Soundboard too thin, can it be saved?

[NeilG495]

Feeling a bit dispirited today, to say the least. A lack of concentration and over jealous sanding has left me with a soundboard thickness of 2.2mm (0.086”)
I’m now wondering if I should;
1. just carry on and see if it holds up.
2. try to remove the board and make a new one
3. scrap the whole box.

Any advice gratefully received.

[John Parchem]

A steel string? What size guitar? It is a bit thin a lot of mine are 2.5 mm. It is thick enough to be structurally ok. Be careful with the brace heights and it should be OK. If it is a classical you are in good shape.

[NeilG495]

Hello John, thanks for getting back. It’s basically a Martin OM steel string design that will have light strings on for finger picking. The box is already closed so I can’t change the braces, which were 1/4” scalloped. If you think it’ll be structurally sound, I’ll carry on building it. The thought of cutting the top off and putting a new one us too daunting a task for me.

[Herman]

Very doubtful.
-If you don't want to take the top off, I would go for 0.010"strings, keep the string height low and make a large bridge.
-Otherwise take the top off. Take a household iron and warm the top edge for some minutes. You will see the top come loose very easily.
-There is no need for discarting the body.

Don't be hard on yourself. Let it sit for a day, choose a way and go for that.
Good luck
Herman

[peter havriluk]

How we fix mistakes is to back up past the error, do the right thing, and carry on. That way the error ceases to exist and there's no messing with workarounds. Take the top off, make a new one, and resume building. Nothing else has errors that need correcting.

[John Parchem]

It is easier to change unbound. I changed tops at that stage of the build a few times when they were not stiff enough. I would take a spectrum graph of the tap tone, if the top was around higher than 175 Hz the top is stiff enough. You might be able to feel how stiff the top is as well just using your thumb to see how much it resists.

[NeilG495]

Peter, John, Herman: Thank you for the advice gentlemen, I was going to carry on building it but after some deliberation I’ve decided to bite the bullet and take the top off. The thought of going through all the work to finish it just have it fail under string tension is too much. I’ll try the hot iron technique first, wish me luck.