# Loctite and brass



## kelvin2164 (Jun 28, 2015)

I have a 32mm dia brass disc, 1mm thick and need to drill accurate holes at 24PCD. The plan was to glue it to the end of an aluminium bar and drill it in the rotary table.
I used 7471 primer and 680 loctiite and allowed to set for 2 days. The first touch of the drill and it broke away. Tried several times. Same result. The loctite sticks to the aluminium, but has no bond at all to the brass. 
What am I doing wrong.


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## RichD (Jun 28, 2015)

Don't have an answer for the locktite issue, but have you considered making a counterbore in the aluminum to hold the brass disc for you? Be sure to leave a center hole in the aluminum for popping out the disc when finished.

Rich


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## Blogwitch (Jun 28, 2015)

Kelvin,

It is for little awkward jobs like this I tend to use mechanical means to hold a part.
A pot chuck or soft jaws in the chuck you will be using. Easy to do if you have or can make either. In fact I won't buy a self centring chuck unless soft jaws are available for it.

There is a reason for going down that route. 
Certain non ferrous materials can be very hard to bond together because there are so many different mixes in each type of alloy, one of those components could be the reason you are not getting a strong bond on the 'brass' side. So unless you know EXACTLY what materials you are using, then contacting Loctite for a solution, you are in fact stabbing about in the dark hoping that it will work. 
99% of the time, Loctite will give a very good bond, but in your case, I think you may have that odd 1% that is causing your failure.

For real quickie jobs, which have very little maching forces involved (such as drilling small holes), I have used that very high strength black coloured double sided tape that is used for permanently sticking trim (number plates, mirrors etc) onto the outside of vehicles, that seems to stick to almost anything.

I know these are only alternatives to your solution, but you may have to go down one of these routes in the long run.

John


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## bazmak (Jun 28, 2015)

Have you tried using a longer piece of brass and use the rotary table to drill first.Then part off in the lathe


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## abby (Jun 28, 2015)

Brass does not like Loctite , even grit blasted surfaces part company, ordinary super glue sometimes gives enough hold for light work .
Other options are wax/resin chucks but my preference for holding thin brass parts for machining is to soft solder them on to a suitable block or bar.


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## Tin Falcon (Jun 28, 2015)

Look up shellac chuck. Clock makers have used them for over a hundred years. 
Also known as wax chucks. 
Just a mod of you original idea. You Want machine some concentric grooves in the aluminum . basic concept melt shellac for a hot glue. Machine part. Apply heat to release.dissolve residue with alcohol.
Tin


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## WOB (Jun 28, 2015)

abby said:


> Brass does not like Loctite


 
This is an incorrect and gross over generalization. The anaerobic thread lockers  like 242 , 270, etc. love brass and will react rapidly.   680 is a methacrylate ester which is a different chemical. See http://www.henkel.com.au/aue/content_data/327273_UPGRADE680EN.pdf

Loctite makes hundreds of different adhesives of many different chemical compositions.  You have to be selective if you want good performance.


WOB


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## Herbiev (Jun 28, 2015)

I find a hot melt glue does the job.


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## doc1955 (Jun 28, 2015)

Loctite 680 is not a adhesive it is a retaining anti airobic. It has a high shear strength but not so good on a tinsel strength. You are trying to use it for something it was not intended to do. Switch to a Loctite super glue or one of their adhesives and you will have much better luck.


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## ruzzie (Jun 28, 2015)

Double sided tape works also


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## AlbertdeWitte (Jun 29, 2015)

Good day

I do that a lot with normal super glue, after machining I use a small hammer to tap it loose and then I soak it in acetone, it removes all super glue in 5min...


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## kelvin2164 (Jun 29, 2015)

Wow! Thanks guys. Lots of info there.
I eventually did it using super glue. I also needed to turn a spigot, silver soldered to the disc. I did this very carefully and when finished, lifted it off with a screw driver. It came away very easily and certainly wouldnt have stood up to much machining pressure. Again, no visible bond to the brass. The hot glue sounds good, but not too sure about getting even thickness. At least Loctite has a thin, parallel bond. Maybe shellac (if I can find any these days)
I need more Loctite expertise.


