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Years ago I got a 1/16 scale Monagram F 40 Ferrari, did some work on it including priming the rear (clear) window. I couldn't find what color it was supposed to be and assumed it was to be painted along with the rest of the model.

Recently I got to thinking about whether it was supposed to be painted and decided it shouldn't have. I put into a pot of brake fluid I'd used to strip something else black and primed.

Oh, boy what a mistake and disaster. The window was stripped of the primer, or at least softened so I could brush it off under the faucet. Now for the problem, it seems to have been dyed gray. I tried to get it clear by sanding and later by dipping into alcohol but nothing seems to have worked.  

1102(2).thumb.jpg.581862187f808f06aaa6ebbc34849b49.jpg5ae1ce8774407_1104(2)small.thumb.jpg.ab0751f0c5940df82ec5526059f13593.jpg

Sorry the images are so large, should have made them smaller to start with.

I know I should have provide fresh brake fluid but I didn't (didn't really think about it being dirty) so now I have a gray window.

Is there any way to de-dye it? or do I have to sand blast it? It is very thick so if I have to I can sand it until the color is gone.

I suppose I could just put them back into clean brake fluid but since both sides are that gray color I'm not sure it would help.

Any suggestions would be appreciated.

I don't have that small airbrush sand blasting kit and can't afford it just now.

Robert

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It's not dyed. It is etched by the hot primer, It need sanding and polishing to bring it back.

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29 minutes ago, 935k3 said:

It's not dyed. It is etched by the hot primer, It need sanding and polishing to bring it back.

Dr. Snake's second opinion concurs. You'll have to sand and polish.

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Forget it.

The clear plastic may also have been attacked chemically by the brake fluid. Different plastics react differently, and clear parts are chemically different from not-clear parts.

Even if the problem is only etching on the surface (from the primer or the brake fluid), it would take a lifetime of painstaking work to sand and polish all those little areas.

If you want to broaden your skill set, the part is probably large enough to use as a master to make a mold to make a vacuum-formed clear replacement from.

If it were me, I'd try to find a gluebomb that has a good window. Not impossible, but it will take some looking.

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Thanks all, I guess I'll try sanding first. The thought of using it as a mold is a little daunting but I have a vacuum pump from an old auto air condition station that I have always thought of using for vacuum forming but have never tried. Making a vacuum forming machine would be a bit of a job but since I've kept it all these years I might as well get going.

Besides it would certainly do my modeling skills a world of good.

Wish I'd known what Bill said about the possibility of the brake fluid attacking the plastic. Learn something new every day.

Robert

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16 minutes ago, Ro3bert said:

 Making a vacuum forming machine would be a bit of a job but since I've kept it all these years I might as well get going.

 

Maybe not as difficult as you think. The only problem is finding a Radio Shack (or something similar) that is still open for business

http://www.modelcarsmag.com/forums/topic/101743-poor-mans-vacu-form/

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2 hours ago, BigTallDad said:

Maybe not as difficult as you think. The only problem is finding a Radio Shack (or something similar) that is still open for business

http://www.modelcarsmag.com/forums/topic/101743-poor-mans-vacu-form/

Unfortunately the images on that site don't show up. Here is what I see: Vac0001.jpg

So I don't know how that person did it. I think I will try You Tube, they must have tutorials on vacuum formers.

Robert

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56 minutes ago, Ro3bert said:

Unfortunately the images on that site don't show up. Here is what I see: Vac0001.jpg

So I don't know how that person did it. I think I will try You Tube, they must have tutorials on vacuum formers.

Robert

I must be missing something...that site and this site are one in the same...modelcarsmag.com

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It's pretty easy to build a vacuformer. Grab a piece of perfboard; Radio Shack is where I found mine years ago. They used to carry plain perfboard without any metallic surfaces (at least on one side). Take some 1X4 lumber, and build a box just large enough so that the perfboard sits on it. The box should be 4" tall. Take some brads and fasten the perfboard to the top of the box. Cut a piece of Masonite or plywood  to the same size as the perfboard, and fasten it to the bottom. Drill a hole in one of the sides large enough for your vacuum cleaner hose (it should be a tight fit), and tape all the joints of the box.

If you can't find perfboard, try the home improvement stores. They have perforated sheet metal that may be useful, or maybe you could even use hardware cloth as a base, and cover it with window screen.

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1 hour ago, BigTallDad said:

I must be missing something...that site and this site are one in the same...modelcarsmag.com

I have found a few other posts on this forum with the same indication. Some have images, in fact, most but some that rely on Photobucket do not show up except for the image I posted above. It's a shame not to be able to see what people want to present. Frankly I don't think it is the posters fault and certainly don't understand why something should be "temporarily disabled" especially as I have gone back to posts that still have images that are "disabled".

Robert

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1 hour ago, SSNJim said:

It's pretty easy to build a vacuformer. Grab a piece of perfboard; Radio Shack is where I found mine years ago. They used to carry plain perfboard without any metallic surfaces (at least on one side). Take some 1X4 lumber, and build a box just large enough so that the perfboard sits on it. The box should be 4" tall. Take some brads and fasten the perfboard to the top of the box. Cut a piece of Masonite or plywood  to the same size as the perfboard, and fasten it to the bottom. Drill a hole in one of the sides large enough for your vacuum cleaner hose (it should be a tight fit), and tape all the joints of the box.

