Sexauer/'16

[tekaitora]

Thank you for the fascinating pictures, Bruce! Am I correct that your bracing on this guitar is more substantial in size and strength than I've seen in the past on some of your larger instruments? The O size allows for a thinner top than an SJ for instance? Feel free to treat those questions as rhetorical if they ask you to reveal too much proprietary info.

BTW, I would buy a calendar featuring your guitar building photos! That last picture of the top and back is just tickling my synesthesia. I can see the harmony built into the structure.

[Bruce Sexauer]

I do not think i have proprietary information, but thinks for letting me off the hook if I need it.

I used to use just one finger brace and one tonebar on my single 0s, but since I started treating them more seriously (as though they were "real" guitars) they have become noticeably better.

I have found making the top braces too narrow causes them to telegraph excessively on EuroSpruce, so I make them the same width as larger guitars. These braces are slightly lower in the peaks than my last few steel strings, and MUCH lower in the valleys, perhaps as much as a mm! I found the top to be around .095" if I recall. I did measure it, but cannot check right now as the back is being glued on.



Here's a previous single 0 for comparison's sake:

[tekaitora]

Thank you! I placed the two images of the tops in a picture view where I can see them side by side. To my untrained eye, there are many similarities?

When you mention a change to a brace of a single mm being significant, it gives me a glimpse of the level of understanding you have regarding your art. I would love to see a detailed dimensional analysis of the differences in the two, and hear your insights into how they effect the performance outcome. Actually, a YouTube of you playing each finished instrument would be brilliant, come to think of it.

Kind regards,
Scott

[Bruce Sexauer]

Close(d), but no cigar :







OK; Cigar!

[Bruce Sexauer]

Took my car to the Auto-X track yesterday for the first time this season. I have been having trouble with it catching fire in extended right hand turns, literally, so I put on new (Weber DCOE 40) carburetors. It runs better than ever! This course had a HUGE right hand turn at high speed (55 mph which is the top of 2nd gear), 700 compass degrees; the car caught fire! Twice in 6 runs. Too exciting. We have a highly experienced club, 52 years and 350 members, and we are stumped as to why this is happening. Any experts out there?

Here is between fires:

[LouieAtienza]

Originally Posted by Bruce Sexauer

Took my car to the Auto-X track yesterday for the first time this season. I have been having trouble with it catching fire in extended right hand turns, literally, so I put on new (Weber DCOE 40) carburetors. It runs better than ever! This course had a HUGE right hand turn at high speed (55 mph which is the top of 2nd gear), 700 compass degrees; the car caught fire! Twice in 6 runs. Too exciting. We have a highly experienced club, 52 years and 350 members, and we are stumped as to why this is happening. Any experts out there?

Here is between fires:

Where is it catching fire? Not creating a "lean condition" in the gas tank? Gas tank have baffles?

[tekaitora]

Centrifugal force, time duration, and localized heat. How full was the gas tank when it caught fire in comparison to the not as exciting times... Seal allowing fuel (leak) to reach hot surface during stress of corner. All of which you and your fellow racers have no doubt considered, but that's all I got.

For the sake of the art of luthiery's future, I am hoping you get this sorted.

[tadol]

Clearly, the answer is to convert it to electric -



;-)

[Bruce Sexauer]

There were two fires at the track yesterday, counting mine as one. The other was an electrical fire.

My fire is at the carburetor, and is almost certainly fuel sloshing out the large hole where the air goes in. Symptoms suggest that it's running over rich a few seconds into a maximum effort right hand turn, causing sputter then backfire, igniting the excess fuel. Fuel level at the tank does not seem to matter.

[tekaitora]

That makes sense. Would some sort of air horn filter arrangement help?

[maurerfan]

Brings back memories ... I used to have a '65 Sunbeam Tiger with the Cobra package including Holley 4-barrel and Edelbrock high-rise intake manifold. Gas .. I assume from gasket leakage .. used to pool-up in the the manifold pockets at the base of the carburetor. On hard turns it would run out and down over the valve cover and straight onto the exhaust manifold. I would pack up little wads of paper towel and stuff them into the pockets to soak up the gas. That took care of it ... until one day I totalled it ..

[printer2]

Might be of some help.

http://www.opelgt.com/forums/afterma...2-36-dgev.html

[dneal]

Originally Posted by Bruce Sexauer

There were two fires at the track yesterday, counting mine as one. The other was an electrical fire.

My fire is at the carburetor, and is almost certainly fuel sloshing out the large hole where the air goes in. Symptoms suggest that it's running over rich a few seconds into a maximum effort right hand turn, causing sputter then backfire, igniting the excess fuel. Fuel level at the tank does not seem to matter.

What's the length of the velocity stacks?

[Bruce Sexauer]

Checked out the Opel forum link. They are talking about tuning issues (I have some grip on that and mine runs great) and their Carb is a very different design.

The velocity stacks on mine are the standard issue, about 2 1/2 inches long. I'll make a picture later.

[Bruce Sexauer]

Originally Posted by dneal

What's the length of the velocity stacks?

Here are my carbs with the fire extinguisher detritus still in place. No sign of fuel leakage on the trip home, IMO.