More Boss 429 Intake Manifolds

I have three Boss 429 Inline Carb manifolds to cast, an open plenum singe plane which I've made before, and a couple individual runner versions, one with and one without an integral water neck. It's rare that I have three complete patterns in the shop at once. I take a modular approach to the patterns and can easily modify, mix, and match the pieces to assemble the variants. Foam patterns pictured below.



Also have a couple lids to cast too, one for a CrossBoss and one for a Bud Moore MaxiPlenum.



Gonna have to fire up the big furnace and melt some metal!

Best,
Kelly

 

All gated up. You know what comes next.....



Best,
Kelly

 

No. It's just a matter of required stock thickness, material utilization, and/or remnant size I happen to have on hand. Pieces that require stock thicker than 2" use green (Kingspan Green Guard LG). I still stock 1", 1.5", and 2" thick pink XPS (Owens Corning Foamular 150). The two brands have identical specs in all regards but the pink does seem to machine and sand slightly better than the green......must be pore size. These are all 1.3-1.5lb/ft3 density.

I use the white EPS for the feed system primarily because it's lower density so it melts faster with less decomposition material to expel, uses less melt energy, and distributes the melt across the pattern faster and more evenly (at least in my mind). It's also free and seemingly of inexhaustible supply which keeps it out of the landfill, and as a minor benefit, for the sake of show and tell, the color contrast helps visually distinguish the pattern from the feed system. Density can vary but is less than colored XPS.

Best,
Kelly

 

Thanks RM, It's going to take me a couple dedicated days to cast everything.

The intake manifolds require the use of my larger flask, which is an extended 30-gallon drum. It holds 500-600lbs+ of sand, which has to come out for molding and again for demolding (and go back in ), which means I have to throw 1000-1200lbs of sand for each. When I do two in the same day and move North of a ton of sand by hand, this old man's back feels it. It also takes more effort to resize 35lbs of ingot/returns for the crucible and roll my large furnace and gantry out (and back into) of the shop too.

Contrast that with something that fits in a 5-gallon flask which is only 90lbs x2 and I don't even move my small furnace out of the shop to do that.....just walk the crucible out the overhead door. The price of poker goes up with casting size.

Best,
Kelly

 

Got the patterns dip coated.



I had an accident with the first. The other two came off without incident. The first one separated from the piece of wood I glued on to hang it above the vat. Instead of just harmlessly falling back into the slurry, the pattern hit the rim of the vat and was damaged. I was not happy!



But, the breakage was clean and pieces recovered. I wiped away all of the slurry from the affected area and let dry overnight.



I hot melt glued the pieces back onto the pattern, and detailed the area by light sanding and applying wax to patch the affected area. Hard to tell from the picture due to the translucence of the wax but by feel with my finger, I think it will cast as if it never occurred. Sign of a craftsman is how well he can cover his mistakes! -We shall see. I brush coated the repaired pattern area.

Rain in the forecast. Looks like it may be a few days for casting weather.

Best,
Kelly

 

Always seems I get a bunch of patterns made and then the weather doesn't cooperate, but had a few weather windows and managed to get them cast. The repaired area on that damaged pattern came out great. Need to heat treat them and then onto machining.



Best,
Kelly

 

I cast with A356 so T51 is almost always my choice because it is easy, poses no risk to the casting, and achieves 80%+ of the mechanical properties and machinability compared to T6.

T51 is all precipitation phase and just requires ~455F for 7-9hrs with no cool down control which is easily done in a kiln or even a kitchen oven. For sand castings, T51 achieves ~20 kpsi yield vs 24 kpsi for T6.

T6 requires Solution treatment first which is ~1000F for 12hrs followed by water quench, then solution treatment at 455F for 3-5hrs. These temps and times can vary a little depending upon the source.

Problem is, the castings are very weak and nearing hot/short at 1000F. The castings need to be well supported at that temperature. In the case of these intake manifolds they should really sit flat on their base and since I heat treat in my 16" bore resistive electric furnace they are too big to do that and must stand on end. Even if I could, when you quench, you also risk warpage, and sometimes fixtures can be required. Close temperature control is also necessary to avoid damage and although my PiD reads a rock solid temp, I know there is variation from top to bottom and the biggest problem is radiant heat transfer from the bright orange coils which can cause localized damage to casting surfaces that are close and have a very short path to them.

In the past, for T6'ing smaller parts, I shielded them from the radiant exposure by putting them in a steel can or rolled sheet metal cylinder but these castings are too big to do so. So, I conclude T51 is good enough.

Best,
Kelly

 

Got the intakes machined. Still have some machine work to do on the valley pan plenums but need to make a few upgrades to my CNC Router before I do so.



Video of the deed.



Best,
Kelly

 

Increased Z travel
Increased height under gantry
Conversion from V-wheels to linear bearings on X & Y axis
Conversion from Acme to ball screw on Z-Axis

Best,
Kelly