Adhesive advice

[RumrationParticipant @rumration]

Which glue?

[RumrationParticipant @rumration]

I am about to fit the keel strake between the wooden hull and the brass outer prop shaft, but I am unsure which of my glues to use to make the best bond between the metal and the wood surfaces. Advice much appreciated as always.

Regards, Glyn.

[BanjomanParticipant @banjoman]

Glyn,

What you describe sounds to me like the sort of joint for which I would pretty much without thinking put my hand out for the epoxy glue. This would most likely be a 24 hour variety (i.e. one where initial setting time is around 30 minutes [you will usually find them labeled as 30' epoxy] and where the epoxy has gone off fully after about 24 hours), as the final bond will be stronger and less prone to turn brittle than is the case with the instant grip varieties ("5 minute epoxy"; "rapid epoxy&quot. It also gives you a longer time to adjust everything to your liking before there is full grip in the joint, but on the other hand you do ideally need to be able to apply pressure to the parts for 24 hours, too.

I also prefer to buy two-bottle system epoxies, rather than the self-mixing syringes that you find in DIY stores, and then mix what I need by weight; it comes out much less expensive, and also I have found that the longer setting time epoxies are harder to get hold of in syringe form.

Any excess glue can easily be wiped off from the joint edges with methylated spirits, provided it hasn't yet set and – important! – on condition that the surface you are wiping down will not react to the spirits (some acrylic paints for example might start to dissolve).

Mattias

[Paul TParticipant @pault84577]

Glyn

Mattias is absolutely correct, I couldn't build a model boat without epoxy glue.

There are some cheap versions on fleabay like the orange and black ones shown below, it is best to avoid these cheap/non branded products as sometimes they don't work.

Evo-Stick and Araldite are the manufacturers that I use but as Mattias says it is best to test all of the products on a sample before using them on your project.

Paul

[RumrationParticipant @rumration]

Ok got it thanks. I have Araldite so will use that.

Obliged, Glyn

[Ray Wood 3Participant @raywood3]

Hi Glyn

I have spent hundreds of pounds over last 40 years on fancy well known brands of 2 part epoxy resin such as Devcon & Araldite & Zap Cyano

Then the Poundland products came along for 5 minute epoxy and super glue from the Tommy Walsh range Forget the named brands these products are great ! Regards Ray & there only £1.00

Edited By Ray Wood 2 on 02/05/2017 08:29:54

[RumrationParticipant @rumration]

Cheers Ray,

I have often seen them but always been somewhat dubious about buying them! I'll give then ago when I need to restock.

Glyn

[Martin Field 1Participant @martinfield1]

I can confirm that the above work very well, BUT….the two plungers need to be separated with a saw first as they never push out equal amounts and once opened, make sure the pair stand up with the cover upwards or they leak and make a God awful mess. I find they might go off initially in "4-6 minutes", but take a good couple of hours to reach best strength, so I always do the joint just before tea, then go in and leave it over night. I always have other things to do and a pair of planks a day ain't bad progress.

Martin

[Dodgy Geezer 1Participant @dodgygeezer1]

I have been using these glues for a long time now.

The cyano is very good and performs well. The epoxy in the syringe works well – adheres strongly and is slightly flexible for the first year or so. To get an even amount out you simply press harder on the side of the plunger which you think is flowing least.

I have tried the epoxy in separate tubes twice. Both times it refused to set at all. Avoid it – it’s a waste of money.

[Martin Field 1Participant @martinfield1]

I never use superglue, so can't comment, but you only have a slight ability to lean on one side of the epoxy. Much easier to cut the handle through and the strange structure between. One resin is slightly denser than the other.

Martin

[Dodgy Geezer 1Participant @dodgygeezer1]

Try pushing directly over one syringe while holding the other end up! Alternatively, cut through the syringe plunger alone. You don’t need to separate both tubes.

If you do separate them, how do you sort out the cover, which is designed to be used with the tubes together?

Incidentally, you do know that the ‘strange structure’ is the cover, don’t you? This might explain the mess!!

Edited By Dodgy Geezer on 02/05/2017 13:43:03

[Martin Field 1Participant @martinfield1]

I never said separate the whole thing, just the plungers and the strange structure 'twixt the plungers. Much easier to lift the plungers back up one at a time too, to ensure no resin in the nozzle.

Martin

[BanjomanParticipant @banjoman]

Except the very occasional syringe for joints where the applicator reach comes in handy, I only ever use mix-your-own epoxies that come in two separate bottles, usually either BSI Slow-Cure 30 Minute (**LINK**) or Zap Z-Poxy 30 Minute (**LINK**), although I also have a 15 and a 5 minute variety to hand.

I always measure out the quantities by weight, using a set of digital fine scales accurate to within a tenth of a gram, and have never had any problems at all with the epoxy not setting.

Mattias

[Martin Field 1Participant @martinfield1]

Not sure what you mean there by applicator. I don't use enough to warrant buying bottles, but if I haven't got any rapid set, I used West with micro balloons or colloidal silicon, left over from my full size boat restoration.

I suppose if you have poor judgement f quantities weighing is best and I do that where odd proportions may be concerned like 1/5th hardener to resin, but where 50/50s concerned judgement is fine. I have only ever had one epoxy not work at all and there is a chance I mixed two Bs, thinking it was an A and a B!

Martin

[Armando LoniParticipant @armandoloni78860]

Glyn – a useful tip, if you haven’t started yet, is to roughen up the brass prop shaft at the area to be joined….. Sandpaper will suffice. This gives a good ‘key’ for the epoxy to grab to.

[RumrationParticipant @rumration]

Hi Armando,

Thanks for the tip, pleased to say I did that. Hey, I got something right for once!

Cheers Glyn.

[Dave MilbournParticipant @davemilbourn48782]

Posted by Banjoman on 02/05/2017 14:00:25:

I always measure out the quantities by weight, using a set of digital fine scales accurate to within a tenth of a gram, and have never had any problems at all with the epoxy not setting.

Mattias

Every now-and-again I read something that is so blindingly obvious yet devilishly cunning that I wonder why on earth it never occurred to me before. Well it didn't, but now I have the solution to keeping the levels in those Z-Poxy finishing resin bottles equal. I've been using graduated 60ml polythene measuring cups for mixing but the stuff is so viscous that it's practically impossible to "eyeball" equal amounts in the small quantities I mix. A set of 200g/0.01g Digital scales have now been ordered!

Once again I am indebted to you, Mr H.

Dave M

[RumrationParticipant @rumration]

Dave,

Better not let the boss catch you with her favourite kitchen scales. Been there, wasn't pretty!

[BanjomanParticipant @banjoman]

I say, Dave! I'm very glad to hear that you found the idea useful — for my part, I initially got the set of fine scales for mixing paints (not pints, paints) in small quantities with as consistent results as differences between manufacturers' batches allow. However, once I had them I realised that here was also a ready-made solution to those two-bottle epoxies, where one bottle would always run out before the other. Also, although I believe most epoxies have a mixing margin of error of +/- 10%, when you are mixing up a total of, say, 1.2 grams (which is the sort of amount I'd mix for sticking together a couple of parts), that margin of error is not huge in absolute terms, and I find that weighing gives nice, consistent results.

Mattias

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