When building a new chassis, what do you guys use to bond the alu panels to the chassis and what spacing do you place the rivets to make it as stiff as possible?

I was thinking windscreen bonding and 2" gap between rivets, what do you reckon?

Rob

Tigerseal is the usual stuff people use (this is a hugh strength PU adhesive - basically exactly the same stuff as windscreen adhesive AFAIK!).

As for rivet spacing, I think it varies on your approach. I thought of the rivets as a backup to the adhesive, so I went for a spacing of about 75-100mm on my side panels (less on the floor), or less where the shape etc made sense to make the spacing smaller. Some people go to less than 25mm between rivets, but I am not sure you would gain much in stiffness in doing so if you have a well bonded joint as well.

50mm centres

I thought the rule of thumb was 10 times rivet diameter - any more and you are drilling too many holes in the chassis and weakening it that way.
Regards
Hugh

Sylva build manual recommends 4mm rivets on 40mm spacing on the floor panel, (50mm on side panels) + Tiger seal (PU)
That would equate to 10 times diameter.

I use this on a daily basis, just use a structural rivet on each corner to prevent shear

I have a question on bonding the floor panel to the chassis if I may.

If the chassis is powder coated, is the bond between the powder coat and the chassis stronger or weaker then the bond of the sikaflex, what about a painted chassis?

I know that the PU sticks like good stuff to a blanket but not normally seen people using it direct to steel which is what I would have thought is the best way? I have used Sikaflex on the aluminium side panel's of the car and only resorted to rivets top and bottom and not all over the sides as I think it looks better that way. Doubt if you could get away with it on the floor.

Cheers

Adrian

quote:

---

Originally posted by Mark Allanson
I use this on a daily basis, just use a structural rivet on each corner to prevent shear [/quote

Any where in the UK sell this? Looks to be USA only online

---

Mark Allanson - 8/11/12 at 08:06 PM

Every bodyshop and paint factors in the country will stock it, You should be paying around £35.00+vat, and if you speak to them nicely, they may lend you a gun. the nozzles are non reuseable and are about £1.50 each. 3M8115 from memory

---

Rob55 - 8/11/12 at 08:31 PM

Ok cool, last question how many tubes roughly would I need for the floor, sides and rear bulkhead?

---

Mark Allanson - 8/11/12 at 08:37 PM

I would only use it for the floor, bit of overkill on the sides and bulkhead, I would guess the 2 tubes would do it.

---

FuryRebuild - 9/11/12 at 08:15 AM

Has anyone gone for expoxy? My plan was to bond that way to get something truly structural.

If you're riveting only you want cherry or Advil rivets. Soft ally rivets don't give a structural clamping force. If you can put tthe rivet in with a hand-riveter then it's not a structural rivet.

---

mcerd1 - 9/11/12 at 12:19 PM

quote:

---

Originally posted by AdrianHIf the chassis is powder coated, is the bond between the powder coat and the chassis stronger or weaker then the bond of the sikaflex, what about a painted chassis?

I know that the PU sticks like good stuff to a blanket but not normally seen people using it direct to steel which is what I would have thought is the best way?

---

standard practice on a dax rush

take that side of the tube down to bare metal, leave it a bit rough (course emery tape?) to get a good key and key the edge of the alloy sheet too (just the bits that will be covered in PU)

thats aswell as using rivits at a fairly close centres (depending on the rivet size, some parts of the chassis use bigger rivets than others)


re: epoxy, wouldn't that be too brittle ?
don't underestimate the strength of decent PU

[Edited on 9/11/2012 by mcerd1]

---

Rob55 - 11/11/12 at 10:08 AM

Well nowhere near me seems to have even heard of 3M panel bond, best they can offer is Tiger Seal or Sikaflex.

I know the local Autoglass man so he has agreed to come out and bond the panels for me using their bonding and primer, he reckons with the primer it will never move.

---

Mark Allanson - 11/11/12 at 10:12 AM

Ring any of these and ask where they get theirs

---

umgrybab - 29/11/12 at 11:41 PM

I would be confident using any structural adhesive given it shows signs of having a high sheers strength and good metal bonding characteristics. I used to use Loctite 9430 for bonding aluminium, and if you want a super strong bond, etch the ali with some acid for a minute first.

---

PSpirine - 29/11/12 at 11:46 PM

Sikaflex is used to bond glass by OEM's. It does come in different flavours, but they all stick pretty damn well.

---

Rob55 - 30/11/12 at 12:11 AM

In the end I got them bonded by a mate in Autoglass. First stage was the primer and then the bonding applied using their electric gun.

Ain't going nowhere now!

---

loggyboy - 30/11/12 at 09:09 AM

I went for Sikaflex ETB as it was easy to get from Screwfix.

Circa 50-60mm centres on most runs. 25mm on crossmember under floor panel.





Not forgetting waxoly down the holes:

---