O.B.Bolton I.C.12 1.5cc compression ignition engine build

[moose4621]

I have had these castings and plans for, well I don't know how long.
I started building it at one stage but decided the castings were unusable due to parting line missmatch and overzealous flashing removal. It sat for years until a few years ago when I decided to 3d print some patterns for investment casting. I started machining the new castings, which weren't perfect.
But then I got busy again. And distracted. Etc.
But here it is again, new castings, and posting it here to hopefully inspire me to complete this engine and tick it off the list before I start a new project.
These are the original castings.

And my first attempt at replacement castings.

And parts machined so far.

And today's failure. Incomplete burnout of the pla pattern

After a search on Google turned up nothing on this engine, I wondered if anyone here has come across it in there adventures?
More to come after the next casting.
Chris.

 

[moose4621]

I am surprised to see the kit is still available here.
I would have thought there would have been more hits on google.

 

[moose4621]

So, on to the next casting attempt.
I have to admit, I rarely do inverstment casting. I usually am casting in green sand and is something I do often.
But the few investment castibgs I have done in the past have gone well. Up until now!!

Son I printed out another set of patterns from PLA, filed and sanded them a little and set them in investment to make the mold.
I use a mix of 2 parts fine "brickies sand" to 1 part plaster of paris. I know that castable refractory is expensive and hard to get where I am. The sand and plaster of paris works well as long as I am gentle with the mold after burnout.

I use hot glue to attach the PLA patterns and tin container to the plastic sheet. The attachment points become the sprue and riser. Then fill with the sand and plaster of paris mixed to a "ploppy" consistency. There's probably a better word than ploppy to describe the consistency or viscosity of the mix but that seems to fit. Wet enough to fill the voids and allow the air to bubble up but not thin enough to run like a liquid. I the vigorously tap the whole thing on the concrete in an effort to force the mix into every nook and cranny and to release any air bubbles before it sets.

The patterns glued to the plastic sheet ready for the tin casing.

The tin case glue to the plastic sheet enclosing the patterns.

The plaster and sand mix, (investment) has been added and rattled and banged on the concrete to release trapped air.

Now I wait for a few days for it to dry out as much as possible before beginning the burnout process.

 

[KenC]

O B Bolton does not ring a bell with me, but your engine looks a lot like the engine well known to engine builders as the "Battiwallah" after the pen-name of the designer when it was published in the Model Engineer in 1948/9. The idea was that it was a home-build as an experience of die casting. Here is a snap of one that I built from casting made by an Australian pal and a scan of the plan.

 

[moose4621]

O B Bolton does not ring a bell with me, but your engine looks a lot like the engine well known to engine builders as the "Battiwallah" after the pen-name of the designer when it was published in the Model Engineer in 1948/9. The idea was that it was a home-build as an experience of die casting. Here is a snap of one that I built from casting made by an Australian pal and a scan of the plan.

Wow. That's it!
Dimensions all match perfectly.
There is no mention of "Battiwallah" on the plans that I have. Well done for recognising the engine.
The kit I got contained poor quality sand castings. So I guess O. B. Bolton has done a cheap knock off of the original kit and passed it all off as his own? There is no credit given to any other party on the drawing I have.

 

[perko7]

O.B.Bolton (Bolton Scale Models) is/was an Australian distributor for a number of established steam and i.c. engine designs as well as having designs of their own. They are now known as E&J Winter but their website at Model Engineering still recognises the Bolton heritage. They mostly deal in steam loco casting sets and accessories these days but I believe still sell a reasonable range of stationary engines.