I would be too worried that any flexing of the chassis would eventually break the glue bond.
atb
steve
I rivited my panels and used a 'i can beleive its not nails' stuff under the panel as well.
Is there not a more modern method of fixing panels etc. to the chassis than rivets. I would of thought in this day and age that there would be a
adhesive, tape/glue type thingy that could do the job and look a dam sight better than a row of rivets?
Any ideas
Col
[Edited on 28/10/02 by Macca]
There are many alternatives, mostly adhesives. The most common is Polyurethane sealant/adhesives such as Sikaflex or their cheaper 'generic' counterparts. Also tape adhesives, especially pure acrylics like 3M VHB tape, although you would still need the odd rivet especially with PU etc. to allow time for the adhesive to cure. Oh and yes I used to be a Rep for an adhesives company but I now make an honest(ish) living instead of lying through my back teeth!
i know that glues are very advanced nowadays, and hold a lot of the bits on airplanes, but then they probabably have better processes than I have in
my garage.
I would be too worried that any flexing of the chassis would eventually break the glue bond.
atb
steve
I rivited my panels and used a 'i can beleive its not nails' stuff under the panel as well.
Hi Steve
PU sealant/adhesives set like hard rubber and are compiant to a degree. On a std locost chassis after a while lots of the rivets at the front of the
car have stretched and are doing nothing anyway. I wish I'd used some on mine!
hi PTM
yep, i can imagine that alu rivets might sheer if the front flexes. However, im hoping mine wont so much as i provided cross-diagonals down the side
of my car out of inch rhs rather than the single round tubes in the book.
id just be happy to have it on the road and worry about flexing afterwards!
atb
steve
Well said, which is why I may be putting a few extra tubes in over the winter!
quote:
Originally posted by locodude
Hi Steve
PU sealant/adhesives set like hard rubber and are compiant to a degree. On a std locost chassis after a while lots of the rivets at the front of the car have stretched and are doing nothing anyway. I wish I'd used some on mine!
Hi James
Any automotive supplier, panel supplier, fastening and adhesive suppliers. Don't let them fob you off with Sikaflex. It's the best but it's also £12 a
tube. Don't pay more than £4. You want no name Polyurethane sealant/adhesive. Watch out when applying it, it gets everywhere and it's a pig to get
off. Takes about 24hrs to cure. Also it's not like silicone, you can't block the end up and use it again. It cures with the moisture in the air. I
sealed my floor with it, which is why when it rains it fills up, ask ChrisG!
Got mine from RS. Its Loctite 5220, 5221, and 5222, this is 3 different colours black, grey & white; p/n 313-8653, 8669 or 8681 £5-71/tube. It can be kept for several days once opened by removing the nozzle, cover the open end of the tube with a piece of polythene sheet & replace the nozzle (clean the nozzle 1st ready for use). As with most adhesive its best to degrease the mating surfaces before use.
Hey the Wickmeister!
The accepted method for preserving PU is ally foil on the end but it really should be used asap. As for degreasing you're right but male sure it's
alcohol based, not oil based like white spirits/turps etc as they leave an oily film. Jesus I thought I'd got out of the adhesives game for good and
here I am in selling mode no.1. I think I need a stiff drink!
make sure it's alcohol based
quote:
Originally posted by locodude
Hi James
Any automotive supplier, panel supplier, fastening and adhesive suppliers. Don't let them fob you off with Sikaflex. It's the best but it's also £12 a tube. Don't pay more than £4.
Chris, Any peel and shear strengths for these things, being a fat git dont want to use it on my floor only to fall through when I step on it.
I wouldn't worry about that. You'd destroy the surrounding panels trying to part them! You'd still have one or two rivets in anyway to hold it while it cured.
So just to see if I'm on the right track here - We are talking about adhesives instead of rivets are we?
If so this has to be a bloody good idea I would have thought.
So:
Will the appropriate adhesive help to create a stronger chassis by virtue of bonding the panel over the whole contact area rather than just the area
of the rivet heads? I presume also that it can only be a good thing not to drill hundreds of holes in the chassis. How would bonded panels affect
the various stiffness calcs done by various people on this group?
If it is potentially styronger is a PU based adhesive the best for this or is there something better?
What about paint? Can this process be effecive on a painted chassis beacuse the bond will be with the paint and not the metal and can only be as
strong as the metal/paint bond? If this is the case what is the best paint system to use as I canot see the domestic gloss that seems to have becopme
a firm favorite with locost builders having sufficient adhesion to the metal surface - otherwise they could use it as a cheap way of gluing planes
together!!
