View Full Version : IV back board
I have a little bit to go, but I am just about to glue the back on my IV kit. I have a little problem that can be fixed, I just need to know the best way to go about it.
When I put the backboard on the rim of the mandolin, it fits fine in some places, but in others there is about a .050" gap when I hold them together in a way like a clamp would.
My message may be a bit jumbled, but that is how my mind works. Sorry
Perhaps someone has a better method but I used sandpaper (2 sheets) glued down onto a piece of glass. Started with 80 grit and Using chalk to mark the rim I gently sanded the calk away.....did the same with back. Only the back had a tendancey to bow so I had to be carefull to hold it flat against the glass (exerting equal pressure across the whole back edge) while sanding. In all, I used three different grits and ended with 220 grit. The objective was not to take too much material off but to level it.
Seemed to work well enough.
I think your back may be too narrow right at the center edge. you can fix this by installing binding or if you are sunbursting it or varnishing it dark, you can glue on wings. I can offer to exchange the back for you so that you do not have to do that extra work. Many folks did like adding that binding on the back. Please contact me so that I can make sure that you have a back that is wide enouph if you do not want to do those extra steps.
Did you level the rim after gluing in the lining for the back?
Leveling the lining and making sure the back is level on the edges is most likely the culprit.
The back on mine has what looks like planer snipe in a couple of places on the edge which will make it fun to make a good fit.
I leveled the rim and the back with a large piece of sandpaper from Taylor rental intended for use with their floor sander glued to a piece of plate glass.
I,m probably going to do what I can with a couple of shims and I am going to bind the back. Does anybody know where I can get some binding that is the same size as the binding that came with the kit? It is about .245" tall and about .050 thick.
Read this first. #You may be lucky.
It sounds like 2 issues are being described in the replies. Is the issue that the back plate does not seat to the rim and there is a gab between the two or, does the back plate not completely cover the rim?
My first reply considered the flush mating of the back and rim. If the problem is overlap then Mike may be spot on. The sides in my kit were not perpendicular in the widest part of body.
I created a form for the mandolin that fit snug where the top joined the ribs and forced the body into the form which brought the ribs back into square. The bottom lining was installed with the mandolin in the form. Once removed the ribs are near square but not quite there so I will glue on the back in the form as well. Sadly I had to cut out a portion of the form to fit around the neck so it now requires a clamp to pull it back square. Oh well.
It was a pain to create the form but I had so much time in graduating the plates that I wanted to finish the kit rather than ask Ken for a replacement. On the other hand, I'm confident of my ability to create a form for the scratch mandolin (top and back carved) that has been patiently awaiting my return.
The backboard overlaps the rim of the mandolin. That part is ok, it is just that it meets the rim in some places, but in other places there is a gap. I am just concerned that in time it all will seperate.
That gap you are talking about will change back and forth as long as it is laying there free and unsupported, with the change of moisture in the air. Not to worry. Much more than .050" is totally common, and once it is glued down, you can forget about it.
Sledge.. Never feel the need to skip around a problem that I can quickly take care of but I must say, THANKS! for working things out on your own. I am always willing to switch or replace parts.
BLUEGRASSPLAYER I can send you some of that White binding if you like. I may be able to rob some from another kit. Please let me know. I like to see Maple binding myself on those Kits. Plus.. it glues up easier.