Radar Arch Removal / Painting

[TommyB]

Looks like I am going to need to remove the Radar Arch. Paint, bondo (guess it's bondo) some green, some brown, and some red looking material that they used to fair it.
Big hunks of it just comes off in 8" to 10" at a time if picked at with fingernail

How much does the arch weight?
How hard to remove?
Best way to paint this thing?

any idea as to why some places on top are 1/2" thick in bondo?
Not this best pics, was raining and did not want to remove the duct tape to show the actual 1/2" bondo/fairing stuff. Trying to get it to dry out

Thanks!

 

[SeaEric]

Is there a reason why it cannot be prepped and painted in place?

 

[TommyB]

Is there a reason why it cannot be prepped and painted in place?

No , would it not be easier to work with if off the boat?
and could take it to some paint shop, or do it in my garage depending on how hard to take off

 

[saltshaker]

Is there a reason why it cannot be prepped and painted in place?

That's what I'm wondering. Why would you want to take it and all of the equipment on it down? Most likely it's a bad patch jobfrom something that was removed. Should be isolated to that area unless there are other bad repairs. I'd fix it in place. If you're not comfortable doing it, a good glass guy can do it and most likely won't remove it.

 

[Red Hatt]

That's what I'm wondering. Why would you want to take it and all of the equipment on it down? Most likely it's a bad patch jobfrom something that was removed. Should be isolated to that area unless there are other bad repairs. I'd fix it in place. If you're not comfortable doing it, a good glass guy can do it and most likely won't remove it.

On my Dad's hatt the painter built a tent like structure around the Arch and did all the repairs and painting in the tent. No problems.

 

[TommyB]

well after much debate and grinding. Decided to remove the Arch
Only 4 2 1/2" 1/2 bolts on each side hold it down. I loosened one side to test the bolts and they came out easy.

Any Idea what arch would weigh? going to try and get it down with my davit

I Removed all the mounted stuff, and the unused cabling / wiring that was just crammed in there.
So, going to remove arch, have it sandblasted, after the 100 holes on the top are welded. Some holes are 1/2 all the way to 3" in diameter.
Have to decide now do I want it powder coated, or should I just stick with paint?
Any issues you guys know of with powder coating vs paint?
Prolly put a seaview mast up there to mount all the old/new stuff

Reason it's coming off, is this arch is trashed with pits / corrosion etc.

 

[TommyB]

Divit should be close enough to move it?

 

[drburke]

Hi Tommy,

Thanks for posting pictures. You said only 4 bolts held it on--where do they go: straight down?

Someday I will replace my arch with a tubular type and this is good background...keep the pics coming.

DAN

 

[TommyB]

Hi Tommy,

Thanks for posting pictures. You said only 4 bolts held it on--where do they go: straight down?

Someday I will replace my arch with a tubular type and this is good background...keep the pics coming.

DAN

Yea, straight down. They are in that access panel in the pics above. Easy to get to.
I was amazed at how easy the bolts came off. Hopefully that's all that holds arch there unless it's also glassed on

Not much thread of the bolts is even used. bolts are about 2 1/2 inch long, and probably only about 1/2" of it threaded into the hole (which is a little scary to think that is all that holds it on.
Looks to be a piece of threaded aluminum plate the bolts go into.
Will know more tomorrow

Paint looks good in the pics, until you pry at a piece of it, and a 10" section comes off that is not even adhered to the aluminum. lot of water under the paint which means lot of pits and corrosion.
Can spend a month grinding or hopefully 3 / 4 hrs of sandblasting to get it back to shinny

 

[34Hatt]

Aluminum Best to take it off and it should be sandblasted then acid washed followed with Alodine then primed with out it sitting around in-between for days. Best is all with in 2-3 days max it makes a difference in how long it will hold up! No matter what you do that will happen again some day
Unless you keep it in your back yard and you don't live on the coast

 

[jim rosenthal]

You could have it powder coated- that might last longer than paint, if you can find a powder coating shop with a big enough oven to do it.

 

[TommyB]

You could have it powder coated- that might last longer than paint, if you can find a powder coating shop with a big enough oven to do it.

Yea, the powder coat guys are the ones going to do the sand blasting.

They mentioned they could powder coat it.
As long as the metal is in fairly good shape

these guys are about 1 mile from my boat
they have 4 ovens that are
Curing Ovens (11' x 7' x 40' max. capacity)
even have a 2000 degree burn off oven whatever that is for

http://www.excellcoatings.com/services.html

 

[drburke]

Burn off takes away paint, oil, etc. that's too difficult to sandblast before power coating. Just leaves dusty ash. A lot like your basic self-cleaning household oven.

DAN

 

[34Hatt]

If going to powder coat it helps to bake it once or twice before coating it many times Aluminum will bubble the coating due to crap coming to the surface depending on what Aluminum its made out of.

A 2000 degree oven would turn your arch into a Puddle though!

 

[TommyB]

If going to powder coat it helps to bake it once or twice before coating it many times Aluminum will bubble the coating due to crap coming to the surface depending on what Aluminum its made out of.

A 2000 degree oven would turn your arch into a Puddle though!

hahaha
Almost a puddle of rust now
Got the welders coming over tomorrow to see if it's even worth taking to their shop to fill in all the holes.
Needs to make sure he can weld it without doing to much more damage. IF not, Guess it's sandblasting,primer and paint instead of powder coat.

I'll take pics on wends once we start the removal process. Waiting for rain to stop and getting a trailer all lined up

 

[rsmith]

Looking at your pics I would say that the arch was not properly bonded to the zinks. I would bet the severe corrosion is from electrolysis. DC bleeding through salt film will eat metal faster than AC.

 

[mdshore]

blast it, remove all filler, coat it with strontium chromate immediatley (pettit 4400), then epoxy fiberglass wrap and epoxy filler pettit 7050 where needed to restore structure.prime and paint . done right itll be there for years.

 

[drburke]

Looking at your pics I would say that the arch was not properly bonded to the zinks. I would bet the severe corrosion is from electrolysis. DC bleeding through salt film will eat metal faster than AC.

Great point; this never occurred to me.

DAN

 

[SKYCHENEY]

My arch had two big bonding wires attached to it, one on each side.

 

[TommyB]

My arch had two big bonding wires attached to it, one on each side.

mine also, bonding wire about as thick as my thumb.

Here's the removal