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## petertha (Jun 29, 2015)

This video might be helpful. He is makes CA/superglue holding fixtures with grooves in them (~ 3:00 min mark). This same technique is repeated for other brass parts in other videos. He mentions light cuts & not allowing the parts to heat up excessively from machining.
https://youtu.be/qOHSTxxAjFs


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## kelvin2164 (Jun 30, 2015)

Nice video. Makes me feel so inadequate.
I dont get the grooves though. I understand it requires the abscence of air for super glue to harden (that's why the bottles are only half full) and he is providing air filled grooves? What is happening here?


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## petertha (Jun 30, 2015)

Wondered the same myself & only going to take a guess. I've also experienced the not-fully-cured state on CA-d parts & noticed usually the common factor is non permeable materials. I can get them to work better with kicker (accelerator or primer) but that doesn't lend itself to careful positioning. 

This link/excerpt kind of supports the theory I've heard. The thread locking 'locktite' kind of glue cures in absence of air whereas krazy / normal CA / superglue requires humidity which is sufficiently provided by only a bit of air. No air = no humidty = incomplete or lack of CA cure. May say the 2 glues are the exact same thing & maybe even use them interchangeably, but doesn't look to be the case. 

I can see where a large surface area joint of 2 impermeable materials like metal to metal may not cure properly with CA because the metal can not give up any air from itself. Equally large joints of say wood-wood or wood-metal don't experience this because the wood itself is porous, meaning containing air & provides what's required. Plus wood fibers are probably assisting CA cure as a function of shape/surface area (the smoking hot baking soda trick). Small metal-metal CA joints might be getting by & achieving full cure from relatively larger periphery air exposure? 

So what I think the mandrel grooves are accomplishing is giving enough air supply from the gap valleys to serve the adjoining CA joints either side on the flattened mountain tops so to speak. Basically introducing artificial porosity to impermeable materials.

The kickers are another kind of mystery. They are intended to accelerate cure, but maybe in these metal-metal cases they provide the joint something equivalent to moisture to complete the bond in absence of air?

CA link
http://www.ipmsstockholm.org/magazine/2004/10/stuff_eng_tech_ca_glue.htm

_A common source of confusion is mixing up CA glue with Locktite thread locking glue. The main reason for this seems to be historical. The Loctite brand that initially produced the thread locking glue became for many users synonymous with that type of glue. Nowadays, Loctite has an entire variety of glue products in its range, CA glue among them. The main difference between the two types is in the medium activating the bonding reaction. In the thread locking glue, polymerisation starts in the absence of oxygene (air), while CA bonds with the aid of humidity._


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## Cogsy (Jun 30, 2015)

When I used to sell the Loctite range in the bearing industry, there were at least 7 or 8 different CA-type glues in the Loctite range. The 2 most common were 406 and 401. Identical bottles with identical looking adhesives but 1 was for porous surfaces and 1 for non-porous. For my own, non-critical gluing, both seemed to work equally well. The rest of the range became more specialised with different viscosities, wicking, etc, and specialised for materials, glass, ceramic, etc. I know from experience that the Loctite rear-vision-mirror adhesive will bond a rear view mirror to the windscreen that well that pulling hard on the mirror will remove a chunk of glass from the windscreen rather than breaking the glue bond!


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## abby (Jul 1, 2015)

Thank you for your observation WOB , I imagine that I am pretty typical of model makers , I have the standard thread lock as stocked by my local auto-spares shop and have found it's failure rate , for the subject of this thread (no pun intended) , unacceptable .
I am aware that Loctite make a wide range of products , one or more  may well be suitable for the bonding of brass parts however contact  with suppliers of these products have never recommended anything as  particularly effective .
As a model engineer  I want to spend my time  making models not trying out various Loctite products until I find one that works.
Brass is probably the most widely used material for the model engineer and as many users will have found out it is very difficult to get even paint to stick without etch primers etc.
Like most model engineers I want a quick , simple , reliable and inexpensive solution to my work holding problems , something that is very easy to obtain , preferably that I have in stock
soft solder ticks all the boxes for me.


