Block Cleaning - Hot Tank or Oven - Pros/Cons
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Having 1 oven (Bayco), 3 spray cabinets, 2 ultra-sonics, and a pair of "steel-shots", we find we very rarely "light" the oven anymore. With natural gas prices where they are and feeding the oven through a 3.000" main, it's too costly. Also, I've never really took a liking to the ovens, they tend to "bake" too much of the "core-oil" out of the castings. If the tanks are maintained properly they do just fine. I will add however, we don't handle too many used parts anymore either. 20/25 years back, before new castings "flooded" the market we managed to "bake" some 30/40 heads a week, many came from the local "junkyards" here. Thanks, Gary in N.Y.
P.S. We had one "major" issue years ago with a bad "thermo-couple" in the oven and it proceeded to melt an alloy head down into the "trolley" and the wheels. It took a while to clean up the damage. We came in on a Monday mornig and found molten aluminum coming from under the oven door. The shop was up around 100 degrees. All the safetys failed.
P.S. We had one "major" issue years ago with a bad "thermo-couple" in the oven and it proceeded to melt an alloy head down into the "trolley" and the wheels. It took a while to clean up the damage. We came in on a Monday mornig and found molten aluminum coming from under the oven door. The shop was up around 100 degrees. All the safetys failed.
Sandy,
If the block is old and rusty, I cannot imagine a hot tank getting it as clean as an oven / shot blast system does. We have had a oven and shot blaster since 1988 an I cannot imagine cleaning old cast iron parts any other way. They turn out looking like new catings. You do have to be very thorough in getting the shot out. Our system has a big rubber lined drum that you tumble the blocks or heads in after they come out of the blaster. It bounces them around pretty good and we have never had a problem with shot retention. We also run every thing through our spray washer after machining so that helps too. I only tried running aluminum one time and was not real happy with the way the blaster beat up the castings, so we still spray wash and glass bead aluminum.
If the block is old and rusty, I cannot imagine a hot tank getting it as clean as an oven / shot blast system does. We have had a oven and shot blaster since 1988 an I cannot imagine cleaning old cast iron parts any other way. They turn out looking like new catings. You do have to be very thorough in getting the shot out. Our system has a big rubber lined drum that you tumble the blocks or heads in after they come out of the blaster. It bounces them around pretty good and we have never had a problem with shot retention. We also run every thing through our spray washer after machining so that helps too. I only tried running aluminum one time and was not real happy with the way the blaster beat up the castings, so we still spray wash and glass bead aluminum.
G
Guest
·I figure it won't be much longer before the last generation of old-man Machinist shops bite the dust b/c of the EPA!
The hot tanks use Cresol and, (I think), boiling water as the cleaner AND it is one bad actor, environmental-wise!!
pdq67
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
The hot tanks use Cresol and, (I think), boiling water as the cleaner AND it is one bad actor, environmental-wise!!
pdq67
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
G
Guest
·No, I think they only toast it to about 450 degrees or so..
Just long enough to turn all the crap to ash...
Heck, we can toast heads on an old covered gas BBQ grill, but I wouldn't want to cook anything on it later..
pdq67
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
Just long enough to turn all the crap to ash...
Heck, we can toast heads on an old covered gas BBQ grill, but I wouldn't want to cook anything on it later..
pdq67
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
Joined
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6 Posts
I know this might sound stupid but if I had an old kitchen oven turned it to 450 degrees and stuck one of my old sbc head in it would it work? and if so how long do i leave it in there?
Joined
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7,294 Posts
Camaronut,
no 450 won't make it.
Couple of points:
Hot tanks & jet washers for cast iron use Caustic soda as the main ingredient for cleaning. It does little for rust.
I would never put an aluminum anything in an oven for cleaning.
The oven runs at about 700 degrees for cast to do a decent job. Any less will not bake all the greases & oils off especially synthetics & some of the "trick" additives out there.
A controlled 700 degrees will not adversely effect metallurgy.
Many stories abounded when ovens first came out with horror stories about how the block would warp, mains would wander off into never to be fixed land,,, all crap & probably perpetuated by hot tank manufacturers.
When I first got an oven we did a ton of blocks measuring main bores both before & after.
A few changed & my opinion is in these cases the oven relieved stresses in the block that somewhat like the Bonal system does only to a lesser extent.
This is a good thing in my opinion as I would rather have the stress relieved before machining & running rather than after,,,
Here is a post I did in another forum regarding cleaning systems.
http://www.speedtalk.com/forum/viewtopic.php?t=1719&highlight=oven
I use both & if you are only getting one for now the jet washer is your friend
You will probably want two eventually, one for cast & one for aluminum.
