Kiss of the K-wall at Laguna 'no es' Seca: Need non-authorized chassis repair ideas - Page 3 - LotusTalk - The Lotus Cars Community
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post #41 of 116 (permalink) Old 02-25-2009, 08:13 AM Thread Starter
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Phil-

Coming from you, that means a lot. I have been following, closely, some of your projects and it's clear to me that you're pretty thoughtful when it somes to mechanical issues.

For what it's worth, here's some of the "Money Shots" (as in will cost me a lot of money!) -- This is what it looks like from the OUTSIDE:


Oil bloom on pavement from busted oil cooler. Rainy day in Monterey...





Note the curvature of the radiator horizontal vanes as it moves outboard -- Best guess was that impact was at something between 60 - 70mph

Thanks for the encouraging words.

Best,

John

2005 Lotus Elise - Artic Silver/Black/LSS/LSD/TC/HT/TOUR/SS
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post #42 of 116 (permalink) Old 02-25-2009, 01:21 PM
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oooo, Ouch glad your ok John,

Good luck with the project have faith
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post #43 of 116 (permalink) Old 02-25-2009, 08:16 PM
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One thing which I see repeated on the forums so often people now believe that it is true is that the Lotus tub is too thin to weld. This is rubbish - even I can weld 1.5-3mm alumimum without drama. The issue is that the alloy used in the tub is a heat treatable alloy. Once welded, it will be dead soft, and a fraction of the original hardness & strength. A secondary issue is that the welding will distort the chassis. If Lotus was going to use a heat treatable alloy, why not use 7050 or 7075? (70% stronger!) Or if they were to use a non heat treatable alloy like 5052 or 5083 then it would be both stronger and also weldable. The only thing good about 6063 is that it looks good.

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post #44 of 116 (permalink) Old 02-26-2009, 05:15 AM
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why weld? rivet!
sam

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post #46 of 116 (permalink) Old 02-26-2009, 06:11 AM
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Quote:
Originally Posted by dstevens View Post
One thing which I see repeated on the forums so often people now believe that it is true is that the Lotus tub is too thin to weld. This is rubbish - even I can weld 1.5-3mm alumimum without drama. The issue is that the alloy used in the tub is a heat treatable alloy. Once welded, it will be dead soft, and a fraction of the original hardness & strength. A secondary issue is that the welding will distort the chassis. If Lotus was going to use a heat treatable alloy, why not use 7050 or 7075? (70% stronger!) Or if they were to use a non heat treatable alloy like 5052 or 5083 then it would be both stronger and also weldable. The only thing good about 6063 is that it looks good.
correct, if you weld you are effectively annealing the metal which makes it much easier to work and drill but does not help with the strength. Fortunately I can see most repairs of the tub/extrusions not needing any welding as long as there is enough joining surface to support bolting or riveting. Thats why I suggested fitting one extrusion inside the other which effectively eliminates any movement except in the lateral direction (e.g. the extrusion sliding back and forth.) In fact the bolting itself will likely provide enough support to handle the stresses from the arm but I would still recommend bonding the extrusions together as it provides an excellent safety factor and limits the possibility of shearing at the bolt holes in cases where the inner extrusion has a bit of play inside the outer one.
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post #47 of 116 (permalink) Old 02-26-2009, 06:59 AM Thread Starter
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ZAMMY1, Dragon, rob13572468-

Thank you all for your input. I have also received some correspondence via PM on the matter and an offer to provide a well-researched and documented description of a literal repair using many of the methods and techniques suggested above.

Assuming that I can obtain a reasonable cash settlement with the insurer to allow me to proceed with a repair on my own, I will likely work with our LT Moderators to establish a new thread to fully describe and document the repair methods/process that I undertake. I'm NOT likely to get as crazy as the Brit who debonded his tub and reassembled with straight salvage parts -- I'd like to document a field-repair approach that uses many of the methods you all have suggested above. It'd be nice to have a body of literature/online reference that provides the community with guidance on these types of restorations. Hopefully, I can act as an aggregator of the great information being provided to me and with the contributors' permission and with appropriate attributions, make this information available online at LT.

What a kick/shot-in-the-arm it is to have such a great group of folks on this virtual team! THANKS, ALL!

