Gluing acrylic end to end

[jbg230]

I'll be making a stars and stripes blank and need to glue two alumilite segments together, end to end. Is there a special acrylic bonding adhesive I should use like JB Weld or Weld-on 3 or should clear Gorilla glue work? DAP Rapid fuse? Thin CA? Sorry for another gluing question; I just haven't had to glue two 1" acrylic sections, end to end before. Thanks!

 

[1080Wayne]

Alumilite Clear (a polyurethane) or Alumilite Clear Cast (an epoxy) ?

 

[magpens]

You say the sections are 1" diam ..... at present before turning down to final size.

Will the blank eventually be on a brass tube ?

What I am thinking is this. . The end-to-end gluing is always a dicey business. . What has worked for me is as follows.

I change the end-to-end glue-up to a stepped gluing, with the step at a radius greater than the brass tube radius but the step at a smaller radius than the final diameter. . The glue joint is thus stepped and the glue can bond to a larger surface area ... plus there is a short cylindrical portion to the step which helps a lot with regard to the strength of the joint.

If you have room between the brass tube and the final size, you can leave a few thou of extra room to hold some extra glue.

Or here is another way .... at the radius where you would make the step, you can cut a very thin circular groove at the end of each of the two pieces.
The glue will then press into this groove and this gives extra strength to the "butt joint". . You would press the pieces together in the same way to let the glue bond to the pieces while it cures.

Making such a circular groove on the end of each piece can be tricky. . But even a shallow groove will be a big help to strengthen the joint.
I have made such a groove with a very narrow blade like a parting tool blade. . Obviously the groove has to be very narrow in order to fit.
You can buy sets of "picks" at a tool store. . I grind the sharply-pointed tip of such a pick down slightly to make an appropriate grooving tool.
It takes some care to get things right. . I practice on the ends of some blank cutoffs.

 

[jbg230]

I think the blanks are Clear Cast epoxy. These are the blanks: https://www.exoticblanks.com/stars-...en-blank.html#product-details-tab-description
What are the products that you would use for either poyurethane or epoxy though?

The diameters are not 1", they're 3/4". I'll be using a bolt action type pen kit so it's only one brass tube. I'd like to cut out a 1" section of the stripes blank and a 1" section of the stars blank and glue them together end to end to make one blank to glue onto the tube.

As much as I appreciate the advice above which sounds like a great way to make it secure, I just don't have the time for the learning curve to feel confident that I'll be doing it well.

Maybe another way is to use a thin piece of aluminum or a section of credit card, with scored up surfaces, in-between the two blank sections to allow for a stronger bond as opposed to just the two blanks "stuck" together.

 

[magpens]

I think you would have to make the thin piece of aluminum (or credit card) an actual feature of the design .... some folks do that, in fact, to good effect.
I don't think such an insertion, of itself, would help with the glue-bonding issues. . I'd still recommend the stepping or grooving approach as well.

"What are the products that you would use for either polyurethane or epoxy though?" .... I would use epoxy glue for both.

"I just don't have the time for the learning curve to feel confident that I'll be doing it well." .... we all face such challenges; no real shortcuts, I fear.

The challenges that each of us face very often seem to have some characteristics that are unique to our own individual requirements, methods and materials. . Customers throw various curve balls that require us to do some technique research & development which is time-consuming.

In addition, with that particular pen kit (the 30 Cal. Bolt Action kit) you do not have much room to use the methods I have suggested.
The barrel O.D. is only about 60 thou bigger than the brass tube diameter.

Another approach completely is to get a blank made up to your requirements. . There is a wood inlay blank designed as you require .... a stars and stripes wood inlay for the bolt action pen kit .... I think it is sold by .... www.KallenshaanWoods.com ....

I have also seen a similar blank for the bolt action ..... starts and stripes ..... made from colored feathers and other bits/pieces.
The maker of those was Seamus Rooney, but I have not seen him around here for quite a while. .
Seamus is probably still a member of IAP. .
If you need help contacting him, let me know. . I might be able to help. . But it all takes time which you many not have.

EDIT:
I see that Seamus is still around. . He has a website ..... http://www.Texomapens.com

Another avenue is the maker of the actual blanks you plan to use ......
He might be able to help you out, or make something specifically for your need. . Check with Exotic Blanks about contacting him.
The owner of Exotic Blanks is on IAP with name .... ed4copies

 

[mnerland]

Is this a pen or an ax handle? Seems like alot of engineering involved for a pen. I would think a clear epoxy on the ends.
Then drilling and glueing with epoxy would be fine. Any kind of torque would be taken up there by the tube. Unless I'm missing something.

