Thanks: 0
Likes: 0
Needs Pictures: 0
Picture(s) thanks: 0
Results 16 to 30 of 30
-
27th Feb 2019, 10:47 PM #16Most Valued Member
- Join Date
- Aug 2009
- Location
- Sydney, NSW, Australia
- Posts
- 1,844
Maybe Mick can ask a boat shop that welds pressed 3 to 4meter tinnies they are 2-3mm thickness alloy and run full seams
What is the rate of heat from a normal mig at 70-80amps vs a pulse mig at the same amps?
Hope u get it sorted mick that is a good looking boat
-
28th Feb 2019, 12:22 PM #17Diamond Member
- Join Date
- Aug 2006
- Location
- Melbourne
- Posts
- 1,106
Used to do small stitch welds say around 25mm long every 200 - 300mm apart and then they would get scalloped out with a 4" carbide tipped blade to avoid contamination.
Gazza with aluminium you are nearly running twice the amps you would use compared to mild steel.
-
28th Feb 2019, 01:46 PM #18Most Valued Member
- Join Date
- Aug 2009
- Location
- Sydney, NSW, Australia
- Posts
- 1,844
Com couldnt remember if it were 25amps per 1mm or 40amps per 1mm of thickness
That carbide cutter is a good idea
Mick a lot of the big boat builders grind down thete welds so dont be to worried about astetics
-
28th Feb 2019, 03:35 PM #19Diamond Member
- Join Date
- Aug 2006
- Location
- Melbourne
- Posts
- 1,106
Most of what I was working with was 5mm material so around 200 Amps. Aluminium is like a heat sink so it likes to suck the heat away.
If you do use those carbide blades, make sure you use a grinder with a deadman (trigger type grinder, not on-off switch) preferable pneumatic. They are very dangerous if not used correctly. Would also recommend full face shield and gloves as swarf goes everywhere.
-
2nd Mar 2019, 02:57 PM #20Golden Member
- Join Date
- Feb 2010
- Location
- Ballina, NSW
- Posts
- 900
There was a youtube series of a guy building a boat (I think it was a boat). I couldn't find it again, but I remember that he was using one of these meat axes. I remember thinking it was an accident waiting to happen. Anyway, it got to episode 4 or so, then a delay, then the next one is the guy showing off his bandages. Build on hold. Doctors reckon it'll take a year for him to get some function back into his hand. I've had one of these contraptions, but trashed it - wouldn't have even felt good about selling it to someone. Even a trigger/paddle grinder wouldn't be any good - nobody's reaction time would be good enough. I currently use a carbide burr to feather tacks. I have used a small plunge cut circular saw before - which worked well, but haven't got one at the moment.
Cheers
Mick
-
2nd Mar 2019, 03:23 PM #21Golden Member
- Join Date
- Feb 2010
- Location
- Ballina, NSW
- Posts
- 900
The photo is my current boat (when it was new - I just got bare bones and have been adding to it) - but looking to build a bigger one myself.
Regarding the welding - any reasonable mig or ac tig will weld these planks. Burn through isn't really a problem, even though it is 2mm because it is on the corner of the 2 planks.
On my current boat I welded an extra plank on the front deck - which required 2m horizontal welds facing down as well as up (i.e. 1G and 4G). The 1G one was easy to MIG (can't remember the settings exactly, but was using 1.2mm wire). However the 4G one it I was having a bad day and ended up tigging it instead. This was 2m of weld lying flat on my back with the weld about 30cm above my face. My tig torch was smoking after that, but credit to my tokentools welder - it didn't miss a beat. I remember running quite hot, I'm guessing it was over 160 amps. Distortion wasn't really an issue as it was inserting a plank into a reasonably rigid structure.
I definitely won't be grinding these welds down - just wasted time. This will be a work boat, but the welds have to look good and be watertight to satisfy the certifier (for commercial registration).
Cheers
Mick
-
2nd Mar 2019, 04:54 PM #22Diamond Member
- Join Date
- Aug 2006
- Location
- Melbourne
- Posts
- 1,106
He obviously wasn't using it properly, you only have a certain area of the blade you can use before they will kick back. I would say most aluminium fabrication places would be using these things. I have spoken to others before and they have used the same thing. A carbide burr would work, but slow going and probably not as cost effective or versatile.
