Ok I see the end results and I like it. I have heard of this before and now I can see why someone would do it. So can someone spill the beans on how this is done? What temp and how long? Can this be done in an oven? I have a spare that I clean and season cast iron dutch ovens in. Thanks, Scott
The process of thermal cleaning is that the blocks are supported in a steel rotating basket and then for one hour the machine is set for 600 degrees to remove all unwanted debris.
There are two 500k BTU burners that get the oven to the temperature but the flame doesn't come in contact with the part/s being cleaned. it's the heat that does the work not the flame.
Once the oven shuts off and part/s cool down they are then transferred in the same basket to the steel shot machine to remove any of the leftover"fluff" and rust that the bake oven doesn't remove.
The steel shot blaster removes an any all of the leftovers and also stress relives it. The parts are thoroughly cleaned once they come out of the machines and ready to be crack checked as all of the Jb weld and rust and old paint,rats nest,acorns are all removed.
You may have noticed in another link Thanks to Dave Mazza for posting the pictures,how clean the block is after doing so.
I also may add that there's no hazardous waste after the cleaning process. What comes off the parts just gets swept up and tossed out.
What you are talking about is a burnoff oven. Most paint shops have them for removing overspray from the hooks and hangers they use. Dan
Thermal cleaning is only 1/2 of the cleaning process, It will "bake" all the grease, nuts, rust scale, oil and ???. But it will not make it all "turn loose" You will need to do some mechanical cleaning also. I use a section of speedometer cable about 2 foot long with one end frayed. I then insert the good end into a variable speed drill. Then insert the frayed end into the block or head. With the drill running at a comfortable safe speed let it "thrash" around into all the corners and passages you can get it into. I also use a 2 foot long piece of car antenna with the small end bent at aprox a 45 degree angle and about 2 inches from the end. I use it the same way. The thrashing will remove all the baked scale that has not turned loose. I have a couple photos showing the amount of trash that came out of a head that had been "baked". Ill try to post them this evening. They are in another post from a couple months ago I think titled "look what I found" Im on the "smart phone" so Im not "smart" enough,at this time, to try and find it for a link. One more thing. The shot bead blasting will stress relieve to a small extent, and get some of the scale. But the shot can only work in a direct "line of sight" to the openings it is blasted thru. There are lots of corners and hidden spots it will not be able to get to.
What does this do to Babbit bearings?
Donnie is right. Even with the paint hooks they must be pressure washed after they are "cooked".
Bearings?? One guess what will happen to them. Dan
The shot blast removes all of the debris you are removing with the speedo cable.
We don't have to do anything other than magnaflux our parts once they are removed from the bake blast.
To bad many machine shops using this method Have gone south. Great way to start a rebuild. I have to use what's on hand!
J&M Machine. I am going to have to disagree with you to a certain extent. I will attach a pic of a pile of trash and scale that came out of a head that was baked to 600 degrees for I believe 2 hours and then cooled. It was then shot blasted. The head looked great. I had also looked inside with a small flashlight. You could see the nice clean blasted surface inside and out. I laid the head on the bench and was getting the paint to paint it. When I picked it back up the dirt dobbers nest shown in the pile of scale, shown in the pic fell out. "where the *&%^$ did that come from" I got my old trusty speedometer cable out and went to work. The pile of stuff and the wire shown in the pic is what I got out of the head. (not the washer pieces at the side of photo) You can tell from looking at the dirt dobbers nest it is "toasted" It is black from the baking. There was a small amount of the shot beads still in the head when I first received it. They were small beads but definitely shot and not just glass beads. Now the "to a certain extent" of my disagreement. I have seen in the past, shot that was about the size of a "BB" If a person is using large shot instead of small shot, it may work into all the passages and corners with enough force to knock everything loose. If using very small shot for the blasting I do not feel it has enough force to break all the stuff loose, and a direct line of sight is all you get. The builder that built my engine and had the machining and baking done went back to the shop that does the baking, because it shocked him to see how much scale came from the head. . They said that the baking and shot blasting will get most of the crud out but there still needs to be some mechanical cleaning done. I would be very interested to know what the size of the shot is that you use. I see from your posts the high quality of work you do, But different shops may do different ways, and just because it is baked and shot blasted does not always mean it is clean. Im not trying to make anyone mad, I just want to add to why I think mechanical cleaning should be done Respectively submitted
700 degrees. 4 hours. Shot preened and then tumbled
Thanks Mike. I was unsure how long it was baked.... I remembered it was over one hour....
It's alright to disagree.
all depends on the equipment and steel shot used.
We don't typically get that out of our machine It does a through job.
We're using smaller steel bb consistency of coarse sugar and 15 minutes is all It takes to remove the worst crud there is.
if the part is really flaky as yours was then yes I would agree that it won't get it 110% but it's far better than anything else out there.
I agree that there is nothing better than baking the blocks or heads. But a little mechanical cleaning will verify it. Keep up the good work because I have a 1908 Highwheeler engine Im going to need help with ....
Be careful with shot blast. It can mask some inclusions. For the most part magnetic particle inspection whether in a liquid suspension or as dry powder doesn't have a problem with it but it can hide an inclusion when using Dye Penetrant.
Thermal cleaning has been around for a while for shops to get away from caustic hot tanks. It reduces oil, paint, and sludge to ash which can then be removed by pressure washing or shot blasting and then pressure washing. The washing is done in something called a jet clean or jet wash machine, basically a dish washer for car parts. I use a mild detergent in mine for final cleaning of machined and babbited engines for assembly. More aggressive solutions are used in other situations.
Babbit bearings will not survive thermal cleaning. They will melt at below the temperatures involved.