Which Loctite

In "Model Steam Locomotives" by Tim Coles he suggests using Loctite to construct the water tanks of a tank engine. This seems an admirable suggestion to lessen the labour involved but which Loctite should be used? I imagine it would have to be gap-filling otherwise leaks would be difficult to avoid. Can anyone help? Is this such a good idea?

Thanks in anticipation

Howard

Howard,

I know nothing of building trains etc. but I would take a guess that you are asking for Locktite 330. It is a two part (spray an activator on one surface, glue on the other) product and sticks like nothing else if you do the prep correctly. It is very expensive - not much change out of 20 quid but it is worth the money.

Mark

I would think one of the two part polyurethane adhesives would be best. They are waterproof (used on boats) and have slight flexibility so won't crack.

Russell.

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Howard,

As will be obvious from the other replies ... The suggestion my Mr Coles is not sufficiently detailed.

Loctite is a brand name, not a specific product.

MichaelG.

Thanks everyone. My own researches on Google suggest Loctite 3090 may also be suitable but there are so many of them out there (including alternative brands) it is difficult to choose between them all. 330 sounds interesting and if it saves a lot of rivetting and/or soldering would be worth the expense.

Howard

I have never built a loco tank, but I would guess that soft solder may be easier than trying to glue the joints . Solder will last forever and is easy on clean metal.

Loctite 303 is great

I was advised to use this by a salesman to repair some stainless steel water trays that held a mild acid solution ..they had sprung open on a joint.

It was expensive but a little goes a long way

its a tube of glue like uhu consistency and a spray activator

Before i started I tried it on some stainless sheet scrap

2 pieces 3 x 3 " and glued them overlaping about 1/2" they did not want to come apart when cured

even with one side in a vice the material bent rather than the joint failed...it took serious effort to break the joint with a chisel down the joint

Ian

Ian,

The 303 sounds very similar to 330 - they are both acrylic based and the physical descriptions sound about the same (I have used the 330). The 303 is aimed at composite materials I think looking at the spec. I spoke to the Loctite tech support as I need to bond aluminium (not the easiest thing in the world) and they advised 330 with a special surface treatment to convert the oxide layer (not an acid etch). The 303 has a tensile rating of about 24 Nmm2 if I remember correctly putting it at close to half the tensile for the Aluminium alloy I am using!

The 303 looks to be aimed at fast UV cure rather as well, I don't know if that applies to 330 but I imagine it would be hard to do uv cure on a metal joint?

Mark

Hi Howard

If you go to Loctite.co.uk you can search there full range of products or you can email them as I did and they will answer your question.

I e-mailed Loctite and was impressed by the speed of their reply. They suggested Teroson MS939 or, as a cheaper alternative, Unibond FT101. I'm not sure about these as they appear to be more like sealants. However, I shall see how their speciofications match up against 330/303, which appears to be the consensus here, and then decide whether to try one or go down the more traditional route of soldering.

Thanks for your help

Howard

Howard,

I might take the advice from Locktite - the stuff they suggest is very elastic and the 330 (and probably the 303) is not. I can see why they would recommend it.

Mark

Just my 2 c worth. Tim Coles book is a great read but I've learned to take some of the comments in the book with a grain of salt!

For my tender construction, I used 306 stainless sheet, brass angle screwed with a few brass screws in a few places and soft soldered to seal it all up. I love using Loctite for retaining nuts and screws and the unbeatable thread sealing compound but can't get comfortable using the sealant range. (yet)

Cheers, Andrew