MIMF

Hello all !
Been reading through the collected wisdom in this forum for few weeks.
Incredible resource you all have created.

I'm a life long semi-hollow player. Made my living as a session player for 30+ years (yeeesh!)
I've owned nearly every semi at some point and have a few ideas I'd like to try regarding center blocks on semi's.

I have decent basic woodworking skills so I'd like to attempt removing the back off of a few 335's and altering and/or removing and replacing center blocks. Re-attach the back and see if how my ideas work out.

Hoping you'all can point me to some tutorials on how to steam and remove the backs.

I'm a sucker for rescuing abused 335's. Have a room full of them. A few are good candidates as they have no value after the abuse they've suffered.
(one had a massive Kahler installed at some point!).

Appreciate any pointers.
or if anyone knows the right luthier that might want to take this one instead .......

Thanks much,

Having built a couple of semi hollow electric guitars I think taking the back off would be a nightmare. The center block has a huge gluing foot print and I don't see any way to get either steam or heat into the joint. You would want to remove the neck first which is a daunting task in itself, the steam the rim, finally the center block.

In my humble opinion if you have ideas for the center block build one from scratch incorporating your ideas (and post here) and attach the back with tiny screws to the rim and center block, and a screw on neck so you can take it apart to try your ideas. Here is one style of center block used on many 335's the block itself may be spruce, mahogany or other woods, you can see the kerfed filler pieces that are arched to fit the curvature of the top.
Different models of semi hollows have used different blocks and bracing, here is a "short block"
And here is a hollow body with just two beams supporting the bridge and pickups. This guitar uses a floating bridge and trapeze tailpiece instead of stop bar.
If you do build something and glue it together I would suggest hide glue to make it easier to get it apart. I have seen a mandolin builder who screwed the back on his mando so he could take it apart during the voicing process, you might want to consider that.

FWiW, I do have a build thread for the first guitar (the one with the kerfed block) at another forum. If you are interested I could send you a link.

I forgot to add to my first post that you will also need to route the binding off the back to access the glue seam, then replace it when you are done. The neck heel will overlap the binding which is why I would also remove the neck, but you can maybe work around that.

If it's exclusively a test mule being made from an otherwise dumpster-bound guitar, and you don't mind replacing the back (maybe with a flat back) then the easiest course might be to route off the back. It would need a little creative fixturing to hold up the router as you route over the internal block but I suppose it could be done.

Actually, I shudder to even think of doing this. Seems mean and wasteful, cruel and unusual.

Freeman Keller wrote: ↑Mon Nov 04, 2024 1:37 pm Having built a couple of semi hollow electric guitars I think taking the back off would be a nightmare.

...

And here is a hollow body with just two beams supporting the bridge and pickups. This guitar uses a floating bridge and trapeze tailpiece instead of stop bar.

IMG_3525.JPG

If you do build something and glue it together I would suggest hide glue to make it easier to get it apart. I have seen a mandolin builder who screwed the back on his mando so he could take it apart during the voicing process, you might want to consider that.

Freeman, In that last guitar, do the beams under the top really need to be that heavy? I'm guessing the top is laminated (i.e. relatively strong). I wonder if the acoustic performance would be improved at all by lightening the braces. Or is the acoustic performance so far beside the point that it's not even worth wondering?

Oh - just remembered one other thought. I built an arch top a few years ago and knew I would need to hear it played and make adjustments to bracing (since I had little clue about how stiff to make the top and no point of reference to compare the stiffness it had with any standard). I glued the top on with paper in the glue joint. I just used Titebond Original. It held up well for several months and was easy to take apart by sliding a sharp knife along the joint. In its temporary configuration the top had an overhang like a violin (and no binding).

This idea is not original to me. I read it somewhere online. Sorry I can't give proper attribution but I can't even remember what I had for breakfast. I think it's an idea that's been around forever and used by many.

Bob Ionta wrote: ↑Mon Nov 04, 2024 4:56 pm

Freeman Keller wrote: ↑Mon Nov 04, 2024 1:37 pm Having built a couple of semi hollow electric guitars I think taking the back off would be a nightmare.

...

