Frequently Asked Questions. A Quality Guide.
Isn't modern two pack paint better than cellulose? Why then do you use cellulose still?
There are a number of answers to this. Firstly it depends on what is meant by "better". In terms of flexibility and moisture resistance, it is better. However, if shine characteristics are considered, then for classic cars it is far too shiny and does not look right. Look at a quality finish in cellulose and it looks far better on a period car, as it is original. Why be fastidious in originality in all respects other than the paint? That is not logical!
Moisture resistance issues can be negated by using two pack primer as a base, with cellulose top coats.
Cellulose is far more forgiving than two pack. It is easy to repair blemishes and damage, by touching in and blowing in, followed by flatting and polishing. While people will tell you that you can do this with two pack too, and it is done, in practice you can always tell, it does not look good, and is bad practice. It is almost impossible to blow in a two pack finish. It is also really a "from the gun" finish, and no other reworking should be undertaken. As a comparison, try flatting and polishing your shiny black plastic television surround. It won't look the same! It is therefore much harder to obtain a blemish free finish. Cutting out dust and dirt and re polishing will degrade the original shine, which is too shiny anyway for a classic.
Cellulose doesn't need any special booth provision as all blemishes can be reworked until they disappear completely, and the finish restorable and is easy to blow in and polish.
One of the great things about classic and vintage cars is their longevity and repairability and maintainability. Cellulose finish is right up there in the maintainability stakes. It is number one for its ability to be repaired and reworked. You can fill scratches and stone chips so that they are invisible, and blow in damage repaired sections so that you would never know that there was a repair. You can do none of this with two pack. Orange peel finish is the preserve of two pack. With cellulose if a sprayer is unlucky enough to end up with any, he can flat it out. Not with two pack for the reasons already given.
What about awkward box sections, brackets etc. and compound curved panels which need renewing?
Bought pattern parts are very often very expensive and do not fit without considerable work. We have the facility to produce repair panels on site, by hand, tailor made to any pattern supplied, with compound curves and flanges where required, and to produce refabricated sections of all kinds. See the section on refabrication, and the various detail photographs on the projects concerned.
How do you repair rust holes and replace sections with new metal?
The only way to repair rust holes and sections so thin and pitted that their longevity is seriously compromised, is by letting in new steel to an area covering the whole section, going back into good metal all round.
The only way to do this is to cut out all the old section entirely and let in new metal cut to exactly the shape of the hole. Butt welding is the order of the day. Overlapping joints are not allowed and neither is covering up old rusty metal.
The end result is a section which should be indistinguishable from the original section, when the welds are ground off suitably. Obviously in body work finishing this goes without saying, but it also applies to undersides, chassis work and inner wings etc. too, as there is nothing worse than ugly patches slapped on, to cover holes, which will rust out again in no time at all due to moisture retention.
Bodywork refinishing with butt seamed welds will result in minimal use of filler skimming over the top. I have seen a quarter of an inch of filler used over lapped tack welded repair joints in body work, which then starts to bubble off due to moisture causing rusting in between the tack welds from the rear! Awful.
Filler skimming and use of filler primers will be mandatory in producing a high quality spray. It is just not possible to obtain the required surface flatness without it!
Use of body filler?
Like everything, body filler has its place. We have come a long way since the first monocoques fell apart with rust in the 1960's, and were patched up with gallons of Plastic Padding and loads of newspaper or aluminium mesh!
This is probably why it has a bad name, but actually, filler and filler primers are an essential ingredient to a truly superb finish.
It is just not possible to level off a panel surface to a high degree without it. When using it, the only way even then, to properly level a surface, is to sand, fill, sand, fill, sand, fill, several times, using a long bed sander blind and then using guide coats to check for levelness. Using dark colours, this process is essential for that mirror flat finish you so desire.
What preparation is needed for respraying?
People come to me looking for a "blow over", expecting it for a couple of hundred pounds. I just look at them and politely steer the conversation around to questions of what they expect out of a spray job.
The most important part of any spray job is the preparation. This accounts for 95% of the time involved, and applying the colour coat is only the last couple of hours of the work!
The devil is in the detail, and to me, "blow overs" are a waste of time and money, and I won't do them. One reason for this is that I don't want anything to do with a spray job which will start peeling at the edges after twelve months, as it is my reputation at stake, as a sprayer, and I don't want to be associated with cars that start having rust encroachment into a new spray job from areas which you couldn't prepare properly to start with as it was not in the remit.
It is important that customers are made aware of the issues which resprays bring up. What does a customer require from a respray? If it is because the paint is just a bit tired, then T cut will do the job! If it is because there is rust needing treatment, then this has to be done one way, properly. If a complete respray is ordered, then this will sort out all the nooks and crannies which may be already rusting so far unseen, and prevent these from encroaching, and it will entail proper rust treatment where needed, and not just a rub down!
Resprays therefore entail removing all glass and fittings, taking doors off, to do the pillars properly, all holes in the shell will have to be exposed for new paint, and all old paint flatted back to good layers as a minimum, by hand, or to bare metal, and to expose and clean out all potential rust traps etc.
Preparation then entails phosphate treatment of steel with any surface rusting evident, which there often is, unseen under paint, and then the application of several thick layers of two pack filler primer, after any serious undulations in panels have been stopper skimmed if that has been necessary.
Preparation then goes on to sanding down of the two pack primer and application of cellulose filler primer, again in several layers, and in a contrasting colour. Rubbing down this should not go through into the two pack layers, and if it does, then further coats are applied until subsequent rubbing down does not penetrate through before the panel is level. Only after this operation is undertaken and guide coats applied to ensure all blemishes are removed, can we contemplate applying colour coats.
Don't you get that sort of quality from any body and spray shop?
No you don't. I have yet to find a body shop that prepares a car this thoroughly. This is a very specialised sector and this sort of detail is simply not available from any highly commercialised body shop. Simply, it is time, money and overheads, and they need volume throughput. They have all the dust free booths etc. and the cars look very nice when they roll out, but they are still treated like any other (modern) car.
That simply won't do when you are preserving thirty, forty or seventy year old metal, which has inevitably become rather frayed and rusty in all sorts of places.
Look at the Sunbeam Lotus page three for an insight into the detail prepping required. The link to the MG pages shows more, and there will be more to follow in the future.