 

[jttheclockman]

Do not overthink it. It is plastic weather alumilite or silmar all the same. It is not wood and it is not metal. Personally I would turn the stars blank round and the stripes round and drill for the tube using a collet chuck. Now I would true up the ends using a skew or parting tool. Do this to each blank. Then use a epoxy with a long open time and do a on tube build and glue both the tube and the joint at the same time and clamp. Leave the blank a little proud so that when you clamp you are clamping the blank and not the tube. Sand down later. If you do it this way there is no stress on that joint from drilling and when pen is done there is no stress on it at all except if you drop it.

Forget Weld-on3. That is for sheet goods.

 

[magpens]

The last two posters make good points .... mnerland and jttheclockman.

If you drill the blanks, face the ends, glue the pieces together ON THE TUBE, and clamp ..... waiting a day or so before further work
then you SHOULD have no problems.

HOWEVER, the butt joint gluing is intrinsically very weak. . . Also, the glue between the barrel pieces tends to get sqeezed out by the clamping.
So even a little "cupping" of the butt joint is a big help to improve the bonding of the glued-together end faces.

I have been down this road. . It may be that I am "overthinking" ..... but I tend to do that in this situation of doing a butt joint.
Most of the stress will be taken up by a soundly glued in brass tube. . You can roughen up the surface of the brass tube.
But it is hard to roughen up the interior hole in the "plastic" barrel pieces, and that glue joint is a bit hard to guarantee.

And, of course, the stresses here are not as high as in an ax handle.

But I like to take precautions, and my suggestions are not that hard to do .... particularly on a metal-working lathe, which affords easier control.
I do not think it is "overly" engineered.

 

[jttheclockman]

The last two posters make good points .... mnerland and jttheclockman.

If you drill the blanks, face the ends, glue the pieces together ON THE TUBE, and clamp ..... waiting a day or so before further work
then you SHOULD have no problems.

HOWEVER, the butt joint gluing is intrinsically very weak. . . Also, the glue between the barrel pieces tends to get sqeezed out by the clamping.
So even a little "cupping" of the butt joint is a big help to improve the bonding of the glued-together end faces.

I have been down this road. . It may be that I am "overthinking" ..... but I tend to do that in this situation of doing a butt joint.
Most of the stress will be taken up by a soundly glued in brass tube. . You can roughen up the surface of the brass tube.
But it is hard to roughen up the interior hole in the "plastic" barrel pieces, and that glue joint is a bit hard to guarantee.

And, of course, the stresses here are not as high as in an ax handle.

But I like to take precautions, and my suggestions are not that hard to do .... particularly on a metal-working lathe, which affords easier control.
I do not think it is "overly" engineered.

Mal if you start cupping the ends you run the risk of being a void when turned down and all you have is glue between the butt ends. I suggest not to do that and make them flat. If you want some tooth then use a sharp knife and make a few scratches in the ends.

 

[magpens]

@jttheclockman

Yes, John, you are right ... there is that risk, of course. . Any such cupping has to be done very carefully and kept to the region significantly below the final turned diameter. . I have done that to counter the problem of glue squeeze-out. . Keep the cupping very close to the brass tube. . It is a difficult compromise because the final turned diameter is only about 0.47", and the tube diam is 0.37" .... for that Bolt Action pen kit he is using.

I should have expressed things differently .... a short (1/8") enlarged drilled portion (to about 0.44") both sides of the butt join ... Because of the drill tip taper, the shape of the result resembles a "cup", sort of, for lack of a more accurate term. . (my numbers may not be quite consistent)

 

[jttheclockman]

@jttheclockman

Yes, John, you are right ... there is that risk, of course. . Any such cupping has to be done very carefully and kept to the region significantly below the final turned diameter. . I have done that to counter the problem of glue squeeze-out. . Keep the cupping very close to the brass tube. . It is a difficult compromise because the final turned diameter is only about 0.47", and the tube diam is 0.37" .... for that Bolt Action pen kit he is using.

I should have expressed things differently .... a short (1/8") enlarged drilled portion (to about 0.44") both sides of the butt join ... Because of the drill tip taper, the shape of the result resembles a "cup", sort of, for lack of a more accurate term. . (my numbers may not be quite consistent)

Hey if it works for you then all is good. Good luck.

 

[RobS]

I have used the wood inlay version of what you are attempting.

Drill the stripes, glue to the tube, turn so it is just barely round. Then turn the area where the stripes will be down to the tube.

Then drill the stars, and square the side that will butt up against the stripes. I have Rick's Sanding jig so I use that to square my blanks.

Epoxy the stars onto the tube, and clamp as noted above.

In this cases, the tube to blank interface is providing the strength, not the butt joint.