-
2nd Mar 2019, 05:55 PM #23Most Valued Member
- Join Date
- Aug 2009
- Location
- Sydney, NSW, Australia
- Posts
- 1,844
Ah Mick so i think i hear u right now your looking for idea's on how to weld the hull without laying under the boat have u thought about making a rotisserie stand? u could do one quiet easily out of steel or wood that way u can stand welding left to right or vise versa, i have never tried to weld over head but i can imagine how hard it must be and tig at that bloody hell awkward much
-
2nd Mar 2019, 06:13 PM #24Member
- Join Date
- Apr 2018
- Location
- Lismore Northern NSW
- Age
- 50
- Posts
- 81
I'll never forget when I saw a guy who had just had one of those blades bounce up into his face... it cut from his jaw up to his eye right through into the bone. You could look into his mouth through the gaping wound and he was hosing blood. I got a pic of him (NFP) but essentially what you'd expect to see if someone hacked you in the head with a sword.
-
2nd Mar 2019, 07:01 PM #25Diamond Member
- Join Date
- Aug 2006
- Location
- Melbourne
- Posts
- 1,106
-
2nd Mar 2019, 07:02 PM #26Diamond Member
- Join Date
- Aug 2006
- Location
- Melbourne
- Posts
- 1,106
-
2nd Mar 2019, 07:15 PM #27Golden Member
- Join Date
- Feb 2010
- Location
- Ballina, NSW
- Posts
- 900
No definitely not as quick. As with anything, a dangerous tool can be safe in well-practiced hands. As I said, I used to have one - and am certainly aware of how well they work, but in my case I wasn't using it every day and the margin for error was too slim. I recently was at an auction selling off all the tools at a large aluminium fabrication place and that was one tool was notable by its absence.
Yes a rotisserie would certainly be great particularly with my bad back. It wouldn't have helped in that particular case as the boat already had the motor etc. on so flipping wouldn't have been a great idea.
With 4G TIG it can be quite therapeutic if comfortable. The trouble with doing a long weld in this position is that it just takes a minute lapse of concentration and - as I did - let the the arc length get a bit long, which resulted in a blob of molten aluminium dropping down. As my face was right under it the blob landed on my mask, but the first I realised something was up was when I started seeing flames rising up through the visor whilst still welding. The blob had dropped at the edge between the visor and the shield and set the plastic underneath alight.
-
2nd Mar 2019, 07:18 PM #28Golden Member
- Join Date
- Feb 2010
- Location
- Ballina, NSW
- Posts
- 900
-
2nd Mar 2019, 07:24 PM #29Golden Member
- Join Date
- Feb 2010
- Location
- Ballina, NSW
- Posts
- 900
Oh yeah... found the video I was talking about. Don't click the link if you don't want to see blood.. https://www.youtube.com/watch?v=_BUTvREU3ZY&t=296s
Not quite the circumstances that I remember - but not pretty either.
-
4th Mar 2019, 02:20 PM #30Most Valued Member
- Join Date
- Sep 2010
- Location
- Lebrina
- Posts
- 1,915
If there was one thing I could happily see removed from the face of the earth, it would be carbide cutters for grinders.
I don't know how they are still in widespread use as they turn a grinder into a circular saw, which by law must have a spring loaded guard, which of course, grinders do not. Way more dangerous than a chainsaw as a chainsaw has a both a chain brake and a much better handle system than any grinder.
Similar Threads
-
Small aluminium boat trailer build
By gazza2009au in forum TRAILERS & OTHER FABRICATED STUFFReplies: 9Last Post: 22nd Dec 2017, 12:43 PM -
Boat building for fun & profit
By PDW in forum METALWORK PROJECTSReplies: 9Last Post: 13th Dec 2015, 01:44 PM -
Building a Aluminium I Beam Trailer
By gazza2009au in forum TRAILERS & OTHER FABRICATED STUFFReplies: 58Last Post: 30th Mar 2015, 11:45 PM -
Building a shed - long time viewer, first time poster!
By bj_dove in forum WELDINGReplies: 44Last Post: 24th Aug 2014, 07:51 PM -
Protecting new unpainted aluminium boat
By seanlark in forum METALWORK GENERALReplies: 27Last Post: 21st Sep 2013, 03:55 PM