Replicating Bruce Satra's M-1 and M-5 engine

[dnalot]

I also didn't know that there was 'resin' investment

I use Ransom & Randolph Plasticast.

The shrinkage is most noticeable in thick prints. If your part has a mixture of thick and thin areas you will see some part distortion.

Mark T

 

[dnalot]

Wow some of those resins weigh in at $300/bottle

Some of the best resins cost well over $300/bottle. Siraya Tech cast at $80/bottle is doable. It is a very good general resin for both large and small prints. And it does have some wax in it. The resin is very thick and needs a short wait time before the UV light turns on to allow the resin to flow out from under the build plate and settle down. The resin is very brittle and you need to peel off of the FEP slowly or you will rip the print apart or break the supports.

Mark T

 

[Bentwings]

Thank you for the heads up on this. I wasn't aware of a shrinkage issue. I have some prints done in iFun 3122 that I was waiting to invest after I figure out the mess I made of my shop moving everything. I even started piling stuff in the bed of my '41 ford pickup project.

I will have to measure them and see what kind of shrink I get. They will still be useable to figure a burn out schedule even if they are undersized. I haven't tried Siraya but have heard from several people that it's good stuff. I also didn't know that there was 'resin' investment. I guess I was just so comfortable with my good ol tried and true investment I never thought to look and see if there was something better suited to the job. Almost makes me want to just stick with the good old wax stuff that I know. Almost.....

I'm waiting on a quote from a local company on the cost to move the mill. Once it's up on the hill I can get back to finishing the cylinder molds.

coming from the really old days of ammonia blue prints scaling a print simply did not work the paper was really weak creased easily and ripped and decomposed quickly . At one pint I was tasked with recreating 3D models from
Prints and drawings that were older than I was some 35 years. The Mylar ones and velum ones were at least in one piece but scaling or over laying them that was done to make assembly drawings was truly a mess. There were so many mistakes that I often had to just find a machine in the warehouse to actually measure . Many of the manufacturing steps guys just had marked up ancient drawings they just adjusted part by welding and grinding or machining to fit . It’s no wonder the company was losing money on manufacturing . I had a rough time bringing new cad drawings out to the floor for a while “ that’s not the way we make that part” was common. Many times I had to go to the supervisor to get help . Gradually I became “ that new guy knows his stuff” when things started fitting exactly my life became easier.
But old runts just are not great . I have some model plans that are pretty old that don’t match up to the nw cad drawn ones . I don’t trust kit cutters as I’ve had endless problems with pars that don’t fit or made from the wrong materials . I cut my own kits even Fiberglas fuse planes I made all my own wood parts as needed.

 

[Dragondark]

Just an update, I'm still working on this while trying to get stuff sorted after the move to the new shop. I didn't want anyone to think it was a dead thread.

 

[Richard Carlstedt]

Good to hear from you again !

Rich