Thoughts on Installing Steel Flares, Epoxy or Weld? Options

[BigD9146gt]

My question is why you spent the money on steel to glue the things on? If this was fiberglass then sure... but thats your only choice. Ed hit the nail right on the head. Newer cars are epoxied... but keep in mind the main chassis is still welded. The outer panels do very little in the way of protection. Its like carbonfiber/kevlar. The strenght in chassis made of those components also have alot to do with the aluminum honey comb plates that give the chassis compression strenght. Door skins are epoxied on too, but still seamed-over around the corners to give them strenght to the door shell.

[IronHillRestorations]

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif)

As much as these car flex, I wouldn't even consider going the epoxy route if the car didn't have some good chassis stiffening, and I mean more than the GT plates.

[SpecialK]

Yep, epoxy is some tough stuff!

I was going to throw some "bonding tips/tricks" out there, but you guys pretty well got it. Only suggestion I can think of is using "scrim cloth" at the epoxy joint. It's a very lightweight fishnet stocking looking material that insures the correct amount of epoxy remains in the joint under clamping pressure.

Ospho, or Oxysol the area prior to bonding may help prevent any future corrosion problems.

And heat is the best way I've found for making a metal-to-metal joint throw in the towel (as suggested by several members), but if you're trying to undo a composite-to-metal bond (FG flares, etc..), be careful not to overheat the composite or it'll crystallize the matrix [insert Keanu Reeves smiley], and turn your composite part into compost.


I could give you the Mil-spec number, and process specification for bonding procedures..........but then I'd hafta kill ya!! (IMG:http://www.914world.com/bbs2/html/emoticons/ar15.gif)

(IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[IronHillRestorations]

Oh geez, I see Ed V. (a great body man with lots 'o' experience) has thrown the whole thread off, by ACTUALLY KNOWING WHAT HE'S TALKING ABOUT (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

[DuckRyder]

QUOTE (BigD9146gt @ Jan 31 2005, 10:09 PM)

... but keep in mind the main chassis is still welded. The outer panels do very little in the way of protection.

Cut the roof and or quarter panel off a "newer" car and run a crash/rollover test.

In fact, just cut the windshield out and run a rollover test.

Get back to me and tell me if you still believe that.

[SpecialK]

QUOTE (DuckRyder @ Jan 31 2005, 06:55 PM)

QUOTE (BigD9146gt @ Jan 31 2005, 10:09 PM) ... but keep in mind the main chassis is still welded. The outer panels do very little in the way of protection. Cut the roof and or quarter panel off a "newer" car and run a crash/rollover test. In fact, just cut the windshield out and run a rollover test. Get back to me and tell me if you still believe that.

(IMG:http://www.914world.com/bbs2/html/emoticons/huh.gif)

I must have missed something here...

[ppickerell]

Uh, Elise chassis are bonded, not welded.

[redshift]

Adhesive starvation at the joint would be catastrophic.

There are plenty of adhesives that have the shear strength, but flex enough to make balloons out of~!

I am glad this came up, an Kevin answered a question that I have always wondered, but never never asked, about the mesh for control of joint thickness.


M

[rick 918-S]

Controling the joint for the adhesive on a steel flare would be hit and miss. If your going to bond something to the car just use glas and save the cost of steel. I've used the adhesives on about a hundred door skins and other parts. I wouldn't even consider it on the continous curve of a flare. The body work would be extensive to blend the joint even using a panel crimper to step things in. If your shop isn't skilled enough to install the flares properly find another shop. Who would want the possibility of an open or weak joint on the back side of a panel and the gross over lap that would be required to use this method. Bad science I say. There is no short cut to the best results.

[SpecialK]

QUOTE (rick 918-S @ Jan 31 2005, 10:42 PM)

Controling the joint for the adhesive on a steel flare would be hit and miss. If your going to bond something to the car just use glas and save the cost of steel. I've used the adhesives on about a hundred door skins and other parts. I wouldn't even consider it on the continous curve of a flare. The body work would be extensive to blend the joint even using a panel crimper to step things in. If your shop isn't skilled enough to install the flares properly find another shop. Who would want the possibility of an open or weak joint on the back side of a panel and the gross over lap that would be required to use this method. Bad science I say. There is no short cut to the best results.

I can see your point of view on this Rick (metal-to-metal=weld it), but bonding with the correct epoxy and procedure nets one bad ass connection between metal parts (do it damn near every friggin' day....unfortunately (IMG:http://www.914world.com/bbs2/html/emoticons/headbang.gif)), I'd put it up against welding any day in a tension/fatigue test.

