Water Tank Adhesive

[Andy PParticipant @andyp67691]

[Andy PParticipant @andyp67691]

Hi chaps, I am currently building the side tanks for a 7.25″ loco. The tanks are constructed from brass plates bolted to internal brass angles with countersunk brass bolts. I hope to use adhesive rather than solder to assemble the tanks. I have heard of  slow curing 2 part epoxy such as Araldite been used. Does anybody have any experience (good or bad) of this method of construction, and can anyone suggest a suitable adhesive that will not deteriate over time.

Best regards

Andy P

[CirclipParticipant @circlip]

Try this link Andy

 

  http://www.model-engineer.co.uk/forums/postings.asp?th=34657

 

  Ok. the plates on yours are brass, but the peeling effect still applies, What’s wrong with pre-tinning the joints and then heating to flow the solder??

 

 If using a sealant, you need a flexible STAB type.

 

  Regards  Ian.

Edited By Circlip on 30/12/2009 13:27:14

[mgjParticipant @mgj]

Generally speaking epoxy edges and water are not a very good thing. The water molecules bond to the epoxy rather easily and in time will displace the bond between metal and epoxy.

 

This is why the handles of cups repaired with epoxy have a habit of falling off after a bit of time in a dishwasher.

 

If you intend the tender to really last, it might be wise to look at tech specs. 

 

What was that 3M paint on etch stuff. You painted an activator on one side and the glue on ‘tother and though not a contact adhesive as such, they stuck when you applied the two bits. That was waterproof – stuck racing monococques together with it to avoid welding distortion.

[MichaelRParticipant @michaelr]

I sealed the flanged joints on my 3″ scale traction engine tender (Brass ) with slow curing Araldite, I used a hair dryer to warm the Araldite which then flows like water and capillary attraction pulls the araldite into the flanged seams, and I can say after 15 years of use the tender hasn’t yet leaked, I have also done a Masie tender the same way and this is still water tight.

[Ian S CParticipant @iansc]

meyrick that sounds like “Redux”that Vickers used to stick the Viscount together.Got a nephew building super yatchs in Christchurch,must have a word with him some time about the glues they use,there must be something interesting there.Ian S C

[Laurence BParticipant @laurenceb]

There was an article that appeared in the model engineering presss a while ago by John Cousins.He had recommended using a resin compound that restorers of old cars and motor bikes have used to repair rusty and leaky petrol tanks.

[nick feastParticipant @nickfeast85472]

Hi Andy,

Your question caught my eye as I plan to use a novel method of construction on the Q1 tender in the series currently in the ME. I have constructed the first tender out of steel as I have a dislike of brass for model locos, anyway real tenders are steel aren’t they? The sides were brazed to the base but this involves too much heat and distorts the panels. Soft soldering steel is difficult as the steel is difficult to keep clean and then there is the flux residue to clean up. The petrol tank sealer stuff or hammer finish paint will stop most of the rusting.

If you look under the bonnet or boot lid of your car you will see a bead of mastic compound holding the panels together. The windscreen will also be held in with a mastic of some kind and this is how I hope to assemble the Q1 tender tank. There are mastics that are applied from the standard mastic gun cartridge and simply set off with time or two part compounds that require an accelerator or catalyst. By the time the article appears in print towards the end of 2010 I hope to have proved a technique and should be able to recommend a suitable generic product. I think windscreen mastic has the best chance being black and air curing, with good structural strength. I have never has much success with two part epoxy resins where water is involved. Remember that when your boiler clacks play up as they inevitably will, then you will get steam heated water tanks.

I have also made tanks using brass and soft soldering, It is a matter of getting the right order of assembly and using just enough heat, can be difficult for beginners. Some kind of jig to hold everything in the right place would help.

 

All the best for 2010 and beyond, Nick.

[CirclipParticipant @circlip]

One of the commercial sealants used by the motor industry was “Sicoflex”, others were a rubbery non-setting type. DON’T use silicone (Bath) sealants, they also peel in time.

