Thu Jan 06, 2005 9:18 pm

I notice that our local Walmart now carries the little siphon feed sandbalsters that have a tube you just stick down in a bag of sand for $20.

Fri Jan 07, 2005 7:13 am

John - If you get one of these please post a review.

Did I understand correctly that if one left a part in an electo tank long enough that it WOULD remove paint?

ken

Fri Jan 07, 2005 8:00 am

I've found electrolysis will quickly remove all but the most tightly held paint. If the paint looks loose, I've put the whole thing in the tank, particularly if it's a complex shape. But if the paint looks tight, I first try to strip off as much paint as possible, using oven cleaner, wire wheel, etc. After an hour or two in the tank, I usually pull the part out and if there are spots where the paint doesn't look like it going anywhere, I'll help out the process with a scraper or wire brush.

Getting off as much paint as possible simply reduces the amout of time the part has to stay in the tank. Same thing for degreasing. If good surface isn't exposed, you don't get efficient electrolysis. Scraping off grease and degreasing accelerates the process. I've found oven cleaner works well for both grease and certainly paint. Haven't had great luck with the green and purple degreasers, although in combination with pressure washer it is a start in stripping off the heavy stuff.

I just don't like the potential safeth implications of leaving the power supply on overnight and, after all electricity does cost something.

Also, after electrolysis the part is "electrochemically active", which means it will rust faster than before it was electrolyzed. You can't leave it the way it is, or a fine rust coating will begin overnight. I've found the phosphoric acid based metal cleaners passivate the surface. A coating of etch primer will then hold the part until I have enough parts done to get out the spray gun for priming/painting. This is the process I worked out last year, by trial and error (mostly error . . . ) on my first Cub project.

Fri Jan 07, 2005 8:09 am

That was going to be my next question - What brand name / type primer would be good? Is there a better type for say an engine block that will get real hot vs say a sheet metal fender?
Ken

Fri Jan 07, 2005 9:44 am

Ken:

Paul explained it quite nicely. But there is always a but. It has been my experience with the tanks that a couple interesting things seem to happen which I have yet to get a good explanation on.

A prime example is the front wheel rims. These puppies were in really sorry shape. Lots of rust, lots of loose paint and a fair amount of pretty tight paint. These ones I left in the tank for about 3 or 4 days - (mostly cause I got busy with something else and forgot about them). When I took them out of the tank, my son took the 4-1/2" grinder with a twisted wire cup and started cleaning them.

With very little time and effort - maybe 5 for an easy rim to 10 mins for a stubborn rim, he had all four cleaned up in very short order. No paint left on at all. What paint did not just fall off came off real quick with the brush. Needless to say, I also forgot to prime them. That was last May. They are still sitting in my shop, no primer and not a speck of rust on them.

Not sure why, but after they have been cleaned they did not rust as expected. Also, my two front axles show the same phenomenon, no rust. However, the two A battery boxes I left in the shop and forgot to prime do have a light coat of rust on them (new fabrications). Go figure.

The only reason I can see is possibly the concentration of TSP that I use. I do the finger check. I stick my hand in the solution (power off mind you) and rub my fingers together. If the solution feels a little soapy I guess you could call it, it is about right.

I start off with a 2KG package of TSP. After about 2 weeks I add another 1/4 kilo and maybe another 1/4 kilo after another 2-3 weeks. I seem to get to the saturation point then as any additional does not seem to affect how the tank works. Oh - I also top off the tank with fresh water as needed to make up for the process and secondary evaporation as well.

Oh - 2 kilo's is about 2.2 lbs to help in conversion.

Also, keep in mind that after about 12-24 hours the amperage output from your battery charger will reduce from say 6 amps to 1 amp. The reason for this is the electrodes has collected too much crud. I clean each electrode (re-bar) with the 4-1/2" angle grinder equipped with the twisted wire cup. I also clean the chain where it makes contact with the part being cleaned. Presto, amperage output is back up to 6 amps. Just something to keep in mind, helps the process go a little quicker.

I also clean the re-bar and chain in between parts getting dunked.

As for primer, you can use a rattle can type of cheap primer as a dust coat to keep the part from rusting. All other good primers require a hardener, so you have to have enough parts ready to use up a paint cup worth of primer. ( that is quite a few parts depending on size ).

After you have collected enough parts, then I have been using Dura Build red oxide as a base and then Dura Build Hi Build as the second coat. Gives a very nice base for the top coats of 2150. Also, the Dura Build red oxide is almost chip proof which I like.

Hope this helps some.

