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Jeffries/dipper Action Board Repair Question

Jeffries repair

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#1 Dan Worrall

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Posted 12 February 2018 - 11:57 AM

I have a lovely old Jeffries 30 button that I recently purchased. It had been completely rebuilt in the 1970s by Colin Dipper, and is a wonderful player. However, it has developed an air leak. Investigating, i found the culprit -- a hairline crack has opened up in the action board, extending about 3 inches from the air button hole down to a nearby note hole, along the grain. The crack is only wide enough to see daylight through, but it is enough to render the instrument sluggish and leaky.

 

The soundboard, built during restoration,  appears to be spruce or some such, and is single wood (not a ply). In later days, Colin used plywood for these boards, for just this reason....stability and resistance to cracking; my 1991 Dipper's action board is made with ply.

 

No doubt the change in climate from the UK to here in Texas had something to do with this crack developing. And of course, there is the issue of dry air from inside heating during the winter. 

 

I'm thinking of spreading some wood glue into the crack, on both sides, to seal it. Or possibly some rubber cement. Any suggestions on this from seasoned repairers?

 

Cheers,

Dan Worrall



#2 Theo

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Posted 12 February 2018 - 12:40 PM

My usual approach to very fine cracks like this is to use superglue/cyanoacrylate because of its ability to reach the full extent of the crack by capillary attraction.  Precautions to take:  Remove any pads that lie over the crack.  If the wood has moved up or down on either side of the crack forming a step then you must arrange some clamping that will bring the edges back into line before applying any adhesive.  I start with the least viscous grade of superglue, if any wider parts of the crack are not completely filled then you can add a little of a more viscous grade.  Wipe away any surplus immediately.  Leave it to cure for longer than the instructions say.  To be on the safe side I usually leave it a few hours before attempting reassembly. 



#3 Robin Harrison

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Posted 12 February 2018 - 01:26 PM

.......there is a trick I have recently discovered when repairing the nut on a guitar or similar, whereby superglue and baking soda are used together.

     Would this be useful for filling wider gaps in wood in an instance like this ?

Robin



#4 alex_holden

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Posted 12 February 2018 - 03:24 PM

This is one of the rare cases when I'd be tempted to fill it with epoxy, because you want something that isn't going to shrink as it dries. You need a thin watery epoxy (e.g. West Systems) that will run down into the crack, not the rapid repair adhesive stuff.

This quick video covers the basics:
https://www.youtube....h?v=jcJKzQaW3Ps

#5 d.elliott

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Posted 13 February 2018 - 07:19 AM

Personally, I prefer not to rely on glues and fillers too much, if I have enough of a split to let air through, or create then a step then I tend to open the crack a bit more and set a strip of thin wood into position, clamping only to ensure that any 'step' is taken out. if the split is just a hairline crack then I wipe PVA glue into it. One thing I never do is to try to close a crack or split in these circumstances. If the crack has happened then the structure is de-stressed and stable, I just repair the fault. 

 

Dave



#6 Dan Worrall

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Posted 13 February 2018 - 10:51 PM

Many thanks, all!

 

It is just a hairline crack, with no step, thankfully. I think I'll go for the PVA glue and will let you know how I get on with it!

 

Dan






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