Double Bass American Standard Rehab

[ctregan]

What started out as an emergency repair, has now grown into another project. Since I am changing a few things around, this is not a restoration, more of an overhaul to get the bass to play and sound its best.

The neck was falling to one side. No amount of bolts, screws, dowels, and threaded rod could save it.

 

[ctregan]

I made a new neck block, then cut a new joint.
Since the top of the block was narrow, I went with a dovetail.
Its deep, 1 1/4", and 1 1/2" wide. The old dovetail was 3/4" x 3/4".

I also rebuilt the neck heel and and cut the male dovetail to fit.

 

[ctregan]

Increased the overstand to 1 5/8 or so. (could be a bit high?). The bridge ht. is at 7".
The string length is now at 42" down from 43"

I will have to shape the heel and find the D stop. This is a dry fit.

 

[ctregan]

Edge repair, this is always fun.

 

[ctregan]

Did a belly patch. I used spray foam and scrap wood for a counter form (wrapped the top in plastic first). Had some foam expansion issues but it worked.

Used 1/8" redwood for the patch, no more lumps in the belly.

 

[ctregan]

Original factory bass bar. Came out in one piece.

 

[ctregan]

Found a nice original red finish under the machine heads. Made me think of refinishing.....

 

[ASBass]

This is great stuff, thank you for the descriptions and detailed pictures. I am restoring an old Epiphone, have the top and neck off now, starting on the edge patches and contemplating the belly patch. I'm just not sure how to fit it in there. I like your spray foam idea. My neck block is good, I think. I will keep my original finish, what's left of it anyway. Long live the old plywoods!!

 

[Matthew Tucker]

The problem with the dovetail is it's much much harder to adjust the rake of the neck later! 7" bridge sounds OK. The overstand could be reduced a bit and the bridge height would still be OK. How does it feel to play in the upper register? Lay a straightedge from the upper bout edge across the fingerboard. I find that if it hits where the G string touches the FB, that ends up pretty playable.

How did you attach the new neck heel to the old neck?

 

[ctregan]

This contemplating the belly patch. I'm just not sure how to fit it in there. I like your spray foam idea.

I used a vacuum bag to press down the patch.
Plaster of paris might be a better way to make a mould, or at least thats how the professionals do it.

 

[Huy Nguyen]

Wow the neck is bolted on?

 

[ctregan]

How did you attach the new neck heel to the old neck?

I used West System epoxy from a marine supply store. There is a wood dowel in there too.

The dovetail joint has to be right on the first time. Not much adjustment in that type of joinery. Next time I'll try the Italian method.

 

[ctregan]

Since the above belly patch is redwood (very soft), should I consider a sound post disk or patch of harder wood veneer? I was thinking of a small piece of maple veneer, 2" round, glued in place, to keep the sound post from digging in too much.

I am not sure if this is necessary or will help the bass sound wise.

 

[Jake deVilliers]

Do you think the redwood is softer than the original spruce? I kinda doubt it, myself.

I think it will do just fine CT.

 

[jabjab]

What started out as an emergency repair, has now grown into another project. Since I am changing a few things around, this is not a restoration, more of an overhaul to get the bass to play and sound its best.

The neck was falling to one side. No amount of bolts, screws, dowels, and threaded rod could save it.

I wish i could do work like this!your a skilled man!!

 

[spaghettiwestern]

I used a vacuum bag to press down the patch.
Plaster of paris might be a better way to make a mould, or at least thats how the professionals do it.

could you explain the vacuum bag a little more? like a vacuum clamp?

 

[ctregan]

could you explain the vacuum bag a little more? like a vacuum clamp?

This can explain it better than I can. Invalid Link Removed

 

[forester]

redwood, one janka click harder than spruce.. maybe burnish the patch at the contact area of the SP. it's a ply top? i'd skip the small patch..whereas you are a very busy man

 

[spaghettiwestern]

This can explain it better than I can. Invalid Link Removed

that's a pricey piece of equipment. what's the poor mans' way to do this?

 

[Huy Nguyen]

http://www.woodweb.com/knowledge_base/Vacuum_Veneered_Drawer_Faces.html

You just need to figure out how you're going to get a similar bag. I can see doing the ribs the corners and such, but the bottom rib might be a little harder.

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