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## kelvin2164 (Jul 1, 2015)

Well I'm glad I'm not alone in the forest of Loctite products that I dont understamd.
The video that Petertha linked to showed the operator using considerable maching pressure on his CA bonded brass. If I could achieve that I would be very happy.
Tried again tonight. Another less than satisfying result.
Aaaaaaargh !!!!!


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## goldstar31 (Jul 1, 2015)

It's appalling simple! It could be almost child's play. Look into the mouth of a modern child with orthodontic work or call it a brace.
Today, well, most don't use silver solder olr a little turret spot welder to do stainless work- as my wife did. Our daughter simply glues her wire etc to teeth and this has to stand being immersed in assorted ingestions- until the job is complete.

Me, well, I'm not quite accident proof and I stuck my finger in the doctor's waiting room door just before our month's holiday. I used one of 5 tubes of CNA which cost the princely sum of a humble quid( £1) to hold the the torn flesh better than stiches or whatever. Our dear old friend of 95 was next door and had stumbled and 'torn her arm badly'. The local Spanish had arrested the bleeding but with better stuff( nice color) on the dear old dragon! I busted my nose on the tailgate on on the little High and Dry and I patched myself up- a bit cross eyed, but OK.
Last night, my wife had an argument with a wheelchair and there was blood dripping  on the airport floor. Patched with glue- at midnight. in true vampire style.

OK, the surgeons are even doing internal surgery with the stuff. Presumably, my daughter is doing teeth and her husband the internal plumbing heart surgery with much the same sort of stuff that I mended the garden gate- and my nose and finger.

This Loctite thing about brass was an urban legend- long before most of you were born. It's like me- we've lasted well.

Oh, and my wife has just reminded me. Centuries ago, I stuck a diamond back in one of her rings. Another success story!


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## Tin Falcon (Jul 1, 2015)

> Maybe shellac (if I can find any these days)


Not realy hard to find. you can get hot melt sticks here http://www.shellac.net/merit_burn-in_sticks.html sticks are $ 3.75 each or $36 per dozen.
Tin


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## petertha (Jul 2, 2015)

I've always wondered.. is the woodworking shellac as suggested any different that what is sold under work holding shellac?

http://www.riogrande.com/Product/Orange-Flake-Shellac/118066?Pos=3


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## Wizard69 (Jul 3, 2015)

WOB said:


> This is an incorrect and gross over generalization. The anaerobic thread lockers  like 242 , 270, etc. love brass and will react rapidly.   680 is a methacrylate ester which is a different chemical. See http://www.henkel.com.au/aue/content_data/327273_UPGRADE680EN.pdf
> 
> Loctite makes hundreds of different adhesives of many different chemical compositions.  You have to be selective if you want good performance.
> 
> ...




I was going to say something to this effect but this is right on so I will just emphasis.     Loctite  thread lockers are known to have an affinity for brass.   Given a clean surface you should be able to use the red thread locker to bond brass to just about anything.


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## goldstar31 (Jul 3, 2015)

Well, I'd never had any bother doing 4 division plates for a Thomas Dividing head- which I used a Thomas Universal Pillar Tool ( nowt like a successful designer).

Anyway, I',m farting about on plastic gutters and broken joints- we are having a series of thunderstorms.
One of my mates suggested something called Stix like Sh1t which comes in a tube.
He's an old Coldstream Guardsman out of Blackadder and Whiteadder Country- and is like me- an Atkinson. So will let you know - if I can get out of the blanket( Armed Forces joke)


Cheers


N


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## Tin Falcon (Jul 5, 2015)

> I've always wondered.. is the woodworking shellac as suggested any different that what is sold under work holding shellac?
> 
> http://www.riogrande.com/Product/Ora...c/118066?Pos=3



I am sure  there are minor differences. when in doubt get the right tool for the job. and the price seems cheaper on the workholding stuff. thanks for the link.
But if you have a woodworking supply store in your block and the the nearest jewelry supply store is 500 miles away. I would try what is available. 