Finally there is an obvious disadvantage to this approach in that it would make repairs or modifications to the chassis bloody difficult. Has anyone
else any thoughts on the advantages/disadvantages? (another advantage - no rivet heads rattling around inside the tubes!!)
Not Finally afterall - I've just though of another question.
On a related subject I once posted a question about prestressed aluminium panels, as used on some C******* models but no-one either knew the answer or
was interested so I'll ask it again as it is kind of relavent to the subject in hand.
What is the process of pre-sstressing alu panels? Is it something within the technical abilities of a Locost builder? and finally (really this time)
is it worth the effort?
Cheers,
Phil
Definitely interested in the glue apporach. Are there any testimonials out there from the manufacturers that I can read up on?
Sorry - Just trying to bring it to the top again
I'm nearly at the stage of panneling. I am really interested in persuing this.
For me, I think the finished car will look much better without the rivet holes, and will implicitly give a seal around the joints.
Could someone comment on Phils posting?
True to my usual form, my panels are 'glued and screwed' - well, PU's and pop-rivetted, anyway.
I did a few tests with the PU (read: "oops, I spilt some where I shouldn't have") and it really does stick things together, given clean surfaces and
time to cure.
David
My preference is to use just glue.
To allow curing in the correct position I aim to use clamps and wood along the joins.
does anyone see a problem with this?
John, are you alowed to 'glue' the panels as the 'book' shows rivets. Also if you get bashed, how easy will it be to repair/ staighten ?
Only asking as I could do the same !
Missed you on Sunday, was looking for a chat on racer progress
Interesting start but still some questions unanswered -
What about bonding over paint or should I bond alu to steel and paint the chassis afterwards?
What about surface preperation?
Which of these glues is best?
And most importantly - Is it a good Idea? - I think it is but I've been caught out by thinking before!!
Phil.
quote:
What about bonding over paint or should I bond alu to steel and paint the chassis afterwards?Phil.
If bonding large panels, you need to consider the question of differential expansion. If one material expands more when warm than the other, then you
need to use an adhesive that allows a certain amount of movement. If you use a 'hard' adhesive it will tend to give way completely if overstretched
I'm not saying this will be a problem on a locost, but might be worth some consideration
John
I left the paint on when I fitted the panels - the polyurethane was meant to be more of a sealant than a glue, with the rivets doing the mechanical
work.
The fact that PU is a very good glue is a bonus, as far as I'm concerned.
David
If expansion was a problem with glue it would surely be a problem with rivets too.
There is not much point in bonding with a glue with give in it, as part of the concept of bonding with glue is to increase the stifness by increasing
the bonding between the chassis and panels as compared to rivets.
As regards painting - I've given this some thought and I think that painting the chassis with a strip of masking tape along all bonded surfaces is
probably the answer.
quote:
Originally posted by philgregson
If expansion was a problem with glue it would surely be a problem with rivets too.
I'm gonna use this stuff:
http://www.decoratingdirect.co.uk/viewprod/s/SIRPF15LM/
Along with some rivets,(inner panels, tunnel etc) manly becouse getting the drill in is gonna be a right bugger and 90 degree ones are £££.
Graham
I would personally stay away from using just adhesives if you want the panel to be structural in any way. The pro's can do it but it takes a lot more
technology than we have. Some of the epoxy based glues have good shear strength but they all have pretty poor peel strength. The technique used in a
lot of race car construction is to use structural rivets and structural epoxy adhesive. if maximum strength isn't required then you can substitute
sealer for the epoxy. In both cases make sure that the metal is perfectly clean e.g. lightly sand and then wipe with acetone JUST before bonding.
One trick you can use to keep paint/rust from the areas of the chassis to be paneled is to use masking tape. With a suitable kind of tape you can also
use this technique when getting the chassis powder coated. This leaves nice clean metal to bond the panels to.
Someone was asking about preformed panels. Are you referring to honeycomb panels or something else?
quote:
Originally posted by gjn200
I'm gonna use this stuff:
http://www.decoratingdirect.co.uk/viewprod/s/SIRPF15LM/
I used to work at a well known Automotive paint manufacturer starting wtih Du (Not Dulux!!), and they had a number of factory chassis from
manufacturers like Aston Martin, Lotus, Ford etc for testing, and they all use PU adhesives for fibreglass repairs, and even for sticking parts of the
chassis together, in order to use less rivets or welds. The PU Glue is as strong as a weld, and rarely cracks. Its a definite part of my build,
though im going to weld the chassis, and just use glue on sheet metal or fibreglass. Square or round tube IS better welded, because of the limited
surface area. 
[Edited on 5/8/08 by MakeEverything]