If you can't find perfboard, try the home improvement stores. They have perforated sheet metal that may be useful, or maybe you could even use hardware cloth as a base, and cover it with window screen.

So, Bill a household vacuum cleaner has enough power to evacuate a small former? I thought it would take a vacuum pump. Maybe I've kept that item for no reason, oh, well I will keep your idea on the back burner for a while.

Not sure what that perfboard is for. I can visualize a frame to hold the positive form and another above it to hold the piece to be formed. I guess an image of hand drawing would help me visualize what it would look like when finished. I do have an idea but have never attempted a device like that.

If I do make one and it is successful I'll post a how to thread.

Robert 

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Maybe I should have used the word frame to describe what is built out of the 1X4s. The end result is a box with a perfboard top, and a hole in the side for the vacuum source. The box shouldn't more than about 6x6 inches, so a decent vacuum cleaner with a clean bag and unobstructed hose should work.  I wouldn't try an upright vacuum without a hose.

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You also need to purchase (if you don't have one already) a heat gun.

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It's not a certainty that the brake fluid damaged the part internally, though it's a possibility. I know if you put naphtha on styrene and stress it in any way, it will crumble like a cookie, but let it dry out completely and it's fine again.

I'd at least try polishing a small, easy section to see what it looks like. I'd use #1000, then #1500, then #2000 wetordry, wet, and then Wright's Silver Cream. Walmart's Trim nail stick 3-set would make quick work of it, but they haven't had them in almost a year and I don't know if they ever will again.

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Get a Mattel Vac-U-Form Machine if you don't want to bother with building one. Here's a complete set available on ebay. And, you won't need to get a heat gun either. :) 

s-l1600.jpg

 

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I dug out my old homemade vacuum former for reference.  I made this after reading an article in a model mag, somewhere in the 90's. I had good access to plexiglass at the time.

It was designed to use a shop vac.connected via the plumbing connectors. I have so been unable to find the metal framework with handle that would clamp around a sheet of plastic (8.5 x 11). 

The method of operation was to place the buck (item to be copied) on the top and heat the plastic sheet mounted in the framework, place it in a toaster oven   until the plastic started to sag. Then quickly place it over the vacuum box and hit the shop vac "on" switch. 

I only used it once to try and duplicate a Cobras Daytona body for slot car use. Unfortunately it would not curve inwards at the base of the sides. 

 v1.jpg.8c8e5c35d0acbad900f1bcacb52028c0.jpgv2.jpg.97456ef7d608ecba78cb6bde04402c5f.jpgv3.jpg.6941b29bd13fbd60a96e920e0fb0b365.jpg

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That is almost exactly what I was describing without the # internal bracing, and built of wood. It ain't rocket surgery; pretty much any available material can be used that is sturdy enough to stand up to a mild vacuum. The red part is the perfboard. Thanks for the pictures and instructions, Jon!

I would support the part with modeling clay or something similar to prevent distortion or damage to the part, especially with a part of questionable quality.

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50 minutes ago, SSNJim said:

That is almost exactly what I was describing without the # internal bracing, and built of wood. It ain't rocket surgery; pretty much any available material can be used that is sturdy enough to stand up to a mild vacuum. The red part is the perfboard. Thanks for the pictures and instructions, Jon!

I would support the part with modeling clay or something similar to prevent distortion or damage to the part, especially with a part of questionable quality.

I filled the Cobra body with clay, now that you reminded me. Not sure what plastic I was using thou ?

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On 4/26/2018 at 11:26 PM, Ro3bert said:

So, Bill a household vacuum cleaner has enough power to evacuate a small former? I thought it would take a vacuum pump. Maybe I've kept that item for no reason, oh, well I will keep your idea on the back burner for a while.

Vacu-forming does not need high vacuum, but it needs a vacuum pump with fairly high cfm rating.  When the hot softened plastic hits the mold, it needs to be sucked down over the mold in less than 1 second. That is because the thin plastic sheet cools down and hardens very rapidly. Typical vacuum pumps will not be able to evacuate all the air trapped under the sheet of plastic in such a short time. Most small vacu-formers use a vacuum cleaner  type of motor/impeller to get the air evacuated fast.

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Peter,

I never thought of CFM and you are right a vacuum pump does not have much. However we have a Kirby vacuum cleaner which I suspect will have sufficient CFM to to the job. Too, there is the problem of heating the plastic, what kind of heating thingy should be used.

I suspect I should go to YouTube to check out the making of vacuum molding implements.

I will not be doing any vacuum molding in the near future but it never hurts to have your ducks in a row before you start.

Robert

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Posted (edited)

A vacuum formed copy will have very soft detail for those vents. Polishing will also soften the hard lines. IMHO, your time would be better spent looking for a replacement kit part. Put an ad in the wanted section. You never know what might turn up. I just sent off 3 packages to other members of this site, and I still need to get one sent out to Ace Garage-Guy.

Edited by LDO
Grammar

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Robert, here are the missing photos:

Vac0001.jpg.73834aba794f49697b622f1edbde015c.jpg

Vac0002.jpg.276ae31bfae1bf02379d4d2101a82cc5.jpg

Vac0003.jpg.002ae8177b146d09e9d3e4bdc0df5999.jpg

Hope this helps.

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