If the autobody guy knew WTF he was doing (metal prep, butter up both pieces, scrim cloth, etc..), and had the correct flanger (depth equal to the thickness of the flare metal), the "squeeze out" of the epoxy could actually be used to fare in the joggle in the from the flanger, the bondo required would be minimal.

We use "cleco's" at work during drill-outs to hold skins in place, or during bonding procedures (cleco's sprayed with mold release.......don't forget to spray the cleco's (IMG:http://www.914world.com/bbs2/html/emoticons/slap.gif) , ask me how I know (IMG:http://www.914world.com/bbs2/html/emoticons/alfred.gif) ), they exert approx. 20lbs. of pressure each, and spaced every two inches or so would be more than sufficient and even pressure to insure a warp-free installation for a metal flare.

If I was to ever install any kind of flares on one of my cars, I'd bond them on.......and you'd know why if you saw how good of a welder I am! (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)


clecos and pliers.......

[redshift]

QUOTE (Special_K @ Feb 1 2005, 04:23 AM)

the "squeeze out" of the epoxy could actually be used to fare in the joggle in the from the flanger, the bondo required would be minimal.

I work with glue as a primary tool... hehe... people break a buncha git-tars..

I am with you about using the squeeze-out for filling, I use files to bring dried glue to finish level, for invisible repairs to cracks all the time.

I just used a 5 minute epoxy I found at FLAPS to repair one of the guitars I gave to kids at Christmas. The break has a constant 230lbs of pressure *pulling* at it, it's straight across the neck, right at the end of the fingerboard. It's undetectable, as far as lines go, and a kid has been wailing on it for a month..

(IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

Ok, I am bored, can't sleep, and I think we know where I stand.. and no, I am not an Epoxificationist, nor do I lobby Congress for Big Epoxy.


M

[SpecialK]

QUOTE (redshift @ Feb 1 2005, 12:35 AM)

QUOTE (Special_K @ Feb 1 2005, 04:23 AM) the "squeeze out" of the epoxy could actually be used to fare in the joggle in the from the flanger, the bondo required would be minimal. I work with glue as a primary tool... hehe... people break a buncha git-tars.. I am with you about using the squeeze-out for filling, I use files to bring dried glue to finish level, for invisible repairs to cracks all the time. I just used a 5 minute epoxy I found at FLAPS to repair one of the guitars I gave to kids at Christmas. The break has a constant 230lbs of pressure *pulling* at it, it's straight across the neck, right at the end of the fingerboard. It's undetectable, as far as lines go, and a kid has been wailing on it for a month.. (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) Ok, I am bored, can't sleep, and I think we know where I stand.. and no, I am not an Epoxificationist, nor do I lobby Congress for Big Epoxy. M

(IMG:http://www.914world.com/bbs2/html/emoticons/lol2.gif)

That's right, I forgot, you're a "omni-adhesive frisbeetarian" (don't believe in one glue holding the universe together)! (IMG:http://www.914world.com/bbs2/html/emoticons/chairfall.gif)......... (IMG:http://www.914world.com/bbs2/html/emoticons/huh.gif) well, it sounded funny when my dog said it........now where I leave my doob at (IMG:http://www.914world.com/bbs2/html/emoticons/smoke.gif)

Same problem bro....just got off work, drank waaaay too much coffee, and don't have enough Becks in the fridge to counteract the caffeine.

[DuckRyder]

QUOTE (Special_K @ Feb 1 2005, 12:29 AM)

QUOTE (DuckRyder @ Jan 31 2005, 06:55 PM) QUOTE (BigD9146gt @ Jan 31 2005, 10:09 PM) ... but keep in mind the main chassis is still welded. The outer panels do very little in the way of protection. Cut the roof and or quarter panel off a "newer" car and run a crash/rollover test. In fact, just cut the windshield out and run a rollover test. Get back to me and tell me if you still believe that. (IMG:http://www.914world.com/bbs2/html/emoticons/huh.gif) I must have missed something here...

BigD914 said:

QUOTE

Newer cars are epoxied... but keep in mind the main chassis is still welded. The outer panels do very little in the way of protection.

That is just not true; nearly every panel on a newer car is a structural part. The only modern car that comes to mind for which it is true is some Saturn’s. Even the windshield is a structural part in most cases.

Nevertheless, that is getting off subject.

The opinions in this thread mirror the opinions in the Industry. Adhesives are gaining acceptance fast, particularly in the actual shops where they are found to be faster and just as strong and durable. Car manufacturers are reluctant to embrace them for welded panels, because no one that I am aware of has done any crash testing on bonded vs. welded panels, and exterior body panels without question contribute (significantly) to overall body shell stiffness.

