Painting chassis repairs

[boyse7en]

I've had a bit of welding done on the inner and outer sills on my shed, and want to coat it with enough wearing paint to prevent a rusty recurrence.

Its bare metal at the moment, so i was planning on giving it a coat of rust convertor first to get rid of any micro rust, then Upol etch primer, a coat of regular primer and then a coat of smooth hammerite to give a tough finish. Then give the whole area a coat of waxoyl underseal.

That sound about right? or is there a better method/product to use. Bear in mind its an old Honda, not a concours Ferrari

[Belle427]

Hammerite isnt much good these days, i would just clean up and paint with something like rustoleum combicolour, no real need to prime with this paint.
Bilt hamber UB is also a much better product than Waxoyl, UC if you want a clear coating.
Some of the epoxy paints look very good but may be overkill.

[996Type]

POR 15 is very good and sets hard.
Once that’s done, spray with Dinitrol or similar.

POR 15 is best kept away for direct sun light but if it’s under the car it should be OK…

[DaveF-SkinnysAutos]

Is there any rust left at all? If so do all you can to remove as much as possible otherwise you are wasting your time with everything else.

Then if there is any trace of rust use a converter, I personally love Miparox, if you dont care about the finish get the emulsion and brush it on, it seals everything underneath.

I then use Gravitex which is easy to apply and again a great barrier on sills. Its over paintable so you can do what you want after to make it look prettier.

Try not to leave them bare metal for long, you are just attracting moisture, get some etch primer on if nothing else if you plan to leave them for any period of time to get some protection on them.

I wouldnt bother with normal primer, its not a moisture barrier, epoxy is but it sounds like your just looking for an easy fix for a daily runner from your question.

Edited by DaveF-SkinnysAutos on Wednesday 22 October 14:17

[boyse7en]

DaveF-SkinnysAutos said:

Is there any rust left at all? If so do all you can to remove as much as possible otherwise you are wasting your time with everything else.

Then if there is any trace of rust use a converter, I personally love Miparox, if you dont care about the finish get the emulsion and brush it on, it seals everything underneath.

I then use Gravitex which is easy to apply and again a great barrier on sills. Its over paintable so you can do what you want after to make it look prettier.

Try not to leave them bare metal for long, you are just attracting moisture, get some etch primer on if nothing else if you plan to leave them for any period of time to get some protection on them.

I wouldnt bother with normal primer, its not a moisture barrier, epoxy is but it sounds like your just looking for an easy fix for a daily runner from your question.

Edited by DaveF-SkinnysAutos on Wednesday 22 October 14:17

Thanks for the tips.
It was welded yesterday, so I'll get underneath and put a coat of etch primer on tomorrow, and i'll get some of the Gravitex for next week once the weather has dried out a bit. Does it have to be painted over, or can the Gravitex just be left as the top coat once sprayed on?

Yes, it's just an old Honda shed, so appearance isn't the major priority. I would just like it to last a couple more years while the kids are at college/uni and funds are a bit limited.

[DaveF-SkinnysAutos]

boyse7en said:

Thanks for the tips.
It was welded yesterday, so I'll get underneath and put a coat of etch primer on tomorrow, and i'll get some of the Gravitex for next week once the weather has dried out a bit. Does it have to be painted over, or can the Gravitex just be left as the top coat once sprayed on?

Yes, it's just an old Honda shed, so appearance isn't the major priority. I would just like it to last a couple more years while the kids are at college/uni and funds are a bit limited.

Gravitex comes in black, white or grey, there are other brands that do the same thing. If you have a small compressor you can spray it on with a general undersill cheap spray gun and then it comes out with the stone chip texture, if not you can pour it out into a pot and brush it on but obviously the finish then has the brush strokes in it. You can put another coat on top with a brush and sort of speckle it on if you want a better general texture but its very easy to spray if you do have the kit and gives a very easy DIY professional finish.

You can simply leave it if you want, but it is overpaintable, so if you are bothered you can put a rattle can of colour over the top if thats what you are after, depends how visible the welded parts are?

The most important part is getting something on the bare metal asap and not leaving any untreated rust underneath, or you are wasting your time as it will continue to rot under. If its clean, dry and rust free when you apply, you are sealing goods metal and onto a winner.