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Back Strip Advice
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=43316		 Page 1 of 1
Author:  DannyV [ Sun Apr 27, 2014 3:09 pm ]
Post subject:  Back Strip Advice
Has anyone ever attempted installing a back strip after a box was closed? In my haste to shave off a couple of hours on a build I chose not to do a back strip. The set is Philippine Ebony (I think). The sides are very sweet and a great book match.
Attachment:
rsz_img_4681.jpg


Not so much with the back. The book match is pretty poor. I don't know if it's the piece of wood or it was cut with a large kerf blade. Whatever the case, I think a back strip would draw your eye away from the lousy book match.
Attachment:
rsz_img_4680.jpg


I suppose using a flexible straight edge and some means of clamping it well. I've never tried this before and it would suck to botch it up at this point. Any advice?

Thanks,
Danny
Author:  jshelton [ Sun Apr 27, 2014 3:21 pm ]
Post subject:  Re: Back Strip Advice
It shouldn't be that tough if you have a steady hand just rout about 1/16" deep. Clamping the strip in would be the tricky part, if it's not too tight I suppose you could just use weights. That wood is called Kamagong in the Philippines. It's pretty, bends well and hard but in my experience it's very prone to checking.
Author:  WudWerkr [ Sun Apr 27, 2014 3:25 pm ]
Post subject:  Re: Back Strip Advice
Yes I did , Made same mistake . Couple of thin 3/8" Pieces x 2" wide ( one each side of router base width ) so they will bend to match the back radius but wont flex side to side ... measure CAREFULLY and clamp at head and heel .... Measure again .. check clamps ... insert correct router bit and set depth .... Measure and check clamps again ..... Router it out ....... measure again ...... LOL get the point
Author:  Hesh [ Sun Apr 27, 2014 3:43 pm ]
Post subject:  Re: Back Strip Advice
Yeah it's not difficult with a flexible straight edge and light, shallow passes.

But.... IMHO I think that the back as is looks fine. It's wood and wood is imperfect. Further my design eye thinks that adding a back strip will only serve to further draw one's eye to the mismatch.

Leave it as is and call it a feature.... :D
Author:  ernie [ Sun Apr 27, 2014 3:58 pm ]
Post subject:  Re: Back Strip Advice
I second hesh/s comment Looks fine to me.
Author:  Mike OMelia [ Sun Apr 27, 2014 4:07 pm ]
Post subject:  Re: Back Strip Advice
I wouldn't do this. If ANYTHING goes wrong, you will be routing the back off. It looks good as is. Did u do a very tight joint?
Author:  James Ringelspaugh [ Sun Apr 27, 2014 4:22 pm ]
Post subject:  Re: Back Strip Advice
The back boards are bastard cut (meaning it goes from vertical grain/quartersawn to flatsawn over the width of the board) and you put the flatsawn area in the middle. While quartersawn/vertical grain is very forgiving regarding bookmatches, you'll never get a perfect bookmatch from flatsawn grain no matter how thin the kerf and/or how good the cut. This is one reason why most guitars you see with bastard cut backs are joined at the quartersawn edge.

As others have said it shouldn't be a big deal to rout if it bothers you... just make sure everything's super secure before hitting the power button
Author:  DennisK [ Sun Apr 27, 2014 4:39 pm ]
Post subject:  Re: Back Strip Advice
Sounds like a good place to use one of these :) http://www.leevalley.com/en/Wood/page.aspx?p=64300&cat=1,41182,68490

But I agree with Hesh. Under finish, it will probably be dark enough that it doesn't really draw the eye that much, whereas with the strip it will be highlighting the difference as a feature.

And anyway, it's a lot less jarring to my eyes than bookmatched curly woods where the curl inverts at the centerline, and people do that all the time.
Author:  Alex Kleon [ Sun Apr 27, 2014 4:47 pm ]
Post subject:  Re: Back Strip Advice
I agree with the others that suggest to leave it as it is. Wood should look like wood, not like HPL.

