Prepping a Saw for Painting

[Deleted]

I know many people use a very fine bead blast to prep for paint, but if you don't clean magnesium first you will drive dirt and oil into the softer metal and therefore compromising the finish. After the saw is apart, I usually scrub and scrape the heavy stuff off in the parts washer and use a carb cleaner, brake cleaner rinse. After it dries, find a mop bucket or small tub to clean it in. The solution that many agree works best(you may have to double the amounts to get the saw really coated and submerged) is 30 grams (little over an ounce for non-hippies), of sodium carbonate (soda ash pool chemical), 30 grams of trisodium phosphate (TSP, sold in the big box stores), 1 gram of synthetic soap (seventh generation dishwashing detergent from Walmart), and 1 liter of distilled water. I would double or triple these amounts to give the saw a good bathe and be able to dilute the oil and dirt in a larger volume of solution. A toothbrush and stiff cleaning brush works well to scrub and clean the surfaces. You don't have to do a clean water rinse, but I like to rinse any residue off with clean distilled water and let air dry for 24 hours. You may want to blow the parts of with a air compressor and store them in a dust free environment while drying. These steps will greatly improve the finish product whether you are using hi-aliphatic polyurethane or rattle cans, and its fairly easy to do. Remember to wear eye and skin protection and at least a small particle mask.

[sweepleader]

4 oz of dry powder in 1 liter of water? Is that right?

[Deleted]

May 6, 2018 20:01:55 GMT -5 sweepleader said:

4 oz of dry powder in 1 liter of water? Is that right?

A little over 1 ounce of sodium carbonate, the same amount of TSP and 1 gram of synthetic detergent in 1 liter of distilled water, to make a larger quantity just increase amounts exponentially.

[sweepleader]

I didn't read that right the first time, that is still a very strong solution. Thanks for straightening me out.

[Deleted]

I'm using an automotive lacquer primer filler, I spray, sand, spot fill, spray, sand, and spot fill, then spray over the spot filler. Last round of sanding will remove most of the primer except where spot filler is and bare spots were. I'll use my small vacuum and a tack cloth to remove any dust and paint with the metallic finish later this week when the humidity gets below 80 percent. If I'm not happy with the color I'll have it reformulated and shoot it again. Most people leave a full coat of primer on a saw, I think this is a mistake on magnesium using the primer products that most of us use. Unless we have blasted the saw bare and use a catalyzed urethane primer, the primers we most often use are the weak link in the final product. The only place I want to see primer is on spot putty and low areas that were feathered out.


20180519_211702 by Al Michaels, on Flickr


20180519_211713 by Al Michaels, on Flickr


20180519_211718 by Al Michaels, on Flickr

[onlyhomelites]

I look forward to seeing some pain on this one!