MK7
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| posted on 5/5/04 at 03:12 PM |
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sikaflex failure
I'd welcome some advice / guidance as to how best to get out of this problem...
In the final stages of preparation for SVA and my passenger side panel half fell off!!!
I've used a Poly Urethane sealant supplied by MK called something like Joint de France, I think it's made by Total.
The back end of the panel around the wheel arch is firmly held, the front part from about the scuttle forward is now hanging off.
Using a Stanley knife blade I've managed to scrape the PU from most of the powder coated chassis (and quite a bit of powder coating too) but
there are patches where I can't reach.
The PU seems to have stuck well enough to the chassis but not the GRP.
I'd welcome any suggestions as to what can be done to rescue this situation, particularly in terms of what preparation I should do to the GRP
and chassis to ensure better adhesion next time.
Any suggestions as to how I might succesfully remove the rest of the side panel without damaging it?
Thanks
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Hugh Paterson
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| posted on 5/5/04 at 05:42 PM |
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Pair of rubber or disposable gloves, wipe the grp with acetone to degrease it then try again. Your on yer own with regard to getting the panel off
without wrecking it, but working along the edge with a hot air gun as you peel it back might help. powder coating is however flamable tread carefully
Shug.
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MK7
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| posted on 5/5/04 at 07:11 PM |
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Thanks Hugh,
I'll have a go at re-sticking the bit that I can get to, there seems plenty of surface to work with.
Russell
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Peteff
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| posted on 5/5/04 at 07:53 PM |
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It would be a good idea to put a rivet or self tapper at each end when you reattach the panel to stop it from peeling again.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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MK7
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| posted on 5/5/04 at 09:33 PM |
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anyone know if clutch / brake cleaner is as good and usable as acetone for cleaning GRP?
It contains naptha, pentone and isopropyyl alcohol...
Thanks
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Hellfire
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| posted on 6/5/04 at 12:06 AM |
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I'm curious as to how it has fallen off in the first place? Did you have grease/oil on your hands when assembling, or is there a chance of
contamination/dust between the surfaces to impede adhesion.
Our front arches are held on in this way only... no problem.
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spunky
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| posted on 6/5/04 at 12:14 AM |
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I've had similar problems.
If you've been working the fiber glass at all you gotta give it a good clean with acetone 'cos the fine dust settles on the surface and it
appears to bond then breaks away after it cures.
Does it with epoxy, silicon, PU.
John
Waaahey.... I'm a Builder now...
I'll go to bed
[Edited on 6/5/04 by spunky]
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MK7
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| posted on 6/5/04 at 07:26 AM |
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Not exactly sure what caused the failure but I suspect it was dust, possibly from working this and other panels before hand.
It's also possible that I didn't have sufficient clamping force at the front of the car.
We live and learn eh?
Before assembling the panel some 6 months ago I cleaned the relevant surfaces with methylated spirits which I think was mentioned in the 'which
Kit' build of the MK Indy.
This time I'll try and source some acetone, failing that I'll use brake and clutch cleaner, that seems to work well enough at degreasing
metal surfaces.
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splitrivet
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| posted on 6/5/04 at 09:14 AM |
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Sounds like a contamination problem to me too,just as an aside dont bother trying to use solvent free no nails its absolutely crap, tried it on my
side panels and there was no adhesion at all, ended up siliconing them on and they are stuck fast.
Cant comment on the solvent kind of no nails which it seems is very hard to get hold of now.
Cheers,
Bob
I used to be a Werewolf but I'm alright nowwoooooooooooooo
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stephen_gusterson
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| posted on 6/5/04 at 09:30 AM |
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no nails doesnt even hold down edging on a wooden panneled floor in a house properly!
Id expect large parts to fall of my car if I had used it without rivets as secondary fixings.
Some 'no nails' also fails if it gets wet....beware.
atb
steve
[Edited on 6/5/04 by stephen_gusterson]
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David Jenkins
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| posted on 6/5/04 at 09:53 AM |
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Another thing I've found with PU adhesives - when you first open the tube you get an incredibly sticky and fairly fluid goo that sticks like the
proverbial to anything that comes near (usually not what you want to connect!). Leave that tube for just a few days and the stuff is thicker and less
ready to stick to anything. A few days later and the stuff is near-enough useless for anything apart from sealing a gap between 2 items.
Moral of the story? If you have a lot of stuff to glue together, save all the jobs until you can do them together with a freshly-opened tube of PU
(or be prepared to open a new tube for each job).
David
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steve m
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| posted on 6/5/04 at 09:56 AM |
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my side panels are held with no nails
and have been for about 5 years
no problems so far
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splitrivet
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| posted on 6/5/04 at 10:15 AM |
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5 years ago you probably had the solvent based no nails Steve which is sort of like evofix, this solvent free one is like a gritty tile adhesive. It
does say on the tube that one surface should be absorbent but thought I'd give it a go anyway,should have known better I suppose.
Cheers,
Bob
I used to be a Werewolf but I'm alright nowwoooooooooooooo
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MK7
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| posted on 6/5/04 at 10:20 AM |
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I'll be using loctite 5220. Before re-fixing the panel I'll be giving it a hose down with Brake / clutch degreaser.
I'll be fixing the rear panel and cycle wings at the same time, hopefully this'll be the last time the PU will be needed.
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billy
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| posted on 8/5/04 at 08:56 PM |
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grip fill
im a chippy and use gripfill alot,and it is solvent based and it will stick anything to anything,not that i used any on my build cos you wont be
getting it off again . im a great lover of silkafix cos its the best thing since sliced bread.
luego-lo-cost finished,vauxhall 16v 2.0,twin 45s de-dion rear set up
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Mr G
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| posted on 8/5/04 at 10:19 PM |
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I would'nt like to try a sandwich round your house billy.........
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NS Dev
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| posted on 10/5/04 at 04:32 PM |
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I haven't used it on my locost yet but for a lot of other metal to metal jobs I use "Polyurethane 40" available from Machine Mart
now at fiver a tube. As said further up, sticks anything to anything very well and stays slightly rubbery so won't crack (as with nearly all
polyurethane adhesives)
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SteveO
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| posted on 11/5/04 at 08:49 AM |
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u have mail.
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MK7
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| posted on 13/5/04 at 09:52 PM |
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I re-sikaflexed the panel having thoroughly degreased both surfaces beforehand.
The panel stuck well so I was happy, at least for a while...
The next problem occurred when I had to fasten the underside of the front panel to the bottom chassis rail in the engine bay. I'd forgotten to
do this at the outset and so needed to get the car on ramps so I could get underneath it properly. I'd decided to sikaflex it and put a couple
of rivets in for safety.
That job went well but, because there was around a 10mm gap between the top side of the panel and the bottom side of the chassis rail, the panel ended
up being compressed, this pressure has now popped off the top of the side panel 
To address this I've ended up putting a single pop rivet on the top panel close to the front bonnet catch.
I'm not best pleased with the fit of these panels nor the rear panel which appears to be around 10mm too wide. I may end up replacing these
panels once the beast is through SVA...
Others had similar experience / problems or is it just me???
Russell
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CairB
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| posted on 13/5/04 at 10:24 PM |
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Russel,
I seem to remember there being a gap between the top and bottom flanges of the MK GRP side panels and the chassis. I remember thinking that the gap
was large but it was better that way than an interference. If thats the clearance your refering to I don't remember it being 10mm though. I
fitted some 3mm ally packing pieces between the top chassis rail and the side panel top flange. I used Sikaflex on all surfaces and M4 taptites to
secure top and bottom. My panels are still on ok, well they were last time I looked
Cheers,
Colin
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