None of that really matters for the flares. This is one of those cases where there is more than one "right" way. It is my personal feeling that there would be less bodywork in the majority of cases using the adhesive. If you really want them butt welded, find someone who has done quite a few of them. It is rarely a good plan to force a shop to do something in a manner contrary to what they believe is the best way. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

[BigD9146gt]

Robert,

Take it easy man! I'm not trying to start anything here, I'm working off my knowledge, and keep in mind that i was a autobody guy for a few years in a top-rated shop. (Granted i haven't been doing it for 20 years, but i've gone through college autobody classes, and during those two years, spent alot of extra time learning).

The purpose of my statement was that you CANNOT compare an Elise, Porsche Carrera GT, Ferrari composite chassis, etc etc with a common mass produced steel/aluminum cars with some adhesive panels.

Yes, the epoxies are becomming very good for bonding cars to gether, and will find its way into the industry more and more as time goes on. But also consider which cars they are on now... like you said, Satern. But check out the rollover stats on Saterns....

Yes, the front windsheild has structural strenght on all newer cars. What about the 914? 911? 356? VW bug? They are all rubber seals with the exception of the 914... which is glue that is not an epoxy. You can give me examples all day long, and so can I.

With regards to the roof... are we comparing a car with no roof to a car with an adhesive attached roof? (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif) If so, then sure, attaching the roof solidly makes sence (like the factory 9146GT cars. But doing a roll over with just regards to the roof isn't enough, taking into consideration how the rest of the roof is attached (ie A pillars, B pillars, material, thickness) has alot more to do with the overall equation. I guess i need more information from you before i can answer your question . Or was it just a retorical point with no purpose of having a meaningful conversation?

[DuckRyder]

I'm cool,

Sweeping generalites in either direction won't do anyone any good.

As for the roof, I'm saying that the metal roof panel gives the unit body stiffness in newer cars.

Perhaps we misunderstood each others statements, I wasn't attacking you I'm sorry if it sounds that way. I'm just saying that newer cars DO derive structural stiffness from the exterior sheet metal.

[rhaas]

any adhesive supplier that supplies to industry will be able to get you spacer beads at the proper thickness. this allows you to clamp the parts as tight as you can without having adhesive starvation. the adhesive thickness is determined by the size of the beads. these spacer beads are routinely used in composite shops. they ensure that there is a proper adhesive thickness.

[SpecialK]

QUOTE (DuckRyder @ Feb 1 2005, 10:42 AM)

As for the roof, I'm saying that the metal roof panel gives the unit body stiffness in newer cars. Perhaps we misunderstood each others statements, I wasn't attacking you I'm sorry if it sounds that way. I'm just saying that newer cars DO derive structural stiffness from the exterior sheet metal.

Absolutely....that's probably why the targa tops squeek when you drive down the road (chassis flex), and why the 916 had a non-removable steel top.

And I totally agree with the statement that the exterior sheetmetal (excluding the trunk lids and doors) add to the overall stiffeness of the vehicle in a unibody design, they all carry some load, but it would take a good model and some serious software to know to what extent.

Exact same reason I was questioning the conventional wisedom of venting V8 front mounted radiators via large holes cut into the inner fender wells, and subsequently decided if I ever did a water-cooled conversion in the future, it's getting vented out through the trunk lid.

[The views expressed by Special_K do not necessarily represent the views of the 914world.com, or any of it's affiliates. Any logical representations of structural integraties are purely coincidental..........or wild-ass guesses] (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[bperry]

So a question from the audience.....

With all these amazing epoxies, why wouldn't more people
glue in their replacement battery trays and support?
(Assuming surrounding metal is good, which may not be the case)

Sure sounds tempting.

--- bill

[DuckRyder]

bperry

I just haven't gotten around to it yet... (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[BigD9146gt]

bperry, there is nothing stopping anyone from doing that, its a good idea. I think most weld it in because you first have to clean the metal prior to welding (as you would to epoxy it in) and because the car was orignially welded, folks like to stay with what worked then, works now. Either way, its the finish work to keep rust out thats the most important factor.

Duck, a bit off topic, but what year is/was your 323??? I have an '82 thats my next project!. I've gathered most the parts for the 2.7L 325 motronic motor... but will keep the stock 2.3 (the previous owner completely dissasembled the metering head (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif) , its alittle leaky to say the least). And it came wtih some 16" Alpina rims for it too!