Best,

John

2005 Lotus Elise - Artic Silver/Black/LSS/LSD/TC/HT/TOUR/SS
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post #48 of 116 (permalink) Old 02-26-2009, 07:37 AM
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John,

The information you've gathered so far, does it mention preparation of the aluminum surfaces prior to bonding? Aluminum oxidizes which creates a poor bonding surface. There are chemicals available that stabilize the surface long enough for bonding. Curious if the adhesive you've located requires a preparation step.

John

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post #49 of 116 (permalink) Old 02-26-2009, 11:55 AM
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John,

I see you are in the Sierra's? I am in Shingle Springs (by Placerville) and have a pretty good shop available to me and a couple of very very good fabricators. If we can be of assistance, please let me know. From the photos I agree that it is fixable, given our race car experience there are many "totaled" Lotus's that I would not hesitate to fix.

Just because Lotus chooses to glue the chassis together does not mean that is the only acceptable method of bonding the materials to each other.

Heck, we have won races with chassis parts being held on with safety wire.
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post #50 of 116 (permalink) Old 02-26-2009, 12:10 PM Thread Starter
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Hey Rick-

Thank you very much for the "shout out" as it were. I suspect if you were yelling a little louder, I might have heard you 'cross the Mokelumne -- I'm up off Highway 4, near Camp Connell/Big Trees State Park (snow country this time of year...)

Per some of my previous posts, I am going to do my darnedest to eliminate some of the FUD around these types of restorations. I received some amazing photographs, along with an extremely detailed narrative documenting one repair (with vendor citations, materials P/Ns, etc.) Looking at that one particular repair, it appeared that the fix was much more substantial than the original chassis (at some modest penalty in terms of absolute weight -- As someone has said previously, it's a lot cheaper to skip dessert when it comes to shaving pounds!)

I will let you know how it goes. Once we determine an appropriate approach, if I need fabrication assistance, I will not hesitate to take you up on your offer.

Best,

John

2005 Lotus Elise - Artic Silver/Black/LSS/LSD/TC/HT/TOUR/SS
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post #51 of 116 (permalink) Old 02-26-2009, 08:41 PM Thread Starter
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Elancoupe/MaineLotus-

I have had substantial input from others about the repair processes with very specific suggestions for some appropriate adhesives. Specifically one kind contributor, after consulting with a technical representative at Huntsman Corp (an adhesives manufacturer) was able to select a product for use. Based on the requirements, which precluded the use of a whole chassis autoclave, the Huntsman rep suggested their Araldite #2014 product. I went looking for some specific data online to follow-up on the lead. The best site I found was from a company in Western Australia -- The material is readily available in the US, though:

Araldite #2014 Specifications and Applications

MaineLotus -- There is a specific document about surface prep via the links above. One restorer used a relative coarse grit of sandpaper to remove anodization, which provides a poor bonding surface, and to improve the tooth of the surfaces to be mated. This prep was completed with an acetone wash.

Based on all of the great data I've been getting, it makes one think you could corner the market in salvage Elises, repair them to an exceptionally high stronger-than-stock standard and do reasonably well turning them around! I'm not suggesting that the conventional wisdom is hooie, but it sure feels like even problem cases which involve a *straight* (NOT racked...) frame can be conscientiously serviced to a degree where subsequently pushing the vehicle hard should not be an exercise in callous disregard for one's well-being!

Best,

John

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post #52 of 116 (permalink) Old 02-27-2009, 10:24 AM
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Hi John,

You may want to check out this thread, '05 frame for sale.

https://www.lotustalk.com/forums/f95/...e-frame-69317/

I think the frame repair is very interesting though!

John

My car is modified.
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Last edited by MaineLotus; 02-27-2009 at 10:42 AM.
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post #53 of 116 (permalink) Old 02-27-2009, 02:52 PM Thread Starter
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Hi John aka MaineLotus-

Thank you very much for the link. I think I'm with you...I'm thinking that there ARE very solid options for repair. It'd be more interesting at least, that's for sure.

