How strong is Sikaflex?

[Enoch]

Just trying to build my scuttle - I opted for a fabricated one. Being an electronics engineer sheet metal is not my strongest subject so please bear with me. I have made the framework - difficult but got there in the end. I am now attempting to skin it with aluminium, the frame work is all steel. I don't want rows of rivets showing so am thinking of sticking the alli to the steel with Sikaflex. I am struggling to get the alli to form around the frame though. My question is - would the sikaflex be so strong that I can bond the alli to the steel and then bend the alli round the steel without the sikaflex giving way? I am figuring that if I can stick it along the top then leave it to dry it should be much easier to form the alli - if I was using steel I could kind of stitch weld it as I go but I have already bought the alli.
Any advise would be very welcome at this stage - it's driving me quite mental.
Thanks in advance,
Dave.

[HandyAndy]

Hi Dave,

Sikaflex is very strong stuff indeed, but it has a curing time ( dependant on temp of the area), so it may not "hold" the ali in place during the curing period, maybe set it in place but use those cheap straps that you can get from motor factors etc to hold it all together whilst the sikaflex goes off, after it has then i,d think it,ll be a strong enough bond.

cheers
andy

ps.... don,t get the stuff on your hands ......takes ages to get off :eek:

[Enoch]

Thanks Andy, I didn't want to waste time by putting it on and then finding it does not hold. I like the idea of the straps to hold it - I would not have thought of that. Thanks again - you are a legend:)

[Bonzo]

Hi Enoch

Yes sikaflex is very, very strong once set ;)

If you have ever tried to remove a bonded windscreen, you'll know what I mean :eek:
Winscreen bonding is a type of PU adhesive with added UV protection but basically the same as Sikaflex.

If you are going to paint the scuttle !! Perhaps you could give some thought into using some countersink pop rivets to hold the alloy into place whilst the adhesive sets .... slightly over countersink them, skim of filler over the tops & the job will be a good'un :)

[adrianreeve]

Sikaflex tis the Devil's work! It really will stick anything to anything, just make sure you don'e ever want to remove it! As Andy says, strap it down while cures, and it should be fine. I would try to give the ali some form of shape first though, rather than just bending it around the scuttle frame, bonding it and strapping it, as the skin will then always be trying to spring itself away from the frame.

Cheers

Adrian

[slimtater]

2 beads of it holding fibreglass wings to metal wing stays at *20mph (GPS speed) - I would say that is pretty strong!

[flyerncle]

There is a primer for Sikaflex,collar a friendly windscreen fitter and scrounge some and you will have to cut it off to get it apart.
Windscreens are structural and that was the original use for it,also known as "tube of clips" if you get my drift.

[Enoch]

Thanks to all, it looks like that is the stuff to go for. On reflection I think I should have done the job with steel so I could have welded it but I will go with the sikaflex and ratchet straps, I will fold the metal under the frame so I can pout in some hidden rivets. Thanks again guys, I love you all:D
Enoch.

[Bonzo]

Thanks to all, it looks like that is the stuff to go for. On reflection I think I should have done the job with steel so I could have welded it but I will go with the sikaflex and ratchet straps, I will fold the metal under the frame so I can pout in some hidden rivets. Thanks again guys, I love you all:D
Enoch.

You are most welcome mate .... If all else fails .... Give me a shout & i'll come up to sit my lardy ass on it untill the adhesive sets :eek: :D :D

[Davey]

There are several versions of Sikaflex designed for different types of job. Some are just sealants (bloody strong sealants) and others are adhesive sealants (very bloody strong adhesive sealants). I use Sikaflex on a regular basis, either 221 or 521 dependent on the job in hand but to be honest either will hold anything to anything if the prep is done proper like:) . If you're sticking alli then it needs to be ultra clean so stainless steel wire brush the areas to be bonded first then chemically clean with a solvent, then apply the Sikaflex and finally fit the panel. It will be a huge help if you can preform the panel before applying the Sikaflex as it will reduce the need for fixtures to hold it in place while the adhesive cures (can be up to 48 hours dependent on type and temperature/humidity). PU adhesives like Sikaflex are moisture sensitive so damping the glue with a water spray can speed up curing times.

Google Sikaflex to find the best one for your needs.

D.

[Enoch]

Thanks for all the replies guys, I will get the panels bent as close as I can, clean everything thoroughly and then clamp it all up for a couple of days to make sure it is all dry. Thanks Ronnie for the offer of coming round and sitting on it but given Andy's comments about how well it sticks to skin I am not sure this is a good idea. :) I was thinking of some sort of bonnet ornament but perhaps something slightly more subtle than a large bloke would be more appropriate:-) Besides I can't afford to feed you and I'm sure the IVA inspector would have sarcastic comment to make about vision being obscured. Do you have any sharp projections? On second thoughts, don't answer that:)
Enoch.

[Bonzo]

Do you have any sharp projections? On second thoughts, don't answer that:)

Enoch.

I am sure it will go well once you get into the swing of it, alloy is quite easy to form once you get the knack :)

Yes I do have a projection .... I think it is IVA friendly though .... Not protruding more than 5mm from the surface & in any event, it has a nice radius :D :D

[Enoch]

You're a bad man Ronnie:D That's why I like you.
I have found a Sikaflex equivalent, looking at the respective datasheets it has the same hardness when dry and the same strength, it's available in white, grey and black and it's a hell of a lot cheaper. It's called Polyflex. Like Sikaflex there are different grades available, they do LM and HM which are equivalents to 221 and 251 they are both high modulus moisture drying polyurethane preperations. If you search for it on the net you can find the datasheets and stockists that do it for about 3 quid for 300ml. One seller on ebay does two tubes for £4.50.
Hope that's of use to somebody.
Enoch.

[adrianreeve]

Exactly what I've used Enoch - it's good stuff, and as you have seen, cheap!

Cheers

Adrian

[Enoch]

I have just this afternoon put my scuttle together, after about 2 hours I would describe the parts as "stuck". Bleedin ell that stuff is strong! It seems to have bonded very well to the alli, I did not use any special cleaner, just gave it a good clean with some solvent and a quick rub down to roughen the surface a bit. I found it quite difficult to make the scuttle as I had to call on skills I have not used for a very long time and that I was never brilliant at in the first place. I am now quite pleased with the end result, I will update my web site soon with photos. Thanks again to all that offered advice. And, if you are tight like me the Polyflex seems to be a great low priced alternative to Sikaflex.
Enoch.

[Bonzo]

Well done that man :)

Look forward to your blog update :cool:

That PU ahesive is awesome, I use a product called Sticks like S**t, another Sikaflex type adhesive.

It's been holding the 1/4 glass in my Mazda for the last 8 years .... Couldn't bring myself to buy a whole tube of windscreen bonding just for 1/8th of it :o

I'll keep my eye out for some Polyflex as it seems to be even cheaper than my substitute ;)