Im asking this question to help me and anyone else who may have a similar issue.

Are there any methods of restoring atlest minimal downbearing to a soundboard?

These methods are an act of desperation before soundboard replacement or to save an old piano that isnt worth soundboard replacement.

My current project is one not worthy of a soundboard replacement.

Soundboards have crown, strings have down bearing. Between the string and the soundboard is the bridge. The bridge could be replaced or the plate lowered to increase the downbearing. But if there is insufficient crown, the soundboard may "invert" and then have negative crown.

What has been suggested is to make the soundboard stiffer, which is what crown is all about, with an epoxy treatment or with "riblets". But the present downbearing/crown may simply balance each other to nearly zero when under tension, and not be problem at all.

So let me ask you a question. Why do you think the piano will sound better with more crown and downbearing? It might never have sounded good in the first place!

Oh, I forgot another treatment. Engine valve springs have been installed on brackets mounted on the backposts and pushing on the ribs. Supposedly it does work!

As I said before, you are worrying about this too much. Put the piano back together and see how it comes out.

Not very well.

ddf

Shhh...

The piano sounded ok. loose bass bridge and old bass strings made a tubby bass. It had poor sustain, no volume(couldnt even get as loud as a wurlitzer spinet). How is the epoxy treatment or ribblet procedure done? Is putting it all back together worth loosing $250 in strings? What kind of sound am I going to get with no downbearing?

lol

Just curious Amature (sic): How many threads do you intend to start about your soundboard bearing and crown?

As many threads as he requires;

AR if the piano sounded ok before you began working on it, the sound will be the same; a bit cleaner because of the new wire and all; the bass section should be much improved with the improvements you have completed there.

As BDB stated you worry too much; just re-assemble and see what you have. If the project is not worthy of sounding board replacement then it is a moot point.

Remember that people who don’t make mistakes generally don’t make anything at all....

I don’t know what you refer to when you state “epoxy treatment or ribblet procedure”

I have decided just to put it back together, it should sound a little bit better since I repaired the loose ribs. It also will hold a tune well, and Look decent. I would like to get some new hammers for it, anyone know of a place you can get cheap hammers?

Tomorrow Im going to replace the understring felt and start the restringing process.

Farther down the front page of this forum there is a thread about supply houses. You will find hammer sets there.

I would let the glue dry before you begin stringing or the pressure will force the glue to soak through the felt and rust out the wire.

yeah I could leave the original felt in but its faded and ugly my only problem is when I orderd the felt I forgot about the felt in the bass section so I may have to leave it out somewhere

Hopefully you are keeping track of time spent and parts purchased on this project. It's important to track costs so you end up making a profit in the end.

Not for an amateur, nor for a beginner. The most important thing is to get it as close to right as possible. You should not be rushing through the job, nor should you stint on the job until you have a better feel for this sort of work.

This is the BEST interaction I've seen on here in a long time. Bravo!

I will at least break even. Since this was my first I had to get a lot of new tools I wont include that in the price when I do sell this.

I went ahead and took a trip over to the shop and glued the under string felt to the plate so the glue will be dry tomorrow, I will also have to do some trimming is some areas.

It still amazes me how much hide glue smells like wet dog witha hint of pepper.

Interesting definition of "OK" sound!

This is what my piano sounded like before I did anything to it. Tell me what you think.

Im glad I can play the piano better than that now lol

Hey I just posted a link to a vid of the piano before I did any work

The first refers to soundboard treatment I described in a series of articles that appeared several years back in the Piano Technicians Journal. Very simplistically it describes a technique of using very thin coating epoxy to fill minor cracks and stiffen the soundboard panel without adding any appreciable amount of mass to the system.

The second refers to an article written by my brother in the same magazine several years later. Again, very simplistically, it refers to a technique of adding short, auxiliary ribs—i.e., riblets—between the existing ribs to stiffen the area most affected by compression failure within the soundboard panel. I have also used them from time to time to stiffen the area at the end of the tenor bridge to lessen the “end-of-the-bridge” effect.

ddf

Yes of course; this had slipped my mind, I recall having this conversation with Darryl when he was here. I have also read some materials on this forum about the process. Thanks for the reminder.

I've used epoxy to fill cracks and it worked quite well. I'd dry the soundboard out for 36 hours with dry heat, which opened the soundboard cracks as wide as they would go. Then, I'd fill the cracks with epoxy, which dried before the cracks closed up. That prevented filled cracks from opening up again during dry winters, and I suppose added tension to the sound board.

I don't think I'd use heat with moisture, though. That might loosen up ribs, and other glue joints, I would think.

Did you measure crown in the board and string bearing at the bridges before you took it apart?
Does the board have any crown on it after taking it apart?
If it does, best thing you can do when you reassemble is to set absolutely minimal bearing - maybe only 1mm across all of the bridges.
Don't do this in a cool damp shop.

On a QUESTIONABLE OLD sound board.

Dry the sound board to 5% to 5.5% EMC.

Measure your crown.

What ever that number is, you can not have any more bearing than that.

If you have 0 crown at that point, then set your bearing to 0.

If that is the case, I would hire Del for some thoughtful help in stiffening the board.

The rest will be your understanding of what hammers you use and how you make them work with your sound board choices.

Are these what I think they are?

Nice description, isn't it?