Fri Jan 07, 2005 9:59 am

Ken, I had one severeal years ago and recently bought an identical one from Home Depot, just before Walmart had them available. For the average homeowner/tinkerer they do a good job but are a little wasteful of sand due to it's coming out of the nozzle at a lower velocity. I sold my pressureized one and bought the siphon feed because I am no longer able to drag the big one around and fill it. With the siphon feed you can just stick the siphon tube in a bag of sand and go to work. The pressurized units such as I had before ( 40 pound unit form Harbor Freight) do work good, and the higher nozzel velocity cuts a little better, but 40+ piounds of sand, and another 20 or 30 pounds for the blaster is more than I can handle now, not to metntion picking up a 100 pound bag of sand and filling it. Another good idea would be the one Rick (billyandmillie) made from an old 20 pound propane tank. He says it really does a good job, which is not surprising, since it seems that everything he does turns out good when he's done.

Image

Fri Jan 07, 2005 11:34 am

Rudi wrote:Ken:


Oh - 2 kilo's is about 2.2 lbs to help in conversion.


Hey Rudi, I' sure you meant to say 1 kg = 2.2 lbs. Good to see your posts again - hope you are feeling stronger every day.

Fri Jan 07, 2005 11:45 am

Actually, Santa Clause brought me a low end siphon gun/hopper. And last evening I managed to horse trade with my brother to get his 220 portable compressor on a loan deal - :lol:

Now I need to rig up some kind of plywood workstation gizmo to reclaim my media...

ken

Fri Jan 07, 2005 11:49 am

You guys do it the hard way. I just swabbed out the tuna-fish can with a paint brush and brushed in on the dirty front wheels and called the Kitty,s and when they were done the wheels looked like this.

Image

Fri Jan 07, 2005 12:27 pm

I don't see a picture. Does that mean the kitties stole the wheels?

kh

Fri Jan 07, 2005 12:45 pm

Here it is:

Image

Fri Jan 07, 2005 1:29 pm

I think I am going to start wearing my boots when I read this forum. Maybe waders?

Fri Jan 07, 2005 1:41 pm

Hi Rudi

When I took them out of the tank, my son took the 4-1/2" grinder with a twisted wire cup and started cleaning them.

With very little time and effort - maybe 5 for an easy rim to 10 mins for a stubborn rim, he had all four cleaned up in very short order. No paint left on at all. What paint did not just fall off came off real quick with the brush. Needless to say, I also forgot to prime them. That was last May. They are still sitting in my shop, no primer and not a speck of rust on them.


I think what happens when you power wire brush is that you burnish the surface. I haven't experienced that it prevents rust, but I have experienced that it does not leave a very good surface for painting. Maybe it's the same phenomenon.

I found if you go wipe over a power wire brushed surface with paint thinner you'll be amazed how much black residue you can get off. After several paper towels, it will come clean, and then the primer will stick much better. I once wire brushed my front rims without doing the cleaning step, and then primed them. Even though there had been no trace of red paint visible, after priming there were traces of red color bleeding through the primer. Even though it looked like clean metal, apparently there is residue there, and you don't provide as "raw" a surface for the primer to bite into, and therefore not as good adhesion.

Maybe the wire brushing forms a microscopic layer to form which also prevents rusting (oxidation). But brushed surfaces should always be cleaned with solvent prior to priming to remove the burnished residue.

Fri Jan 07, 2005 2:34 pm

Paul:

I think what happens when you power wire brush is that you burnish the surface. I haven't experienced that it prevents rust, but I have experienced that it does not leave a very good surface for painting. Maybe it's the same phenomenon.

I found if you go wipe over a power wire brushed surface with paint thinner you'll be amazed how much black residue you can get off.


You may have hit on it. It could be the residue that is acting as a virtual primer and not allowing the oxidization process to begin.

As for the primer, before I ever begin I use varsol for general cleanup and then lacquer thinner to ensure the surface is as clean as can be before I begin the priming process. Otherwise, the paint would probably flake off. At the price of primer/paint, it makes sense to do it right the first time.

Bill:

Yup, FFS has struck again :!: :oops: :roll: :oops: :D Fat Finger Syndrome that is.

1 kilo = 2.2 lbs. 2 kilo's = 4.4 lbs.

Now I really feel embarassed :!: :!:

Russ:

Good idea. I have used the sand blaster to clean up hard to get at areas on plow's and such and I imagine some areas of the castings may require a little help from the sand blaster.

For those of you who are like me and would rather use what I have around the shop and save cash for IMPORTANT purchases such as Cub Parts, don't forget to check out the Sand Blaster on the Cub Manual Server.. It really does work and it rolls very easily even with a full bucket of sand. Bigger or wider wheels with roller bearings would make it even more moveable.

Fri Jan 07, 2005 2:48 pm

KenHigginbotham wrote:I don't see a picture. Does that mean the kitties stole the wheels?

kh


Now thats weird. The picture was there earlier when I posted it but now all that appears is a small grey blank box. But as usual "Never-Fear" cause BigDogs Saint Bernard comes to the rescue. Thanks B.D.