Frame powdercoat/maintenance

[dazee]

Hi,

you guys are gona get sick of me with all my questions

So now I have the car up on ramps and axle stands and in for what is probably going to be a long hall in fixing this car up just right for me. Now I know the frame is in pretty good condition, probably due to the fact they don't salt the roads much here. But while I have been crawling around the car to start pulling the exhaust to pieces to hunt down that heating issue, I've seen a couple of areas of concern that I want to address. Not rust, but looks to be some heat blisters and general cracking of the powder coating.

Here is the passenger side suspension arm just under where the exhaust was melting that electrical shroud.


and here is the frame just below that.


Have had a look through the forums but generally only see fully body off frame restores and powder coating. I don't think that is a realistic option for me with the local resources and honestly think considering the overall condition of the frame this would be a waste of money better spent elsewhere on the car.

No issues with removing the parts like the suspension arm and getting them redone, but what options are there for fixing that frame beam before it begins to rust?

As a fyi both precats are shot so will be taking the manifolds off and cleaning them out properly.



Had a peek at the cat in the Y piece and this looks to be ok, but rather suspect debris from the precats is stuck in there and reducing the airflow.

[Richard 858]

Hi Darren, I would suggest removing wishbones (suspension arms) & get shot blasted, zinc primed & painted rather than re-powder coating. The reasoning is that a) well applied paint is easier to touch up in the future than powder coating & b) the bushes will have to be removed for powder coating (but not for painting), which unless they're the poly type are a pain in the arse to do, unless you want to change them anyway.

Regarding the chassis (frame) I would rub the bare areas down as much as possible and apply a suitable paint such as POR 15 or Hammerite (the latter may not be what it once was, but in your environment I'm pretty sure it will suffice)2 coats will do the trick.

I removed my pre-cats with the manifolds in situ and I'm not the most skilled, so if you'd rather not bother with removing the manifolds drop me a line for some tips.

In any case good luck with your project and I'm sure everyone on here will help where they can.

[Chuffmeister]

I'm no expert on catalytic converters, but I would imagine a genuinely damaged cat would be covered in deposits and be much darker. Those pre-cats looks as if somebody has made an attempt to remove them and given up half way through. Theres no scoring, soot or other deposits. Definitely work removing them asap!

[dazee]

Thanks Richard, that makes good sense and can be something I can do myself. Am going to be pulling a lot of stuff off and replacing anything that looks perished or worn or there are improved parts available. Definitely suspension and brakes will get upgraded once I do my research and make a shopping list.

Will be removing the manifolds to remove the precats as I want to see what other possible trouble spots I have. I notice a couple of oily areas so am going to clean it all up and look for leaks too.

I personally don't think anyone tried removing them before but could be wrong. When the coil failed and the car was towed home it is from that point I had issues with the over heating. When the new coil was fitted and I started the car up in the garage I did initially have a lot of catalytic type material blown out the back and should have checked on that further then...

[Richard 858]

Darren, if it's any use I've done a front brake upgrade and am working on rears at the moment, so if I can be of any help I'd be glad to. I haven't necessarily gone down the cheapest (and certainly not the more expensive) route but have stuck to assemblies designed specifically for the application (albeit with brackets) rather than adapting other, less costly alternatives. I have nothing against that process but I like the peace of mind of not drilling out & re-tapping fittings to make things fit but rather use components designed to fit the existing hubs etc, this does of course depend on individual budgets and I'm certainly no expert.

As a PHer of 12 months I now await the torrent of critical but helpful responses !!!!!!!!!

[jojackson4]

I'll have a list of your brake up grades

[EGB]

I don't trust powder coating. The TVR stuff cracks and flakes. New outriggers should be galvanized at least. No more worries, hope.

[portzi]

EGB said:

I don't trust powder coating. The TVR stuff cracks and flakes. New outriggers should be galvanized at least. No more worries, hope.

Powder coating is fine if the metal is preped correctly before treatment. TVR in their hay day of manufacture which was the late 90's were powder coating chassis in house, and unfortunately a lot of it was done over rusting steel frames left outside!!!!. There is a P'her on here who has a powder coating business, and although he will be biast to his industry, commented that he was hitting powder coated chassis's with hammers , with no cracking or chipping occurring!!

Mark

[Sardonicus]

Chuffmeister said:

I'm no expert on catalytic converters, but I would imagine a genuinely damaged cat would be covered in deposits and be much darker. Those pre-cats looks as if somebody has made an attempt to remove them and given up half way through. Theres no scoring, soot or other deposits. Definitely work removing them asap!

