Aluminum or Stainless Holding Radar mount

[Old Sailor 2]

OK, so here's the scene. I purchased a new Raymarine e7 and 18" radar Raydome. Cool. Got the estimate for installing it, $1000 to $1500...not cool. I am a fairly handy kind of guy so perhaps I will do it myself. After all I have an old Furuno so the new cables can be pulle in when the old ones are pulled out. So I gathered up my tools, my bosun's chair, my friends, and went to work....easy right? Except I was not aware of the old cable that got hung up inside the mast making the cable replacement about a 3 hour job and three trips up the mast. Took the old Furuno and bracket down easily since the bolts were only finger tight and I actually removed them by hand. Not good. All the cable and power run to the nav station and from mast base to cockpit went quite easily. First day's work is now done and all I have to do is drill 12 holes in the mast to install the radar mounting platform, mount the Raydome on that, 4 bolts and I am done.

After an enjoyable cup of coffee on deck on a beautiful morning in San Diego I gathered my bracket, the 12 stainless steel rivets, my brand new Arrow rivet gun, my portable drill, loaded them in the bucket and had my wife crank me up the mast. So far so good. Drilled the first hole into which goes the stainless steel rivet. Hooked on the rivet gun, tugged, pushed, pulled, down the mast for cheater bars, back up and pulled and pushed and screamed, and a few other words, borrowed the neighbor's rivet gun, pulled and pushed and yelled and tugged and got thefirst rivet in place just enough to hold the bracket in place. The rivet still did not pop ("pop" rivet) but drilled the second hole. Thinking the first rivet had to be faulty I inserted a second rivet into the hole. Same activity and much more frutration and "sailor words". So, I canvassed my neighbors who were all watching by now and 3 hours later, yes THREE HOURS, 4 neighbors said to go with aluminum rivets (stainless came with the bracket), one (PhD) neighbor says aluminum is not strong enough but get a "big momma" rivet gun for $130 and one neighbor says to drill and tap and use stainless steel machine bolts.

The final 10 holes will be done next weekend. "Paper or plactic" turns into "stainless steel or aluminum"....or bolts? Mast is Isomat aluminum. Ihave the tef-gel which "eliminates" galvbanic reactions as recommended by SeaView. So,

What is the concensus of you experienced folks? 2 partial stainless with 10 3/16" aluminum rivets, bigger rivet gun, or drill and tap for machine fine thread bolts??

 

[Barnacle Bill]

So, let's see, add up the hours you have put into this project and multiply it by the hourly rate of your local repair facility and how much have you saved? And, if you were unable to do the job yourself, would their estimate not justify the work needed to be done? Just a thought. If you will never use, or rarely use, the big money rivet gun, why buy it?

 

[Old Sailor 2]

But you can't put a price on satisfaction and the knowledge you gain when doing this. The knowledge? Hire it out next time!

 

[Rich Stidger]

You guys are right. But you have the great advantage of 20-20 hindsight. I too am a confirmed DIYer, and I have my share of jobs that go south. But more go well than badly.

Just a guess, but from your description of the difficulty in getting the rivets to set, it sounds like your rivets are too short. I would measure the thickness of the mast and purchase new SS rivets if your original parts are too short.

I have also been successful drilling and tapping aluminum masts and booms to mount hardware with machine screws. TefGel is still required.

If all else failed, take a break, and take to heart my tag-line below.

 

[Old Sailor 2]

You guys are right. But you have the great advantage of 20-20 hindsight. I too am a confirmed DIYer, and I have my share of jobs that go south. But more go well than badly.

Just a guess, but from your description of the difficulty in getting the rivets to set, it sounds like your rivets are too short. I would measure the thickness of the mast and purchase new SS rivets if your original parts are too short.

I have also been successful drilling and tapping aluminum masts and booms to mount hardware with machine screws. TefGel is still required.

If all else failed, take a break, and take to heart my tag-line below.

AMEN to your tag line. My wife just shakes her head when I say, "It will only take _____ hours to do this job." She starts at 3 weekends and goes from there. I laugh at her but then eat crow when it actually takes 4 weekends.

But you know, I even tried to pop a stainless rivet that was not in any hole at all and I had to virtually stand on the rivet gun to get it to pull the nail out. so you think, Rich, that drilling and tapping and using machine screws, not too long to interfere with the halyards, would do the trick? That would certainly be easier.....

 

[Rich Stidger]

"It will only take _____ hours to do this job."

LOL. My wife simply doubles whatever time estimate I give her. Sadly she is usually closer than I am...

Not all rivet guns are created equal. I have a light duty gun that will handle rivets with a 1/16" nail, and I have another one that takes interchangeable tips that will accommodate nails from 1/16" to 3/16". I have used the larger gun to put in stainless rivets in my mast. I got the HD gun from Harbor Freight.

So if you have a local HF, and you are certain that the rivets are the correct length for the mast and the bracket together, I would be tempted to go and spend $5 on the HD rivet gun. You will probably be likely to need it another time. See the pix below for the one that I have from HF.

Drilling and tapping is not hard either, but being half-way up the mast with a drill, tap, tapping oil, machine screws, etc. is not the easiest job. And don't forget that you just might have to cut the machine screws to the correct length if you can't buy the exact size you need.

I tend to think that the rivets would be easier- assuming that you have a workable rivet gun, and that you don't ever expect to need to remove the radar bracket.

 

[Old Sailor 2]

Thanks Rich. I will visit HF to see about the gun. And I agree which is why this site is so great. Running in machine screws might be a bigger pain that it sounds. Especially with the bracket in place with three rivets half way secure. Ah the DIY challenges!

 

[onecoolair]

Thanks Rich. I will visit HF to see about the gun. And I agree which is why this site is so great. Running in machine screws might be a bigger pain that it sounds. Especially with the bracket in place with three rivets half way secure. Ah the DIY challenges!

I have the same rivet tool they caring them at home depot. Do not get the one with the fancy swivel head. It will not do stainless, and barely aluminum. Had to return return about three of them before I went with cheaper model. It worked on the s.s. but just barely .
My sail maker said you have go up to much more expensive hydraulic model to reliably do stainless rivets.
You would be better served to drill and tap screws for your radar mount. I had to pull my radar mount down for servicing a while back and I was glad the installer had used screws. It would have been total nightmare to have to drill out the stainless steel rivets while 50' feet above the deck. Were I feel drilling and tapping 50 feet above deck to be more of a easier task.
Use hex head fine thread screws that are just long enough so they end up flush in side the mast wall. Make sure to use some goop or something equal on the screw threads to help lock and create a separation of the stainless against the aluminum mast and you will be fine.

 

[propellanttech]

Popping stainless rivets is not an easy job, especially while hanging from a mast.

There are tools in the aircraft industry just for stainless rivets. Imagine a rivet gun the size of large bolt cutters. These are available, and much cheaper than hydraulic rivet pullers. You could probably rent the hydraulic ones though.

I've pull many a stainless rivet, and they always suck.

James L