Electrical precautions when welding on hull

General boating discussion
MacCTD
Posts: 503
Joined: Tue Jul 22, 2008 2:53 pm
Location: MA

Electrical precautions when welding on hull

#1

Post by MacCTD » Fri Mar 02, 2018 8:44 am

I am thinking of having some brackets welded to the stern on my Pacific 1925 for trim tabs and a Power Pole, should I do anything to protect the electronics on the boat? Thanks.
'05 Pacific 1925
Honda 90hp

kmorin
Donator 08','09,'10,'11,'12,'13,'14,'15,'16,'17,'18'
Posts: 1335
Joined: Mon Aug 18, 2008 1:37 am
Location: Kenai, Alaska

Re: Electrical precautions when welding on hull

#2

Post by kmorin » Fri Mar 02, 2018 11:07 am

MacCTD,
AC TIG uses high frequency and some times other wave forms to stabilize the arc while welding. If the work/ground/return lead is put on one end of the hull and the welding done on the other- I have "fried" on outboard control 'brain' module. It was some time ago- I'm told by reliable dealers now... that 'can't happen- but.... I welded- the engine wouldn't run.... I bought the new expensive plastic puck- the engine ran - I report you decide?

I've not cooked any other electronics personally but usually require all the battery supplied power devices to be checked so they're chassis bonded to the hull - green lead from case to mount and mount to hull. This ( I've been told) keeps the AC high freq from using the chassis or power supply as means to get to the chips? I don't understand High Freq well enough to say yay or nay?

If the leads are all close to the work/weld area- I'd say the welding circuit would logically run from arc to work lead and back to the power supply? But then I did cook one control module and now insist that engines be removed to avoid that in the future? NOT sure if the work will be done with TIG or MIG but I've not seen any MIG and electronics interference.

Hope others with more hull work-while-engines-mounted will post?

Cheers,
Kevin Morin
Kenai, AK
kmorin

MacCTD
Posts: 503
Joined: Tue Jul 22, 2008 2:53 pm
Location: MA

Re: Electrical precautions when welding on hull

#3

Post by MacCTD » Tue Mar 20, 2018 9:34 am

Thanks for the info, I will probably just disconnect the batteries and have it welded and hope for the best. On the welding topic, what type of wire should be used for welding on the Pacific 5086 hull? Thanks again.
'05 Pacific 1925
Honda 90hp

kmorin
Donator 08','09,'10,'11,'12,'13,'14,'15,'16,'17,'18'
Posts: 1335
Joined: Mon Aug 18, 2008 1:37 am
Location: Kenai, Alaska

Re: Electrical precautions when welding on hull

#4

Post by kmorin » Tue Mar 20, 2018 9:50 am

MacCTD,
the most widely accept welding filler alloy for 5086 and 5052 is; 5356, for both TIG and MIG processes.

Cheers,
Kevin Morin
Kenai, AK
kmorin

kmorin
Donator 08','09,'10,'11,'12,'13,'14,'15,'16,'17,'18'
Posts: 1335
Joined: Mon Aug 18, 2008 1:37 am
Location: Kenai, Alaska

Re: Electrical precautions when welding on hull

#5

Post by kmorin » Tue Mar 20, 2018 7:04 pm

MacCTD,
there is a new FILLER alloy (a few years old?) that does not have wide acceptance yet, but does show promise in some parent metal alloys' joining by welding. If the welding work is done on 6061 alloy extrusions -welding to 5086 (or 5052) then I'll mention 4943 alloy filler because of recent very favorable reports about this relatively new alloy of filler metal.

If the material you're adding on AND the hull are both 5086 then I'm not suggesting this filler alloy is applicable- I'm only mentioning that some welding sites mention this alloy 4943 as applicable to matching 60 series (most extrusions) to 50 series alloys. Please do not confuse 4ZERO43 that is 4043 with the newer 4943 in reading my remarks!!

A tab bracket might be extrusion? a power pole might be 6061 pipe? and other brackets may all be 60series NOT 50series extrusions????? IF THAT IS the case?? THEN 4943 may be a valid alternative to 5356?

I test all alloys by welding in coupon forms, then cut and bend until they break- without individual testing by ANY/ALL welders' of the alloys discussed, in the weld joints proposed then there is no way to make pronouncements online.

Cheers,
Kevin Morin
Kenai, AK
Last edited by kmorin on Tue Mar 20, 2018 7:08 pm, edited 1 time in total.
Reason: phrasing improved and clarified.
kmorin

MacCTD
Posts: 503
Joined: Tue Jul 22, 2008 2:53 pm
Location: MA

Re: Electrical precautions when welding on hull

#6

Post by MacCTD » Wed Mar 21, 2018 9:59 am

Hi Kevin,
Thanks for all the info, my plan was the buy some .250 5086 and bend the brackets I need then have them welded to the hull, I am thinking about a couple for trim tabs and one for a Power Pole.
'05 Pacific 1925
Honda 90hp

kmorin
Donator 08','09,'10,'11,'12,'13,'14,'15,'16,'17,'18'
Posts: 1335
Joined: Mon Aug 18, 2008 1:37 am
Location: Kenai, Alaska

Re: Electrical precautions when welding on hull

#7

Post by kmorin » Wed Mar 21, 2018 12:00 pm

MacCTD, that's definitely a pure 5356 alloy filler show- MIG or TIG.

cheers,
Kevin Morin
Kenai, AK
kmorin

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