Dobro screens

[Rory]

Hi folks,

Just finishing up another slide guitar & here's a question for you that do dobros, etc. The round soundhole screens- how do you install them? I cut a round hole just slightly undersize, then use sandpaper to slowly work it out to a tight press fit. Still if you put them in dry, they inevitably come loose, rattle or fall out. So, after press fitting quite tight, Ive tried everything from a bit of silicone caulk on the inside edge (in the guitar), to that sticky putty that some pickup installs use. I'm tempted to slather some construction adhesive in there as it seems no matter what, they dont just want to stay press-fitted. I wish they were threaded with a ring that tightens on the inside of the guitar but not holding my breath for that.

Any bright ideas?

 

Rory

[Greg Mirken]

Dobro has always just pressed 'em in. Loosening is not so much a problem on a ply top. You could wrap a length of 1/8 inch masking tape around the ring to add some squishiness.

[Rory]

Greg,

Thanks, yeah I figured about as much from dobro. No ply on my guitars so theres a real fear with pressing in too tight a hole and splitting the grain. That would be real sad seeing as the screen goes in at the end of the build after lacquering. But you might have an idea there with some type of tape though. But in my case I wouldnt go around the ring (its already press fit quite tight in the hole), rather id run it on underside in the guitar top to hold the ring down, if you follow.

 

Any other methods out there from solid top reso builders?

 

Rory

[Greg Mirken]

What's wrong with a couple of dots of silicone caulk?

[William F.Eden]

Well for what it's worth I just put one drop of THICK C.A glue on one side just in the one spot .And they never come off.Bill......................

[Rory]

William,

hadnt considered CA...,I think Im gonna give this a try next time-  thanks!

Rory

[Rory]

Greg,

Silicone seemed to work for a while but still didnt stay down nice & flat & eventually gave way.

 

Rory

[Rob Mercure]

Being totally out of my league here (don't laugh is this sound silly) is it not possible to use three very thin letter "sized" screws that thread into an epoxied (or soldered - I assume chromed brass ring - scrape the chromium off) to hold them in?  While I can't recommend a supplied is decades of disassembling electronics, musical, medical, and industrial equipment I've acquired a few screws with "fancy" floral patterned heads that are about as this as 1 1/2 credit cards!  Recently I've been trying to sort out and organize all of my zillion containers of fasteners and such and you may be surprised what's available out there is you can find a sources.

Rob

[Rory]

Rob

That thought had occurred to me. Problem as I see it- much of the instrument buying world tends to be very fickle about everything looking exactly the same as it has for the last 100 years. I could see the thing sitting on the shelf- 'eewww- look, he used screws to hold his screens in place, he must not know what hes doing'. Your idea of a ring got me thinking though- I wondering about a fairly stiff rubberized ring, like a mini mason jar seal, that slips around the edge inside the guitar. That would take glues, putties out of the picture and be a neat & easy way that they could be removed if necessary.

 

Thanks again all for the input! Its so helpful to have like minds to jam on ideas. Ive already got a few new things to try.

Cheers,

Rory

[Rob Mercure]

Rory,

While taking a nap a minute ago I had another thought (although I still feel that fasteners with heads that look like flowers or such could fool people):  The reason given that the "industrial" ones don't have the problem is that plywood won't split when they are jammed in - will since you've got control before final assembly would it be possible to thin out CA enough to have it wick into the Spruce (I guess) far enough to prevent splitting?  And/or could you not make an internal bracing ring perhaps not even the thickness of the top but with the grain running at 90 degrees to the top?  With the further and/or of shaving this ring really thin and making two laminates?  Lastly same idea but using a wood that's quite hard to split like Sycamore (platanus) or American Elm (I heard that european else isn't has hard to split as American - I've had to plunge cut through the middle with a chainsaw before I could keep a splitting wedge from bouncing out of an 18" piece)?

Sometimes when I'm tired my mind does everything else bu "sleep!"

 

Rob

[charley erck]

I think Rob has hit on it here! The creating a ply ring right at the holes. Rory , what are the screens like in the way of smooth?  The ones in my experience are somewhat rough around the part that stuffs into the hole and this helps to lock them in.Where did you scource yours? What is the top wood , by the way? My Scheerhorn is maple and the maker has reinforced the sound/resonator cone hole underneath with a narrow ring of maple, but I'm not sure of the screen holes. I tend to think the are un reinforced . The screens fit quite tight and don't have any tendency to work loose.I will pull one and check if they are reinforced with a ring of wood under neath.

[charley erck]

Rory, the holes on the Scheerhorn are indeed not reinforced.The maple is quite thick,3/16 plus.The ring under the top is hard maple ply and extends into the resonator hole to form a seat for the cone..What is your top wood? If it is a matter of the fragility of the wood i think Mr. Mercure's idea of reinforcement would be the best rather than any of this glue stuff. Also, on the subject of the smoothness of the screen ring, maybe , if it were the case of too smooth, a treatment on the principle of Frank Ford's fret tang crimper could be devised/applied.

I think a long history of success with friction fit indicates it is practical!

[Rory]

More great ideas folks.

My top wood this time is figured maple, but can be blackwood, koa, etc. Top wood thickness is much thinner than typical dobro- more like regular guitar top-this is a hollowneck Weiss style with spider cone, so a hybrid- the intent being the body is much more resonant than dobro bodies.

Im sure the other thing that happens with the thin wood contact area is that there is more likelyhood for some expansion/contraction with heat/humidity changes.

I think I'll back the screen holes next time with a thin built up ply or wood ring with grain at 90 degrees to the other and added surface area with press fit & maybe a bit of CA should do it.

 

Thanks again guys for all your attention to this itty bitty detail!

 

Its all in the details, aint it.

Rory