Best glue to repair cracked plastic head?

HDSarah · Post by **HDSarah** » Tue Aug 12, 2003 7:12 pm

The plastic head of my Feadog whistle developed a crack over the weekend. I know it's only a cheap whistle, but I'd like to see if I can make it playable again with glue. Does anyone out there have experience in this? What kind of glue should I use -- "Superglue", epoxy, something else?? Should I take the head off the tube to glue it (which would take some stress off the crack and allow it to close), or glue it with the head in place on the tube?

And do you think this is a divine sign that I need to accumulate more whistles??

Sarah

Bloomfield · Post by **Bloomfield** » Tue Aug 12, 2003 7:18 pm

I use superglue for cracked heads. Try to gently bend the crack open a little bit and to get some glue in there. The trick is though to use as little glue as possible. I'd also clamp it for some time (I think pressure not duration is what makes superglue harden). Afterwards use some fine sandpaper to sand the inside of the head so that it will fit on shaft nicely.

Most cracked heads for me are Generation Cs (they resist being removed), and they glue up nicely. Some have largish glued cracks that wouldn't close, but still play well. I use plumber's tape if the seal isn't tight anymore.

Jerry Freeman · Post by **Jerry Freeman** » Tue Aug 12, 2003 7:23 pm

Allezlesbleux posted some time back that he's had success wrapping the neck of the whistlehead with flat dental floss and coating it with fingernail polish. That creates a sort of fiberglass casing and should be very strong.

I assume you mean the crack is on the part of the whistlehead where it engages the barrel.

Best wishes,
Jerry

P.S. I believe Bloo is correct about superglue. If there's good surface to surface contact, pressing the parts firmly together while the glue is wet facilitates a good bond. And too much superglue makes a poorer bond.

HDSarah · Post by **HDSarah** » Tue Aug 12, 2003 7:56 pm

Jerry Freeman wrote: I assume you mean the crack is on the part of the whistlehead where it engages the barrel.

Actually, the crack doesn't extend all the way through the part that engages the barrel. (Yet.) It starts above that, and extends all the way up to the blade. Because of the involvement of the blade, I have serious doubts about being able to return it to its former glory, but there isn't much lost in trying. If it doesn't work, I could always get a Whitecap head for it . . . but the shipping would cost more than the Whitecap, so to justify it I might have to buy one of those quiet narrow-bore Hoover D whistles at the same time . . .

Sarah

Jerry H. Freeman · Post by **Jerry H. Freeman** » Tue Aug 12, 2003 8:21 pm

Hi, Sarah.

Now that you've described the crack, here's what I would recommend.

Get some slow setting epoxy (like one hour, not five minute) and work it into the crack. Do your best to fill up the crack all the way to the bottom. Use a pin or something tiny to work it in. I'm thinking a single strand of copper wire from a stranded electrical cord might work if it's stiff enough.

You don't have to clamp the whistlehead because epoxy will fill gaps solid and strong. I wouldn't clamp it because if you clamp it, it will recreate the dimensions that generated the original stresses that broke it in the first place. If you fill the crack without clamping it, the whistlehead will be the right dimensions to fit without stress. I would glue it with the head mounted on the barrel, as long as you can avoid gluing them together in the process. This, also will help prevent recreating the dimensions that caused the original stresses.

When you're done, you can carve off any extra dried epoxy with an exacto knife or similar tool.

Best wishes,
Jerry

Blackbeer · Post by **Blackbeer** » Tue Aug 12, 2003 11:01 pm

I just wanted to add some of my experiences with super glue that may give you some ideas as to its usefullness. First off it was developed, I believe, as a replacement for stiches in VietNam. You can get it in different thicknesses at any hobby store that sells radio control airplane stuff. It actualy developes its own heat for curing once it is exposed to air. That is why less is better. For filling gaps it is magic. Just pick up some chopped cotten which is used as a filler for epoxy. It is very fine almost dust like cotten. Take the cotten and fill the gap with it. Once that is done and you are happy with the shape of it drop a few drops of super glue on it and watch it cook. Oh by the way the fumes will knock you out so don`t get to close to admire your handy work. I once patched a hole in the block of one of my model airplane engines in this fashion and it never let go. It seems to work on just about any thing. At the hobby shop you will also find all kinds of aditives for it, quick drying spray, glue remover, you name it. Oh don`t use it on foam. It eats it. I also used the fill techneque on a bunch of cracks in an old bamboo flute I hauled around with me for 25 years. Worked like a charm. The thicker glue gives you some working time. If you use the quick set spray you can get every thing the way you want it and then spray it and presto the glue is set.....
So it realy is magic stuff and a whistlers friend. Just don`t become part of your whistle-)

Tom

Tony · Post by **Tony** » Tue Aug 12, 2003 11:52 pm

Another trick is to fill the crack with baking soda before applying the superglue. Just rub it in with your fingers making it smooth. The superglue will 'wick' itself into the crack and bond the baking soda to the plastic, easily filling any small cracks.

ALLOW AMPLE TIME for the glue to harden and clean excess with sharp knife or sandpaper.

Zubivka · Post by **Zubivka** » Wed Aug 13, 2003 1:27 am

Cyanoacrylate won't fill a crack if i't's left open. You need a vise, or better screwed collars for rubber hoses to close the gap.

