Please help, 1st time painter

Brad

I'm flattered but it is not really deserved. I am no different than any other DIY except that I have been messing around with automotive paint on and off for a good many years and have learned to read and follow available manufacturer's information. Today's internet has made that job real easy with manufacturers having the information available on their websites. I can remember having a difficult time getting the tech sheets from a jobbers stash in the back room, if he had them at all. Both PPG and DuPont used to publish (for purchase - not free) excellent manuals on all aspects of automotive painting geared specifically to their own products. PPG's was called "Ditzler Repaint Manual". DuPont's was called "Auto Refinishing Handbook". They were both excellent reference materials in addition to the individual tech sheets for each product. I don't know if these things are still published. I had to specifically request my jobber to order them for me when I got mine. That was a long time ago. I suspect any current versions would give primary attention to base/clear finishes and much less to single stage.

If you are a first time painter on a limited budget, I recommend you think twice before using a hardener in any paint. You are unlikely to have or be willing to purchase ($400 and up) the appropriate breathing protection for using such additives. The subject has been discussed many times in this forum. Do a search on "isos" or "isocyanates" for more than adequate background information. Your good health is more important than your paint job.

I do not recommend using a reducer or a hardener not meant or specified by the paint manufacturer for use in his product. If you are going to use a dealer paint, follow the specific instructions on the can label for all mix ingredients and proper usage.

A big no to the use of lacquer thinner for a cleaning/degreasing agent. That and other similar products, such as gasoline, evaporate too fast for proper surface cleaning. Use a product designed specifically for the purpose. A search of this forum should yield recommendations for materials and practices in that area.

Products used to clean equipment are usually specified on the can label.

There are no secret tricks or magic formulas for a good paint job. Following instructions and lots of practice are the rules. Avoid mixing and matching materials that were not specifically intended to be mixed together. Follow the paint manufacturer's written usage instructions. Adhere to the fine-print recommendations regarding safety, particularly relative to the use of hardeners. Those are the best ways to achieve success, no matter which paints (high-end or low-end) you choose to use. There is plenty of information to be found for the beginning painter by browsing the threads and archives of this forum - more than you'll probably want to read. See also the thread just below started by DavidO on 8/19. And do some practice-painting on something else before you tackle your tractor. An old car hood or door would be a great place to start.

Rod

Depending on your local air-emission laws, you may have to purchase the MS250 for the 181 instead of the standard MR reducers. The MS250 is an exempt solvent (basically acetone). Check with your supplier first before you buy any MR reducer. I once bought some 181 and was forced to buy the MS250 along with it at the same time, even though I had plenty of the standard MR reducers on hand - which can be used since they are on the tech sheet for the 181. If you do use an MR reducer in the 181, I'd recommend a slower than normal one for the temp involved. It's easy to wind up with a dry spray with a fast reducer in a lacquer based product.

Be aware that I have never used the exact combination of products that you mention. I simply believe that you would not have a compatibility problem using them. The 181 over 170 is per the tech sheet so the risk there is zero - no problem. The only issue in whether there is something in the solvents used in the 2150 that could cause a problem with a lacquer-type surfacer. I doubt it, but can't guarantee anything. I think it would be worth a small test sprayout to be sure. If there were to be a problem, I think the fix would be a coat of reduced (per tech sheet) MP170 over the 181 to act as a sealer prior to the 2150. You could even do that anyway as an insurance item. I am very confident there would be no problem with 2150 direct on 170. Don't forget the time window you'll be dealing with on the 170.

I am not familiar enough with DuPont's NASON line to comment specifically. I don't know what the 414 stuff is at all. I don't see it listed on DuPont's website. NASON is DuPont's "value" line of products and should be similar in cost and quality to PPG's OMNI. I do know that NASON's Ful-Cryl II acrylic enamel cannot be used without an iso-containing hardener. That's unlike the OMNI MAE acrylic enamel. In fact, it's unlike most acrylic enamels. The devil is always in the details.

If you want to avoid a surfacer product and minimize sandscratches at the same time, I'd recommend a final machine-sand with something like 320 grit prior to applying the 170. That's a little finer than what the 170 tech sheet calls for but I have done it successfully w/o having any adhesion problems. If your sheetmetal is in good shape and you don't need to do any sanding (e.g. you're using a chemical stripper to remove any old paint) and it's rust free, you can even use a Scotch-Brite hand pad to scuff the clean metal, remove any sheen and get at least some tooth for the 170 to adhere to. Epoxies are great anyway but having a little tooth always helps. If there is any hint of light rusting on unsanded sheetmetal, you should do a phosphoric acid cleaning/conditioning metal treatment using products like PPG DX579/DX520. A Scotch-Brite pad is used with these products also so you'd get rid of the rust (light only), etch the metal and provide some tooth at the same time.

As CNKS says, dents, pitting etc, require additional steps to eliminate or at least minimize their appearance afterwards. At some point, you really do get diminishing returns for your effort. Unless you are a real stickler for detail, I'm sure you will do just fine with the plan you have. I think your biggest problem will be to get a little spray time under your belt to build up your confidence level. That means doing some practice painting.

On new (or excellent condition) steel with no rust, after degreasing with DX330, I've just scuffed with a maroon (general purpose) Scotch-Brite pad, applied two coats of 170 and topcoated directly with MTK. No hint of any "sandscratches" and no later problem with adhesion, at least after three years. The maroon Scotch-Brite grit equivalent is 360. I suppose if I knew that a particular part was going to be subject to particularly rough treatment, like abnormal flexing or something, I would probably choose to go with the 120-180 + surfacer per the tech sheet. Mostly though I would not, unless I knew beforehand that surfacer was going to be needed anyway because of dent or pit repair or something else requiring grits that coarse.

Some time back, on Autobodystore.com, I recall seeing the results of adhesion tests for application of polyester filler (Bondo). The issue was whether it was "better" to apply the filler directly to bare metal or apply epoxy first and then the filler. Opinions differ sharply on this, just like they do on epoxy vs etch primer. The conclusion was the application of the filler to bare metal was better than to epoxy, all other things being the same. That is, of course, something that I rarely ever do. For unrelated reasons I much prefer applying the epoxy first and then the filler. I have found that method to be perfectly satisfactory, even though it may not be "as good". In other words, I accept the fact that it's "best" to apply filler directly to metal from a strict adhesion standpoint but I remain unconvinced that the difference is serious enough for me to change from my preferred method. I think a similar reasoning can apply to the rather heavy sanding of otherwise smooth and clean sheet steel, especially when an epoxy is going to be used.