Alex
Author:  Clay S. [ Sun Apr 27, 2014 5:27 pm ]
Post subject:  Re: Back Strip Advice
I've done them on closed boxes before. Clamp a straight edge, use a square base router, and rout in the direction that pulls the bit into the straight edge. I glue the strip in with superglue.
Author:  Trevor Gore [ Sun Apr 27, 2014 7:19 pm ]
Post subject:  Re: Back Strip Advice
I've done a few after closing the box. Here's one.

I use a 5mm thick (3/16") perspex straight edge taped down with heavy duty double stick tape (the carpet variety) and a router with an adjustable fence to run against it. Use a router bit narrower than the intended inlay, say 1/8" for a 1/4" inlay. It's the first cut that will wander if any does and with a narrow bit you can straighten the groove out as you widen it. I leave the fit tight and press in the back strip, which, depending on your design, can be trimmed to exactly how tight with a block plane. I prefer gluing in with Titebond. CA has a tendency to turn "white" woods yellow but works fine if no white wood is involved.
Author:  DannyV [ Sun Apr 27, 2014 7:53 pm ]
Post subject:  Re: Back Strip Advice
Hey! You guys are right. It will look fine. I did have a set up worked out and it would have gone fine, if I was careful huh Wud. :D If the jury of peers says leave it, it stays. The wood turns pretty dark with Naptha so it will probably darken up with nitro.

James Ringelspaugh wrote:
This is one reason why most guitars you see with bastard cut backs are joined at the quartersawn edge.


I had no choice with the glue up. I got the set off Ebay and it was already guitar shaped.

Mike O'Melia wrote:
Did u do a very tight joint?


duh Of course Mike. My jointer is well set up. :lol:

[quote="jshelton" That wood is called Kamagong in the Philippines. It's pretty, bends well and hard but in my experience it's very prone to checking.[/quote]

Thanks John. Kamagong eh. It is very pretty. The sides look a lot like Mun but a little more purple. It should look very nice under finish. I'll try to post a few photos.

Thanks All
Author:  WudWerkr [ Mon Apr 28, 2014 4:11 pm ]
Post subject:  Re: Back Strip Advice
Be absolutely honest , I agree with the Majority .. Looks fine to me.
Author:  Hesh [ Mon Apr 28, 2014 4:34 pm ]
Post subject:  Re: Back Strip Advice
Darn it, now James has me self conscious and looking in the mirror to see if I go from vertical to quartered to flat since I have been called that word before too.... :D
Author:  RusRob [ Mon Apr 28, 2014 4:41 pm ]
Post subject:  Re: Back Strip Advice
I agree that it looks fine, it is wood after all...

You could tone it down a bit by just lightly shading the one side before putting the final clear on it but don't over-do it. I would just tint the sealer and airbrush it or if you are good you could use a glazing brush to blend it in. I would probably go with the latter myself since I have done a lot of glazing in the past and if done right you would never know it wasn't that close of a bookmatch. The nice thing about glazing is if you don't like it you can just wipe it off.

But again, it is wood and no 2 pieces are ever exact.

Cheers,
Bob
Author:  Joe Beaver [ Mon Apr 28, 2014 8:38 pm ]
Post subject:  Re: Back Strip Advice
Some good points from James, and yes, I share Hesh's concern. I believe I have been in attendance with aforementioned group.

I could go either way, leave it raw and sexy or put the back strip in. A winner either way!!!
Author:  Mike OMelia [ Mon Apr 28, 2014 10:01 pm ]
Post subject:  Re: Back Strip Advice
The reason I asked about the tight joint was because if one was intentionally planning to not use a back strip, the surface finish of the joint is not as incredibly important than if one was planning to rout out a backstrip channel. If it's incredibly flush, then u are set. Sorry if it sounded like I was questioning ur technique. :)

Mike
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