But as Blackbeer points out, it works if you have a filler material.

I've used some mix of "super-glue" made by a Repar-Ex Co., Germany.
It will fill securely any crack.

It's in two separate bottles:
1) A regular liquid cyanoacrylate glue (i.e. crazy/super/duper/younameit)
2) A second vial with glass microbeads
These glass beads flow even better than liquid out of the thin nozzle.

This stuff is identical to the beads sold as "lubricant" for some "Indian billiard" games I've seen in toys or novelties stores. It has many other applications, like a variation on sandblasting (called microbeading I reckon), so it's pretty cheap.

First apply liberally the glue. It dries slower if in the open (i.e. not compressed).
Immediately, fill the crack with glass beads. They sink in the glue.

A side advantage is cyanoacrylate plus glass remains translucent, colourless, and shows little over whatever plastic base you apply it to.

Tony · Post by **Tony** » Wed Aug 13, 2003 1:52 am

Zubivka wrote:Cyanoacrylate won't fill a crack if i't's left open. You need a vise, or better screwed collars for rubber hoses to close the gap....

Zoob... the baking soda powder IS the filler material. Since the plastic already cracked due to stress, it's often better to leave it instead of trying to squeeze it back to it original size/shape.
Why go out to buy some exotic glass bead filler or over wrap the fipple with cotton or dental floss when the baking soda can do the job?

Zubivka · Post by **Zubivka** » Wed Aug 13, 2003 2:10 am

Tony wrote:Zoob... the baking soda powder IS the filler material. Since the plastic already cracked due to stress, it's often better to leave it instead of trying to squeeze it back to it original size/shape.

Agreed 100%

Tony wrote:Why go out to buy some exotic glass bead filler or over wrap the fipple with cotton or dental floss when the baking soda can do the job?

wow! I'll try it! Would it work over wood?
I got a few nasty thin cracks on this ebony antique fully-keyed flageolet (plus piccolo head) I just snatched on German eBay.

Tony · Post by **Tony** » Wed Aug 13, 2003 2:52 am

It lends itself perfectly to working with wood. Many modelers use baking soda and CA adhesive to reinforce fillets on aircraft.
If you want to restore thin cracks in wood... you won't need any filler. Otherwise, you might do better with fine sawdust of the same wood you are trying to fill, this way you'll have a better color match.

Zubivka · Post by **Zubivka** » Wed Aug 13, 2003 5:17 am

Thanks, Tony.
I used to be an aircraft modeller... 30-odd years ago.
The materials DID evolve since these days of bungie-propelled, lacquered-paper free-flight models

On the positive nostalgia side, beside rubber-band and Cox Pee-Wee, we were allowed pulse-jets (pulsoreactors) pop-pop-pop-pop-pop, or "tongued triplets" to be known as WMD (wartime model dynamiTs)

burnsbyrne · Post by **burnsbyrne** » Wed Aug 13, 2003 6:56 am

I have mended whistle heads with superglue. It worked fine. The cracks I mended were on the cylindrical end that goes over the tube (too much teflon tape).

Incidently, when I was playing flamenco guitar I reinforced my right hand nails with superglue with nail filler powder to give it bulk. Corn starch or talcum powder work too. The glue could be filed and shaped like a regular nail and could be repaired with more glue when bits broke off.

That superglue is amazing stuff.

Mike

Jerry H. Freeman · Post by **Jerry H. Freeman** » Wed Aug 13, 2003 8:46 am

I would go along with the superglue/filler technique. I haven't used it myself, but have read of it in places like Fine Woodworking magazine. I believe in the article I read, it was used to fill cracks in a guitar nut, so it must be very strong when done properly and fully set.

Best wishes,
Jerry

allezlesbleus · Post by **allezlesbleus** » Wed Aug 13, 2003 9:24 am

Jerry was correct in recalling my dental floss repair. I had a couple of Gen Fs that both cracked up through the blade. What I did:

1) Take Glide dental floss (it's flat like a tape) and carefully wind it around the bottom of the headpiece. As you wind it on, pull it hard and it will pull the crack closed from the pressure (ever worn an Ace bandage? Those get pretty tight pretty fast). Be sure to wind the floss on flat, don't get it twisted around.

2) Once you've built up a layer of floss (3-4mm) then paint it with nail polish. This will act as the resin matrix for the floss. It'll take about 3 feet of floss to do it right.

3) Carefully paint the blade with a layer of nail polish to smooth the surface out. (Don't paint the bevel, just the surface)

This should work better than the filler + epoxy since it actually pulls the crack closed again and adds an extra layer of reinforcement. The floss + polish composite material is strong and serves to reinforce the weakened area. Dental floss is really strong (if you try and tear it with your hands, you'll probably cut yourself) and so is nail polish (don't want chips now!).

If you want to get really fancy, you could take your whistle into the store and color match the head with the color of the polish and you'd have a pretty subtle repair!

I also like polish better than superglue since it's thicker and sets up better on the floss than the thin glue. Superglue also dries white and flaky if you are sloppy. Polish is available everywhere, it comes with it's own applicator (the brush), doesn't require any mixing, and has a nice set up time. Acetone is a quick cleaner-upper (if I can use my mom's word) if sloppiness occurs.

Let me know what y'all think!

PC