Sika 227

[Tins]

I’m in the process of doing some bodywork on the OKA. The panels are basically 2mm sheet over a rhs frame. Originally they were spot welded and sealed with something like bathroom caulk I don’t want that and I would like to do away with the welds. There are of course a gazillion products that claim to be good for this. Someone suggested 227. Anyone have any experience?

[TonyC]

Ring the Sika tech line, I've found them very helpful, they will have something.

Tony

[p38arover]

Anyone have any experience?

Wear gloves. It's a bugger to get off one's hands.

[V8Ian]

Wear gloves. It's a bugger to get off one's hands.
Both, I'd imagine. [bigwhistle]

[prelude]

Anecdotally I know sika to be fairly good stuff but I can't recall the number :( the 227 seems to be more of a sealant than an adhesive though and reading through the product sheet I do not believe it is the best fit for your application.

For my own (4x4) camper I was provided with TEROSON MS 939. I reckon that the panels or aluminium will give way before the adhesive does. 3M also has something similar, a panel bonding adhesive. IIRC a car was once built with just adhesive in stead of spot welds and it turned out the be stronger in the end :)

Cheers,
-P

[oka374]

John there aren't too many spot welds most of them were just stuck on with a Sika like product. The ones I've repaired and removed all were just stuck.
Some of the cab ones I suspect are spotted but most of the big side panels on the bus are just stuck.
I've used Sika IIFC for most of my repairs and attaching solar panel mounts to the roof etc, they've (solar panels) not moved in 15 years.
For advice on specific panels Ian Jones might be able to assist as he supplies and repairs all of them.

[Lionelgee]

Hello Tins,

Take a visit to Sika's website. It should provide you with enough resources to be able to contact their help centre and ask some precise questions. Accessed 29th June 2025 from Vehicle Assembly Bonding, Body Panel and Structural Adhesives (https://aus.sika.com/en/industry/transportation/body-panel-adhesive.html)

Kind regards
Lionel

[Tins]

John there aren't too many spot welds most of them were just stuck on with a Sika like product..

Mine are lifting, especially behind the coffin panel, so probably NOT Sika like......[bigwhistle] I'm a little concerned that the unpainted RHS behind them won't be in great shape.

[prelude]

if the RHS is rusted, that won't hold so it might be that the adhesive worked well and is still sticking, but only to a bunch of rust that has let go from it's donor :)

-P

[oka374]

John when we bought 374 the oonly obvious rust was the passengers side coffin panel at the very top and the RHS frame rust had pushed out the sheet about 6mm.
i used a hacksaw blade down between the RHS and the sheet and kept cutting and "filing until the panel would go back into it's correct position. Then sucked lots of crap out with a small hose on the vac and then lots of sir into the gap to remove any remaining dust.
Then used a tube on the sika to force it down into the gap and then let the panel come back into place with lots of sika around the edges to seal it.
Then I dug out every roof seam and redid them all with sika then painted it. Didn't have any more leaks.
I also sika'd the roof rack mounting bolts and the sunvisor central mounts as well as resealing the windscreen with correct mastic sealant as i figured if the water couldn't get in then it would hold off the rust.
Lots of fishoil every few years also helps

[Lionelgee]

John when we bought 374 the oonly obvious rust was the passengers side coffin panel at the very top and the RHS frame rust had pushed out the sheet about 6mm.
s

Hello OKA374,

You got me ... what is a coffin panel on a motor vehicle? A photograph would be good.

Kind regards
Lionel

[V8Ian]

In the 80s, semi-trailer manufacturer Freighter were using double sided tape to attach the roof sheets to vans. The sheets were 4' wide with two side by side to cover the 8'2½" van. The remaining 2½" being side and central SHS, this required careful alignment of the sheets. The first time this new method was employed, the first sheet was taped flush with edge of the trailer and the second butted up to it, resulting in the second sheet not quite meeting the SHS. Attempted realignment of the sheets resulted in destruction of the sheets.
So John, perhaps 3M have a suitable sticky tape for your application.

[V8Ian]

Hello OKA374,

You got me ... what is a coffin panel on a motor vehicle? A photograph would be good.

Kind regards
Lionel
Assuming it's the engine cover between the seats.

[Tins]

Hello OKA374,

You got me ... what is a coffin panel on a motor vehicle? A photograph would be good.

Kind regards
Lionel

This bit, behind the door and in front of the rear body. So called due to its shape, apparently.

193971

[Tins]

if the RHS is rusted, that won't hold so it might be that the adhesive worked well and is still sticking, but only to a bunch of rust that has let go from it's donor :)

-P

That's what I'm worried about.

[Tins]

So John, perhaps 3M have a suitable sticky tape for your application.

I would consider that for the roof, but the side panes have no access from behind ( Well, I'm to lazy to pull out all the boards inside ) so a panel bond of some description would be preferred. I am hoping not to have to remove the entire sides, and do it like Peter did. It's going to depend on what I find I guess. Windows have to come out, that's certain.

Not mine, thankfully, but it will give you some idea.

193972193973193974193975

I didn't get pics of the sections that I'm doing, because some muppet has covered the bottom panels of this one with about a ton of steel checker plate and then taken it to French Island. The bloke doing this job point blank refuses to take the stuff off, as it's probably the only thing holding it together.

[cjc_td5]

An OKA is like a series landy. Everything can be fixed with RIVETS! [bigsmile]

Chris

[Tins]

They do say that an OKA is for when you grow out of Defenders.

[oka374]

There would normally be hardly any pop rivets in an Oka from the factory, most of the skins are stuck on with a sika type product and do take some removing.
The biggest problem was that they never did ANY corrosion proofing during or after assembly. Little or no prep before painting either.
All that steel checker plate would make it much heavier than it should be but as your repairer says it might be holding it all together.

[Tins]

There would normally be hardly any pop rivets in an Oka from the factory, most of the skins are stuck on with a sika type product and do take some removing.
The biggest problem was that they never did ANY corrosion proofing during or after assembly. Little or no prep before painting either.
All that steel checker plate would make it much heavier than it should be but as your repairer says it might be holding it all together.

That one is a terrible car, condition wise, and I hate to think what the checker plate is covering up. As for the weight, that one is in bus configuration, seats and all. Mine, which has a similar but not the same body has a GVM of 4995. ( I weighed it once. Full tanks, fuel and water, food and me. 4990. People tell me I should get a dog.... Are Chihuahuas cheap? ). That thing would be very heavy, but I guess VicRoads don't visit French Island often.

And yes, OKA back then believed the blue stuff on RHS would prevent corrosion.....

[oka374]

they did use Duragal (or similar) for most sections but they never treated any welds or exposed ends before assembly.
I cut into the large box section on the lower inside of the bus/van body 15 years ago when turning mine into a camper and you could still see the white powder created when welding gal coated sections so no enclosed sections were ever treated for rust prevention.