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View Full Version : Ultrasonic Cleaner to strip paint



Mac
3rd Sep 2017, 08:53 AM
I saw some great videos of folks using these to strip paint off of metal and plastic miniatures and have been dabbling with stripping paint off of some passenger cars.

https://www.youtube.com/watch?v=hCiqRUB3Ums
https://www.dakkadakka.com/dakkaforum/posts/list/30/420110.page

Anyway, I just ordered one but have not received or tested yet (I may position this as a gift for my wife to clean jewelry). I bought this one:
http://www.ebay.com/itm/Pro-2500ML-Digital-Ultrasonic-Cleaner-Bath-Timer-Jewelry-Cleaners-Heater-Timer-/332295368426
EDIT: confirmed the inner tank on this unit is 24.5cm*13.5cm*8.0cm (looks same or similar to the unit selling at Harbor Freight for $79.99.

I almost got this one which seemed to have a large enough reservoir for passenger cars -- http://www.ebay.com/itm/Aucma-Ultrasonic-Jewellery-glasses-Watch-and-Denture-Diamond-Cleaner-600ml-/332164287047 -- but opted for larger sized unit with a heater (smaller unit may have said not to run for more than 5 minutes).

I thought it would be interesting to post results here but also for others to post their experience if anyone is using these to strip paint off models.

Celidude
3rd Sep 2017, 12:51 PM
I've been looking to try one of these for a while now so I'm interested in your results. Last year my grandma bought me a "sonic jewelry cleaner" but it was one of those vibrating kind and not actually ultrasonic so I've been hesitant to buy another one and get the same thing.

rrjim1
4th Sep 2017, 07:27 AM
I purchased a cheap sonic jewelry cleaner and it worked OK. I then purchased a real Branson UltraSonic Cleaner and the difference was like day and night. It did a way better job in less than 1/10 the time.

Mac
4th Sep 2017, 07:51 AM
I purchased a cheap sonic jewelry cleaner and it worked OK. I then purchased a real Branson UltraSonic Cleaner and the difference was like day and night. It did a way better job in less than 1/10 the time.

Interesting -- those Branson's are pretty pricey (more than I could spend given likely infrequent use) -- on auction you can get some used / 'untested' for much lower prices so wonder how reliable vs. complex / fragile these units are. I went a step up in the cheap units so lets see how things go.

Mac
11th Sep 2017, 09:16 AM
Ok so after the first couple of trials I am not that impressed (although I may have been looking for miraculous results).

Ran some of my wife's jewelry through a few times (480 second setting) and it was definitely much easier to take tarnish off with tarnish-removing / silver-cleaning towel (just needed to wipe once and remaining tarnish came off and apprently normally wife has to really apply some elbow grease). Chains got better but ring and bracelet still need a bit more time and work. I used water with drop of dish soap.

Then tested on some trains -- first a before picture. Most trains have already been through 24 hours of soak in 91% alcohol bath and scrubbed a fair bit with a toothbrush (so these are the more difficult cases I was trying to strip). The B&O one in the middle had not been cleaned at all yet and the second from bottom is one I had stripped then painted with Rustoleum plastic-appropriate spray paint then tried to strip again. Others were painted (really badly) by someone else so not sure of paint.

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Ran them through the ultrasoninc cleaner a few times (480 second maximum length setting is really a limitation with the unit I bought -- you need one that can run for an hour or so I think). Used Simple Green cleaning solution (so hard to tell if my results are based on ultrasonic cleaner or based on Simple Green -- changing two parts of equation at same time is very bad form for experimentation (sorry).

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Here are the results after very minmal scrubbing. That blue Amtrak paint is really tough to strip. The B&O one is going back in for another couple of cycles and more soaking.

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Anyway, I think I would go for a more expensive unit. It seems like the differences come down to the length of time they can run -- go for something that can run for at least 1 hour -- as well as watts for the ultrasonic part of cleaner (this one is 35 watts but others go up to 60 watts and higher -- the Harbor Freight model that costs about 2.5x what I spent says it is 160 watts although I am not sure if that is all ultrasonic cleaner or also heater). The heater also seems to be a feature to look for since it may help break-down the paint / primer.

