'49 Caddy Tail Light & Signal Buckets

I had some aluminum soldering rods around so I figured I had nothing to lose, so I tried to lay some on the castings. I wet sanded with 600 and scrubbed the castings with a tooth brush to try to get the dirt out of the pits then tried to solder over them. There's a lot of mass to these so a propane torch couldn't generate enough heat. I switched to an acetylene torch and got the solder to flow. As I suspected, the solder would flow over the pits but didn't flow down into them. When I started filing it off, I could see the pits reapper one by one. A few of the larger ones did fill but most are still there. I had a lot of extra material there so I knocked them down to the minimum and there are still some pits left. I managed to get about 30% of them out but I have to stop before I ruin them. I'll detail them and polish tomorrow. I think that when that's all done, I'll scrub the polishing compound off and dot the remaining pits with some silver paint. As they are now, they're black and really get your attention. I think if the pits are there but silver, they'll be a little less noticable. I am always after the best results possible but this is the one drawback to any "lost" casting. If you have any problems, you have to start over from square one. I'm not going to do that, I don't have the time and there's still no guarantee that a second attempt would be any better than the first.
I only mentioned the pitting FYI. These were fairly complex patterns with some shapes that made casting them tricky. The input is just FYI in case you come up with a similar project that might need attention to this potential problem.
If I were to recast these, knowing what I know now, I would do them in two pieces. The bucket and the outer frame would be cast separate. Possibly even make the buckets from plastic and bolt them to the aluminum frames. Anyway, it was an interesting experience and I learned a little about casting. It's not as simple as it appears to be.

 

The grilles and mirror stands are nearly spotless. One or two very tiny pits on the stands and I sanded a little more and got them out. I won't need to polish the parking lamp buckets, they'll be mounted inside the fenders so they'll never be seen. I have some 24ga polished stainless sheet that I will line the inside of them with so they reflect the light.

 

For larger pits you could clean them up with a small drill bit, then they would likely be clean for the solder.

 

Neither was I suggesting that lost foam is a bad method or creates excessive porosity, but as long as I'm burping gas up through the sprue I'm assuming that is creating some porosity. All the lost foam I've poured and investigated (granted, not much has been cut up) I have porosity. I may be all wet on where my porosity is coming from.

And it might be a sin
But I'll take your bet
And you're gonna regret
'Cause I'm the best there's ever been

I raise you one and I'll use remelted soda cans and window frames. But I will test mine on air and then send them to you for the official seep test. Am I right that air will leak where water won't? In truth I think we'll both be successful.

 

I think the bubbles on the tailights are different than the unfurled bifilm in my rims. As Kelly mentioned there was wood glue and beeswax, and possibly voids in the pattern so air may have created a bubble trail that stopped at the coating or just under it and it is exposed by polishing. They just look more spherical than my flaws.
It's a bummer because Jack made nice patterns and we have seen what Kelly has been able to do with his foamies.

 

Well, I was referring to my lost foam experiences.

Yeah, The Devil Went Down to Georgia

I look for leaks in a water bath. But I can see where a very tiny leak would show a wet spot if it wasn't evaporating as it came out, does the antifreeze fix the evaporation issue?

I've got too many irons in the fire too, and I'm retired. But I'll sand cast some tubes.

What would you do to minimize the pitting? The few lost foam castings I have polished had porosity.

 

Guys, lets take it down a notch! Here's the way it is; I was clearly headed down the wrong path with next to zero experience with any type of casting or pattern making. Kelly stepped up and offered some advice and eventually offered to do the casting for me. He cast 13 individual parts that were far from professionally patterned. This was my first time making foam patterns and I have no experience with how to gate or sprue or the pouring process.
The tail lights should have been made in two pieces but Kelly gave it a shot. Of the 13 castings, he produced 13 usable parts. A couple needed some additional work but 13 out of 13 in a less than ideal situation with uncooperative weather is impressive. If you look at the pictures below you can see that I finished polishing the tail light housings and some of the other parts. There isn't one single pit in the 10 other parts. I might leave the tail lights as is.
Other than the odd douche bag crawling around on all fours with a magnifying glass, I doubt that anyone will spot the pits. I'll be talking to a plater in the near future and I'll see if it's worth plating them.
I think these forums are important. Passing on skills and knowledge goes both ways. I left Kelly some feedback regarding porosity so he knows what to consider if he comes across another similar project in the future. NOT as a complaint or criticism! Without his help I had nothing. Now I have everything I need.

 

I hope nothing I have said was taken as criticism. I'm trying to learn and admire Kelly's work very much. He has helped me learn to do decent lost foam casting. Not great but decent. Jack's car looks great and everyone is a little saddened by the porosity. Kelly did a great job in a short period of time. And, the value of this forum is exchanging ideas and learning. We learn by talking about problems more than talking about successes. Kelly is his own critic, the rest of us know we can't do as good in the lost foam realm.

 

I've been following this thread with much interest and I was glad to read Jack's response. To have the balls to take on someone else's foam patterns, sprue and pour them is something else. Andy sums up the ongoing discussion better than I can.

 

pssst.......



ceramic shell that foam!!!!!!

 

Thanks!

Didn't know that about molecular sizes, but it makes sense that one oxygen would be bigger than two hydrogens. I'll bite the bullet and make a mess with antifreeze.

OK, cleaner on bottom. Thanks.

My problem with ceramic shell is maintaining the mix. I can see investing a fair amount of money then having it sit there and go bad on me. Besides, I want to become somewhat proficient at sand casting because my main interest is old methods and crafts.

But I think it is great to see all the different approaches to the same problem, and they can all be successful. Many times the success of a method is purely the skill of the practitioner. It took me many years to understand the meaning of "there is more than one way to skin a cat". I interpret that to mean there are multiple successful ways to skin a cat, and in the end, the cat is skinned. And once the cat is skinned, the method is insignificant. It is easy for each of us to assume the method we know to be successful is the best method, but in reality, in every field, there is seldom a true "best method". There are different methods which can all yield excellent results. In the right climate adobe walls last as long as concrete block or wooden walls. Charcoal, propane, motor oil, and electricity all melt metal. There is not one best fuel for melting but there are lots of preferences.

Rant over, thank you very much.