Gluing Delrin and copper together (Fipple)

[Grexrell]

Does anyone know any glues that would work well for gluing together a Delrin and Copper Fipple?
I'm currently working on a Copper Low D Whistle and will be using Delrin for the fipple block. I've got a wooden fipple block in its place at the moment being held in by friction.

Any suggestions would be great. Thanks.

[Feadoggie]

I pin delrin plugs. It just doesn't glue very easily.

Here's what DuPonyt says.

"The adhesive joining of Delrin acetal resin is generally
limited to prototype models with low shear
forces. This is because the shear strength achieved
with most adhesives is only 2 to 10% of the available
shear strength of Delrin acetal resin. The best
adhesion requires a special roughening step such as
sanding with 280 grit emery cloth."

DuPont lists several epoxies that are useful with the preparation listed above.

I read of a new prep for delrin or acetal somewhere that that helps improve its gluing but I can't put my finger on it just yet. I'll keep looking.

Feadoggie

[Carey]

You could achieve the same thing as pinning if you drill some holes or groves (laterally) in the fipple and some holes or ridges on the ID of the copper tube. Then your epoxy would make a mechanical link between the two much like pinning it, but you wouldn't have to have the "pin" visible from the outside. I'd put the "features" on the fipple block and tube so they match up when the fipple is in place to ensure the epoxy spans the two properly. Roughing up the serfaces does the same thing, but on a smaller scale.

But pinning like feadoggie suggested is way easier.

[Feadoggie]

Carey's suggestion is a good one for delrin. You really don't need a strong bond but you want the plug to stay in place.

As for pins being visible from the outside - make it a design element. That's what I have done. Look at a Sindt whistle, as one other example. He pins his heads and the brass pin contrasts with the black delrin mouthpiece to create a "gold dot" accent which is quite rich looking. A brass pin might look sharp against copper.

Another thought I had is to use another plastic material which might work better with glues. Food grade PVC is available in solid rods of different diameters. I have used it in quite a few whistles. It machines well, polishes well and is resistent enough to the elements. It is not as chemical or temperature resistant as delrin but that's why one can be glued and the other is difficult.

Feadoggie

[brewerpaul]

I use this cyanoacrylate glue with pretty good results:

http://www.drmikesglue.com/prodinfo.html

Go for a nice snug fit. Cutting grooves into the Delrin for the glue to grab helps, or you can rough it up with coarse sandpaper. Press the fipple into place, then put some glue on the joint between the Delrin and the copper. This glue is water thin and will wick into the interspaces.
A couple of years ago I actually called Dupont technical support and asked what to use to glue Delrin. The rep's reply was "Good luck!"

[syn whistles]

I've been doing some research on the subject myself and it seems that Paul's suggestion of cyanoacrylate is the best glue for the job. Unfortunately it's not available here in Oz, I'd love to get hold of some for glueing the brass and Corion mounts onto a set of Delrin smallpipes I'm making up. There may be a titebond product which comes a poor second to the cyanoacrylate, I've still got to find which one!

[MTGuru]

Unfortunately it's not available here in Oz

Are you sure, Eric? Here in the US, cyanoacrylate is sold under the names Super Glue, Crazy Glue, and others. In Australia, the Flash brand seems to be available from hobby and woodcraft shops:

http://www.hobbytools.com.au/category14_1.htm

Cheers!

[syn whistles]

Oops, sorry, that should read cyanopoxy. I understand its speciality is for glueing together 'slippery' plastics. Have a look at the cool-chem website.

[ZAK]

I was reading the thread on the topic of glues for delrin, does anyone have any information regarding a filler or acetal resin that can be used to fill a hole in a delrin table top? I find myself in the uncomfortable position of having cut to deep into the top of a CnC table top that belongs to the shop next door to mine.

Thanks

[Thomas-Hastay]

Keep the glue in the tube!

I suggest using a "through pin" made of copper. A rivit size pin installed from side to side will become invisible when both sides are flattened in countersunk holes and then polished. Using a pin to secure the fipple plug will allow the service person to easily remove/replace the pin if the plug must be removed for access to the bore. A pin will also secure the plug from "wandering" due to heat.

Another option would be a small centerbolt and washer installed on the plug so it could be secured "Flute Style". By tightening the center screw/bolt, the delrin plug will expand outward to the sides and secure the plug. This will also allow the advanced or expert player to adjust the plug for the "cutoff frequency" between registers.

[Daniel_Bingamon]

Pinning is good but sometimes the pin slips if the hole allows some play.
And yes, a brass pin actually looks decorative.

Thomas, the centerbolt thing sound interesting - ideal for a tuneable whistle a non-tuneable Low-D would need a really long screwdriver.

To add to all of this:

I recommend some "traction marks" using an "Exacto knife", score little diagonal lines in both directions on the gluing surface. Be careful not to scratch the windway area. Do this both on the copper and on the plug, then apply the glue. These little slits give the glue something to hang onto. You can do this with or without pinning - consider pinning as extra insurance against it coming loose.

PS - It also holds the plug in place while you're trying to pin it.