 03, 2012 3:48 pm

Re: Sanding Issues

Post by John Reid »

Wanted to give an update.

I followed your advice, John. I sanded it all off – again. Did coats of shellac sealer, then pore filler then sealer, then started with coats of Tru Oil. Early on it looked a lot better than it did before. So happy to be back on track again. Still has plenty of flaws, but I’m much happier with the way its going.

I’ll add that after I followed John’s advice and things were looking good, I spent an evening poking around reading past forum posts. That also helped a lot to see what other do and think.

I think I still have another week of carefully finishing the back, sides, neck and top, but I’m nearing the end, I think.
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