Bikers Workshop Series

Part 1; Accident Repairs, the basics.

By Steve Saunders.

We all do it sooner or later, that is we are ride motorcycles for years without bumping into anything or damaging our precariously balanced relationship with our insurance company. Then one day we drop our pride and joy (or scrape it on a gate post), probably at low speed and almost certainly due to a lack of concentration. When the initial relief that no-one that we know actually saw the incident (aren't you glad you wore a full-face helmet and a face mask too!) passes and the damage report has to be done, you would be amazed at the high cost of getting the repairs done professionally. The reason for the high labour cost is of course because panelbeating and spraying are highly skilled jobs and quality results take time which costs money. Having said that, a lot of people have some skill in various aspects of automotive & motorcycle work and also may have access to a workshop. You don't need to do the whole job from start to finish yourself, if you can at least get the basic repair done to a decent standard, your local spray painter will more than likely be happy to do the final stages for you and this means that you will have saved a few hours labour costs.
This article is aimed at those willing to tackle accident repairs themselves and who have a moderate amount of skill. I will be using laymans terms rather than trying to impress people with lots of fancy names, after all we are not talking rocket science here! The handy shortcuts and items that I find useful in my day to day work will be mentioned too and I may add more motorcycles to the series as they come in for repair, that is if I remember to bring my camera to work!

The first repair job is this Vespa 125, which has a pressed steel frame and body and is ideal for demonstration purposes.

Click on the thumbnail pictures to view the full size ones.

As well as repairing cars, some of my work involves repairing accident damage to motorcycles, usually sent in to me by motorcycle dealers. This one had only 45 miles on the clock when it was dropped, the record so far is a Vespa PX200 which was dropped with only 2 miles on it! The damage in the photo's is typical of a low speed slide.

When panelbeating the damaged area out, try to get it as close to the original shape as possible. Inexperienced workers tend to either not beat the area out enough and then put huge amounts of bodyfiller into the repair, or they beat it out too far which makes it difficult to recover the shape later on. Patience is the key here, a proper panelbeating hammer and dolly are not expensive and gentle rapid tapping will get a better result than going at it with a lump hammer. While this is easier said than done, practicing on a scrap car wing or door will work wonders in improving your existing abilities and confidence. The photo's here show the repair areas after shaping and buzzing of the repair with a mini sander used with 40 grade sanding discs.

Getting the panel shape as close to perfect as possible means that you will only have to put a light skim of bodyfiller on the repair. You will need to put several skims on, allowing each to harden and then use 80-120 grade sandpaper to get a rough shape on the area before putting more filler on. When the area is looking good, use 220 wet & dry paper (used wet) to get close to the final shape. The golden rule when running your hand over the area to check the repair is that if you can feel any bumps or dips then they will certainly be very visible after the final paint coats go on. You must also feather the edges of the filler into the undamaged area in order to avoid an ugly "map" around the area.

Use an aerosol can of any dark colour car paint to cover the repair area with a guide coat. You don't have to put it on as heavy as in the photo, this is just to show the procedure better. The initial look of the paint will give you an idea of whether you are a million miles off or just a little bit off a perfect finish. When the paint is dry, use 600 grade wet & dry (used wet) to gently rub over the repair.

The dark areas where the guide coat paint is heaviest mean those areas need more filler, while the small spot which has been relieved of paint is too high and will need to be sanded down. When you have recovered the situation with more filler and used 220 grade wet & dry to get things right, apply another guide coat and check the repair again. The more time you spend getting this right, the more likely the job will turn out perfect. It is all too easy to get impatient and rush things and when you put the final coat of paint on, realize that you could have done a lot better with a bit more time. The end result is always dependent on the amount of time and effort put in! Use 600 wet & dry on the whole area to be painted before applying primer. A final rubdown with 600 and then you can wipe the whole area to be sprayed with suitable degreaser. Some people use petrol on a rag, while bodyshops will cringe at the thought of this (petrol dries too quickly for a start but still does the job and is cheaper than degreaser), I know many professional sprayers who use petrol to remove traces of wax from the paint. Make sure to cover the area around the repair too. Mask off all the areas to be sprayed with masking tape and paper.

When applying the primer, use a high build type, it covers the minor sanding marks which you may have missed. The spray gun set to between 40-60psi will suffice to suck the primer out of the pot and onto the repair. Two or three coats, rubbed down between coats with 600 grade wet & dry will suffice. Another rub down with 600 and a final degreasing should be followed by a light rub of a "tack rag" which is a sticky cloth used to remove bits of fluff, dust etc. Don't forget to use a proper mask suitable for spraying paint & solvents! Make sure to wet the floor of the work shop and close all doors (leave a window open so you can breathe through your mask and the fumes). Dust is the enemy of any spray job and a damp floor will stop any stray breeze lifting the dust onto the paint.

This bike being a metallic silver means the silver base has to be applied first. Set the pressure at the regulator to between 30-40psi and spray the basecoat on in a haze rather than in lines (which you do with the lacquer coats). Spraying metallic paint in lines often results in a "zebra stripe" effect. A distance of around 10" is okay for this. Several coats of basecoat (with a few minutes between coats) will be needed to cover all traces of the repair.

After the base has dried fully (at least 20-30 minutes at a room temperature of 20 degrees Celsius) you can spray the lacquer coats. One light coat followed by a heavier final coat is the norm. Allow 10-15 minutes between coats. When spraying the lacquer you should keep the gun a distance of around 10" from the surface and work from side to side. Overlap each pass slightly and release the trigger after each pass to avoid runs.

This is the Vespa next day, prior to buffing and reassembly. The buffing & finishing process in the following photo's show a different bike just to make things more colourful.....

..... a young lady bought this new Vespa from Skooters in Dublin but she wanted a pink one. Unfortunately at the time they didn't come in pink so she bought a white one and paid the shop extra to have it sprayed in the pink of her choice. The two shots here show the garage junior doing the messy work, stripping all the main bits off the bike.

The first coat of paint applied after the usual preparation. This job was handy enough and just required that the existing paint be rubbed down wet with 400 wet & dry and of course degreased and wiped with a tack rag. I had to suspend the bike from the roof so that I could pass the spray gun under the base.

These shots show the bike being lightly flicked with 1500 wet & dry in order to remove any bits of dust which got onto the finish, this should be done around 24 hours after the paint has hardened fully. Compound is then spread over the panels and a buffing machine used with plenty of water puts the final finish on the paint. This can be done by hand but will take a lot longer. Some people use the accessory pads with a buffing cloth attached to a power drill, but be warned that the average two speed drill spins too fast for this sort of job and can leave burn marks in the paint. If you must use a drill, make sure it is a variable speed type set to around 1400rpm and at all costs keep the pad flat on the panel. Be extra careful when passing the buffer over panel edges as it is all too easy to remove the finish here. Needless to say, use lots of water here, especially on the second and later passes because this gives the shine. Don't wear your Sunday best for this job because the machine throws water and compound all over the place and has a habit of finding the power point where you plugged into if it is close! A plastic bag over the plug & socket will save potential grief here. Wash the bike properly soon afterwards before the splattered bits of compound get to dry on the paint. Dried compound is a real pig to remove from any vehicle.

The finished article, all ready to be bounced around in the back of a delivery van on it's way back to the bike shop!

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