Technical > Body work

Part 1: Preparing bare panels, priming and surfacing Tutorial.

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Sirpent:
Hi all,

Well I promised I would write a tutorial for some of the guys on the forum with regard to my bare metal preperations and application of EP (Epoxy Polyester) primer.

Now I know that many will find this very basic and boring, however the guys who asked for it and many who may read it may not have had the experience of having tackled something like this previously.

I have written it in a way I would have used to explain the process to one of my first year apprentices years ago, very simple step by step instructions and pics.

If anyone finds this useful I will go the next step with application methods and material types followed by surfacing techniques.

Please wait till I load all of the instructions and pics in this thread before adding comments, I will write END OF PART ONE after the last is loaded, then you can all start throwing knives.

Cheers

John

Sirpent:
Part 1

Preparing bare panels.

Any restoration is only as good as its preparation, as I would often say to my apprentices, that extra 5% during pre-paint constitutes 80% of the finish quality.

The following is a step by step tutorial on achieving a solid base as far as pre-paint preparation, there are numerous opinions and methods used by the DIY restorers and these differ greatly from what may be executed in a fully equipped panel and paint facility, these steps are the ones I undertook in order to achieve the best possible results within a home garage environment.

Work Area.

Most DIY restorers will have access to limited space, and limited equipment, fully filtered and environmentally controlled areas are a rarity, when conducting this type of work its important to consider not only your own safety when dealing with hazardous chemicals and equipment, but also those of your immediate surroundings, family and neighbours, your local municipal officer could put a quick end to your restoration ambitions so take all this into account before commencing.

Equipment.

One of the biggest mistakes I see the DIY restorers make is their choice of compressors and application equipment, many people run noisy temperamental 2HP air compressors that make a racket, but more so the problem with these units is the fact that they cycle very hard due to their low volume capacity.

What happens then especially on humid days is that the compressed air collects in the tank and condenses into water which eventually makes it through the airline, the gun and into the material being sprayed, you wont notice it until long after the final spray job has been applied and the finish develops blisters.

The other problem with compressed air is that the material coming out of the spray nozzle is highly atomised, and you end up spraying in a cloud of floating particles that eventually come to rest on every surface in the work area, that’s OK if you are using a single Pac as opposed to a 2K material as the mist will dry before it settles turning into dust, but 2K will land as fall out and end up bonding to a surface.

So, your $199.99 2HP compressor from Bunning’s ends up being a bit of a very noisy, very loud, temperamental liability, what’s the alternative.

Well may you all laugh, but the best alternative to counter all these problems  in a garage environment is something simple like one of these, it’s a little beaver reverse vacuum spray system, it draws air in via a filtration system and basically uses that air to then deliver the material via the spray gun, very portable, as loud a small vacuum cleaner, no chance of condensed water particles making it into the sprayed material, minimal if no overspray, and perfect for the delivery of heavy concentrated primer fillers, this item was sold on EBay for $73.99, mine is a blue one but I nabbed this pic as I didn’t have one of mine.

I wouldn’t be using this for a final finish, although there are people who have with great success, but when it comes to priming up a vehicles I honestly cant go past it, and just how well it does the job will be revealed later.

Sirpent:
When it comes to panel preparation, even the best industry tools will do you little good if you don’t have the attitude from the start that the preparation of panels is like pouring the foundations of a house, you cant build on something that is sub standard and expect everything added on top will somehow conceal what’s underneath, simply it wont.

For panel preparation you need only very basic items that used correctly will not devastate the surface but achieve a viable good base.

The following are what were used for this tutorial in the preparation of panels.

#1    This is a heavy duty wire brush designed to really attack heavily ingrained surfaces, I usually hit smaller areas with this first, not every part of the panel.

#2   A medium wire brush used on a drill perfect for curved areas such as arches etc.

#3   A lighter wire brush used for seam areas where 2 panels meet to work away any material deposits.

#4   A Nylon based brush wheel that is used on seam areas as a final prep to rid the area of any remaining matter or rust deposits.

#5 & 6 I rarely use these, but occasionally you need to just hit back a sharp like a spot weld or jagered edge so rather than a grinding wheel these flap wheels do the job, the Scotch Brite wheel may come into play on a surface that may just need a quick run over to remove a small remnant of paint material in an obscure place where non of the others is appropriate.

#7   A good orbital sander is a must for flat panels, this Makita unit uses a rubber pad that allows the use Velcro sanding discs, I prefer these as the self adhesive types tend to come flying off after a while and become Frisbees, for panel prep, I use 180 grit discs which provide a workable smooth surface for primer application.

Sirpent:
The panel.

This panel was soda / garnet blasted some 4 months ago, over that time it
started to deteriorate, the effects of moisture, bare hand handling, overspray
from doing the undercarriage, and weld spit all had their effect, and apart from
these factors, not even blasting can totally rid the surface of every last form of
foreign matter, the following 4 shots show the extent of what had to be prepped.

Sirpent:
Shots 3 & 4

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