Proper glue for assembling a rosette

[btberlin]

The last time I assembled a rosette in a spruce top, i used epoxy. After I did that, i read somewhere (doggoned if i recall where) that some glues can stain spruce (not from drips, but leach color out of the rosette into the surround), and somewhere in the depths of my mind i filed a note that this might apply to epoxy.

So, the question is - does epoxy stain the surround after a while? I need to assemble a rosette of thin plastic, mother of pearl and cocobolo. According to my notes and photos, last time i used the same materials, i used epoxy, imbedded teflon strips in place of the MOP, and when the epoxy cured, pulled the teflon, and glued the MOP into the channels with white Cyano. I don't see any such discoloration around the rosette i did a couple of years ago with the same materials as the one I am about to do.

But, before I go ahead - is my recollection correct? Will epoxy, particularly the darker ones like the All-Wood glue, eventually stain?

thanks
Bert

[Diane Kauffmds]

I know that ca glue (superglue) will discolor spruce; as far as I know, cleaer epoxy won't, but I'm not sure about dark epoxies. There is a Youtube video by Robbie O'Brien about installing rosettes; he suggests sealing the cut channel, to prevent staining by some glues. He doesn't mention which glues stain though. If you seal the wood with shellac first, make sure to use a glue that will adhere to the surface for your rosette.

I believe that Fish Glue will adhere to a sealed surface. I'm sure that John Hall could speak to this for sure.

Here is the Tip Dujour from Robbie O'Brien: https://www.youtube.com/watch?v=PFxfdpbfw_U

[johnnparchem]

Thin CA will wick into unsealed spruce Most seal with shellac or nitro. Reading your installation method the epoxy probably sealed the end grain as well.

[btberlin]

Thanks for the quick responses. I did use white-colored Cyano from Stewmac to embed the MOP after I pulled the teflon on the first rosette. I guess that's why the issue of staining caught my attention (after, of course, I had already used the CA.) Looking at the old rosette, though, i don't see any signs of staining, but, no harm being careful - so I will have to dig up my bags of flake shellac ( just moved into a new house) and mix up a dab to seal the freshly routed channels. I actually have the DVD of R O'B that comes with an LMI kit - I don't think I've watched the rosette chapter though. NOw's a good time to do that!

Again, thanks for the replies.

bert

[tippie53]

I do about 50 rosettes a year
here is what I learned
Best glue is duco cement
this doesn't add any water and if it starts to tack more glue reactivates the glue so it help to get things to set into the grooves. If I use pearl I will later glue that in using tite bond.

Wood rosettes and here I mean larger rosettes I will make the wood rosette on a backer and will use tite bond and a weight to clamp it in.

I have learned that CA and Epoxies are not very good for rosettes . Adding any water can take a dry fit and swell it in a hurry. The Duco or weldon are perfect as the acetone base won't cause the wood to swell.

[btberlin]

Thanks John. I think i may have a tube of Weldon that survived my move. Will check. IIRC, at the Martin factory, they use something like Duco or Weldon to glue rosettes into their channels. One concern I have is that either of these solvent-based glues may distort or soften plastic purfling lines that i will put on either side of the MOP and Cocobolo to give better visual definition. I use black/white purfling with the white side towards the MOP. Around the coco, i have the black side of the purfling against the coco. Won't these solvent glues wreck the plastic purfling?

b

[Diane Kauffmds]

I do about 50 rosettes a year
here is what I learned
Best glue is duco cement
this doesn't add any water and if it starts to tack more glue reactivates the glue so it help to get things to set into the grooves. If I use pearl I will later glue that in using tite bond.

Wood rosettes and here I mean larger rosettes I will make the wood rosette on a backer and will use tite bond and a weight to clamp it in.

I have learned that CA and Epoxies are not very good for rosettes . Adding any water can take a dry fit and swell it in a hurry. The Duco or weldon are perfect as the acetone base won't cause the wood to swell.

John, you said that when you use pearl, you later glue it in with Titebond. Can you elaborate a bit on that? If I want to make a wooden rosette containing a pearl inlay, should I inlay the wood rosette, then later route the channel in the rosette for the pearl? I didn't know that titebond glued pearl. Do you use the original Titebond?

[tippie53]

There are a number of ways to do this. On a standard rosette you use a spacer that is made of polyethylene that pulls out and you work a dab of tite bond and snap and break the pearl as you go around. I use mostly abalam as it is a great product and it is environmentally friendly.
On a wood rosette I do a number of different methods from one piece to tiles but in the end I do them on a backing , often thin spruce or mahogany. Then when I set them into the rosette this is what I do.

First I have the rosette on the backer as a large disk sized to the outer ring then I cut it free on the inner side. Often they are about a 3/8 wide but you can make them any size you wish. The key here is to make the outer cut on the top before you cut the rosette free.
using the center you set the cutter to your rosette and make the first cut on the top. Then I do make the 2nd cut on the to and adjust the cutter to that to separate the rosette.
If I want to put pearl in the rosette I will do this next step.

With the rosette not glued but fit to the rosette channel I will cut the rosette in the middle. If I have a tiled rosette I may spin one half so the tiles become staggered. I then put a space in the cut and glue in the rosette . After the glue dries I sand off the backer but don't cut the sound hole . Then I can open a groove in the rosette to drop in the pearl. I will often take a .020 bit and run a groove along the edges of the rosette inside and outside and drop in a thin black line.

[Bob968]

I do about 50 rosettes a year
here is what I learned
Best glue is duco cement
this doesn't add any water and if it starts to tack more glue reactivates the glue so it help to get things to set into the grooves. If I use pearl I will later glue that in using tite bond.

Wood rosettes and here I mean larger rosettes I will make the wood rosette on a backer and will use tite bond and a weight to clamp it in.

I have learned that CA and Epoxies are not very good for rosettes . Adding any water can take a dry fit and swell it in a hurry. The Duco or weldon are perfect as the acetone base won't cause the wood to swell.

Hi John,
when you later glue in the pearl (pulling out the polyethylene spacer), why do you use Titebond instead of Duco ?
Thanks