Many of us have other hobby interests and are members of other forums. I became acquainted with one of our newer members by way of a custom car build project of a 1949 Cadillac with modern Cadillac drivetrain and amenities. http://allmetalshaping.com/showthread.php?t=14068 He’s been at it since the Summer of 2015. Here’s where he is heading. Jack has employed many different fabrication disciplines in the course of the build and one special need was castings for taillight and turn signal housings. Since this was going to require one each of six different castings, I suggested he consider lost foam. Jack made these patterns, and I must say, as his first attempt at working foam I was quite impressed as they are complicated geometry. Must have been a lot of hand carving and sanding. Since it clearly took some effort to produce the patterns, I figured I’d better not blow them up in failure. Here are the patterns as supplied by Jack. Here they are prepped. Happy to report the first round of casting the turn signal buckets and lense frames was successful. I have one of the two tail light buckets prepped but have had a weather interruption. Will try to get those cast this weekend. Best, Kelly
Thanks David. Here's hoping you feel the same way after the tail light buckets are poured........feels like when the kicker is lining one up and the announcer says, he hasn't missed one from this distance all season. Best, Kelly
I'm glad he went the foam route with you! Because the wax route and coming to see me would not have turned out this good first try!!! CBB
Still blown away by what can be done with a piece of foam and some patience. Turning out great Kelly...but you knew that already. Al
I took advantage of a small window in the weather and cast the tail light housing. Here’s the prep. The jury is back with the verdict…..and here’s the result. Looks good so far…..but, there is a flaw. The pattern was very thin in that area. It’s the oldest Foundryman’s excuse in the book Jack……blame the pattern maker! It can probably be tigged up and with a little fettling no one will know…..oh, except everyone reading this. OK if I fatten up the pattern in that area on the other one Jack? Best, Kelly
Yes, go ahead and thicken from the inside. Whatever you need to do. Can you add a second sprue so that area is not the last to fill? I roughed in an extra pattern for the tail lights when I was making them. Do you want me to finish it and send it to you? I could have it to you before next weekend.
Your photographic skills hiding the cold shut are exceptional! Glad you didn't make the pattern. He poured it too cold, Jack.
Plenty hot. I poured at 1600F. The pattern really was only about <.090" thick there and you just aren't going to succeed in sand at that thickness very often. When I drilled the hole through the emblem embossment it was also very thin. I did thicken that area up to about 1/4" but not the area that didn't fill.....didn't know that it was there. Based upon how the lower portion of the casting filled, if the walls are 1/4" or so and there aren't any thin spots I think it will run just fine. Sure. Don't hollow out the area behind the embossment.....isn't necessary. Best, Kelly
I was just giving him a little ammunition. We all know you keep track of your temperatures. How did you thicken that? With wax?
I did that. I used a mixture of the dust from sanding the foam and some wood glue. Looks like crap but it filled. I didn't know you could use wax. I just hope it will burn out. A little bit of knowlege is a dangerous thing.
Start with this Fit a filler piece, and attach with hot melt while applying pressure to make it conform. Then blend with bull nose bit in die grinder. Hot wire some thin foam plank, dry fit it up, and glue in place with hot melt. Trim, blend, and detail it. Mud that sucker up Pour hot metal on it.....oh wait, haven't done that yet. Supposed to be 50mph winds tomorrow.....crap! Don't know if I will have a chance to cast. Best, Kelly
Had a go at the second tail light bucket today. It was about 20F and very windy, 50mph gusts! I tucked my lost foam rig in the corner to shelter it the best I could and clamped a piece of cardboard in place to try to shield the cup from the wind. Here’s the result. There is a small fold flaw at the very bottom of the casting. It may polish out depending upon how much material Jack removes when he fits them up and polishes them. Worse case, slight touchup with the TIG torch. Here’s the family photo. One more tail light bucket to go. Best, Kelly
Looks pretty good! Did you super heat your melt before pouring in those conditions? I was going to pour my clamp today but got suckered into going to get some free tools.
I already consider 1600F to be superheated. It's such a short time, 5-10 seconds, from when I grab the crucible and pour it's more about the wind quenching the thin stream being poured. I could see it skinning over at the end of the pour. -Not ideal conditions. I did the best I could with what I had. Best, Kelly
The left housing looks good. I can have that welded up no problem. Actually I could have the right one welded up if I have to. I am almost finished with this other right side pattern. I have to put the emblem boss on in the morning and do some finish sanding. I'll drop it off at FedEx sometime tomorrow afternoon. Don't scrap the right housing till we see what we get with the second attempt we'll use the best of the two. I left some extra thickness in the lower area that gave you trouble in the first pour. we'll use the best of the two.