And here is a hollow body with just two beams supporting the bridge and pickups. This guitar uses a floating bridge and trapeze tailpiece instead of stop bar.

IMG_3525.JPG

If you do build something and glue it together I would suggest hide glue to make it easier to get it apart. I have seen a mandolin builder who screwed the back on his mando so he could take it apart during the voicing process, you might want to consider that.

Freeman, In that last guitar, do the beams under the top really need to be that heavy? I'm guessing the top is laminated (i.e. relatively strong). I wonder if the acoustic performance would be improved at all by lightening the braces. Or is the acoustic performance so far beside the point that it's not even worth wondering?

Bob , that guitar was not intended to have any "acoustic performance", it is totally an electric guitar. It does have an acoustic voice but its not particularly great and I aways play it plugged in.

I don't remember the actual dimensions of those braces. I have a set of ES-175 plans and they are shown as 1/2 wide but no dimension for the depth. I'm sure mine are significantly taller and wider than they need to be, they have to support the 50 or so pounds of down force at the bridge. The top is a laminate (spruce and I don't know what). The 335 clones in my previous posts are maple laminate and have almost no "acoustic voice".

I have built a carved topped X braced acoustic archtop and I did spend a lot of time carving and voicing the top on it. I would call it OK compared with other archtops that I have played, its a little brighter than I really like.

Thanks all.

Freeman - your builds are very much inline with things I'd like to tryout. Maybe even less of a center block.

I asked because of the Rich Robinson restoration article showing Historic Makeovers taking apart his flood damaged '64.
Seemed like they took the back off first. Steamed out the center block then Had to trim the centerbock true as it twisted due to water damage.

Those guitars are really quite different. The one with the big block and the hollow body have SD jazz pickups, the small block has StewMac PAf copies, Both 335 style have gone to other owners, the hollow body is my personal jazz style guitar. Each is inspired by different Gibson guitars but none is a direct clone.

I do know that over the years Gibson has used a variety of different construction methods, woods and pickups in semi hollow guitars, but I am not enough of a gibson historian to know what is what. I think the idea of making a test mule is interesting - can you hold everything else completely constant while you change just this one variable?

But as a builder/repair person I will add that removing the back just seems like a monster of a project. I've taken fretboards off by heating the neck with my silicon heat blanket that I use to bend sides, you could lay that on the back and work pallet knives in from the tail block end. You would still have to deal with binding and the seam at the rim. If you decide to do it be sure to post some pictures here as well as the results

Thanks for the response Freeman. One other quick question - of those 3 guitars which has your favorite plugged-in sound?

Bob Ionta wrote: ↑Tue Nov 05, 2024 8:18 pm Thanks for the response Freeman. One other quick question - of those 3 guitars which has your favorite plugged-in sound?

Bob, these were built some period of time apart so its a little difficult to compare The 335 with the small block was built for a left handed player so I really couldn't play it before shipping it off to him (I did have a local lefty play it for me first). He wanted traditional vintage sound and we agreed on the StewMac golden era PAF clones, I have the in my les paul clone and I think they gave it that 60's rock sound that he wanted
The one with the big block was built for a local jazz player. He spec'd the SD Benedetto pickups and a Bigsby tremolo. I think the guitar has a warm almost lush sound
Ironic that they are both cherry red, eh?

The third is a true hollow body, it does have some acoustic tone but it is certainly not a great acoustic instrument. I built it for myself and was so impressed with the Benedetto pickups that I used them here. The guitar probably has more resonance than the big block, it certainly has that archtop attack and note separation. I've played both thru the same amp but not at the same time so its a bit hard to say
Maybe if it was painted red.

(Weird how the forum software rotated those two pictures)

Thanks Freeman. 3 beautiful guitars that I'm sure are a joy to play.

How about this?

There are several 335 kits out there. Stew Mac had one but I think they ran afoul of Gibson and that kit disappeared. But there are a bunch of Asian kits and they are already in pieces. You could build one with the screw on back (adjusting for the neck joint) and go to town. If you don't like the hardware then cannibalize from your pile of 335s.

As an aside, many people have tried to buy that screw back mandolin. Good thing I don't play mandolin.