Double Bass Popping the top off an Engelhardt...

[Rebop]

Fair. Here's some.

 

[SAlcott]

OK actual luthiers-your turn.

 

[Rebop]

There was only an inch of glue holding the bar down. The rest was gap filler and never got squeezed out properly when clamped.
The very tip of the bassbar makes contact with the top before anything else can touch. I'll double check tomorrow or the next day when I can get back to it, but it seemed like an absurd amount of force would be needed to make full airtight contact along the entire length of the bar.

 

[Steven Ayres]

There was only an inch of glue holding the bar down. The rest was gap filler and never got squeezed out properly when clamped.
The very tip of the bassbar makes contact with the top before anything else can touch. I'll double check tomorrow or the next day when I can get back to it, but it seemed like an absurd amount of force would be needed to make full airtight contact along the entire length of the bar.

Wow.

 

[KUNGfuSHERIFF]

Time to fit a new, unsprung bar. Lucky you!

 

[Rebop]

I'm not going to do that. If I try to remove this bar the rest of the way there's no chance a new one will go in. Not sure how I'd remove that much glue and get to clean wood. I think last time it broke it took some veneer with it; which was not patched or replaced.

My plan involves doing some sandpaper pulls in the open joint to get rid of the excess glue and get the two surfaces more or less identical (similar to the method used when resetting an acoustic guitar neck). Then regluing and adding linen to the ends.
I'm still piecing together the edges though. My plan has time to evolve.

 

[KUNGfuSHERIFF]

I’d let chemistry do most of the work by parking vinegar-wetted rags on the glue and scraping it with a razor blade when it softens, but your problem is going to be getting that crap out of the pores.

Years ago I worked on a school Engel that the shop teacher or somebody tried to repair the usual neck heel break with yellow glue without slacking the strings, which went as well as you’d expect.

A pint of white vinegar later, after the second try at repairing it with hide glue failed, I had to resort to ironwork before I reset the neck for the third time.

 

[Rebop]

This bass met the same fate. Someone got to the neck break before I did, more than once maybe. Glue, dowels, brown spray paint to hide it; the works.

Neck is solid now but I had to use a bolt where one of the dowels were. It had been in pieces for too long getting bashed and smashed.

I was hoping that's all this bass needed. Then I dropped it.

I'll try vinegar and cuss words on the yellow glue first.

 

[KUNGfuSHERIFF]

I’ve made my recommendation about the bass bar. You may have to re-edge the top if the inner laminates are contaminated. Luckily poplar plywood is cheap at the hobby store.

 

[Rebop]

Re-edging the top is probably easier to do than repairing all the ripped up plywood I'm piecing back together right now.

I'm going to take my time making these next few big decisions. Right now I'm gluing the splintered stuff back so I can see what I'm working with. It'll also be easier to set aside and take a break if the top is in one piece.

Thanks for the advice again. Perhaps I have more to deal with than I had previously considered.

 

[Greg Clinkingbeard]

Look. It’s an Engelhardt and the last guy is at fault for using PVA glue. If that was in my shop I would glue the existing bar with titebond and add linen reinforcement to the ends. You will open a big can of worms trying to replace the bar and in the end it probably wont matter. You will never remove the existing glue to the extent that hide glue will hold. Put it back together and move on. Hide glue is probably advised to repair the veneers.

 

[Rebop]

Coming along slowly.
When I get to the bass bar I'll have more questions I'm sure.
Still putting the puzzle together.

Here's a before and after sample

 

[KUNGfuSHERIFF]

Don’t skimp on the glue, and I’d consider re-edging the top with whatever cheap veneer the craft store has that day so removing the top again isn’t hard.

 

[Rebop]

I actually picked up some pieces of basswood veneer from the hardware store yesterday. It's too thick by .020" but that should be easy to plane down. I only saved the large pieces of original wood and glued them down with the strongest mix of hide glue I could reasonably work with. It gels almost instantly but boy is it strong.

 

[Rebop]

This is more fun than I thought it would be.
It's a time sink and my mind is wandering into some weird places, but fun nonetheless.

 

[james condino]

The 3 most important and often difficult words you have to learn as a luthier:

"No thank you."

 

[Rebop]

Luckily I have no choice. I bought this for $100 from the Goodwill auction site.

"It only has a broken neck..."

 

[Rebop]

6 months later and I'm getting this bass back into shape. I had some other (paid) projects get in the way, and I strongly dislike working on my own stuff during the winter in my unheated shop.


New poplar edges.


Harbor Freight clamps are the real hero!

All of the advice I've received has helped. Thanks, gang!

 

[notabene]

"t's a time sink and my mind is wandering into some weird places, but fun nonetheless."

MANY YEARS AGO I HUNG OUT IN LA HONDA. SO... HEARING OF YOUR STRONG VINEGAR WORK, THE CONNECTION WITH ACID AND MIND WANDERING INTO WEIRD PLACES SEEMS INEVITABLE. INSIDE JOKE PERHAPS.

 

[Rebop]

I'm walking distance from Ken Kesey's old house. There must be something in the water here.