11 October 2011

Alone3 and SumPod Painting Part 2

Regardless of this success, I have yet to published any pictures from my SumPod painting sessions.  This post remedies this situation and I say sessions, because of the interruptions, some of which you can hopefully avoid with advice from my previous post:  Paint, Paint, Glorious Paint!

My primer of choice for intricate parts is Plasti-kote Primer Super, it's a solvent based primer that sticks to pretty much everything; multiple coats (including sanding) are possible in a matter of hours, with a touch dry time of twenty to thirty minutes.  Product details are available here.

It was not made clear in my previous post, that a solvent based primer should be used to minimise swelling of the MDF.  My thanks to Freyr for highlighting this important point in the comments.  The Safety Data Sheet for the Plastikote Super Primer is here.

Having read the comments on my previous post and the deterioration of weather here in the UK, I am revising my advice to use spray paint, unless you are lucky enough to live in a warmer and drier climate or have the facility to use spray paint indoors, then use a paint brush to apply primer.  Speaking to Richard (Mr SumPod), all of his demonstration units were painted using a paintbrush.

The following pictures were taken of prep during the last day or so of nice weather, that was the last of the British summer.

SumPod and newspaper ground protection bask in the British Sun
First picture of the 'exploded' SumPod as clouds gather
Main body, inside of left hand panel (upside down)
Main body, top of base
Main body, inside of back panel (upside down)
Main body, inside of right panel, with PCB cutting bed above
Main body top

Main body inside of front
 The LCD mounting space is clearly visible in the middle of the screen.

I will amend this post later with additional images from my other camera.

I started with the main body because this will have the most exposure to grubby fingers and 'stuff'.  After the first coat coverage is like this:

I'm paid a visit by Folly the thirteen year old fox terrier bitch, wondering what the hell I'm doing and not paying her attention.  Dogs can be sooo helpful.

Ideally the undercoat should consist of several thin layers of primer to provide the best base for the top coat.  Here yo can see the coverage of two (or three I can't remember) coats of spray primer.

Because the main body is held together by interference joints, moving it has caused this corner joint to loosen. Try to avoid getting and paint into these joints because it will make the joint even tighter and may create an unsightly gap.
A corner on the main body starts to separate
Z axis linear bearing mounts

It is clear how the routed surface of the MDF has soaked up the paint, compared to it 'normal' surface.  Speaking to Richard the soaking in is less of a problem with thicker brush applied primer.

My intention was to slowly build up the number of coats of primer.  Each subsequent layer is absorbed less and less buffered by the previous coat.  Following are pictures of later coats as painting and sanding progress:

Like it or not, the dual feeder backplate is not reversible

The first coat of gloss goes on as the night draws in.

The second and final coat of gloss will be applied tomorrow by brush as the weather here is currently less than conducive to painting outdoors.  Of the different finish options I've selected the slightly more difficult to apply liquid gloss - the finish should be fantastic!

Until then SumPod Guinea Pig signing off 


  1. Where you say "the main body is starting to separate" will this give problems putting it all together, or will it shrink when it dries?

  2. It's not a problem. The two panels making the joint started to come apart as I handled the main body. They are only held together by the friction of an interference fit.

    I took the picture while the paint was still tacky and I didn't want to apply unnecessary pressure at that would have damaged the paint.
    Before sanding and the next coat of paint, I pushed the parts back together to prevent paint ingress of the joint.

  3. Coming along nicely there. Looking forward to see it doing some work :)

  4. I've u got a manual to build it or not? And many thanxs for all ur advices!

  5. Sorry, I do not have a build manual. Unfortunate for me, I also do not have the left side of my print bed - I'm still awaiting delivery of it from SumPod HQ.