bare metal or over old paint?

[FrankM83]

Hi i am about to start preparing my van for paint how do you recommend to prepare it? should I bring it back to bare metal or just a wipe down the old paint with sand paper will do it? Thanks

[Alec]

Hello Frank,

it depends on how good the old paint is, what type of paint and how many times it has been re-painted before. Also it depends on what sort of finish you are looking for, in other words, the difference between a knock about vehicle and a concours one, in which case a bare metal job is the way to go.

If the finish is sound and does not have an excessive paint thickness (re sprayed a couple of times) then I would flat back and paint over the old finish. You may need to use a barrier coat to prevent interaction between the new and the old paint, so seek advice from your paint supllier.

Alec

[chickenjohn]

I agree with Alec, only need to bare metal any rusty areas to get rid of the rust.

[FrankM83]

well the van is going to be sprayed by myself and it's going to be the first thing i ever sprayed in life hehe im hoping to get a good finish some told me to sand it down with wet n dry and then spray a coat of filler primer before giving the colour coat what do u think?

[Alec]

Hello Frank,

I suggest that you buy or borrow a book on spraying cars to give you a guide as to what needs doing. You will need to use something like 400 - 600 grit wet and dry before the primer and 800 to 1000, before the top coat. I would opt for the coarser options I quote myself but others have more patience than I.

The key to a good finish is to get the preparation right, this is about 80 to 90% of the work and is harder than you might think.

Alec

[jonathon]

If the paint is original, i.e cellulose then make sure that you do not use filler on top of it, you should cut back to bare metal to do this to avoid any sinkage. If you are using cellulose primer and top coat the also be prepared for sinkage on any filler repairs done under the top coat you have. This is mainly due to the high thinners content of a cellulose primer/topcoat which re activates previous repair work.
As Alex says its best to apply a barrier coat to avoid incompatability. Also always use the best possible quality paint. Use panel wipe to make sure that all nasties such as grease,oil, waxoyl, etc is removed then tack rag when this has been wiped off.
I'd apply 4 coats of primer, which would be guide coated and flatted back with 600 then 800, then spray on a gripper coat, (light dusting) for the susequent colour top coats, of which I'd build up around 4/5 good coats. This can if need be flatted with 2000 and mopped to a finish.

[bmcecosse]

The paint and thinners you will need for all these coats add up to several hundred £s !!
I also heard that celly will no longer be supplied after 2006 - anyone else heard that ?
You MUST NOT attempt to spray 2 pack paint without a proper fresh air breathing air supply - a simple 'dust' mask will not do. It a) coats your lungs with rapidly hardening 2 pack paint - and if you survive that then b) it will give you asthma !! Don't do it.

[jonathon]

Well, yes, no one said that painting was cheap if done properly. Obviously if you are on a budget then just paint where required or blow in with aerosols. You should be fully aware/informed as to the proceedure and cost of all aspects of work on the minor, before you start work.

[brixtonmorris]

dont bare metal ye ha!