There's also something about "Time is money," too....That's a great deal for the raw chassis ($2,000 + whatever it takes to freight to the opposite coast), but it would be a very loooong project to move bits from one vehicle to the other. As much as I like to "putter in the garage," that might be more than I really want to sign up for.

I sincerely appreciate the fact that you brought it to my attention, though!

Best,

The "other" John

2005 Lotus Elise - Artic Silver/Black/LSS/LSD/TC/HT/TOUR/SS
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post #54 of 116 (permalink) Old 02-27-2009, 06:27 PM Thread Starter
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Got the "official" repair quote -- $33,605. As we knew, it's a text-book total. I hope to be able to propose a cash settlement to the insurer that saves them the misery of a total and the paperwork and overhead associated with same, while providing sufficient insurance proceeds to allow the vehicle to be restored to a reasonably high standard.

The principal cost is for the $12,639 replacement chassis and the labor to swap bits around. I think the labor to replace the chassis is significantly understated. There's no detail for moving the motor, etc.

This ought to be interesting!

John
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File Type: pdf Lotus-IELISEI-Repair-Quote.pdf (233.1 KB, 464 views)

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post #55 of 116 (permalink) Old 03-01-2009, 09:41 AM
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Hi guys, found this thread after a quick browse. I work in composite engineering in the UK, and have repaired a few chassis with the same damaged.

The method someone mentioned of putting a new extrusion inside the old one is the best way to proceed.

BUT.....

You must never weld the tub, main reason is that you will de bond the remaining adhesive.

You need to rivet and glue the extrusion into place. The nearest adhesive to use is Huntsmann Araldite 2015. They also sell a red die which Lotus also use. (2014 listed goes off too quickly and can not be used for this type of repair).
This cures @ 25 deg C in 24 hours.

For reference, Lotus do not use an autoclave to cure the chassis, they do it in a oven @ ~ 90 Deg C for faster cure time (approx 90 mins). Joints show the same mechanical properties if cured at room temp.

I normally post on SELOC in the UK, where you have probably read some of my posts of how to repair the chassis's in more detail.

Last point, this should not be tried by anyone, the repairs I have done were in a controlled laboratory, with the ali being pickled and fully prepared before bonding.

Hope this helps though
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post #56 of 116 (permalink) Old 03-01-2009, 10:47 AM Thread Starter
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Hello Andy-

Thank your for your comments and insight. I just got off the phone with an LT'er that had done the research directly with the technical representative at Huntsman, etc. We, too, discussed the extrusion "inserts" (although we thought we might have to use a C-section to accommodate the rivets underneath the A-arm as shown in some of the photos.) Also, it may require some milling of the A-arm bushing surround to provide clearance and adjustability, etc.

One of the most significant points/comments that we discussed was to test "trueness" of the frame through the LOWER A-arm/wishbone mount points. One method to do so is to polish a three foot (3') length of 3/8" steel rod -- the polishing allows it to be inserted through the two lower wishbone mounts, both front and rear. If there is any deformation that prevents the rod from being smoothly run through these aligned bores, it's probably a lost cause as there is likely no way to field-repair these bits (even when getting creative and using techniques similar to those described above.)

Andy -- I searched SELOC reasonably well and had a hell of a time locating *specific* repair techniques/photos/etc. As a matter of fact, I actually bookmarked one of YOUR post replies (as it provided plenty of encouragement...I've been meaning to drop you a U2U/email, what have you....)

One of my good friends knows an excellent pattern shop outside Detroit. I grew up outside same and he works for GM's race/performance engineering group. With the drawings you describe above, I could likely get parts fabricated, etc., if/as necessary.

Thanks for checking in -- You were absolutely one of those that were referred to/described earlier in this thread.

Best,

John

2005 Lotus Elise - Artic Silver/Black/LSS/LSD/TC/HT/TOUR/SS
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post #57 of 116 (permalink) Old 03-01-2009, 06:42 PM
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A comment on welding heat treatable aluminum alloys - there is a problem that arises in the heat affected areas called intergrainular corrosion. The alloys in the aluminum don't like the process, and will begin to exfoliate, or cause layers of the parent metal to literally flake off after some time. The loss in strength is substantial.

