Sikaflex

[Levanter]

I have used Sika products in the marine industry. They create incredibly strong bonds and are used extensively for bonding wood to glass fibre, metal to wood, plastic to metal etc etc. Special products are used for bonding glass and for sealing as supposed to adhesives.

One of adhesives properties (Sika 292i) is that it retains resilience and is excellent for vibration damping. It sounds perfect for many applications for some projects I have underway including a Yamamoto 1600 with a glass fibre fuselage. Tank mount, servo tray, bulkheads and so on. It says fuel resistant but this would mean petrol or diesel. I have no idea if it is resistant to glow fuel so I am going to do some tests likewise I have no idea if it is foam safe.

Has anyone else used this product in their planes? Theoretically you could bond an engine mount to a firewall without using fastenings but that test is going to have to wait for a retiring engine and an airframe that is on its last legs!

[kevin b]

Working in the automotive industry (you bend em, we'll mend em) I am very familiar with these and other similar adhesives. I think you will find that it is not glow-fuel proof enough for engine mountings. We have many products at our disposal that may have a use in model making and I am trying them out on a regular basis. The main thing we have to watch out for is not strength, but weight. There are some really great adhesives, but some of them you have to be very careful of because they are heavy. It's the same with the paint materials. Great spray on 2 pack primers, but watch the pounds (sorry kilos) pile on.

I have a Yamamoto trainer to learn with, but it is extremely heavy due to being fibreglass and needs a 50 + engine really. However I live in a fairly windy area so I will just have to get used to a not so "floaty" trainer and build up my reaction speeds !

Kevinb.

[Foxfan]

Sikaflex is a great flexible sealer/adhesive, but is very expensive. A superb alternative is Marineflex. Check out Trade Sealant's website. They're currently offering big discounts on even their cheap prices. Hard woods need a one shot epoxy primer, which they also supply, but once that's used you will always break the wood before the Marineflex. I repaired many bits of my wooden canal boat before the complete rebuild and I was breaking new oak, taking it apart where the Marineflex had been used. It comes in a caetridge and can be bought singly.

When I worked in prototype car building we also used it when we couldn't get Sikaflex. GRP to aluminium to wood and all the other chewing gums and string of which show cars are built!

Highly recommended.

Martin

[Panther1]

Sik is great but would be limited in our hobby. It needs to be fresh to get maximum adhesion and in our climate (Australia) I found it can solidify in the tube fairly quickly after it has been opened. I doubt I would ever get to use a full tube on models before it went 'off '. Apart from that, it is damned awful stuff to get off your hands and other places it shouldn't be. lol However, that said, it could have its' place with experimentation.

[Braddock, VC]

I'd say bonding an engine mount to the firewall would be counterproductive, engine mounts can and do break and not necessarily in a crash.

Blind nuts and allen head set screws make removal straightforward whereas debonding may be much more time consuming.

[Engine Doctor]

De- bonding could also be unpredicted and dangerous . use proper fixings for engine mounts and high stressed areas . Altough a great flexible adhesive a dowside to sika flex is that once opened it will cure in the tube, an expensive waste . Curing in the tube can be delayed by taping up the tube thoroughly but not stopped .As already said go the blind nut/tee nut and cap head screw route .