HELP, what am I doing wrong?

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Rosewood

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Joined
Apr 27, 2009
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46
Location
George County Ms.
Yesterday,I attempted to glue up Walnut and Alum.. I scuffed the walnut and alum. what I thougt was real good. Rounded it down,attempted to drill for a tube and they came appart,at the glue line. I tried to do the same with a plastic C/C had the same results? The glue is about 1 1/2 years old,works on wood to wood,very well,no seperation. Stored in the ref. until use. New on on me,any help?
 
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Glue ups with alum are difficult. I too prefer CA (not trying to start an epoxy vs CA fight here, but I see it coming anyway)...

Some may say age of the glue is your problem, some will tell you CA is wrong to use, some will point to drill bits, some to heat.

What I've found is that when you get alum in the mix, separation is a risk you take. Very sharp bits (love my drill doctor) and being careful no to let it heat up will significantly reduce the likelyhood of failure. I have very few separate now, and when I do its usually because i broke one of those 2 rules because I got lax.
 
If the epoxy is failing, you might not have equal parts or it's not mixed well enough. I use the Gorilla epoxy and I haven't had any problems.

When using metals in your segments, make sure to keep it cool when you drill. The metal heats up very quickly and the glue fails. Since I use plastic instead of wood, I just keep putting water in the hole as I drill.

Good luck with your next attempt.:smile:
 
I would suggest that a sharp drill bit is important. A Drill Doctor is best for sharpening drill bits if you are using twist drill bits. A DD won't sharpen brad points.

This is only hear say, but I have read that you want the center of the drill bit to contact the aluminum before the flutes start cutting.
 
I have a 3:5 success rate with sandwiching. Used both glues and sharp bits. The biggest detractor I've found so far is heat build up. So far, 100-150 rpm, 1/4" and back out. When I do elliptical cuts and mix materials...that gets interesting.
 

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When I do segments that contain aluminum, REGARDLESS of the type of glue I used to glue up the segments, I always overcoat with a "CA Bandaid".

This CA brandaid consists of VERY TIGHTLY WOUND surgical gauze saturated with thin CA glue, followed by a long shot of aerosol CA accelerator. This seems to offset the heat build up from drilling and helps to hold everything together during drilling and turns off easily.

Additionally, BEFORE gluing up aluminum segments I scrub both sides with Acetone and steel wool. Some aluminum has a coating that's very difficult to remove.

I hope this helps......Good luck!
 
I started step drilling - I usually use 3-5 bits stepped up to the needed size depending on the blank - slimlines 2, Statesman 4-5 - no failures with this method
 
When possible, I drill my blank, then bandsaw, CA the aluminum between the sawed pieces and then redrill the hole. No heat because the bit just pops through the aluminum instantly. It works for me.
 
Some observations from my work and internet research. 1. clean and abrade the surfaces to be bonded. 2. degrease thoroughly. I use acetone. 3. smear on the adhesive on both surface before clamping to insure complete wetting. 4 Heat is a major problem in drilling metal/wood laminates, drill slowly, withdraw often. If the bit is too hot to touch comfortably, cool with a dampened paper towel water or alcohol. 5. an outside banding helps too, I use a collet chuck. Wrapping and soaking with CA works too. 6. In general epoxies are less temperature sensitive that CA. CA service temp is about 150 deg F, epoxies from 200 deg F and up. High temp epoxies are available but EXPENSIVE. 7. Give the joints plenty of time to cure, some 5 min epoxies don't reach max strength for 48 hrs. I usually let mine cure overnight for both CA and epoxy joints (I use both).

I use CA especially for joints that are hard to clamp or for inlay type applications. I prefer epoxy for flat laminated type joints with wood/metal laminates.

Good Luck! ( I broken a few joints myself when drilling!)
 
Slow

I think slow is the key. What I like about pen turning has been the relative quick results/success in doing sometihing. (I think there is an acronym for that). But when I tried my 1st segments I learned rather quickly that sharp bits & drilling slow, slow, slow, was the key to succesful drilling of the lamianted blanks. I quit trying to drill on a drill press and instead use my 3-jaw chuck on the lathe. It is a little aggrevating because my tailstock has to be re-positioned 2 or 3 times due to its limited travel, but that allows the drill bit & the laminated stock to cool between drilling operations!
 
low_48 said:
You can over clamp epoxy as well. It likes a thicker bond line and if you clamp it hard, you will squeeze out all the epoxy and starve the joint.
Click to expand...

Clamping pressure is the source of fights, arguments and maybe a divorce or two!! It varies on the adhesive, type of material, type of clamp used and of course...pressure :wink:
 
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