Tin


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## barnesrickw (Jul 5, 2015)

I'm going to guess its the same as woodworking shellac but mixed much more concentrated.  Great thing about shellac is a little alcohol cleans it right up.


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## goldstar31 (Jul 6, 2015)

barnesrickw said:


> I'm going to guess its the same as woodworking shellac but mixed much more concentrated. Great thing about shellac is a little alcohol cleans it right up.


 
Oddly, the history of shellac seems to lost. It's a beetle- it's what a female lac beetle does. In our usage, it is French polish, it is resin, it is sticky stuff and the basis of paints and varnishes and many plastics. It is a hard gloss when dissolved in alcohol and more sensibly is generally too hard and brittle  for as it arrives in flakes. 

As far as an earlier generation is concerned, it was generally modified for all sorts of reasons but it was added with things to soften it. One was yet another natural product- beeswax and rubber. I've still got my couple of rubber plants but I have largely forgotten making and modifying 'resins' 
I was reading Bill Bryson's book 'At Home'. He's the guy that came from Des Moines as somebody had to. His bit about the little lac beetle is worth another read and so is his history of 'a short history of Everything Else.

Today, man can reduce the variables from natural products- you know this quality control lark. I gave it up with snowflakes of thallic anhydride from boiling these beetle things and the other bits that go into 'pot' - and let someone else poison his life.

But that's shellac- been around since Stradivarius varnished his violins and cellos-- and we still haven't worked out precisely how he made the stuff. 

Read it up, it's fun because we are returning to other natural products like- pissing on our steels. Apparently, the urine of virgin little boys was highly prized.
Me, I'm not surprised!

Cheers


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## kiwi2 (Jul 6, 2015)

Probably not the right site to talk about shellac as a wood varnish - but I'm a real fan.
For years I used polyurethane on wood. It was OK but once the can got less than 2/3 full it formed a skin and needed to be strained before use. And of course the brush needed cleaning afterwards as well. Then someone put me on to shellac and I gave it a go. It is brilliant. I make up about 500 ml at a time in an airtight plastic honey pot and it sits permanently on my bench without degrading or going off. I apply it using paper kitchen towels as rubbers so there are no brushes to clean when the job is done. Admittedly you have to apply a lot of coats to build up a nice finish but you can apply them at hourly intervals while doing something else.
I sometimes use 5mm fibre board if I'm making a prototype of something and I find a couple of coats of shellac makes it a lot harder and more stable.
The only thing I worry about is the poor old Lac beetles - if everyone realised how good shellac is, they could go extinct.
I was an industrial chemist but I have to admit that this is one case where the old natural product is in some respects better than the modern synthetic varnishes.
Regards,
Alan C.


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## kelvin2164 (Jul 14, 2015)

SUCCESS
I think I've finally found the right product. Loctite 480. They call it 'ruberised'  CA, and I think this helps absorb the impacts of machining. I've turned it in the lathe, drilled it, milled it and so far nothing has fallen off.


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## goldstar31 (Aug 2, 2015)

I've just stuck a brass sheet under the lathe tool holder on my little Kennet tool and cutter grinder. It was one of those jobs which was put off and put off but I always had to Eye in to get the angle repeatable.

I found a bit of 1/16th brass- cleaned the paint and gunge over it and removed the grease etc from the cast iron. Mixed a bit of two part epoxy from a 'Pound Store'. Yours will probably be  a Dollar one. I left it for a day- it is supposed to be 5 minute stuff! This AM rough cut the excess with the 6 x 4 bandsaw( no fretwork table) and then used the cheap Chinese grinder/belt sander thing to smooth it all. Nothing has moved.

No wonder I'm a millionaire- he joked.

Norman


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