Rustproofing new rear arms

[marinabrian]

Originally Posted by Blink

Thanks Brian - I ordered this in the end though, due to the faster delivery. It's probably pretty much the same stuff though.

It's not the same, but will be better than the original paint

[Blink]

Originally Posted by marinabrian

It's not the same, but will be better than the original paint

Anything will be better than the original paint.

Tbh, I can't see much/any difference between these two:

https://www.rustins.ltd/bonda/our-pr...da-rust-primer-
https://www.u-pol.com/uk/en-uk/produ...r#.XVAn-meB5RC

[marinabrian]

Originally Posted by Blink

Anything will be better than the original paint.

Tbh, I can't see much/any difference between these two:

https://www.rustins.ltd/bonda/our-pr...da-rust-primer-
https://www.u-pol.com/uk/en-uk/produ...r#.XVAn-meB5RC

The difference between the two is in performance, the Bonda primer cannot be scratched off when cured

I've used both paints in the past, and the Bonda primer is far superior in performance.

Brian

[Blink]

Originally Posted by marinabrian

The difference between the two is in performance, the Bonda primer cannot be scratched off when cured

I've used both paints in the past, and the Bonda primer is far superior in performance.

Brian

I was afraid you'd say that.

You used Bonda Primer on the arms - did you use it on the subframe too?

The U-POL Z182 I've bought was intended just as primer for the OSR jacking point. I was going to use POR-15 Rust Preventive Paint on the new subframe and arms straight after they've been sandblasted, then add two coats of POR15 Top Coat. Is that a bad idea? (See steps 3 & 4 here)

Next question is how did you get the paint onto the inside sections of the arms and subframe?

[marinabrian]

Originally Posted by Blink

I was afraid you'd say that.

You used Bonda Primer on the arms - did you use it on the subframe too?

The U-POL Z182 I've bought was intended just as primer for the OSR jacking point. I was going to use POR-15 Rust Preventive Paint on the new subframe and arms straight after they've been sandblasted, then add two coats of POR15 Top Coat. Is that a bad idea? (See steps 3 & 4 here)

Next question is how did you get the paint onto the inside sections of the arms and subframe?

In terms of the arms, I blanked off the holes, then swilled the paint inside after thinning it slightly.

The subframe was slightly more difficult....



..... and required the use of a fair few odd shaped brushes to achieve the desired coverage.

I painted first in Bonda primer, then grey anti rust paint (not primer, outdoor railing type paint) and then four coats of chassis black.

The differing colours were to ensure I covered every surface completely, and prior to the final fit, 1 litre of cavity wax sprayed inside the box sections with a shutz gun with lance extension, after allowing both to warm thoroughly in the sun to ensure maximum penetration into the internal seams through capillary action.

There are no shortcuts to doing the job properly, and the finished items should hopefully outlast the service life car they're fitted to.


Brian

[Blink]

Crikey, that's a lot of work Brian. It looks like it'll do the job though.

Good idea to swill paint around inside the upper arms - I think I'll do the same. Here's a reference pic of the arms for Chris (OP) - 3 holes to blank off. Note the scary face & horns on the one on the right.




The problem with the subframe is it has internal sections that can't be sandblasted and can't be reached with a paint brush either - i.e. most of the two long arms. I'm not even sure if swilling paint around inside them would work because of the sheer size of this thing.

Here's a pic of the underside (i.e. the side facing the road). The long arms have two vent holes on the topside but they're very small.




Then there's the question of what to do with the trailing arms. Again, they probably can't be sandblasted inside (?) - and swilling paint in there will be extremely tricky because those big holes in the tubular section probably can't be blanked of very effectively.




Hmm.

[Blink]

Originally Posted by marinabrian

...... The subframe was slightly more difficult....

..... and required the use of a fair few odd shaped brushes to achieve the desired coverage.

I painted first in Bonda primer, then grey anti rust paint (not primer, outdoor railing type paint) and then four coats of chassis black.

The differing colours were to ensure I covered every surface completely.....

Brian - this is my sandblasted subframe. It's since been painted on the outside. (I used POR-15 Metal Prep, followed by two coats of black POR-15 Rust Preventive Paint - see link). The problem is how to paint the insides of the long arm sections, arrowed red.

Paint can be poured in through the two larger holes marked 'P' but it'll run out of the points arrowed blue as soon as it's swilled about by tilting/twisting/turning the frame in all directions. None of these holes can be taped off effectively because they're all weird angles/shapes. Did you find a solution to this problem or did you not even try to paint inside the long arms?

[marinabrian]

Originally Posted by Blink

Brian - this is my sandblasted subframe. It's since been painted on the outside. (I used POR-15 Metal Prep, followed by two coats of black POR-15 Rust Preventive Paint - see link). The problem is how to paint the insides of the long arm sections, arrowed red.

Paint can be poured in through the two larger holes marked 'P' but it'll run out of the points arrowed blue as soon as it's swilled about by tilting/twisting/turning the frame in all directions. None of these holes can be taped off effectively because they're all weird angles/shapes. Did you find a solution to this problem or did you not even try to paint inside the long arms?

I didn't paint inside the long arms of the subframe, I lashed a full tin of cavity wax on through the "P" holes in the bottom though, turning and drooling the stuff about, as there is no way to paint inside that part effectively.

It can't be any worse than leaving things untreated however

Brian

[Blink]

Originally Posted by marinabrian

I didn't paint inside the long arms of the subframe, I lashed a full tin of cavity wax on through the "P" holes in the bottom though, turning and drooling the stuff about, as there is no way to paint inside that part effectively.

I'm coming to the same conclusion, there's no way to do it apart from dunking the whole caboodle into a massive bath of paint. About 30 gallons should do it - and a few hundred quid to buy the darned stuff. I think I'll just do what you did and unleash an entire can of wax through the P holes (Dynax S50).

PS. As far as I can see with my trusty torch, the factory didn't paint inside either.

[roverbarmy]

The 360 degree lances, supplied with some of the Bilt Hamner products work well when sprayed in through the holes. I did mine, left them to harden, then looked in with an LED endoscope and everything was coated, right into the nooks and crannies. I repeat the coatings each year, inside and out, prior to MOT.