Celidude
11th Sep 2017, 04:15 PM
Can't say how good Simple Green is for stripping paint but that's still impressive results considering how robust those old Amtrak schemes are (definitely one of the toughest to get completely clean). I wonder what a difference of solution like 91% alcohol or brake fluid would produce, and having a longer cycle than 8 minutes would definitely help.

I've used the Harbor Freight air eraser with baking soda and had decent results but too much time in one area can muck up the finer details on a shell. It's been tempting to try my dad's brass cleaner that he uses when reloading ammunition, which we haven't done in quite a few years. I'm just not sure on what would be safe to use on these without being so abrasive to wipe the details clean off :lol:.

Mac
11th Sep 2017, 06:09 PM
Can't say how good Simple Green is for stripping paint but that's still impressive results considering how robust those old Amtrak schemes are (definitely one of the toughest to get completely clean). I wonder what a difference of solution like 91% alcohol or brake fluid would produce, and having a longer cycle than 8 minutes would definitely help. I've used the Harbor Freight air eraser with baking soda and had decent results but too much time in one area can muck up the finer details on a shell. It's been tempting to try my dad's brass cleaner that he uses when reloading ammunition, which we haven't done in quite a few years. I'm just not sure on what would be safe to use on these without being so abrasive to wipe the details clean off :lol:.

I actually started with 91% alcohol (that starting point where most trains are partly stripped was after soaking in alcohol for 24 hours and then with scrubbing). I will try some more that I have not done anything to yet in the simple green / ultrasonic cleaner combo so I can really see how it is working.
grrf recommended using a fiberglass pencil to rub off the final blue Amtrak details.

Celidude
11th Sep 2017, 06:31 PM
Whenever I soak my projects I try to set it on the washer/dryer when they're running, always helps to have that fluid moving to create a little extra scrubbing power. Just something else to take into consideration.

I've used a fiberglass pencil for a few other jobs and it works decently but make sure you wear gloves because it WILL get everywhere, especially with how much you need to remove on those coaches.

ChicagoNW
11th Sep 2017, 06:59 PM
Try using some ELO, it is Testor's/Floquil's paint remover for plastic.

It can be used multiple times, so it is a natural with the cleaning machines. It does get neutralized with water. So use the stuff full strength. Because it is thick I think it will be enhanced by the vibrations. Although I wouldn't drink it or use it as an eyewash, it is not nasty.

Unlike many other home brew chemicals, ELO doesn't react with the styrene in models. I have found that it will start to dissolve Squadron Green Putty if left on too long.

Because my painting skills are so poor, I have stripped some of my streetcar bashes half a dozen times. The bodies did not become brittle or coated with an oily paint repellant, like some of the suggested "strippers".

Mac
11th Sep 2017, 09:21 PM
And for my next trick -- er experiment -- some untouched painted passenger cars... Whoever made these must have strictly adhered to the 30' rule... I will post results...

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Mac
11th Sep 2017, 10:03 PM
After two cycles in the Ultrasonic cleaner (around 16 minutes) w/ Simple Green they are just about down to factory paint and decals (not sure what the paint was on these). I'm gonna put it through one or two more times before I go to bed and leave it overnight to get rid of factory decals. These are all dark plastic so just trying to get down to clean plastic.

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RH Bay
17th Sep 2017, 11:22 PM
I have a real cheap ultrasonic cleaner, but find that 91% alcohol and persistence works on almost any paint job. My cleaner has only one setting- three minutes. If I cycle it a few times, I notice the cars heating up, so I wouldn't want a real long cycle time. (BTW: I got the cleaner for another one of my hobbies - rebuilding classic fountain pens. One warning in that hobby was to only use cold water since an ultrasonic cleaner imparts thermal energy and some old rubber or plastic pen parts do NOT like heat) What works for me is to randomly wander by and push the cycle button while I am painting, model-building, etc, so I might spend a couple evenings slowly stripping paint. When I find a coating that won't even start to strip, I break out the oven cleaner and go outside. It gets almost anything!