Welcome! Please use the navigational links to explore our website.
PartsASAP LogoCompany Logo Auction Link (800) 853-2651

Shop Now

   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver

Antique Tractor Paint and Bodywork

Re: Spraying topcoat around corners and more dummy

[Show Entire Topic]  

Welcome Guest, Log in or Register
Author 
Rod (NH)

05-24-2006 19:39:51




Report to Moderator

Mace,

I'm not sure what you mean by "second coat effect". It sounds like you are talking about what happens when fine paint droplets (overspray)from the current coat application land on a surface where the paint is either already dry or so far beyond the flash point that the fine droplets of fresh paint in the overspray do not melt in well, if at all. I don't think you'd have a problem if you paid close attention to flash times between coats and start the next coat shortly after the previous coat has flashed. I'd do the hard to get at areas first and then proceed to complete that coat. After the flash time has passed, repeat that same method in the same sequence on the second coat. Then do the same for a third. You want the paint at the point where you end up on any coat to melt in nicely with the paint where you started on that same coat. You also need to allow a certain amount of time between coats to permit refilling your gun cup or mixing up more paint, if needed. Hopefully you can estimate the quantity to mix such that no mixing will be required between coats. I'll give you a for instance: If the flash time is 5-10 minutes (for OMNI MTK at 70F), then you don't want to take 20 minutes to complete a coat. With that scenario, I'd plan on spending no more than 5 minutes in applying a coat. Between coats is generally not the time to go for a coffee break. You need to get on with the second coat as soon as possible after the flash time has passed for the paint where you started. As B--- indicated, you should choose the correct reducer (and hardener if used) for the temperature at the time. Air temperature and metal temperature should be the same. Using a fast reducer in warm temps is only going to make it more difficult for you, not only with poor flowout but also possibly with poor melt in of overspray at the end of each coat. The OMNI MTK topcoat that CNKS and I use has four different temp reducers and three different temp hardeners available. The correct one to use is selected based on the temperature at the time of spraying. Most automotive paints are similar. I don't know what paint you are using but you should get the appropriate tech sheet from the manufacturer that would provide this specific information. If you cannot complete the area you're painting without greatly exceeding flash times between coats, then you should mask off the area as needed to do it in smaller, separate pieces.

third party image Rod

[Log in to Reply]   [No Email]
CNKS

05-24-2006 20:04:01




Report to Moderator
 Re: Spraying topcoat around corners and more dummy in reply to Rod (NH), 05-24-2006 19:39:51  
The second coat effect, what I call dieback, usually occurs when I spray an irregular surface and for whatever reason, respray an area that has not yet flashed. As an example, I might paint from the front of the tractor to the back, but not painting the square axle housings which are at a 90 degree angle to the transmission housing. I then paint the housings, but some of the paint gets on a portion of the transmission housing I have just painted, but it has not flashed yet -- not saying I have actually done that exact thing, just trying to think of an example. In that case, I should wait until the paint on the chassis has flashed before I paint the axle housings. I usually don't preferring to give everything one coat. Sometimes it gets me. I don't think I have had that problem to any great degree since my first tractor, though.

[Log in to Reply]  [No Email]
Rod (NH)

05-24-2006 21:20:40




Report to Moderator
 Re: Spraying topcoat around corners and more dummy in reply to CNKS, 05-24-2006 20:04:01  
I know you've mentioned that problem before. I am still puzzled by it and don't have an answer. I guess mainly because I don't recall ever experiencing something like it myself. No matter what you paint, at some point you will return to the place where you started. At that point you will have the new paint, and the unavoidable overspray associated with it, meet up with the paint previously laid down when you started that coat, perhaps only one or two minutes before (well under the stated flash time). That overspray should melt in quite nicely with no loss of gloss. I don't think that just because you are not able to get a perfectly perpendicular application it would make much difference. The only time you are ever able to achieve that and maintain a constant distance to surface throughout the pattern is with a flat plate as a target. That's a nice goal but it's seldom achieved. In your example, I certainly wouldn't stop and wait for previous fresh paint at 90 deg to get past the stated flash time. Quite the opposite. I'd want to get that area sprayed just as soon as possible so whatever did get on the adjacent paint was able to melt in well with it before it reached the stated flash time. After all, as soon as you make a second pass anywhere, the 50% overlap is actually applying more paint to previous paint that hasn't flashed. Maybe I'm all wet here or just don't understand the problem. Perhaps B--- or Ex-pro or someone can add something better or different.

Rod

[Log in to Reply]  [No Email]
B-maniac

05-25-2006 17:26:38




Report to Moderator
 Re: Spraying topcoat around corners and more dummy in reply to Rod (NH), 05-24-2006 21:20:40  
Sounds like overspray instead of die back. I agree with Rod,keep it all as wet as you can without inviting more dirt. Plan your job ahead so your "return to start point" will be underneath or in a nonconspicious area.Sounds like you have it figured out.



[Log in to Reply]  [No Email]
CNKS

05-25-2006 07:31:55




Report to Moderator
 Re: Spraying topcoat around corners and more dummy in reply to Rod (NH), 05-24-2006 21:20:40  
This is probably getting more involved than is justified -- I don't consider it a major problem, just one of the things I mention. One thing about cast iron is that it "hides" defects. In other words it is possible to spray an area that was missed and not worry about blending it in with the previous coat. The defect is indeed there but on sheet metal it would look terrible. That's what I meant about letting the chassis flash, then painting the 90 degree axles. The main part of the paint going on the flashed area will blend in with the previous coat and really won't be noticeable. The "overspray" at the edges will be noticeable as it will immediately dull the finish. It may be 6 of one with your suggestion, and a half dozen with mine, I don't know. Whereas with sheet metal, you would probably have to do the whole panel, regardless of which method is tried. In that case I would mask at a natural break or seam. There are many such areas on cast that if done that way would make it perfect, but would take a lot of time. After saying all of this, I really am not sure that the "dieback" is what actually happens, I just notice some occasional dulling on cast that I do not see on sheet metal, and it shows up some time after painting, it looks ok at first -- so at this point in time my comments are just a big guess. I now have to go fix some screwups on my fenders -- I ordered that small buffer you told me about, gets here in about an hour. I should be able to control it better and get out some of my small scratches that were caused by my large buffer.

[Log in to Reply]  [No Email]
[Show Entire Topic]     [Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:


TRACTOR PARTS TRACTOR MANUALS
We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]

Home  |  Forums


Copyright © 1997-2023 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters

Website Accessibility Policy