|gerry madden||14/10/2018 14:52:32|
|48 forum posts|
Hi all, I'm just after a bit of guidance on workholding using glues. I wanted to mill some small aluminium parts today and thought I would try the technique of bonding them to a aluminium baseplate which would be more easily fixed to the mill table. The parts are 12mm wide, 10 high and 32 long.The contacting surfaces we very clean before glueing. I used a 'retainer' on the 32x12 face and left it for an hour. I couldn't pull it off with my fingers but as soon as I started to mill it detached. I kept my cut very very light. Now I'm about to try a medium strength Loctite, 243.
Is the face area just too small or am I using the wrong glue ? These simple techniques never go wrong in the 'Clickspring' videos !
|Jim Nic||14/10/2018 15:06:11|
199 forum posts
Not sure what you used when you say "retainer". Loctite is best at fixing shafts and bearings into holes and when correctly used for that purpose is difficult to shift.
I often use the adhesive method for workholding and use cyanoacrylate - instant glue. Ensure your surfaces are clean, and oil free, apply the glue sparingly and with pressure. I usually leave the assembly for at least 12 hours before machining.
To disassemble, moderate heat with a paint stripper gun and a light tap usually does the trick.
|Michael Gilligan||14/10/2018 15:06:47|
13531 forum posts
I will start the ball rolling, by saying that the traditional 'anaerobic' retainers [i.e. the type that were the original Loctite range] have very low peel-strength: They are better considered as gap-fillers rather than adhesives.
For this job, you need an adhesive.
Edit: Jim beat me to the start
Edited By Michael Gilligan on 14/10/2018 15:07:55
|Neil Wyatt||14/10/2018 15:22:36|
16226 forum posts
You want to be using a 'superglue' not a retainer.
|Nick Hughes||14/10/2018 15:43:35|
196 forum posts
This vid should point you in the right direction
Edited By Nick Hughes on 14/10/2018 15:44:25
|579 forum posts|
243 application is as a thread locker.
Edited By Bill Chugg on 14/10/2018 16:17:04
|gerry madden||14/10/2018 16:24:20|
|48 forum posts|
Well the Loctite 243 was a disaster too. I then dashed out to the shops with 10 minutes to spare and got some superglue as per your recommendations, tried it and guess what... it works a dream. Thanks all for your instant help !
|Alan Waddington 2||14/10/2018 17:00:09|
|435 forum posts|
Screwfix sell an own brand largish bottle of superglue and an aerosol instant activator in a pack, works great for little cost.
Edited By Alan Waddington 2 on 14/10/2018 17:03:10
|not done it yet||14/10/2018 18:36:20|
|3128 forum posts|
Some low profile holders to prevent lateral movement might be a project for you . Harold Hall has designs for these. Depends on how many small parts you are machining.
I would only use glue in a milling situation (with no other support) if there was no other alternative - just in case something gets thrown at me - unless there was a large contact area.
|Howard Lewis||15/10/2018 15:54:37|
|2136 forum posts|
Anaerobics do not like Aluminium alloys too much, because there tends to be oxygen available in the alloy (especially if there is any porosity) and so do not cure.fully.
For that sort of work, I would aim for less than the normal 0.003" clearance, tending towards size and size.
With Ali, warming the outer will not only expand it, but speed curing.
|Nick Hulme||15/10/2018 21:24:53|
|694 forum posts|
Some think "Locktite" is a thing rather than a myriad of products, of course using the wrong product will not work, did you read the application sheet for your product?
|155 forum posts|
The earlier adverts for super glue showed lifting an elephant with two pieces of metal glued together believe it or not.
As yet I have not lifted an elephant but used it in many fixing jobs.
|not done it yet||16/10/2018 22:19:29|
|3128 forum posts|
Yes, but.... shear forces are a different story. Magdeburg hemisphers could not be pulled apart by horses, but quite likely slid apart if there were no interlocking rims to prevent it. In school, we used small ones to demonstrate the forces needed. Same with magnets, too - more easily detached if they can be slid off the surface
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