|As more people are starting to build their TA71 kits...time to start sharing some of my knowledge on painting and prepping SLS 3D printed bodies. So the last thing I posted on the Bentley build report part 1 was the slight misalignement of the chassis and body. When I checked the chassis I found it had a slight warp at the left rear corner.
Which was fixed in the old school way. Hot water bath and a slow cool down in the oven.
Point of attention, the Bentley chassis is designed not completely flat. The front and rear of the chassis are meant to be at a slight angle.
So take care where you place your magnets, if you need to straighten your chassis,you just want to correct the chassis where it has the warp, don't flatten it completely.
As you can see the body now fits niceley on the chassis, yours might sit a bit higher, for this chassis I've modified the NSR pod to create a 0,75mm offset.
[font='Arial Black'][size=12]Body prepping[/size][/font]
The last stage of TA71 post processing is a final layer of grey primer. Opposed to what Marco writes in his accompanying letter, I found that giving the primer a
final rubb down with anything coarser than 600grit will result in a worse finish wotha you may have started with as you will easilly cut trough the TA71 primer.
Your aim here is just to level off the "high's" of the primer. If you use too coarse emery paper you'll not only remove the "highs" but also cut into the "lows" that the primer filled.
As the material used in 3D SLS printing is very tough and flexible and much harder than the primer..those "highs" will remain but the primer around them is gone..giving you an even more uneven surface.
Just give it a rubb down with 600 -1000 wet emmery paper, and a good wash and brush to clean away any primer residue and your good to go...and you dont have to restrict yourself to acrylic paints.
You can use Tamiya rattelcans, acrylics and zero paints. Been there done that, doing it tomorrow.
If you're more cautious you could use a first thin layer of Fine Surface primer (Tamiya, Zero or Mr Hobby)
Automotive primers (Totip, Halfords) will work, but as they will give a much thicker coat, even more detail will be lost.
So, if you want to get the maximum amount of detail and definition on the bodies, you might want to do what I have done with my Bentley.
[b]Scrape down the excess primer first[/b]
As with any type of primer, you fill in the lows, but the downside is you loose some definition of all the shapes due to paint build up in the small nooks and crannies of recessed panels and corner. All hard egdes are sort of rounded off. Now if you were to try to sand this excess of with emmery paper, you'd only exaggerate this.
So here I take a not to sharp rounded scalpel or even better a Lino chisel and gentley scrape away the excess primer
To give you an idea off the difference this can make I've done these pictures with just the right side of the Bentley "scraped"
It requires a gentle touch and a not too sharp blade (which is why I prefer to use the lino chisel)...
... It just needs to be sharp enough to cut the primer, not the body material.
All you need to do is trace the body panels using the body as a guide...
Scrape along the surface with the blade at a shallow angle, working your way towards the edges
...and one by one the sharp edges that were on the original 3D model re appear. Even the very subtle ones around the radiator extractor openings on the hood.
In the TA71 post processing some of the raised body detail around the edges of these openings had been lost.
Using hard putty or fillers are not an option to rebuild these details as the body is flexible.
But you can use primer which will always remain a bit flexible, at least to the extend that it wont pop off the body if it were to flex a bit during a crash.
Last but not least, you can also use the chisel (or blunt round x-acto/scalpel blade) to retrace panel lines or recut them where the are missing. In the later case its handy to use tape as a guide. Again a gentle touch and patience is important here. Get the right shape first with tape, Just scratch the surface of the primer..and retrace for as far as neccesary.
The trick here is to just cut trough the primer...not the underlaying body surface.
with kind regards