Seconded a right moody attempt

[Richard 858]

jojackson4 said:

I'll have a list of your brake up grades

Details & pics to follow in due course, on a new topic.

[Richard 858]

Sardonicus said:

Seconded a right moody attempt

Thirded, obviously didn't have 4 or 5 hours to spare !!!

[Chuffmeister]

dazee said:

I personally don't think anyone tried removing them before but could be wrong. When the coil failed and the car was towed home it is from that point I had issues with the over heating. When the new coil was fitted and I started the car up in the garage I did initially have a lot of catalytic type material blown out the back and should have checked on that further then...

Here's a shot of a well 'used' and sooted main cat (not from my original Y-piece).


Here's a shot of fully operational pre cat, followed by one of them half way through removal!

[venusdimilo]

Hi Darren

I own a year 2000 Chimaera and I have done my chassis and suspension as I think you want to do. I am lucky enough to have a pit in my garage and so I realise this does make things a lot easier. I used "Stripit" paint and varnish remover to soften bad powder coating and then scraping to remove any loose coating. When rinsed off and cleaned up it is easy to sand the rough edges from the bare metal and sound coating. I then treated any bare metal with Kurust which turns any surface rusted metal to sound metal. I then applied two coats of etching primer followed by two coats of synthetic chassis paint mixed by a local paint shop supplier. Its been two years and all seems well. We had run out to with our club TVRCC Hampshire to Furnherst's last year for an open day and they asked when I had had the new chassis done?? So that was a bit of a result.




Hope this is of some use.

Steve

[Pupp]

When I did the first side of mine, an Aussie neighbour appeared with some tinnies and thought it looked so much fun he dived in with a selection of picks, drills and other picky drilly things while I removed the opposite manifold. He finished (and finished coughing ) just as I got the second one off to find.... no cat

[Chuffmeister]

EGB said:

I don't trust powder coating. The TVR stuff cracks and flakes. New outriggers should be galvanized at least. No more worries, hope.

Have you had yours Galved? This is something I have been looking into as the body off is also high on my priority list (once I have space/ weather recedes). I have read some stories about potential warping from hot-dipping of the entire chassis, but no actual first-hand accounts. I was considering hot-dip galving a new set of outriggers before having them welded on and then perhaps cold galving the chassis and then painting the lot… or even hot spray galvanising!!!??? It's so bloody confusing, as you then have to choose the correct paint to adhere to the galv. Eitherway, its the outriggers I was more concerned about.

Edited to say:

I found this: http://www.pistonheads.com/gassing/topic.asp?h=28&...

Edited by Chuffmeister on Monday 13th January 21:00

[fatboychim]

Richard 858 said:

I have nothing against that process but I like the peace of mind of not drilling out & re-tapping fittings to make things fit but rather use components designed to fit the existing hubs etc,

No need to re-tap with the Cossie conversion Richard, the threaded part is in the caliper bracket, you just drill the uprights to pass the bigger caliper bolts through.

[ChimpOnGas]

Chuffmeister said:

Have you had yours Galved? This is something I have been looking into as the body off is also high on my priority list (once I have space/ weather recedes). I have read some stories about potential warping from hot-dipping of the entire chassis, but no actual first-hand accounts. I was considering hot-dip galving a new set of outriggers before having them welded on and then perhaps cold galving the chassis and then painting the lot… or even hot spray galvanising!!!??? It's so bloody confusing, as you then have to choose the correct paint to adhere to the galv. Eitherway, its the outriggers I was more concerned about.

Hot dip galvanizing is always going to give you the best protection, as it's a complete zinc coating both inside & out.

While its definitely proven best in class protection, hot dipping is not without it's issues especially on less substantial structures.

I wouldn't be too worried about warping but as the TVR chassis is tubular you do have to drill vent holes to let the hot gasses escape, and the heat involved in hot dipping (around 450°C) could easily be enough to anneal the steel.

Holes and a softened annealed chassis has to add up to less rigidity, then there's hydrogen embrittlement that's a known issue when hot dip galvanizing.

In terms of corrosion protection thermal sprayed zinc runs hot dip galvanizing a very close second with none of the disadvantages.

Personally I think sprayed zinc is much better suited to protecting the relatively light gauge tubular steel structure of a TVR chassis, on the other hand if I was protecting a Land Rover chassis I wouldn't think twice about choosing a proper hot dip.

