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Up Topic Welding Industry / Technical Discussions / clear coat for mild steel
- - By Alison (*) Date 04-10-2004 20:58
I welded together some mild steel frames for a friend of mine, and am wondering what are some good ideas to clear coat the steel with? I have used a product supposedly for use on steel if inside (ZIM), but it is water based and creates small rust "blooms" just by being applied. I've used cheap spray on clear coats, but they seem to only help so much. I can't afford fancy and expensive powder coats, and I am looking for something fairly accessible and direct.

Oh and yea, if I didn't already say so, I don't want rust.

Any ideas?
Parent - - By billvanderhoof (****) Date 04-11-2004 03:45
Try boiled linseed oil on a piece of scrap. See if you like the result. It's what grandpa would have used. Not too durable if exposed to the sun.
Parent - By thcqci (***) Date 04-12-2004 12:54
As in all coating operations, surface preparation starts the process and is the most important step. Make sure all the dirt, oils and moisture is off the steel by cleaning with solvent (compatible with your coating) per SSPC SP-1. Does the steel have mill scale? Is it important to remove it if it exists? SP-2 (hand tool cleaning) and SP-3 (power tool cleaning) do not require removal of tightly adhereing mill scale. Resist the urge to sand or grind the surface smooth because you will not be leaving any profile for the coating to adhere to. Are you sand blasting the steel? More thorough, but not necessarily required if lesser preparation is sufficient. I would probably lean toward a moisture-curing polyurethane coating (from the isocyanate group). They function well in corrosion control (primers for steel) and exterior topcoats (aliphatic types). Do not know what part of the country you are in but contact a coating specialist in your area of the country to see what they recommend. Contact SSPC for further information also.
Parent - By CHGuilford (****) Date 04-12-2004 13:34
I assume you are shining up the steel and want to preserve that look? I don't know of any clear coatings that will be very durable over bare steel. Most of them are intended to go over a pigmented base coat of some kind. Pigments do much more than simply color the paint. They help with adhesion, provide the barrier that protects the surface, resist coating degradation, and so on. The clear coat will stick by itself but it usually won't last.
I'd recommend a silver colored paint on top of a compatible primer and apply a compatible clear coat, for a more durable coating. As was mentioned, surface preparation is very important to a satisfactory coating.

Other than that, I would contact a rep from Sherwin- Williams, Carboline, or any other decent paint supplier, for their recommendations on what you want to accomplish. Even your local NAPA could provide helpful info. I have found that those reps often have good suggestions that I never would have thought of.

Chet Guilford
Parent - By thirdeye (***) Date 04-12-2004 14:34
You might also want to talk to an automotive body shop. They have helped me out on some odd projects. The last one that comes to mind is repainting a metal front door. The color selection was unlimited and the finished quality was great. The price was very reasonable.
Parent - By weldsman (*) Date 04-20-2004 20:14
I have a friend that does a lot of metal sculpture, an he uses Future floor wax with great results on bare metal. He told me it will last about a year outside, and then you just re-wax it. Inside it will last a long time. Good luck!
Parent - By uglyjeep Date 10-15-2004 16:25
I do a lot of fabrications such as rollcages and custom off road components. Some of these items that I want clear coated I paint with a clear spray paint made by Plasti-kote, #229, it is a heat resistant, up to 500 degrees, engine enamel style paint that is the most durable and longest lasting clear finish I have used out of a bunch of them out there. I use it on drive shafts and front axle shafts and welded tube structures, and I have corrosion protection, excellent chip resistance, and a great finish that I can see the condition of the metal and welds underneath, and on top of it, the stuff dries superfast, I'm usually able to handle it after 15 minutes!
Up Topic Welding Industry / Technical Discussions / clear coat for mild steel

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