Picked up an old hydrant from the city for use as a landscape item in my backyard. I've stripped it (using "citrus strip" which worked really well). The strip took off probably 95% of the paint. Took my wire grinder to it to remove what I am guessing was left of the primer. Got caps and the top to clean bare metal. The barrel has probably 98% bare metal, but there is still areas that have at most one light dusting of probably primer in the unevenness. I stopped because there are some area where my grinder can't access so I knew I'd have to get some of it blasted.

So my question is, how clean does the metal need to be to powder coat? Pure bare metal? Except for the few inaccessible areas the only thing left on it is some of the red "dusting" in the little bumps.

Also, if anyone has done any media blasting did I waste my time by removing what I could and then having someone do the finish blasting? i.e. will they spend the same amount of time going over the surface area whether there was paint there or not? I would think they would be able to go faster but I'm not in the biz.

 

Sand or media blasting is very quick. It would have done all the paint removal in minutes for you.
How are you powder coating ? Taking it somewhere to have it done ?


I had a fire hydrant in my garden. It was attached to a 4' piece of cast iron pipe that I had stuck in the ground. A very heavy affair. Was in there for 30 years or so. Now it's in a new home.

 

I'm going to go around tomorrow to a few local business to price it out. I was also going to ask them also whether it was a waste of my time to strip it down to what it now. It had a lot of paint on it so hopefully they'll take that into account as what's left won't pollute their media very much.I was also testing out some things while stripping for future reference/project so no matter what it wasn't a complete waste of time.

I'm guessing the hydrant weighs on the plus side of #150 lbs so yes, it's a heavy affair.

Any input on whether powder coating needs complete bare metal to adhere?

 

As far as I know..... yes.... it needs bare metal. They charge the piece electrically and spray it with the paint powder and then bake it in an oven.

I painted mine several times but never did a full paint removal.

 

My oldest son used to work in a shop that built race car chassis's. The completed frame was always sent out to be powder coated. Even though it was all new steel the powder coat shop would sandblast them first. Like Pete it's my assumption that powder coat requires clean bare metal.

When you stop at a shop to get an estimate, take a pic of your cleaned up hydrant with you so they'll have a better idea of what needs to be done and how much to charge. Personally I'd just apply a coat of a rust inhibitive primer and 2 coats of oil base exterior paint ...... but it doesn't hurt to find out how much they'll charge for powder coating.

 

Just an update. The place I decided on said that they blast everything anyway no matter what condition it's brought in. Both of you were correct. The price wasn't bad either. They gave me a bit of a break on price but after talking with them it's obvious it really not worth it to do much prep work as the speed/time difference they incur isn't all that great if paint is on or if it's close to bare metal.

Again, it wasn't time wasted as I was trying out a few different methods for future reference, but if/when I get additional items powder coated, they're getting it as it is.

The reason I'm having it powder coated vs painting is the color red is very susceptible to fading, even with a good clear coat. Plus it'll even out a bit of the roughness whereas paint pretty much shows every flaw.