goin2fast52
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 posted on 15/2/04 at 10:56 PM |
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alternative methods of constuction
for those of us who can't weld and don't want to pay someone else to do it for us, would it be possible to build a spaceframe using
'structural adhesive', as in the stuff used to build monocoques(think elise)?
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200mph
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| posted on 15/2/04 at 11:01 PM |
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I dont know about that... but...
I went from one of you 'cant weld' to a 'can weld' in a couple of days, with a bit of practice. In the past few days have
finished my own chassis, and walking about with a smile from ear to ear everytime I'm in the garage. Plus welding definately has its uses
elsewhere.
I would learn to weld if I was you, but thats just me ( if you know what I mean)
Best of luck
Mark
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flak monkey
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| posted on 15/2/04 at 11:04 PM |
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I wouldnt suggest it  The bonding used in the Elise is pretty special stuff and isn't cheap, and i seem to remember it only works on Ali. And
it isnt just glued. (I had a teacher who worked on that stuff when i was doin my A-levels)  (Well she said she did )
MIG welding isnt too difficult to do anyway. You should be able to teach yourself, with patience. (there was a thread on here about a week ago all
about welding) And if you cant get the hang of it, most colleges do short courses in welding.
Anyway its not as if a welder is really expensive, plus you can seel it when you are done
Cheers
Sera
http://www.motosera.com
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GTAddict
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| posted on 15/2/04 at 11:14 PM |
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Stick to rivets. New Jaguar XJ is bonded, but has rivets anyway because jigging the car is too time-consuming for the volumes, and also it allows a
certain amount of leeway on the adhesive, so to speak.
I've seen the jigs required to bond the prototype monocoques of the new Aston Martin, and whew, there's a few quids worth of clamps in
there. While technically feasible for a Locost, it would probably take you three times as long to design and manufacture the jigs as it would to
design and manufacture the chassis. Probably easier to mould an FRP tub with bonded in strengtheners... never really thought of it for a Locost/7
style car before... not a bad idea!
M.
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James
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| posted on 15/2/04 at 11:16 PM |
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I don't think you could build a Locost chassis using adhesive- I can't believe there's any strength in two steel tubes glued end to
end!
If you redesigned the whole chassis so that it was better for gluing then maybe but I doubt there's much to be gained and lots to be lost in
terms of time.
Go on an evening course at a college and learn to weld.
On my course I feel I gained a lot:
Qualifications in both MIG and TIG.
Access to loads of lovely kit- pillar drills, lathes, TIG welders, gas welders, oxy cutters, brazing, guiltines, tube cutters.
Somewhere to build my chassis.
Met a load of car nuts who know lots of helpful stuff.
Loads of metal! 
Mig welding really isn't that hard when shown how and not that pricey either.
HTH,
James
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DavidM
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| posted on 15/2/04 at 11:28 PM |
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Some bikes (pedal not motor) have bonded frames. I have one myself made from Cromoloy steel tubes.
Bonding requires lap joints to be effective and this is achieved on a bike frame using special joint lugs (sleeves). On a spaceframe you would need a
sleeve at each and every joint, some to connect tubes going in four or five directions. You'd have to make these.
The fit, finish and cleanliness of each joint would need to be of a very high standard, probably beyond that which could be achieved whithout
specialist facilities.
So whilst it's possible to do, it's easier to weld, even if you have to learn first.
I seem to remember that some parts of the Caterham chassis are bonded, but I think these are monocoque elements.
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goin2fast52
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| posted on 15/2/04 at 11:29 PM |
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so i guess that's a no then
the local comm college probably has some welding courses, will have to check those out.
thanks for the responses before i did something stupid
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Mark Allanson
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| posted on 15/2/04 at 11:39 PM |
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3M structural adhesive is the strongest stuff I have ever seen. 6R4's were made with it, in properly designed joints, I would say it is as good
as welding. It certainly is no good at but bonding 1" erw. You would have to redesign the entire chassis, probably like the Lotus Elise, but
even they had a structural rivet at either end of the adhesive pass. also the twin pack adhesive is £40 a go and has to be used within 20 mins of
opening and the applicator gun costs £299!
Learn to weld!!!!!
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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stephen_gusterson
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| posted on 15/2/04 at 11:42 PM |
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unless you have a burning desire to build the chassis yourself, buy something - like an MK or Luego chassis.
Once you come to terms with the fact you will spend around 3k building the car anyway, a few hundred quid for the chassis isnt too budget blowing
anyway.
Making the chassis is fun, but if you cant be bothered to learn to weld, there is at least another way. BE VERY VERY SURE that your welding is up to
scratch before you start, as if your chassis isnt up to standard, your whole car is built on sand.
atb
steve
[Edited on 15/2/04 by stephen_gusterson]
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JamJah
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| posted on 16/2/04 at 10:22 AM |
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I agree with James. Althought I used to live near him I did a welding course in southampton, as i was in the midstd of moving here anyway.
Its a great skill to have. I did a 17/18 week course which I seem to remember was under hundred pounds (so isnt a hefty layout!) and you should be
able to claim money of various skills councils if you can agrue with them that you might possible need to repair your office desk or any other useless
thing you might need it for your job!).
I feel I could do my own chassis, but as a question of saftey I am currently thinking of leaving it to the pros. If I get them to do the rollie at
the same time....!
So in short, do a course. I made a couple wind vaines on mine which paid for it after a short bidding war on ebay!
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DBH12
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| posted on 17/2/04 at 07:38 AM |
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goin2fast52, I looked around the internet for some epoxy specs (http://tds.loctite.com/tds5/docs/HYSAE-120HP.pdf) and some brazing strengths
(http://www.staff.ncl.ac.uk/s.j.bull/mmm373/BRAZE/sld008.htm). The epoxy has a strength on well prepared steel or aluminum of over 4,000 psi. A
brazed joint with a gap of .002 to .018 in. would have a typical strength of more than 10 times that. A welded joint is as strong as the brazed
joint, but is not as sensitive to the gap of the base pieces. One place that you SHOULD consider epoxy for is attachment of the aluminum sheet to the
steel tubes. The typical pop rivets are not very strong or stiff and a bonded joint, if done well, would be both stronger and stiffer, contributing
to a stiffer chassis.
Good luck,
DBH12
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Terrapin_racing
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| posted on 17/2/04 at 09:12 AM |
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You could also consider Sikaflex adhesives for aluminium panels to steel tubes. I use Sika 552 & 221 - excellent stuff! Excellent vibration
resistance - epoxy can tend to break away - unless your using INF spec (I think it's a couple of hundred quid a litre?)
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philgregson
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| posted on 17/2/04 at 01:24 PM |
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Seems pretty much like the old dogs dooh-dahs to me except for one small thing - It's not resistant to gasoline - probably not much of a problem
in practical terms but it does ring bells never the less.
Cheers
phil
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Terrapin_racing
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| posted on 17/2/04 at 01:42 PM |
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And there's more...
forgot to add! - ideally you should seal the area containing the fuel/fuel tank using an intumescent (fire proof) and fuel proof sealant. Merlin
Motorsport sell the stuff - not mandatory unless your racing
Or you could just wear this F1 stuff?
 
Rescued attachment trad26zoom.jpg
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