In either case painting needn't present an issue, all you do is pacify the zinc with a mordant solution like T Wash.

An etch prime followed by an epoxy mastic two component paint is best, in my experience any two pack paint will be far better than the best powder coat job but the more flexible & abrasion resistant epoxy mastic paints are better still.

Powder coating gives a very good looking complete finish for a far more reasonable cost than painting, its also fast & relatively clean to apply which is why it gets uses a lot.

Unlike an etch prime & paint system that bonds chemically to the substrate, powder coating is in effect a wrapping that relies on the complete integrity of 100% of the finished surface coating.

Once you chip it the finish is compromised so you better address it fast before humidity creeps under the coating by capillary action or you'll be chasing blisters and cracks all your life only to discover its a losing battle as sheets of the stuff start to peel away.

And it will chip.

When I do mine it'll get:

1) Media blast

2) New steel where needed

3) Second media blast

4) Immediate zinc thermal spray

5) Mordant solution

6) Etch prime

7) Epoxy mastic paint in silver/grey (2-3 coats of)

Job done & a good 30 years before you need to look at it again, more if you touch up any marks in the finish with a brush (using the same epoxy mastic) every 5 years or so.

Although epoxy mastic is so tough, flexible & long lasting its likely this type of maintenance will be largely unnecessary.

On the other hand if I was selling the car & wanted to do a faster job for less money that looked great for the first few years I'd powder coat it, then let the new owner find out what powder coating looks like after 5-10 years of proper use.

Edited by ChimpOnGas on Wednesday 15th January 08:00

[Chuffmeister]

Excellent information Dave… as always!

So, it is possible to do a quick hot dip of the outriggers… get them fitted and then hot spray the rest before the epoxy mastic. I guess that way, the more prone areas get the best treatment without affecting the integrity of the main chassis.

Edited by Chuffmeister on Monday 13th January 22:29

[dazee]

You guys rock! The time difference sucks for interaction but is so cool for me to post a question and have a wealth of information to read the following morning when I log back in.

Will give this all a thorough reading today and digest. May have some more questions later

Later on I will start a journal on my website of my progress while working though the car. I confess it is not to just record the progress, but also a place to keep detailed pictures of what I am doing so I know where everything goes back on the car after I've had to remove it. Hoping not to have a bucket of "spares" left after it is done!

[ChimpOnGas]

Chuffmeister said:

So, it is possible to do a quick hot dip of the outriggers… get them fitted and then hot spray the rest before the epoxy mastic. I guess that way, the more prone areas get the best treatment without affecting the integrity of the main chassis?

I guess so, but be warned welding galvanized steel is a truly horrid experience, it spits & spatters and you often end with poor welds.

And that's before you've suffered the lovely effects of the fumes welding galve gives off, you really need an external air fed mask although a guy I worked with spent six weeks doing it without.

He was given a pint of milk to line his stomach and was only permitted to weld in 20 minute sessions with long milk breaks in between.

But that was back in the 70's when men were men and health & safety didn't really exist as we know & love it today, mind you people did die of asbestos inhalation, lead poisoning, and other such niceties.

Apparently they paid my mate double time because no body else would do the job for less and the extra money helped him buy his first house, but he told me he'd never do it again and strongly warned me against ever welding galvanised steel.

And he was as hard as nails, for Steve to say all that.... it had to be a bad experience.

Mind you hot dipping the outrigger sections then grinding the weld areas back to bare steel with a flap disc is a good idea, the bare welded areas could then be thermally sprayed when the rest of the chassis was being done.

The first thing you should know about zinc thermal spray coatings is that they're porous, this actually has pros & cons, the benefit being is it'll take an etch & paint system far better than a hot dipped galvanized surface.

The second thing to understand is thermally spayed coatings will peel if they are not applied correctly, the substrate must be pepped properly for it to adhere correctly, and that means a very thorough & course grade grit blasting.

Both hot dip galvanisation & thermally sprayed zinc finishes can be painted effectively, but you must pacify the surface with a mordant solution or whatever top coat you use will flake & peel off.

Zinc thermal spray coated mild steel is corrosion rated at 17-22 years with no further top coating, compare that with 50 years if you hot dip.

But etch prime & epoxy mastic the thermally zinc sprayed mild steel and your looking at a good 40 years of protection, possibly a damn sight longer too.

Do you really need your chassis to last more than 40 years?

To answer that question ask yourself how old you'll be in 40 years, and whether you'll still be driving your TVR then?