Another comment about bonding; in aircraft repair there is usually a layer of "scrim", a thin, loosely woven pre-preg fabric between the structural components being bonded. It allows the bond line to have a little "working room" incase you have a little 'metal-to-metal' interference along the joint. Where there is hard contact between repair elements, the adhesive is totally squeezed out during the clamp-up, & there is a poor bond in this area.

If you are in a large enough metropolitan area, you might consult a "DER" or designated engineering representive. These guys design repairs for aircraft damage not specified by the manufacturer in it's SRM, or structural repair manual. ( kinda like Lotus!) here is a FAA.gov link:

http://www.faa.gov/other_visit/aviat...RDirectory.pdf

scroll down to pg 145 ( I'm assuming California ) for "Structures"

These guys are used to working with aluminum and bonded structures. You might even get lucky, & get a "car guy". They don't work cheap, but with an aircraft repair goes a bunch of responsibility, & you have to pay for the 'insurance coverage'. Hopefully someone will do it for an interesting professional challenge. ( and maybe a ride around the track!)

Steve
A&P IA DAR 38 years in the business

Last edited by thruthefence; 03-01-2009 at 06:47 PM. Reason: add information
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post #58 of 116 (permalink) Old 03-02-2009, 05:40 AM Thread Starter
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Hello Steve (aka thruthefence <-- great handle/moniker -- sets up the "Ask me how I know!" question ):

Thank you very much for your comments and the DER directory. I think I mentioned somewhere here that I was a U206F driver for many years. I sold the plane in June as it had become the rather uneconomical corporate bus between Calaveras County and the Bay Area -- Would love to build an RV-8 or some such as my "commute" vehicle!

The "scrim" material is fascinating! One contributor indicated that Lotus employs some method of dimpling on the mated surfaces to provide stand-offs so that there's "room" for the adhesive. In his restoration, he used a center punch around rivet holes used to prevent peeling of the reinforcement aluminum stock. The raised "crater rim" from the center punch provided a few thousandths offset in whose gap the adhesive would be allowed to spread evenly without metal-to-metal contact (aside from the center punche's raised protuberances.)

Thanks again to your contribution to this thread. Assuming that the chassis passes the "Murray Through-bore Chassis Assessment" described above (polished 3' 3/8" steel rod through lower-wishbone mounts to gauge trueness of same), I intend to proceed with the restoration myself. (If it doesn't pass, it becomes a significantly more challenging field repair and in the absence of unlimited engineering and financial resources, I will likely swallow hard and accept the insurance check for a total.)

Best,

John

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post #59 of 116 (permalink) Old 03-02-2009, 05:57 AM
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Originally Posted by Andy3drc View Post
with the ali being pickled and fully prepared before bonding.
Andy,

Thanks for the contribution. Can you provide more detail regarding surface prep? IMHO, it's one of the most important steps when bonding aluminum. West Systems sells a two part chemical that stabilizes the surface to prevent oxidization, is that similiar to your pickling process?

John

My car is modified.
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post #60 of 116 (permalink) Old 03-02-2009, 07:38 AM
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If you are not familiar with them, "Aircraft Spruce & Specialty" ( no financial interest, of course ) is a huge resource for adhesives, pre preg materials, fasteners, etc. ( by 'pre preg' I refer to materials that have been catalyzed & impregnated into the cloth under controlled conditions, and kept in a freezer until they are used.)

Proper cleaning is very important. Be sure & use the process & materials recommended by the adhesive manufacturer that you choose, to assure compatibility. Under all circumstances, observe the adhesive manufactures' recommendations as to temperature, humidity & 'pot life' when mixing & applying. Also, purchase a gram scale, as the adhesives are catalyzed by weight, and the ingredients must be accurately measured. Resist the temptation to "eyeball" the mix.

Be cautious in stiffening the structure too much in one area. It sometimes causes the loads to be transferred to another area entirely, where they will cause cracks ect where you don't expect. My point is, several layers of aluminum doublers, of descending length, properly riveted & bonded, may be better then one slab of .250" bolted onto those damaged areas.

Any engineering schools in your area? maybe get a structures guy who's interested in cars.

don't get in a hurry, & you will be ok.
steve

Last edited by thruthefence; 03-02-2009 at 11:15 AM. Reason: typo
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