 

   Wonder why it is Nick that some think you need a flame thrower to “Sweat” a joint together??

 

  Another range of sealant to look at are the bitumastic types, full size water valve companies have used that.

 

  Regards  Ian.

[mgjParticipant @mgj]

Ian  I think you are right. I used to build the chassis out of Aerolam board – that was paper honeycomb.

 

Stick I’m glad to hear your tenders have held, but probably the only reason they have held is because you haven’t put them under load. Araldite particularly is very brittle and there are a number of more modern recipes loaded with rubber etc to provide flexibility. (see the 3M website)

 

Genuinely, epoxies generally are very vulnerable to water ingress, especially if the water temp rises, (see Nicks comment) and nowadays there are better choices. Plain tar based mastic is as good as any, and you can get high chemical resistance polyester resins which are good (not the ordinary car stuff) and even your average DIY can supply genuinely waterproof flexible glues – some of which will even adhere when applied under water. About £5 for a tube, but very good and very strong and being crystal clear, are very clean and convenient . Take paint too, but not keen on a lot of etch primer, but fine inside the tender tank to seal rivet lines without the potential distortion of soldering..

 

Edited By meyrick griffith-jones on 31/12/2009 18:00:26

[MichaelRParticipant @michaelr]

Meyrick, I have to take you up on, Re my tenders not being put under load, take my 3″ scale traction engine which is a powerful engine and hauls two adults, a driving trolley with a built in 5 gallon plastic water tank (Not sealed with Araldite ) and coal and water in the engines tender and all hitched up to the tender draw bar a fair old load. the tender is flanged and riveted, the Araldite is just to seal the seams and rivets.

Or maybe it’s the high quality of water we have in Cumbria that is kind to Araldite.

Stick

 

 

 

[mgjParticipant @mgj]

Stick – the tender (sides and drawbar etc) may well have been put under load – but the Araldite hasn’t, and that’s what we were talking of.

 

But I agree, your Cumbrian water is very nice

Talking of tenders, I am a very happy Bunny – having made an own design water lifter based on a converging/diverging nozzle, and spent almost all day plumbing the b—–d thing in (bad placing my choice), at least it works! (and I haven’t got to strip it all down to reposition the steam tube. Good (lucky) guess!!!

Talking of sealing – Loctite do a lovely anaerobic flexible gap filling flange seal. Good stuff – if oyu don’t mind a delicate shade of orange. Doesn’t attack paint either.(Japlac)

[MichaelRParticipant @michaelr]

Meyrick, Well done with the water lifter, I made the lifter on my engine from the drawings but had a trying time getting it to work, after a lot of adjusting and words to the effect of “Why” am I doing this hobby I got it to work and it’s nice to see a bucket of water going into the tender through the lifter.

[John HaineParticipant @johnhaine32865]

I think the handles falling off problem may be more to do with the fact that dishwashers are hot.  Lots of wooden boats are made using the West system with epoxy fillets sealing wooden bulkheads against salt water and subject to heavy impulsive loads, which don’t fail even after many years.  Using epoxy to seal joints which actually depend on bolts for joint strength against clean cold-ish water sounds much more benign.  You could try as an alternative to Araldite West System epoxy with glass microballoons to thicken it as sold by Axminster for example.

[Andy PParticipant @andyp67691]

Thanks for the advice chaps. I now realise that what I need is a slow curing, gap filling sealer that can be sanded and painted when set and is suitable for brass. The strength side of things is taken care of by the 60 bolts I have in each tank. The sealer would need to be fairly runny to allow it to be squeezed out when the bolts are tightened. The automotive mastic Nick mentions sounds interesting as does the Japlac & Sicoflex suggested by Meyrick & Ian. I will have another look on the net to check out your suggestions.

Best regards

Andrew

[Andy PParticipant @andyp67691]

Just an update on this thread. I have been checking out some automotive adhesives and came across one called (Bondtech 4002 metal to metal 60). It looks quite promising for use on the water tanks. Has anybody had any experience with this adhesive either with automotive or modelling applications.

Best regards

Andrew 

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