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I received my radius dishes from LMI the other day. I have sealed them with a couple coats of shellac and now want to mount them on 3/4 inch MDF. The note that LMI shipped with the dishes says to either screw them to the backer or clamp it to the backer board. Can, or rather should, I glue the form to the MDF? Would screwing it down be better? If screws will work, do you countersink them from the top side of the dish? What do y'all do?

Aaron

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Aaron Craig

Really you should have bought them already laminated...no distortion then! (sorry...shameless self promotion). Seriously though, just cut a piece of 3/4" mdf a little over size, use a bunch of carpenters glue (titebond et al) and use about 8 clamps around the perimetre. Leave for 12 hours and then trim the added mdf using a piloted router bit. A bit of sanding and you are done! No screws are necessary. I have built probably over 100 of these now and this is not too different from the process I use, except that I don't carve the dish until I have the mdf laminated...that ensures stability.

Shane

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Canada

That's just what I was waiting to hear. I'll glue 'em up in the morn. Thanks, and I'll try to keep you in mind if I need another dish in the future.

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Aaron Craig

Or just glue 'em together...

I will agree with Shane on this, I replaced a dish that was ruined in my basement flood with one of his and it is a thing of beauty. The one that was destroyed I had to put Baltic birch on the back as it started to warp within a few weeks of getting it. I had 2 of them I bought from a Ebay seller, I just screwed the plywood on the back, though glue and screws would have been better.

Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

I have laminated several pieces of MDF and plywood over the years for things like benchtops, sanding tables, radius boards, etc. I have always used contact cement. Works great. Brush or roll it on smoothly to each surface; let it get tacky; press them together. No need for clamping and setting, no distortion from the gluing, and they don't come apart. Just be sure the parts are aligned when you touch them together because once they touch they are glued. I use the dowel or stick between the parts technique on large surfaces; be sure they are aligned and then take one stick out at a time to set the peices together. Simple, and works every time.

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Chuck Kish

I just use titebond to glue my square blanks together( 3/4" mdf each) then cut the circle and then I cut one radius on one side and the other on the other side. I've used weights and gobars to glue them up too.

I don't use MDf there is a much better product out there that is actually used as a ceramic tile backer. No need to be laminated and stays very stable.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Are you sure about this John? I find that almost every manufactured board product ends up with a hardened surface that results in distortion when one surface is removed. I made some jigs for a friend to shave her reeds for her clarinet and when I was milling the plexi on the milling machine it distorted like crazy if I only removed one surface. That is why I continue to laminate the dishes I make. Other pluses of mdf is the cost but mostly the weight. Having a bit of mass for your dishes, in my mind, is a very good thing!

If this other product truely does not deflect when machined I would be happy to hear more about it.

Thanks

Shane

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Canada

yes it is very stable . While it looks like MDF it isn't. It is a very stable product. It is thicker than MDF and doesn't seem to be affected by humidity. I am not sure of the trade name buy mylex comes to mind. It is also a bit more costly than the MDF.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Thanks for the great advice. I just used Titebond to glue the dishes to MDF. Used a combo of cam clamps, go-bars, and weights to clamp them for 12 hours. Seemed to work fine. Last night I used some spray adhesive to apply some 80 grit to the radius dishes. I think I will also put 80 grit on one of the MDF backs to use when sanding flat surfaces.

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Aaron Craig