Structural Adhesive

[68EFIvert]

I am looking for more ways to streangthen my unibody. I have subframe connectors, just made a Y brace to tie the SFC to the convertible brace on the bottom of the car. I am also planning on bonding some sheetmetal that would connect a flance where the fender meets the area in front of the trunk to the wheel house flange. Does anyone have a reccomendation for a structural adheshive that will do this. It needs to be able to be applied with a normal caulking gun or brushed on. I don't want to spend $50-100 on a gun to put on 4 strips of 8" of material. Thanks!

 

[RyanG85]

I'm having a hard time picturing what youre trying to do...

My local paint/parts store that sells the adhesive will loan the gun out. If you have a decent relationship with your supplier, check with them.

 

[Horseplay]

Take a good read through this one. http://www.sn65.com/Chassis%20Design%20101.htm It will give you some good idea as to where you can gain the most in chassis design. The main problem you are facing right now, as I see it, is that you are dealing with a chassis in a single plane. You can cross-brace all you want but with enough torque your frame will still be able to twist fairly easily. You should really consider putting in a real hoop and some diagonal bracing to get the results you are after.
I don't think glueing in some sheet metal is really going to get you there.

 

[68EFIvert]

I agree it won't be the end all of reinforcements but I figure for $50 it can't hurt. It does help to tie in a vertical support. My plan is to use a piece of sheet metal, maybe even up to 1/8" steel plate that is about 10-12" long. I was starting to get stress cracks on the seam between the quarter panel and the area at the base of the top at the corner of the trunk. I figure if I make that point a little more "solid" if won't flex as much. I will take a look at that link to see what else can be done. If someone else has a way to strengthen a convertible please let me know.

I also agree the right way to go would be to install a 4 pt bar in the car but I refuse to do that. I think they are unsightly in a convertible and can be a hazard to my kids in the back.

 

[RyanG85]

There is no doubt that the structural adhesive is strong but I would feel much better with a weld in an area that has twist or flex.

 

[PJ Moran]

I was starting to get stress cracks on the seam between the quarter panel and the area at the base of the top at the corner of the trunk. I figure if I make that point a little more "solid" if won't flex as much. I will take a look at that link to see what else can be done. If someone else has a way to strengthen a convertible please let me know.

I have the same problem. I don't know to what extent it's convertible-specific, though. It might be.

That joint is a lap joint up under the boot trim. It's also a lap joint inside the trunk drain channel. But, along that visible seam, it's a butt joint of sorts. It apparently is trying to open and close some.

If I had known then what I know now, I would have welded those seams and smoothed them over. No cracks, then.

As for a retrofit to help - don't have much for ya. Anything that clamps those two pieces together as close to the skin as possible will help.

I can tell you that your supplier for the adhesive should have a loaner gun, too. If not, find another supplier. I got Norton SpeedGrip at NAPA and he loaned me his gun several times.

 

[gotstang]

I used Lord Aircraft-grade structural adhesive (Lord #410?). The adapter for a conventional caulk gun was another ~$5. Cost me ~$65 for 4 tubes and the adapter IIRC. The bucket seats I used it on are still solidly mounted after 2 years and ~40k miles. I had to order it from a commercial adhesives co. in Columbus, OH, but it worked great.

If you're interested, I can check the invoice and see what exactly it was that I used.

 

[daveSanborn]

Darreld,

Sorry bud, you're wasting your time. As previously mentioned your main roll bar hoop needs diagonal bracing.

There is an alternative, but it ain't going to be easy..... but think about it.... what has been easy?

Instead of installing diagonal bracing on your "looks too pretty" main hoop... and I agree that it would not only look like crap on your car it would definitely be a no-no with kids in the back seat.... install ANOTHER hoop, but hide it inside the trunk. I'm unsure how much room you have with your vert, but you should be able to design/install a cross-braced (diagonally) hoop that solidly mounts to both rear frame rails.... approx. even with the forward edge of the fuel tank... that extends upward forming a "hoop" directly under the forward lip of the deck lid. Once the hoop is installed it could be cross braced. This would GREATLY limit torsional twist at the rear of the car and probably eliminate the stress cracks that you're encountering. With the deck lid closed you'd never see it.

500 RWHP in a 'vert.... :wor

What it takes to actually use that HP/TQ and not have your car twist like a pretzel..... :headac

 

[68EFIvert]

That is actually a pretty good idea Dave. I'll have to figure out how to get a little more junk in my trunk. Pretty cramped back there but I may have to make some sacrifices. I wonder if I could fit a bar near the well liner of my top area? Here is a picture of the space limitations in my trunk. Like everything on this car it could be done but what else would I have to modify?

 

[Tony R]

If you want another set of eyes and another perspective let me know I would gladly come over to see what we could come up with. The battle axe(MOM) gets evicted tomorrow and moves in with us tomorrow :sad so ANY night works for me.

 

[68EFIvert]

That may be kind of nice Tony. Come on over. Are you still game to go to the PDX roadster show this weekend? If so What day will work best. Saturday is a little difficult for me. I have a soccer game at noon and the wife and I might go out with a neighbor that is moving that evening. Kind of leave tomorrow night or Sunday some time.