I have never found a compound that will clean cast iron that is safe for aluminum.
Our aluminum washer is used for both aluminum & for washing "clean" stuff like after honing a block or doing other machine work prior to hand washing so it stays pretty clean for a long time & stuff comes out ready to finish with soap & water by hand.
The oven with a blaster using stainless steel shot does an excellent job of PRECLEANING but there is still a ton of work left.
Been using the bake & blast for about 10 years now & love it as blocks come out looking like new but it is not a stand alone system regardless of what the salesman tells you.
It removes everything including rust but as Bill stated, you still need to clean the block with either a jet wash or steam cleaner if allowed & a lot of hand work.
I do not like the ovens that are direct flame rather the controlled temp ones like Bayco & Peterson where the flame never touches the part.
Much slower but I feel a lot safer.
If you cheap out & use regular steel shot the block will be filthy.
Stainless shot is expensive but leaves much less dust & crap that is a bitch to get off.
I never clean anything but cast iron heads & blocks in the oven,, again regardless of what the sales guys tell you.
And yes, getting the shot out of everything is a real good idea & is not done by any machine no matter how much you "shake" it,,,
You need to check everywhere but you are doing that anyway,, right?? :lol:
We spend a lot of time hand cleaning after the block goes through the blaster & then it still goes into the jet washer before any machine work is done.
And,,, you probably already know this but all cleaning crap is going to be the single biggest money loser in your shop,,,
The washer may or may not take off all the paint. The aluminum safe one probably won't the majority of the time & the caustic one will take off most paints but not all.
Here are a few pics of a block we did for a fello TC member that needed to run a 327.
Try this in a jet washer
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no 450 won't make it.
Couple of points:
Hot tanks & jet washers for cast iron use Caustic soda as the main ingredient for cleaning. It does little for rust.
I would never put an aluminum anything in an oven for cleaning.
The oven runs at about 700 degrees for cast to do a decent job. Any less will not bake all the greases & oils off especially synthetics & some of the "trick" additives out there.
A controlled 700 degrees will not adversely effect metallurgy.
Many stories abounded when ovens first came out with horror stories about how the block would warp, mains would wander off into never to be fixed land,,, all crap & probably perpetuated by hot tank manufacturers.
When I first got an oven we did a ton of blocks measuring main bores both before & after.
A few changed & my opinion is in these cases the oven relieved stresses in the block that somewhat like the Bonal system does only to a lesser extent.
This is a good thing in my opinion as I would rather have the stress relieved before machining & running rather than after,,,
Here is a post I did in another forum regarding cleaning systems.
http://www.speedtalk.com/forum/viewtopic.php?t=1719&highlight=oven
I use both & if you are only getting one for now the jet washer is your friend
You will probably want two eventually, one for cast & one for aluminum.
I have never found a compound that will clean cast iron that is safe for aluminum.
Our aluminum washer is used for both aluminum & for washing "clean" stuff like after honing a block or doing other machine work prior to hand washing so it stays pretty clean for a long time & stuff comes out ready to finish with soap & water by hand.
The oven with a blaster using stainless steel shot does an excellent job of PRECLEANING but there is still a ton of work left.
Been using the bake & blast for about 10 years now & love it as blocks come out looking like new but it is not a stand alone system regardless of what the salesman tells you.
It removes everything including rust but as Bill stated, you still need to clean the block with either a jet wash or steam cleaner if allowed & a lot of hand work.
I do not like the ovens that are direct flame rather the controlled temp ones like Bayco & Peterson where the flame never touches the part.
Much slower but I feel a lot safer.
If you cheap out & use regular steel shot the block will be filthy.
Stainless shot is expensive but leaves much less dust & crap that is a bitch to get off.
I never clean anything but cast iron heads & blocks in the oven,, again regardless of what the sales guys tell you.
And yes, getting the shot out of everything is a real good idea & is not done by any machine no matter how much you "shake" it,,,
You need to check everywhere but you are doing that anyway,, right?? :lol:
We spend a lot of time hand cleaning after the block goes through the blaster & then it still goes into the jet washer before any machine work is done.
And,,, you probably already know this but all cleaning crap is going to be the single biggest money loser in your shop,,,
The washer may or may not take off all the paint. The aluminum safe one probably won't the majority of the time & the caustic one will take off most paints but not all.
Here are a few pics of a block we did for a fello TC member that needed to run a 327.
Try this in a jet washer
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